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Mycobiota and identification of aflatoxin gene cluster in marketed spices in West Africa

2013-05-18T10:07:33Z

Publication date: November 2013
Source:Food Control, Volume 34, Issue 1

Author(s): G.J.B. Gnonlonfin , Y.C. Adjovi , A.F. Tokpo , E.D. Agbekponou , Y. Ameyapoh , C. de Souza , L. Brimer , A. Sanni

Fungal infection and aflatoxin contamination were evaluated on 114 samples of dried and milled spices such as ginger, garlic and black pepper from southern Benin and Togo collected in November 2008–January 2009. These products are dried to preserve them for lean periods available throughout the year. Fungal contamination was evaluated after plating on selective media with a total of 20 fungal genera identified, ranging from 7 in garlic to 14 in ginger. Ginger and pepper showed high incidence of fungal contamination compared to garlic that had lower levels of fungal contamination. Species of Aspergillus were dominant on all marketed dried and milled spices irrespective of country. Gene characterization and amplification analysis showed that most of the Aspergillus flavus isolates possess the cluster genes for aflatoxin production. Aflatoxin B1 assessment by Thin Layer Chromatography showed that only garlic (1 sample) and ginger (4 samples) were naturally contaminated with aflatoxin B1 ranging from 390 μg/kg to 1045 μg/kg respectively. Previous reports have mostly highlighted the risk of mycotoxin exposure from staple crops and vegetables in Africa, but such risks now need to be evaluated further for other products such as dried and milled spices.

Valuing ecosystem services for conservation and development purposes: A case study from Kenya

2013-05-18T10:07:33Z

Publication date: August 2013
Source:Environmental Science & Policy, Volume 31

Author(s): Silvia Silvestri , Lokman Zaibet , Mohammed Yahya Said , Shem Chege Kifugo

This paper mapped and valued key inter-related drylands ecosystem services of importance to pastoralists, crop farmers, the tourism industry, conservationists, and policy planners in the Ewaso Ng’iro basin, the largest of the five major basins in Kenya. We used an ecosystem services approach where only final benefits are valued to avoid double counting. The final benefits are ecosystem services or commodities which have an economic value. The supply of ecosystem services depends on the functioning of ecosystems, but rarely ecological and institutional boundaries coincide and often stakeholders in ecosystem services cut across a range of institutional zones and scales. Land use and management influence the system processes, properties and components that are the basis of services provision. Although much has been written about the need to quantify and value ecosystem services, there are fewer spatially explicit studies that delineate the supply and demand areas for ecosystem services and assess the trade-offs between ecosystem services over space and time especially on drylands.

Based on the spatial distribution of resources and the existing competition over these resources, this paper assesses the current values attributed to the selected ecosystem services. Then, by mapping existing supporting infrastructure and drivers of land use change such as demographic pressure, we highlight trade-offs and synergies among alternative uses and opportunities for sustainable development. In particular, the paper identifies services that will be lost if a particular part of landscape is modified: e.g. benefits for livestock and wildlife can be affected by the lack of conservation of corridors and rangelands, while water supply and irrigated crops can be compromised by increased water demand as result of human population pressure mainly at the upstream sub-catchments.

We demonstrate the value of spatial analysis to land use investments and management and highlight how conservation and management of ecosystem services require the understanding of the spatial links between ecosystems and human well-being.

Effects of climate variability and climate change on crop production in southern Mali

2013-05-18T10:07:33Z

Publication date: August 2013
Source:European Journal of Agronomy, Volume 49

Author(s): Bouba Traore , Marc Corbeels , Mark T. van Wijk , Mariana C. Rufino , Ken E. Giller

In West Africa predictions of future changes in climate and especially rainfall are highly uncertain, and up to now no long-term analyses are available of the effects of climate on crop production. This study analyses long-term trends in climate variability at N’Tarla and Sikasso in southern Mali using a weather dataset from 1965 to 2005. Climatic variables and crop productivity were analysed using data from an experiment conducted from 1965 to 1993 at N’Tarla and from a crop yield database from ten cotton growing districts of southern Mali. Minimum daily air temperature increased on average by 0.05°C per year during the period from 1965 to 2005 while maximum daily air temperature remained constant. Seasonal rainfall showed large inter-annual variability with no significant change over the 1965–2005 period. However, the total number of dry days within the growing season increased significantly at N’Tarla, indicating a change in rainfall distribution. Yields of cotton, sorghum and groundnut at the N’Tarla experiment varied (30%) without any clear trend over the years. There was a negative effect of maximum temperature, number of dry days and total seasonal rainfall on cotton yield. The variation in cotton yields was related to the rainfall distribution within the rainfall season, with dry spells and seasonal dry days being key determinants of crop yield. In the driest districts, maize yields were positively correlated with rainfall. Our study shows that cotton production in southern Mali is affected by climate change, in particular through changes in the rainfall distribution.

Exploring farmer preferences for contagious bovine pleuropneumonia vaccination: A case study of Narok District of Kenya

2013-05-18T10:07:33Z

Publication date: 1 July 2013
Source:Preventive Veterinary Medicine, Volume 110, Issues 3–4

Author(s): Salome W. Kairu-Wanyoike , Simeon Kaitibie , Nick M. Taylor , George K. Gitau , Claire Heffernan , Christian Schnier , Henry Kiara , Evans Taracha , Declan McKeever

Contagious bovine pleuropneumonia (CBPP) is an economically important disease in most of sub-Saharan Africa. A conjoint analysis and ordered probit regression models were used to measure the preferences of farmers for CBPP vaccine and vaccination attributes. This was with regard to inclusion or not of an indicator in the vaccine, vaccine safety, vaccine stability as well as frequency of vaccination, vaccine administration and the nature of vaccination. The analysis was carried out in 190 households in Narok District of Kenya between October and December 2006 using structured questionnaires, 16 attribute profiles and a five-point Likert scale. The factors affecting attribute valuation were shown through a two-way location interaction model. The study also demonstrated the relative importance (RI) of attributes and the compensation value of attribute levels. The attribute coefficient estimates showed that farmers prefer a vaccine that has an indicator, is 100% safe and is administered by the government (p <0.0001). The preferences for the vaccine attributes were consistent with expectations. Preferences for stability, frequency of vaccination and nature of vaccination differed amongst farmers (p >0.05). While inclusion of an indicator in the vaccine was the most important attribute (RI=43.6%), price was the least important (RI=0.5%). Of the 22 household factors considered, 15 affected attribute valuation. The compensation values for a change from non inclusion to inclusion of an indicator, 95–100% safety, 2h to greater than 2h stability and from compulsory to elective vaccination were positive while those for a change from annual to biannual vaccination and from government to private administration were negative. The study concluded that the farmers in Narok District had preferences for specific vaccine and vaccination attributes. These preferences were conditioned by various household characteristics and disease risk factors. On average the farmers would need to be compensated or persuaded to accept biannual and private vaccination against CBPP. There is need for consideration of farmer preferences for vaccine attribute levels during vaccine formulations and farmer preferences for vaccination attribute levels when designing delivery of vaccines.

Alternative U.S. biofuel mandates and global GHG emissions: The role of land use change, crop management and yield growth

2013-05-18T10:07:33Z

Publication date: June 2013
Source:Energy Policy, Volume 57

Author(s): A. Mosnier , P. Havlík , H. Valin , J. Baker , B. Murray , S. Feng , M. Obersteiner , B.A. McCarl , S.K. Rose , U.A. Schneider

We investigate the impacts of the U.S. renewable fuel standard (RFS2) and several alternative biofuel policy designs on global GHG emissions from land use change and agriculture over the 2010–2030 horizon. Analysis of the scenarios relies on GLOBIOM, a global, multi-sectoral economic model based on a detailed representation of land use. Our results reveal that RFS2 would substantially increase the portion of agricultural land needed for biofuel feedstock production. U.S. exports of most agricultural products would decrease as long as the biofuel target would increase leading to higher land conversion and nitrogen use globally. In fact, higher levels of the mandate mean lower net emissions within the U.S. but when the emissions from the rest of the world are considered, the US biofuel policy results in almost no change on GHG emissions for the RFS2 level and higher global GHG emissions for higher levels of the mandate or higher share of conventional corn-ethanol in the mandate. Finally, we show that if the projected crop productivity would be lower globally, the imbalance between domestic U.S. GHG savings and additional GHG emissions in the rest of the world would increase, thus deteriorating the net global impact of U.S. biofuel policies.

Highlights

► We model the impact of the U.S. renewable fuel standard (RFS2). ► RFS2 would require more agricultural land and nitrogen globally. ► Increasing the mandates reduce GHG emissions within the U.S. ► Increasing the mandates increase GHG emissions in the rest of the world. ► Total GHG emissions increase with higher levels of mandate; higher share of corn-ethanol; lower productivity growth.

Comparison of African swine fever virus prevalence and risk in two contrasting pig-farming systems in South-west and Central Kenya

2013-05-18T10:07:33Z

Publication date: 1 June 2013
Source:Preventive Veterinary Medicine, Volume 110, Issue 2

Author(s): E. Okoth , C. Gallardo , J.M. Macharia , A. Omore , V. Pelayo , D.W. Bulimo , M. Arias , P. Kitala , K. Baboon , I. Lekolol , D. Mijele , R.P. Bishop

We describe a horizontal survey of African swine fever virus (ASFV) prevalence and risk factors associated with virus infection in domestic pigs in two contrasting production systems in Kenya. A free range/tethering, low input production system in Ndhiwa District of South-western Kenya is compared with a medium input stall fed production system in Kiambu District of Central Kenya. Analysis of variance (ANOVA) of data derived from cluster analysis showed that number of animals, number of breeding sows and number of weaner pigs were a significant factor in classifying farms in Nhiwa and Kiambu. Analysis of blood and serum samples using a PCR assay demonstrated an average animal level positivity to ASFV of 28% in two independent samplings in South-western Kenya and 0% PCR positivity in Central Kenya. No animals were sero-positive in either study site using the OIE indirect-ELISA and none of the animals sampled exhibited clinical symptoms of ASF. The farms that contained ASFV positive pigs in Ndhiwa District were located in divisions bordering the Ruma National Park from which bushpig (Potamochoerus larvatus) incursions into farms had been reported. ASFV prevalence (P <0.05) was significantly higher at distances between 6 and 16km from the National Park than at distances closer or further away. One of the 8 bushpigs sampled from the park, from which tissues were obtained was PCR positive for ASFV. The data therefore indicated a potential role for the bushpig in virus transmission in South-western Kenya, but there was no evidence of a direct sylvatic virus transmission cycle in Central Kenya. ASF control strategies implemented in these areas will need to take these epidemiological findings into consideration.

Bluetongue and Epizootic Haemorrhagic Disease virus in local breeds of cattle in Kenya

2013-05-18T10:07:33Z

Publication date: June 2013
Source:Research in Veterinary Science, Volume 94, Issue 3

Author(s): P.G. Toye , C.A. Batten , H. Kiara , M.R. Henstock , L. Edwards , S. Thumbi , E.J. Poole , I.G. Handel , B.M.deC. Bronsvoort , O. Hanotte , J.A.W. Coetzer , M.E.J. Woolhouse , C.A.L. Oura

The presence of bluetongue virus (BTV) and Epizootic Haemorrhagic Disease virus (EHDV) in indigenous calves in western Kenya was investigated. Serum was analysed for BTV and EHDV antibodies. The population seroprevalences for BTV and EHDV for calves at 51weeks of age were estimated to be 0.942 (95% CI 0.902–0.970) and 0.637 (95% CI 0.562–0.710), respectively, indicating high levels of circulating BTV and EHDV. The odds ratio of being positive for BTV if EHDV positive was estimated to be 2.57 (95% CI 1.37–4.76). When 99 calves were tested for BTV and EHDV RNA by real-time RT-PCR, 88.9% and 63.6% were positive, respectively. Comparison of the serology and real-time RT-PCR results revealed an unexpectedly large number of calves that were negative by serology but positive by real-time RT-PCR for EHDV. Eight samples positive for BTV RNA were serotyped using 24 serotype-specific real-time RT-PCR assays. Nine BTV serotypes were detected, indicating that the cattle were infected with a heterogeneous population of BTVs. The results show that BTV and EHDV are highly prevalent, with cattle being infected from an early age.

Global bioenergy scenarios – Future forest development, land-use implications, and trade-offs

2013-05-18T10:07:33Z

Publication date: Available online 2 May 2013
Source:Biomass and Bioenergy

Author(s): Florian Kraxner , Eva-Maria Nordström , Petr Havlík , Mykola Gusti , Aline Mosnier , Stefan Frank , Hugo Valin , Steffen Fritz , Sabine Fuss , Georg Kindermann , Ian McCallum , Nikolay Khabarov , Hannes Böttcher , Linda See , Kentaro Aoki , Erwin Schmid , László Máthé , Michael Obersteiner

Preservation of biodiversity and reduction of deforestation are considered as key elements when addressing an increased use of bioenergy in the future. This paper presents different combinations of scenarios for global feedstock supply for the production of bioenergy under specified social and environmental safeguard provisions. The objectives of this study were threefold: a) to present a global perspective using an integrated modeling approach; b) to frame the boundaries for lower scale assessments; and c) to identify potential trade-offs to be considered in future research. The aggregate results, achieved through the application of an integrated global modeling cluster, indicate that under a high global demand for bioenergy by mid-century, biomass will to a large extent be sourced from the conversion of unmanaged forest into managed forest, from new fast-growing short-rotation plantations, intensification, and optimization of land use. Depending on the underlying scenario, zero net deforestation by 2020 could be reached and maintained with only a minor conversion of managed forests into other land cover types. Results further indicate that with rising populations and projected consumption levels, there will not be enough land to simultaneously conserve natural areas completely, halt forest loss, and switch to 100% renewable energy. Especially in the tropical regions of the southern hemisphere, it will be important to achieve a controlled conversion from unmanaged to sustainably managed forest as well as increased protection of areas for ecosystems services such as biodiversity. The study concludes with the recommendation to focus on targeted regional policy design and its implementation based on integrated global assessment modeling.

Highlights

► A high demand for bioenergy will increase competition for land. ► Bioenergy production is a significant driver of forest loss but not the major one. ► GHG emissions may be substantially reduced by minimizing deforestation. ► Minimization of deforestation may have negative impacts on other natural ecosystems. ► Various policy areas must be coordinated to ensure sustainable use of resources.

Whole-farm nitrogen cycling and intensification of crop-livestock systems in the highlands of Madagascar: An application of network analysis

2013-05-18T10:07:33Z

Publication date: Available online 25 April 2013
Source:Agricultural Systems

Author(s): S. Alvarez , M.C. Rufino , J. Vayssières , P. Salgado , P. Tittonell , E. Tillard , F. Bocquier

Food insecurity, soil fertility depletion and strong competition for biomass are commonly observed in smallholder crop-livestock systems. The objective of this study was to explore options to improve farm-level nitrogen cycling, productivity and economic performance through the analysis of N flows within four contrasting crop-livestock farm systems of Madagascar highlands. Farms were conceptualized as networks where the compartments were the household and their farming activities, all connected by N flows. Indicators assessing network size and cycling, and the organization and diversity of the N flows, were compared with system productivity, food self-sufficiency, and gross margins for the current situation and under four scenarios of intensification (i) dairy production increased by increasing N inputs as supplementary feed; (ii) crop production increased by increasing N inputs as mineral fertilizer; (iii) manure management improved to increase N conservation during storage and application to soils; (iv) a combination of the two most economically attractive scenarios (i and iii). The four case study farms represent local diversity differing widely in terms of network size, with total annual system N throughput ranging from 113 to 1037kgN per capita, and in terms of N cycling, from 3 to 41kgN per capita per year. They differed less in terms of external dependence, from 0.26 to 0.41kgN kgN⁻¹. Improving N conservation through improved manure management (scenario iii) had a positive impact on gross margin, and this in combination with increased concentrate supply (scenario iv) led to increases in whole-farm N use efficiencies from 2% to 50%, in N cycling from 9% to 68% and in food self-sufficiency from 12% to 37% across farm types. Gross margin was the most sensitive indicator to changes in management. Intensification through scenario iv had the highest impact on farm productivity, gross margin, food self-sufficiency, and environment sustainability (N use efficiency, capacity of the soil to stock N).

A note on potential candidate genomic regions with implications for maize stover fodder quality

2013-05-18T10:07:33Z

Publication date: Available online 25 April 2013
Source:Field Crops Research

Author(s): M.T. Vinayan , Raman Babu , T. Jyothsna , P.H. Zaidi , M. Blümmel

A panel of 276 inbred lines from CIMMYT's Drought tolerant maize for Africa program was test crossed to maize line CML312 and the single crosses were evaluated for grain and stover yields, plant height (PH), days to 50% anthesis (DtA50) and silking, stover nitrogen (N), neutral (NDF) and acid detergent fiber (ADF), acid detergent lignin (ADL), in vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) content. Most stover fodder quality traits were highly significantly different among the lines except ADF. These differences were substantial among best and worst lines for the traits, with stover N varying threefold and NDF, ADF and IVOMD by more than 10 percentage units. Among the agronomic traits, significant positive associations were observed among grain and stover yield. Grain yield was significantly negatively associated with DtA50 and Anthesis to silking interval (AtS) and positively with PH. Stover yield was significantly negatively associated with DtA50 and positively with PH. Desirable stover quality traits N, IVOMD and ME were significantly negatively associated with grain yield (R ² =0.25–0.28) while undesirable quality traits NDF, ADF and ADL were significantly positively associated with grain yield (R ² =0.04–0.23). Stover yields were largely unrelated fodder quality traits except for a significant negative association with NDF and ADF (R ² =0.04 to 0.08). GWAS analysis carried out using GBS (genotyping by sequencing) and a 55K SNPs genotypic dataset revealed several regions of significant association for N, ADF and IVOMD, each explaining from 3 to 9% of phenotypic variance for these fodder quality traits. SYN7725 from the 55K chip on chromosome 4 explained the largest proportion of phenotypic variance (~9%) for ADF and had a robust minor allele frequency (MAF) of 0.35. A specific genomic region on chromosome 3 (132.7–149.2Mb) was found to be significantly associated with all the three forage quality traits, with the largest effect on IVOMD. This region merits attention for further validation and marker-assisted introgressions. A cellulose-related candidate gene, Xyloglucan endotransglucosylase/hydrolase (xth1, GRMZM2G119783) was also identified closer to the peak on chr.10 (~76.9Mb) for ADF, which has been previously demonstrated to have a significant role in fiber elongation in cotton.

Relationship between the performance of parental inbred lines and hybrids for food-feed traits in maize (Zea mays L.) in Ethiopia

2013-05-18T10:07:33Z

Publication date: Available online 20 March 2013
Source:Field Crops Research

Author(s): Berhanu Tadesse Ertiro , Habtamu Zeleke , Dennis Friesen , Michael Blummel , S. Twumasi-Afriyie

Prediction of hybrid performance from inbred lines per se is crucial in targeted improvement of new traits such as stover fodder quality. The present study investigated the trend in variability and association between food and fodder traits in inbred parents and the hybrids derived from them and assessed the general combining ability (GCA) of inbred lines for both food and fodder traits. Sixteen inbred lines and sixty single cross hybrids generated by a 10×6 factorial mating design were evaluated for grain and stover yield and a range of laboratory stover fodder quality traits across three environments in Ethiopia. The hybrid and inbred line trials were planted in adjacent blocks in the same fields using an alpha lattice experimental design. Genotypes in both hybrids and inbred trials showed highly significant differences for all the traits studied. Generally, hybrids had higher grain and stover yields and lower stover fodder quality traits than the inbred lines. Both the magnitude and direction of relationship for almost all traits were similar among genotypes in the inbred and hybrid trials. General combining abilities of both lines and testers and specific combining ability (SCA) of line by tester interactions were significant for most traits studied. The highly significant GCA effects observed for most traits and the greater relative importance of GCA (lines and testers) as compared to SCA for grain yield and most stover fodder quality traits suggest the importance of additive gene effects in controlling grain and stover yield as well as stover fodder quality. Important stover fodder quality traits such as digestibility and metabolizable energy were highly heritable (h ² =0.79–0.81) and the genotypic variations among hybrids in these traits will have implications for productivity of maize stover fed to livestock or for the income of farmers selling maize stover to fodder value chains. Significant positive relationships observed between inbred lines per se and hybrid performances for these fodder quality traits suggest the feasibility of predicting hybrid performance from the performance of the inbred lines.

Highlights

► Trends in variability in inbreds and hybrids, association between food-fodder traits and GCA of inbred lines assessed. ► We found higher genotypic variation for food-feed traits and association between traits had similar trend in hybrids and inbreds. ► GCA, indicative of the additive gene effect was important for most stover fodder quality traits. ► The relationship of line per se with hybrid performance and GCA were positive and significant for most stover fodder quality traits. ► Selection of inbred lines at early stage of inbred line development is the best strategy for the development of food-feed type of inbred lines.

A note on suitable laboratory stover quality traits for multidimensional maize improvement

2013-05-18T10:07:33Z

Publication date: Available online 19 March 2013
Source:Field Crops Research

Author(s): D. Ravi , A.A. Khan , M. Saibutcharao , M. Blümmel

A total of 10 maize stovers from two open pollinated varieties (OPV's), four hybrids (one grown in two different seasons, Kharif and summer) and at two different locations and two parental lines were tested for a range of laboratory fodder quality traits and for in vivo digestibility and voluntary feed intake in sheep. Laboratory stover fodder quality traits measured were nitrogen (N), neutral (NDF) and acid detergent (ADF) fiber, acid detergent lignin (ADL), in vitro organic matter digestibility (IVOMD) and metabolisable energy (ME) content. Highly significant (P <0.0001) differences among the stovers were observed for all laboratory fodder quality traits and for dry matter digestibility (DMD), dry matter intake (DMI) and digestible dry matter intake (DDMI) with DMD (%) DMI (g/d) and DDMI (g/d) ranging from 53 to 65, 325 to 635 and 194 to 382, respectively. The total amount of stover refused (DMR) by the sheep did not differ significantly (P =0.67) among the stovers, however when DMR was expressed relative to DMI significant differences (P =0.0007) were observed. Laboratory fodder quality traits most closely correlated to the in vivo measurements were ADF with r =−0.83, r =−0.92 and r =−0.93 for DMD, DMI and DDMI, respectively, and ME with r =0.77, r =0.94 and r =0.94 for DMD, DMI and DDMI, respectively. Applying statistical cross-validation procedures where the predicted values were not used for the development of the regression equations (“blind-predictions”), DMD, DMI and DDMI could be predicted by ADF with resulting R ² for good-of-fitness between observed and predicted values of 0.46, 0.76 and 0.79, respectively. Similarly DMD, DMI and DDMI could be predicted by ME with resulting R ² for good-of-fitness between observed and predicted values of 0.40, 0.83 and 0.83, respectively.

Highlights

► Significant differences were found among the maize stovers for laboratory quality traits. ► Significant differences were also found among the maize stovers for DMD, DMI and DDMI. ► Laboratory quality traits closely correlated to the DMD, DMI and DDMI were ADF and ME. ► DMI and DDMI could be reasonably well predicted by ADF (r ² =0.76–0.79) and ME (r ² =0.83).

Use of agro-climate ensembles for quantifying uncertainty and informing adaptation

2013-05-18T10:07:33Z

Publication date: 15 March 2013
Source:Agricultural and Forest Meteorology, Volume 170

Author(s): Andrew J. Challinor , Mark Stafford Smith , Philip Thornton

Significant progress has been made in the use of ensemble agricultural and climate modelling, and observed data, to project future productivity and to develop adaptation options. An increasing number of agricultural models are designed specifically for use with climate ensembles, and improved methods to quantify uncertainty in both climate and agriculture have been developed. Whilst crop–climate relationships are still the most common agricultural study of this sort, on-farm management, hydrology, pests, diseases and livestock are now also examined. This paper introduces all of these areas of progress, with more detail being found in the subsequent papers in the special issue. Remaining scientific challenges are discussed, and a distinction is developed between projection- and utility-based approaches to agro-climate ensemble modelling. Recommendations are made regarding the manner in which uncertainty is analysed and reported, and the way in which models and data are used to make inferences regarding the future. A key underlying principle is the use of models as tools from which information is extracted, rather than as competing attempts to represent reality.

Highlights

► Introduces the special issue on Agricultural prediction using climate model ensembles. ► Discuss remaining scientific challenges. ► Develops distinction between projection- and utility-based ensemble modelling. ► Recommendations made RE modelling and the analysis and reporting of uncertainty.

Genetic variability of maize stover quality and the potential for genetic improvement of fodder value

2013-05-18T10:07:33Z

Publication date: Available online 5 March 2013
Source:Field Crops Research

Author(s): Berhanu Tadesse Ertiro , S. Twumasi-Afriyie , Michael Blümmel , Dennis Friesen , Demewoz Negera , Mosisa Worku , Demissew Abakemal , Kheri Kitenge

Maize stover left after grain harvest constitutes an important source for livestock feed in most parts of East Africa, particularly during the dry season. In spite of its wide use and greater importance, breeding programs have given little attention to the improvement of stover quality and quantity. The objectives of this study were to assess the genetic variability of experimental and released (checks) maize varieties for stover feed quantity and quality, and their relationship with grain yield. Results from different trials conducted across locations using randomized complete block design (RCBD) in different sites in Ethiopia and Tanzania from 2004 to 2006 showed higher genotypic variation for grain and stover yields and stover feed quality traits. This confirmed the existence of exploitable genetic variation not only for grain yield but also for stover fodder quality and quantity. Positive relationship was also observed between grain and stover yields but the relation between stover fodder quality traits and grain yield, in most cases, was weak. Generally, the study pinpointed the possibility for simultaneous improvement of grain yield and stover traits to address the high demand existing for dual purpose food-feed type of maize genotypes in maize-livestock mixed farming system of East Africa.

Highlights

► 335 maize varieties were evaluated in Ethiopia and Tanzania. ► Genotypic variability for stover fodder quality, grain and stover yields and their interrelationship. ► We observed significance difference for most traits in almost all trials. ► In most cases, we observed desirable relationship among traits. ► The study suggested the possibility for simultaneous improvement of grain yield and stover traits.

Identification of a superior dual purpose maize hybrid among widely grown hybrids in South Asia and value addition to its stover through feed supplementation and feed processing

2013-05-18T10:07:33Z

Publication date: Available online 4 March 2013
Source:Field Crops Research

Author(s): S. Anandan , A.A. Khan , D. Ravi , M. Sai Bucha Rao , Y. Ramana Reddy , M. Blümmel

Six maize hybrids (HPQM-1, HY-TEC 5101, Pinnacle, 30V 92, 900M Gold and NK 6240) commonly grown in South Asia were analyzed for grain yields, stover yields and stover fodder quality traits by a range of agronomic, morphological, laboratory and animal experimental trials. Significant differences were found among the six hybrids in grain and stover yield and stover N, NDF, ADF, ADL, IVOMD and ME content and, when fed to sheep, significant differences were observed for stover intakes and nitrogen retentions. Laboratory traits related to stover structural carbohydrates such as NDF and ADF were highly negatively related with digestible organic matter intake (DOMI) accounting for 90% of the variation therein, while IVOMD and ME were positively associated with DOMI accounting for 90 and 94% of the variation therein, respectively. Stover from two hybrids (NK 6240, 30V 92) with the highest and second highest grain yield but with the laboratory and in vivo stover fodder quality traits falling into the statistically highest and lowest category were further investigated for animal responses through supplementation and feed processing. From these two stovers, complete diet in the form of feed block and mash were designed consisting of 60% stover. Stover-based complete diets in the form of feed mash were superior to diets offered as feed blocks. In the feed mash form, animals fed the superior stover-based diet had more than 30% greater average daily gain than those fed the lower quality stover-based feed mash diet. Stover from the popular maize hybrids were found to differ significantly with regard to the stover quality attributes-feed intake, digestibility and animal performance suggesting the possibility of exploiting these attributes by the maize breeders for developing promising dual purpose maize varieties.

Highlights

► Stover quality of popular maize hybrids were found to be similar to the sorghum stover. ► Hybrids can be exploited through higher fodder value without affecting the grain. ► Feed supplementation and processing provides ample scope for improving fodder value.

REDD+and community-controlled forests in low-income countries: Any hope for a linkage?

2013-05-18T10:07:33Z

Publication date: March 2013
Source:Ecological Economics, Volume 87

Author(s): Randy Bluffstone , Elizabeth Robinson , Paul Guthiga

Deforestation and forest degradation are estimated to account for between 12% and 20% of annual greenhouse gas emissions and in the 1990s (largely in the developing world) released about 5.8Gt per year, which was bigger than all forms of transport combined. The idea behind REDD+ is that payments for sequestering carbon can tip the economic balance away from loss of forests and in the process yield climate benefits. Recent analysis has suggested that developing country carbon sequestration can effectively compete with other climate investments as part of a cost effective climate policy.

This paper focuses on opportunities and complications associated with bringing community-controlled forests into REDD+. About 25% of developing country forests are community controlled and therefore it is difficult to envision a successful REDD+ without coming to terms with community controlled forests. It is widely agreed that REDD+ offers opportunities to bring value to developing country forests, but there are also concerns driven by worries related to insecure and poorly defined community forest tenure, informed by often long histories of government unwillingness to meaningfully devolve to communities. Further, communities are complicated systems and it is therefore also of concern that REDD+ could destabilize existing well-functioning community forestry systems.

Highlights

► Deforestation and forest degradation emit more GHG than transport. ► Black carbon from villagers' cooking stoves is second only to CO2 as a GHG. ► About 25% of developing country forests are to some degree community controlled. ► REDD+ offers opportunities to improve the lives of villagers who control forests. ► Many challenges remain in implementing REDD+ in community controlled forests.

Characteristics of indomethacin–saccharin (IMC–SAC) co-crystals prepared by an anti-solvent crystallization process

2013-05-18T10:07:33Z

Publication date: Available online 27 February 2013
Source:European Journal of Pharmaceutics and Biopharmaceutics

Author(s): Nan-Hee Chun , In-Chun Wang , Min-Jeong Lee , Yun-Taek Jung , Sangkil Lee , Woo-Sik Kim , Guang J. Choi

The creation of co-crystals of various insoluble drug substances has been extensively investigated as a promising approach to improve their pharmaceutical performance. In this study, co-crystal powders of indomethacin and saccharin (IMC–SAC) were prepared by an anti-solvent (water) addition and compared with co-crystals by evaporation method. No successful synthesis of a pharmaceutical co-crystal powder via an anti-solvent approach has been reported.

Among solvents examined, methanol was practically the only one that resulted in the formation of highly pure IMC–SAC co-crystal powders by anti-solvent approach. The mechanism of a preferential formation of IMC–SAC co-crystal to IMC was explained with two aspects: phase solubility diagram and solution complexation concept. Accordingly, the anti-solvent approach can be considered as a competitive route for producing pharmaceutical co-crystal powders with acceptable properties.

Graphical abstract

Comparative evaluation of novel African swine fever virus (ASF) antibody detection techniques derived from specific ASF viral genotypes with the OIE internationally prescribed serological tests

2013-05-18T10:07:33Z

Publication date: 22 February 2013
Source:Veterinary Microbiology, Volume 162, Issue 1

Author(s): C. Gallardo , A. Soler , R. Nieto , A.L. Carrascosa , G.M. De Mia , R.P. Bishop , C. Martins , F.O. Fasina , E. Couacy-Hymman , L. Heath , V. Pelayo , E. Martín , A. Simón , R. Martín , A.R. Okurut , I. Lekolol , E. Okoth , M. Arias

The presence of antibodies against African swine fever (ASF), a complex fatal notifiable OIE disease of swine, is always indicative of previous infection, since there is no vaccine that is currently used in the field. The early appearance and subsequent long-term persistence of antibodies combined with cost-effectiveness make antibody detection techniques essential in control programmes. Recent reports appear to indicate that the serological tests recommended by the OIE for ASF monitoring are much less effective in East and Southern Africa where viral genetic and antigenic diversity is the greatest. We report herein an extensive analysis including more than 1000 field and experimental infection sera, in which the OIE recommended tests are compared with antigen-specific ELISAs and immuno-peroxidase staining of cells (IPT). The antibody detection results generated using new antigen-specific tests, developed in this study, which are based on production of antigen fractions generated by infection and virus purification from COS-1 cells, showed strong concordance with the OIE tests. We therefore conclude that the lack of success is not attributable to antigenic polymorphism and may be related to the specific characteristics of the local breeds African pigs.

Supermarkets and agricultural labor demand in Kenya: A gendered perspective

2013-05-18T10:07:33Z

Publication date: February 2013
Source:Food Policy, Volume 38

Author(s): Elizaphan J.O. Rao , Matin Qaim

Many developing countries are experiencing a rapid expansion of supermarkets. New supermarket procurement systems could affect farming patterns and wider rural development. While previous studies have analyzed farm productivity and income effects, possible employment effects have received much less attention. Special supermarket requirements may entail intensified farm production and post-harvest handling, thus potentially increasing demand for hired labor. This could also have important gender implications, because female and male workers are often hired for distinct farm operations. Building on data from a recent survey of vegetable farmers in Kenya, a double-hurdle model of hired labor use is developed and estimated. Farmer participation in supermarket channels increases the likelihood of hiring labor by 20%, and demand for hired labor by 61%. A gender disaggregation shows that positive employment effects are especially pronounced for female laborers, who often belong to the most vulnerable population groups. Rural employment generation can be an important vehicle for poverty reduction.

Highlights

► We analyze effects of supermarket growth on agricultural labor markets in Kenya. ► We use data from a survey of vegetable farmers to estimate labor demand models. ► Participation in supermarkets increases likelihood of hiring labor by 20%. ► Furthermore, it increases demand for hired labor by 61%. ► Positive employment effects are especially pronounced for female laborers.

Adaptation to climate change through the choice of cropping system and sowing date in sub-Saharan Africa

2013-05-18T10:07:33Z

Publication date: February 2013
Source:Global Environmental Change, Volume 23, Issue 1

Author(s): K. Waha , C. Müller , A. Bondeau , J.P. Dietrich , P. Kurukulasuriya , J. Heinke , H. Lotze-Campen

Multiple cropping systems provide more harvest security for farmers, allow for crop intensification and furthermore influence ground cover, soil erosion, albedo, soil chemical properties, pest infestation and the carbon sequestration potential. We identify the traditional sequential cropping systems in ten sub-Saharan African countries from a survey dataset of more than 8600 households. We find that at least one sequential cropping system is traditionally used in 35% of all administrative units in the dataset, mainly including maize or groundnuts. We compare six different management scenarios and test their susceptibility as adaptation measure to climate change using the dynamic global vegetation model for managed land LPJmL. Aggregated mean crop yields in sub-Saharan Africa decrease by 6–24% due to climate change depending on the climate scenario and the management strategy. As an exception, some traditional sequential cropping systems in Kenya and South Africa gain by at least 25%. The crop yield decrease is typically weakest in sequential cropping systems and if farmers adapt the sowing date to changing climatic conditions. Crop calorific yields in single cropping systems only reach 40–55% of crop calorific yields obtained in sequential cropping systems at the end of the 21st century. The farmers’ choice of adequate crops, cropping systems and sowing dates can be an important adaptation strategy to climate change and these management options should be considered in climate change impact studies on agriculture.

Highlights

► We show the distribution of multiple cropping systems in sub-Saharan Africa. ► We model six agricultural management strategies for adaptation to climate change. ► Crop yields greatly vary between crops, cropping systems and the timing of sowing. ► Low-tech adaptation options are able to reduce negative effects of climate change.

Population attributable fractions of farm vector tick (Rhipicephalus appendiculatus) presence on Theileria parva infection seroprevalence under endemic instability

2013-05-18T10:07:33Z

Publication date: 1 February 2013
Source:Preventive Veterinary Medicine, Volume 108, Issues 2–3

Author(s): J.M. Gachohi , P.M. Kitala , P.N. Ngumi , R.A. Skilton , B. Bett

The primary objective of this study was to assess the impact of Rhipicephalus appendiculatus tick presence (exposure variable) on Theileria parva infection seroprevalence (outcome variable) in a group of cattle belonging to a farm using population attributable fractions (PAF). The analyses were based on a representative sample of 80 traditional smallholder mixed farms. The farms were selected by first stratifying the population administratively and implementing a multistage random sampling in Mbeere district in Kenya. The PAFs were estimated using the stratified, Bruzzi, and sequential partitioned PAF approaches. A secondary objective was, thus, to evaluate the impact of the approaches on the PAF estimates. The stratified and Bruzzi approaches estimated proportion of T. parva infection cases directly attributable to the exposure after controlling for confounding by agro-ecological zone (AEZ). The sequential partitioned PAF approach estimated a PAF associated with exposure after adjusting for any effect that the AEZ may have had by influencing the prevalence of the exposure. All analyses were carried out at the farm level where a farm was classified as infested if the tick was found on cattle on a farm, and infected if at least one animal on a farm was positive for T. parva antibodies. Variance estimation for PAFs was implemented using ‘delete-a-group’ jackknife re-sampling method. The stratified PAF (26.7% [95% CI: 9.0%, 44.4%]) and Bruzzi PAF (26.4% [95% CI: 9.6%, 43.2%]) were consistent in estimating a relatively low impact of farm vector tick presence with a relatively high level of uncertainty. The partitioned PAF (15.5% [95% CI: 1.5%, 29.6%]) suggested that part of the impacts estimated using the stratified PAF and Bruzzi approaches was driven by AEZ effects. Overall, the results suggested that under endemic instability in Mbeere district, (1) presence of R. appendiculatus was not a good indicator of T. parva infection occurrence on a farm; (2) ecological variation could play a role in determining infection impacts. This study provides a preliminary basis for evaluating the potential value and utility of estimating PAFs for variables amenable to control in tick-borne diseases (TBDs) epidemiological studies.

Adapting agriculture to climate change in Kenya: Household strategies and determinants

2013-05-18T10:07:33Z

Publication date: 15 January 2013
Source:Journal of Environmental Management, Volume 114

Author(s): Elizabeth Bryan , Claudia Ringler , Barrack Okoba , Carla Roncoli , Silvia Silvestri , Mario Herrero

Countries in Sub-Saharan Africa are particularly vulnerable to climate change, given dependence on agricultural production and limited adaptive capacity. Based on farm household and Participatory Rural Appraisal data collected from districts in various agroecological zones in Kenya, this paper examines farmers' perceptions of climate change, ongoing adaptation measures, and factors influencing farmers' decisions to adapt. The results show that households face considerable challenges in adapting to climate change. While many households have made small adjustments to their farming practices in response to climate change (in particular, changing planting decisions), few households are able to make more costly investments, for example in agroforestry or irrigation, although there is a desire to invest in such measures. This emphasizes the need for greater investments in rural and agricultural development to support the ability of households to make strategic, long-term decisions that affect their future well-being.

Highlights

► Farmers' perceptions of climate change are influenced by their observation and access to information. ► Many households face considerable challenges in adapting to climate change. ► Agro-pastoralists in arid areas have limited adaptive capacity. ► Extension services, credit, and climate information increase resilience to climate change. ► Livelihood diversification is also essential for adaptation.

IgG antibodies from dourine infected horses identify a distinctive Trypanosoma equiperdum antigenic pattern of low molecular weight molecules

2013-05-18T10:07:33Z

Publication date: 15 January 2013
Source:Veterinary Immunology and Immunopathology, Volume 151, Issues 1–2

Author(s): M. Luciani , C. Di Pancrazio , T. Di Febo , M. Tittarelli , M. Podaliri Vulpiani , M.O. Puglielli , J. Naessens , F. Sacchini

Diagnosis and control of dourine is strongly based on serological evidence, but knowledge of the humoral response of horses during infection is limited. In this study we developed a chemiluminescent immunoblotting (cIB) assay to characterise the Trypanosoma equiperdum antigen pattern recognised by IgGs from naturally or experimentally dourine-infected horses and analyse the kinetics of IgG humoral response following the infection. One compounding factor is that sera from uninfected animals often cross-react with T. equiperdum antigens. Development of the cIB assay was based on the hypothesis that serum IgGs from healthy and infected animals recognise different T. equiperdum antigen patterns. We used sera from 8 naturally infected horses which had recovered from Italian outbreaks and 2 experimentally infected mares. In addition, sera from 10 healthy control animals, eight of which were CFT positive but IFA negative for dourine, were collected from disease free regions. Sera were compared by the complement fixation test (CFT), indirect immune fluorescence (IFA) and the cIB assay.

cIB analysis revealed that IgGs from infected horses, in contrast to IgGs from healhty horses, specifically recognise a T. equiperdum antigenic profile with low molecular weight bands ranging between 16 and 35kDa. A time course experiment indicated that IgGs specific for the 16–35kDa parasite protein fraction appear 17 days post-infection. The cIB assay confirmed all ten infected animals as positive and all controls as negative. This study demonstrated that analysis of IgGs by cIB can provide clear confirmation of trypanosome infection in horses, suggesting that this technique can be applied as a confirmatory serological test for dourine infection.

Generating downscaled weather data from a suite of climate models for agricultural modelling applications

2013-05-18T10:07:33Z

Publication date: January 2013
Source:Agricultural Systems, Volume 114

Author(s): Peter G. Jones , Philip K. Thornton

We describe a generalised downscaling and data generation method that takes the outputs of a General Circulation Model and allows the stochastic generation of daily weather data that are to some extent characteristic of future climatologies. Such data can then be used to drive any agricultural model that requires daily (or otherwise aggregated) weather data. The method uses an amalgamation of unintelligent empirical downscaling, climate typing and weather generation. We outline a web-based software tool (http://gismap.ciat.cgiar.org/MarkSimGCM) to do this for a subset of the climate models and scenario runs carried out for the 2007 Fourth Assessment Report of the Intergovernmental Panel on Climate Change. We briefly assess the tool and comment on its use and limitations.

Highlights

► Most climate model outputs need manipulation before they can be used by agricultural modellers. ► We describe a tool to generate daily data that are somewhat characteristic of future climates. ► The method uses an amalgamation of empirical downscaling, climate typing and weather generation. ► The web-based tool provides downscaled data that can be used directly for agricultural modelling.

Increasing nutrient use efficiency through improved feeding and manure management in urban and peri-urban livestock units of a West African city: A scenario analysis

2013-05-18T10:07:33Z

Publication date: January 2013
Source:Agricultural Systems, Volume 114

Author(s): Rodrigue V.C. Diogo , Eva Schlecht , Andreas Buerkert , Mariana C. Rufino , Mark T. van Wijk

In many African cities urban and peri-urban agriculture (UPA) plays a major role in creating jobs and contributing to food security. However, many small-scale UPA systems are characterised by excessive nutrient inputs to the livestock unit and poor handling of manure. To assess the impact of improved feeding and manure management on nutrient use efficiency within the cattle unit, simulation modelling was used to compare three typical UPA farm types in Niamey, Niger, that comprised: animal husbandry alone (AH), animal husbandry plus gardening (AH+G), and animal husbandry plus gardening plus millet cultivation (AH+G+M). Improved feeding increased annual body weight gain and milk offtake from cattle and reduced the amount of nitrogen (N) excreted in urine, thereby lowering the risk of N emissions. With improved manure management, dry matter (DM) and nutrients recycled per animal and year, and potentially available for cropping, ranged from 321–690kgDM, 8–22kgN, 1.2–2.5kg phosphorus (P), and 3.0–5.6kg potassium (K) in AH as well as AH+G+M farms compared to 221–479kgDM, 5.0–14.0kgN, 0.7–1.6kgP, and 2.0–4.0kgK in AH+G farms. These amounts were up to 2.2-, 2.5-, 1.9- and 1-fold higher than the quantities of DM, N, P and K recycled under current practices. Feeding dairy cattle according to their requirements will enhance milk and meat production; if coupled with regular manure collection and low-cost covering of manure heaps, substantial amounts of nutrients are recycled to cropland and vegetable gardens and environmental pollution is reduced.

Highlights

► Peri-urban cattle farmers can greatly enhance nutrient use efficiency at farm level. ► Better feeding and dung management increase nitrogen recoveries at farm level. ► This reduces environmental pollution through GHG emissions and nitrogen leaching.

Identifying recommendation domains for targeting dual-purpose maize-based interventions in crop-livestock systems in East Africa

2013-05-18T10:07:33Z

Publication date: January 2013
Source:Land Use Policy, Volume 30, Issue 1

Author(s): An Notenbaert , Mario Herrero , Hugo De Groote , Liang You , Ernesto Gonzalez-Estrada , Michael Blummel

In the three major maize producing countries in the East African region of Kenya, Tanzania and Ethiopia, up to 44% of the dietary calorie requirements is provided by maize. It is also recognized that livestock are an essential asset of poor farmers in the mixed crop-livestock systems in this region. One of the major constraints to their productivity is, however, feed availability. A significant proportion of this feed is sourced from maize stover. We engaged in a multi-disciplinary research of dual-purpose maize cultivars with the purpose of contributing to smallholder food security. The specific objective of our endeavor is to better match new maize cultivars to farmers’ needs by including fodder traits in maize improvement programs in Ethiopia, Tanzania and Kenya.

We explored a novel approach for targeting maize breeding research. Agricultural development strategies must recognize heterogeneity in bio-physical, economic, socio-cultural, institutional and environmental factors when devising interventions and investments. The research effort into maize as a food and feed resource was, therefore, carried out in a cross-section of bio-physically and socio-economically contrasting areas across the three study countries. To this effect the International Maize and Wheat Improvement Centre's traditional targeting framework, maize mega-environments (MMEs), was combined with recommendation domains for dual-purpose maize using a Geographical Information System (GIS). The GIS-based approach provided a spatial framework for the structured exploration of opportunities to transfer knowledge and technologies. Results show that maize is potentially an important feed resource in areas with high feed demand. Throughout the different MMEs, a range of different incentives for dual-purpose varieties can be found. The maps with recommendation domains for dual-purpose maize will facilitate better targeting of new maize cultivars. Cultivars with good quality stover can now be preferentially promoted in areas with high demand for stover as feed, while at the same time matched to the bio-physically most suitable mega-environment. This integrated approach is widely applicable and will help increase the impacts from agricultural research.

Genetic variability of tropical maize stover quality and the potential for genetic improvement of food-feed value in India

2013-05-18T10:07:33Z

Publication date: Available online 31 December 2012
Source:Field Crops Research

Author(s): P.H. Zaidi , M.T. Vinayan , M. Blümmel

Sixty elite maize inbred lines were selected from CIMMYT-Asia maize program for stover fodder quality analysis. These lines were selected based on high per se and cross performance across several locations in the Asian tropics and have wide adaptability across the region. The line evaluation trials were conducted using recommended agronomic practices during the off-season of 2009 at ICRISAT farm in Hyderabad, India. Data were recorded on various agronomic traits including yields. At harvest the stover was analyzed for a range of fodder quality traits. On the basis of high stover in vitro digestibility (IVOMD) (a trait chosen because it correlated well with pricing in fodder trading of another coarse stover, namely sorghum) and high grain yield, the top ranking 10 inbred lines were selected and crossed in all possible combinations (excluding reciprocals) using diallel mating design in the rainy season of 2010. A total of 26 crosses along with four commercial hybrid checks were selected and planted in two replicates for evaluation during the dry season of 2010.

A wide range in performance was observed in grain and stover traits. Grain and stover yields ranged from 0.94 to 7.3t/ha (P <0.0001) and from 2.0 to 8.5t/ha (P <0.0001), respectively. Stover IVOMD ranged from 46.9 to 55.5% (P =0.08). Grain and stover traits showed a considerable degree of independency. Grain and stover yield were significantly positively correlated (r =0.53; P =0.003), however, grain yields at around 7.0t/ha showed varied stover yields ranges from 3.5 to 6t/ha. No significant correlation was observed between IVOMD and grain yield (r =−0.12, P =0.52) or IVOMD and stover yield (r =0.03; P =0.98). It is striking that the cross with the third highest grain yield (7.1t/ha) had the second highest stover digestibility (about 55%).

Highlights

► Maize stover was found par with sorghum stover when used as major (50%) components of total mixed dairy rations. ► Significant variations exist in stover quantity among maize cultivars that can be exploited without compromising on grain yield. ► Selected germplasm with superior food and fodder traits appear a promising way to produce dual purpose maize hybrids.

Intersectoral collaboration between the medical and veterinary professions in low-resource societies: The role of research and training institutions

2013-05-18T10:07:33Z

Publication date: Available online 20 December 2012
Source:Comparative Immunology, Microbiology and Infectious Diseases

Author(s): Tanguy Marcotty , Eric Thys , Patricia Conrad , Jacques Godfroid , Philip Craig , Jakob Zinsstag , Filip Meheus , Abdou Razac Boukary , Mallam Abdou Badé , Hamid Sahibi , Hind Filali , Saskia Hendrickx , Cyrille Pissang , Michel Van Herp , Dirk van der Roost , Séverine Thys , David Hendrickx , Marleen Claes , Tine Demeulenaere , Joep van Mierlo , Jean-Paul Dehoux , Marleen Boelaert

Background

Neglected zoonoses continue to significantly affect human health in low-resource countries. A symposium was organised in Antwerp, Belgium, on 5 November 2010 to evaluate how intersectoral collaboration among educational and research institutions could improve the situation.

Results

Brucellosis and echinococcosis were presented as models for intersectoral collaboration. Low-resource societies face evident knowledge gaps on disease distribution, transmission within and across species and impact on human and animal health, precluding the development of integrated control strategies.

Recommendations

While veterinarians have been the main driver of the One Health initiative, the medical profession does not seem to be fully aware of how veterinary science can contribute to human public health. It was postulated that transdisciplinarity could help fill knowledge gaps and that encouraging such transdisciplinarity should start with undergraduate students. Furthermore, intersectoral collaboration on zoonoses should not ignore the social sciences (e.g. assessment of indigenous knowledge and perception; participatory surveillance), which can contribute to a better understanding of the transmission of diseases and improve communities’ participation in disease control activities.

Persistence of the efficacy of copper oxide wire particles against Haemonchus contortus in grazing South African goats

2013-05-18T10:07:33Z

Publication date: 23 November 2012
Source:Veterinary Parasitology, Volume 190, Issues 1–2

Author(s): A.F. Vatta , P.J. Waller , J.B. Githiori , G.F. Medley

A study was conducted to examine the duration of anthelmintic effect of copper oxide wire particles (COWP) in grazing goats, as data for the persistence of efficacy of COWP in this host species is limited. Forty-eight indigenous male goats were infected naturally by grazing them on Haemonchus contortus-infected pasture. When the faecal egg count (FEC) in the goats was 3179±540 eggs per gram of faeces (mean±standard error), half the animals were treated with 4g COWP (day 0; mean live weight=25.5±0.8kg). Eight treated (COWP) and eight non-treated (CONTROL) goats were removed from the pasture on each of days 7, 28 and 56, maintained for 27 or 29 days in concrete pens and then humanely slaughtered for nematode recovery. Mean liver copper levels were in the high range in the goats removed from pasture at day 7 (treated: 191±19.7ppm; untreated: 120±19.7ppm; P =0.022), but had dropped to normal levels at days 28 and 56. The mean H. contortus burdens of the treated versus the non-treated goats were, respectively, 184±48 and 645±152 for the goats removed from pasture at day 7 (71% reduction; P =0.004), 207±42 and 331±156 at day 28 (37% reduction; P =0.945) and 336±89 and 225±53 at day 56 (−49% reduction; P =0.665). Weekly monitoring of FECs after treatment until slaughter indicated that the COWP-treated goats had lower FECs than the controls, the treatment main effect being significant at days 7, 28 and 56 (P <0.01). The day main effect and the treatment×day interaction were only significant for the goats removed from pasture at day 28 (P ≤0.001). Packed cell volumes increased during the course of the experiment (day, P <0.001), but the treatment main effect was significant only for the goats removed from pasture at day 28 (CONTROL 28 d, 28.65±0.52%<COWP 28 d, 31.31±0.52%; P <0.001). No differences in live weight between groups were considered to be of any practical significance. The study indicated that persistence of efficacy of COWP is limited in goats, extending at most to 28 days after treatment. However, repeated COWP administration at three-month intervals may be safe, given that liver copper levels return to normal two to three months after COWP treatment.

Influence of salt additives on phase transformation of guanosine 5-monophosphate disodium in anti-solvent crystallization

2013-05-18T10:07:33Z

Publication date: Available online 21 November 2012
Source:Journal of Crystal Growth

Author(s): Anh-Tuan Nguyen , Jeongki Kang , Woo-Sik Kim

The influence of sodium chloride (NaCl) as an additive on the anti-solvent crystallization of guanosine 5-monophosphate disodium (GMP-2Na) was investigated in continuous Couette–Taylor (CT) and batch mixing tank (MT) crystallizers. The anti-solvent crystallization initially precipitated amorphous solids of GMP-2Na, which then slowly transformed into hydrate crystals in the solution. However, the phase transformation of GMP-2Na was markedly promoted by the sodium chloride additive due to the common ion effect. While the normal phase transformation in the batch MT crystallizer required over 120min of crystallization time without using the sodium chloride additive, the process was completed within 60min when a small amount of the salt additive was added. The phase transformation was also significantly accelerated in the continuous CT crystallizer. Without using the sodium chloride additive, 7min of the mean residence time was required for the production of 100% hydrate GMP crystals. However, when using the sodium chloride additive, a mean residence time of only 2min was sufficient to completely transform the amorphous solids of GMP-2Na into hydrate crystals due to the common ion effect combined with the effective fluid motion of the Taylor vortex for the mass transfer.

Highlights

► The phase transformation GMP was promoted by sodium salt additive in the batch MT and continuous CT crystallizers. ► The phase transformation was much more accelerated in the continuous CT crystallizers than in the MT crystallizer. ► It took only 2min of the mean residence time for the complete phase transformation in CT crystallizer.

Molecular detection and characterization of potentially new Babesia and Theileria species/variants in wild felids from Kenya

2013-05-18T10:07:33Z

Publication date: October 2012
Source:Acta Tropica, Volume 124, Issue 1

Author(s): Naftaly Githaka , Satoru Konnai , Edward Kariuki , Esther Kanduma , Shiro Murata , Kazuhiko Ohashi

Piroplasms frequently infect domestic and wild carnivores. At present, there is limited information on the occurrence and molecular identity of these tick-borne parasites in wild felids in Kenya. In 2009, a pair of captive lions (Panthare leo) was diagnosed with suspected babesiosis and mineral deficiency at an animal orphanage on the outskirts of Nairobi, Kenya. Blood smears indicated presences of haemoparasites in the erythrocytes, however, no further investigations were conducted to identify the infecting agent. The animals recovered completely following diet supplementation and treatment with anti-parasite drug. In this report, we extracted and detected parasite DNA from the two lions and seven other asymptomatic feline samples; two leopards (Panthera pardus) and five cheetahs (Acinonyx jubatus). Reverse line blot with probes specific for Babesia spp. of felines indicated the presence of new Babesia species or genotypes in the lions and leopards, and unknown Theileria sp. in the cheetahs. Phylogenetic analyses using partial sequences of 18S ribosomal RNA (18S rRNA) gene showed that the parasite infecting the lions belong to the Babesia canis complex, and the parasite variant detected in the leopards clusters in a clade bearing other Babesia spp. reported in wild felids from Africa. The cheetah isolates falls in the Theileria sensu stricto group. Our findings indicate the occurrence of potentially new species or genotypes of piroplams in all three feline species.

Graphical abstract

Highlights

A rooted phylogenetic tree showing the relationship between the parasites identified in the present study and closely related parasites from the Genbank.

► Detection by PCR and Reverse Line Blot (RLB). ► Phylogenetic characterization. ► Identification of potentially novel species/genetic variants of Babesia and Theileria among three wild feline species in Kenya.

Could farmer interest in a diversity of seed attributes explain adoption plateaus for modern maize varieties in Malawi?

2013-05-18T10:07:33Z

Publication date: October 2012
Source:Food Policy, Volume 37, Issue 5

Author(s): Rodney Lunduka , Monica Fisher , Sieglinde Snapp

This study uses new data from a household survey (n =179) in Mulanje District, Malawi to examine whether the observed adoption plateaus for modern maize varieties in Malawi partly reflect farmer interest in a diversity of maize seed attributes. Regression results for the study area indicate that specific attributes of different maize varieties are an important influence on their use. The benefits to growing hybrid maize appear to be yield and drought tolerance. Open pollinated varieties are selected by farmers who value early maturity. Local maize varieties are popular among farm households owing to a number of favourable processing and consumption characteristics: storability, poundability, flour-to-grain ratio, and taste. Further research using nationally representative data is needed to assess whether findings for Mulanje District can be generalized to Malawi as a whole. If future studies agree with the results herein then maize breeding research programs in Malawi should consider a diversity of traits beyond grain yield to encompass the range of production, processing, and consumption attributes that are valued by farmers.

Highlights

► We examine if low adoption levels of modern maize in Malawi reflect farmer interest in a diversity of maize seed attributes. ► Results show farmers value local and modern maize seed for different production, processing, and consumption benefits. ► Results suggest Malawi maize breeding research should emphasize several maize variety traits rather than grain yield alone.

Efficacy of two vaccine formulations against contagious bovine pleuropneumonia (CBPP) in Kenyan indigenous cattle

2013-05-18T10:07:33Z

Publication date: October 2012
Source:Research in Veterinary Science, Volume 93, Issue 2

Author(s): Isabel Nkando , Joycelyne Ndinda , Joseph Kuria , Jan Naessens , Flora Mbithi , Christian Schnier , Michael Gicheru , Declan McKeever , Hezron Wesonga

A live, attenuated vaccine is currently the only viable option to control of CBPP in Africa. It has been suggested that simple modifications to current vaccines and protocols might improve efficacy in the field. In this report we compared the current vaccine formulation with a buffered preparation that maintains Mycoplasma viability at ambient temperature for a longer time. Groups of animals were vaccinated with the two formulations and compared with non vaccinated groups. Half of the animals in each group were challenged 3months post vaccination, the other half after 16months. Protection levels were measured using the pathology index, calculated from post mortem scores of lesions from animals killed during the course of clinical disease. In the challenge at 3months post vaccination, the protection levels were 52% and 77% for the modified and current vaccine preparations, respectively. At 16months post vaccination, the protection levels were 56% and 62% for the modified and current vaccine preparations, respectively. These findings indicate that there are no differences in protection levels between the two vaccines. Because of its longer half life after reconstitution, the modified vaccine might be preferred in field situations where the reconstituted vaccine is likely not to be administered immediately.

Detection and identification of Rift Valley fever virus in mosquito vectors by quantitative real-time PCR

2013-05-18T10:07:33Z

Publication date: October 2012
Source:Virus Research, Volume 169, Issue 1

Author(s): D. Mwaengo , G. Lorenzo , J. Iglesias , M. Warigia , R. Sang , R.P. Bishop , A. Brun

Diagnostic methods allowing for rapid identification of pathogens are crucial for controlling and preventing dissemination after disease outbreaks as well as for use in surveillance programs. For arboviruses, detection of the presence of virus in their arthropod hosts is important for monitoring of viral activity and quantitative information is useful for modeling of transmission dynamics. In this study, molecular detection of Rift Valley fever virus (RVFV) in mosquito samples from the 2006 to 2007 East African outbreaks was performed using quantitative real-time PCR assay (qRT-PCR). Specific RVFV sequence-based primer/fluorogenic (TaqMan) probe sets were derived from the L and S RNA segments of the virus. Both primer-probe L and S segment-based combinations detected genomic RVFV sequences, with generally comparable levels of sensitivity. Viral loads from three mosquito species, Aedes mcintoshi, Aedes ochraceus and Mansonia uniformis were estimated and significant differences of between 5- and 1000-fold were detected between Ae. mcintoshi and M. uniformis using both the L and S primer-probe-based assays. The genetic relationships of the viral sequences in mosquito samples were established by partial M segment sequencing and assigned to the two previously described viral lineages defined by analysis of livestock isolates obtained during the 2006–2007 outbreak, confirming that similar viruses were present in both the vector and mammalian host. The data confirms the utility of qRT-PCR for identification and initial quantification of virus in mosquito samples during RVFV outbreaks.

Highlights

► Quantitative detection of Rift Valley fever virus genomes directly from mosquito pool homogenates. ► Higher viral RNA loads were found in Aedes spp. mosquitoes when compared to Mansonia spp. ► Sequencing of a short nucleotide stretch from the viral RNA M segment allows further phylogenetic classification.

A method for evaluating climate change adaptation strategies for small-scale farmers using survey, experimental and modeled data

2013-05-18T10:07:33Z

Publication date: September 2012
Source:Agricultural Systems, Volume 111

Author(s): L. Claessens , J.M. Antle , J.J. Stoorvogel , R.O. Valdivia , P.K. Thornton , M. Herrero

Sub-Saharan Africa (SSA) is predicted to experience considerable negative impacts of climate change. The IPCC Fourth Assessment emphasizes that adaptation strategies are essential. Addressing adaptation in the context of small-scale, semi-subsistence agriculture raises special challenges. High data demands including site-specific bio-physical and economic data are an important constraint. This paper applies a new approach to impact assessment, the Tradeoff Analysis model for Multi-Dimensional Impact Assessment (TOA-MD), which simulates technology adoption and associated economic, environmental and social outcomes in a heterogeneous farm population for a regional impact assessment. The methodology uses the kinds of survey, experimental and modeled data that are typically available in countries where semi-subsistence systems are important, combined with future socio-economic scenarios based on new scenario pathway concepts being developed by the climate change and impact assessment modeling communities. Characteristics of current and future agricultural systems, including land use, output, output price, cost of production, and farm and household size are analyzed and compared for both current and projected future climate (2030), with and without adaptation, and for different socio-economic scenarios. The methodology is applied to two study areas in Kenya. These case studies show the potential of this approach to provide a flexible, generic framework that can use available and modeled data to evaluate climate impact and adaptation strategies under a range of socio-economic scenarios.

Highlights

► We apply the Tradeoff Analysis model for Multi-Dimensional Impact Assessment (TOA-MD). ► TOA-MD simulates economic and social outcomes in a heterogeneous farm population. ► Impacts of climate change and adaptation under different socio-economic scenarios to 2030 are assessed. ► Negative effects of climate change are projected for two mixed crop-livestock systems in Kenya. ► Several adaptation strategies are simulated to be able to overcome these effects.

Feeding value of sweet sorghum bagasse and leaf residues after juice extraction for bio-ethanol production fed to sheep as complete rations in diverse physical forms

2013-05-18T10:07:33Z

Publication date: 10 August 2012
Source:Animal Feed Science and Technology, Volume 175, Issues 3–4

Author(s): S. Anandan , Hazda Zoltan , A.A. Khan , D. Ravi , Michael Blümmel

The fodder value of sweet sorghum bagasse with leaf residues (SSBLR) remaining after juice extraction for bio-ethanol production as major diet ingredient was assessed in male growing sheep measuring intake, digestibility and growth rates. The SSBLR contributed about 450g/kg in total mixed rations and was offered as mash (8mm), pellets (16mm) and feed block (SSBLR chopped). Chaffed SSBLR supplemented with the remaining concentrate components of the total mixed ration-offered for 2h before the chaffed SSBLR-served as a control. Six sheep were randomly allocated to each treatment, balancing the group weight. Intake of all SSBLR based rations was generally very high exceeding 42g/kg of sheep live weight in the control and feed block ration and intake was further increased to 52 and 56g/kg in the mash and pellets rations, respectively. Observed live weight gain in sheep fed mash and pellets were 133g/d and 130g/d, respectively, compared to 90g/d and 81g/d observed in the feed block and control group, respectively. Organic matter digestibility was 0.59 and 0.58 in the mash and pellet group compared to 0.62 and 0.61 in the feed block and control group, respectively. All comparisons in mash and pellet versus feed block and control group were different (P<0.05). SSBLR can be utilized as major ration component thereby mitigating fodder shortages likely to arise from using sweet sorghum stalks for juice extraction for bio-ethanol production. Use of SSBLR as ration component for will also add to the economic viability of sweet sorghum ethanol value chains. In decentralized systems where juice is extracted from sweet sorghum stalks in the villages and options of processing SSBLR are limited, SSBLR can be used in chopped form with similar efficiency than as component of processed feed block. In centralized system, generating large quantities of SSBLR, processing feed into mash and pellets would be advantageous for supporting higher livestock productivity and lower feed transport costs.

Rural Poverty Dynamics in Kenya: Structural Declines and Stochastic Escapes

2013-05-18T10:07:33Z

Publication date: August 2012
Source:World Development, Volume 40, Issue 8

Author(s): Maren Radeny , Marrit van den Berg , Rob Schipper

We use panel survey data and household event-histories to explore patterns of rural poverty dynamics in Kenya over the period 2000–2009. We find substantial mobility across poverty categories using economic transition matrices. Drawing on asset-based approaches, we distinguish stochastic from structural poverty transitions. Few households successfully escaped poverty through asset accumulation (up to 35% of the upwardly mobile), while a large proportion of households (up to 66%) declining into poverty experienced structural transitions. Using household event-histories, we find significant differences across structural poverty transition classes in livelihood strategies, household-level shocks, and other factors.

Dry forest based livelihoods in resettlement areas of Northwestern Ethiopia

2013-05-18T10:07:33Z

Publication date: July 2012
Source:Forest Policy and Economics, Volume 20

Author(s): Degnet Abebaw , Habtemariam Kassa , Girma T. Kassie , Mulugeta Lemenih , Bruce Campbell , Worku Teka

While the importance of forests for livelihoods has long been well-recognized, empirical knowledge of the factors influencing the extent and diversity of household engagement in the extraction of forest products across different socio-economic groups remains limited. In this paper, we use primary data collected through a household survey of 180 households in a resettled dry forest areas of Northwestern Ethiopia. The paper mainly aims at identifying the main drivers of household behavior regarding collection of main forest products in the context of dry forest environment. A multivariate probit analysis was used to explain variation in household participation in collection of different forest products. The results show that households' participation in collection of different forest products is significantly determined by a combination of household demographic characteristics, ownership of oxen and of cows, proximity to forest, access to health and school infrastructure, resettlement history and self-reported change in standard of living. The estimation results also suggest households most likely to engage in collection of forest honey, gum, and wood for fuel and other purposes are those located farther from the forest. Policy implications and outlook for further study are discussed in the paper.

Highlights

► Dry land forests are important sources of livelihoods in Ethiopia. ► There is considerable differentiation among the local population in forest extraction behavior. ► Subjective wellbeing, resettlement history, and schooling and health infrastructure are strongly linked to forest extraction.

Conservation Agriculture in mixed crop–livestock systems: Scoping crop residue trade-offs in Sub-Saharan Africa and South Asia

2013-05-18T10:07:33Z

Publication date: 14 June 2012
Source:Field Crops Research, Volume 132

Author(s): Diego Valbuena , Olaf Erenstein , Sabine Homann-Kee Tui , Tahirou Abdoulaye , Lieven Claessens , Alan J. Duncan , Bruno Gérard , Mariana C. Rufino , Nils Teufel , André van Rooyen , Mark T. van Wijk

Conservation Agriculture (CA) is being advocated to enhance soil health and sustain long term crop productivity in the developing world. One of CA's key principles is the maintenance of soil cover often by retaining a proportion of crop residues on the field as mulch. Yet smallholder crop–livestock systems across Africa and Asia face trade-offs among various options for crop residue use. Knowledge of the potential trade-offs of leaving more residues as mulch is only partial and the objective of this research is to address some of these knowledge gaps by assessing the trade-offs in contrasting settings with mixed crop–livestock systems. The paper draws from village surveys in 12 sites in 9 different countries across Sub-Sahara Africa and South Asia. Sites were clustered into 3 groups along the combined population and livestock density gradients to assess current crop residue management practices and explore potential challenges to adopting mulching practices in different circumstances. Results show that although high-density sites face higher potential pressure on resources on an area basis, biomass production tends to be more substantial in these sites covering demands for livestock feed and allowing part of the residues to be used as mulch. In medium-density sites, although population and livestock densities are relatively lower, biomass is scarce and pressure on land and feed are high, increasing the pressure on crop residues and their opportunity cost as mulch. In low-density areas, population and livestock densities are relatively low and communal feed and fuel resources exist, resulting in lower potential pressure on residues on an area basis. Yet, biomass production is low and farmers largely rely on crop residues to feed livestock during the long dry season, implying substantial opportunity costs to their use as mulch. Despite its potential benefit for smallholder farmers across the density gradient, the introduction of CA-based mulching practices appears potentially easier in sites where biomass production is high enough to fulfil existing demands for feed and fuel. In sites with relatively high feed and fuel pressure, the eventual introduction of CA needs complementary research and development efforts to increase biomass production and/or develop alternative sources to alleviate the opportunity costs of leaving some crop residues as mulch.

Highlights

► Crop residues are an important source of livestock feed across smallholder mixed systems in (sub)tropical Africa and Asia. ► In intensive systems biomass productivity is high leaving surplus residues facilitating a potential adoption of CA-based mulching. ► Extensive systems have limited amounts of crop residues and trade-offs on crop residue use are high. ► Introduction of CA-based mulching in these systems faces diverse challenges and opportunities. ► Agricultural intensification can help to better target CA-based mulching interventions and introduce CA-based mulching practices.

Estimates of economic values for important traits of two indigenous Ethiopian sheep breeds

2013-05-18T10:07:33Z

Publication date: June 2012
Source:Small Ruminant Research, Volume 105, Issues 1–3

Author(s): K.T. Gebre , B. Fuerst-Waltl , M. Wurzinger , J. Philipsson , G. Duguma , T. Mirkena , A. Haile , J. Sölkner

A bio-economic model was adapted to estimate economic values for important traits of two Ethiopian indigenous sheep breeds, the Menz and Horro breeds. To do so, a meat sheep herd for fattening lambs and rearing young replacement sheep was simulated. Traits included in the analysis were: daily gain (fattening trait), live weight of ewes, length of productive life, lambing interval, litter size, stillbirths and lamb survival (functional traits). To avoid double counting, the economic value for each trait was derived while keeping all other traits constant. Economic values were obtained per ewe place, year, and genetic standard deviation. For the Menz breed, economic values in € per genetic standard deviation were 0.63 (daily gain), −0.77 (mature ewe live weight), −0.97 (length of productive life), 1.57 (lambing interval), 0.98 (litter size), 0.41 (stillbirths) and 2.20 (lamb survival). Economic values (in €) of 1.35 (daily gain), −1.26 (mature ewe live weight), −1.15 (length of productive life), 1.98 (lambing interval), 3.67 (litter size), 0.56 (stillbirth) and 3.25 (lamb survival) were derived for the Horro breed. Negative economic values for length of productive life and mature ewe live weight were estimated for both breeds. After setting the economic values of length of productive life and mature ewe live weight to zero, the economic values (in %) for the ratio of the trait complexes fattening: functional traits were 11:89 and 12.5:87.5 for Menz and Horro, respectively. Economic values for litter size, lambing interval and lamb survival traits were sensitive to changes in price for breeding rams in both breeds.

Micro- and minisatellite-expressed sequence tag (EST) markers discriminate between populations of Rhipicephalus appendiculatus

2013-05-18T10:07:33Z

Publication date: June 2012
Source:Ticks and Tick-borne Diseases, Volume 3, Issue 3

Author(s): Esther G. Kanduma , Joram M. Mwacharo , Jack D. Sunter , Inosters Nzuki , Stephen Mwaura , Peter W. Kinyanjui , Michael Kibe , Heloise Heyne , Olivier Hanotte , Robert A. Skilton , Richard P. Bishop

Biological differences, including vector competence for the protozoan parasite Theileria parva have been reported among populations of Rhipicephalus appendiculatus (Acari: Ixodidae) from different geographic regions. However, the genetic diversity and population structure of this important tick vector remain unknown due to the absence of appropriate genetic markers. Here, we describe the development and evaluation of a panel of EST micro- and minisatellite markers to characterize the genetic diversity within and between populations of R. appendiculatus and other rhipicephaline species. Sixty-six micro- and minisatellite markers were identified through analysis of the R. appendiculatus Gene Index (RaGI) EST database and selected bacterial artificial chromosome (BAC) sequences. These were used to genotype 979 individual ticks from 10 field populations, 10 laboratory-bred stocks, and 5 additional Rhipicephalus species. Twenty-nine markers were polymorphic and therefore informative for genetic studies while 6 were monomorphic. Primers designed from the remaining 31 loci did not reliably generate amplicons. The 29 polymorphic markers discriminated populations of R. appendiculatus and also 4 other Rhipicephalus species, but not R. zambeziensis. The percentage Principal Component Analysis (PCA) implemented using Multiple Co-inertia Analysis (MCoA) clustered populations of R. appendiculatus into 2 groups. Individual markers however differed in their ability to generate the reference typology using the MCoA approach. This indicates that different panels of markers may be required for different applications. The 29 informative polymorphic micro- and minisatellite markers are the first available tools for the analysis of the phylogeography and population genetics of R. appendiculatus.

Immunization of cattle with Ra86 impedes Rhipicephalus appendiculatus nymphal-to-adult molting

2013-05-18T10:07:33Z

Publication date: June 2012
Source:Ticks and Tick-borne Diseases, Volume 3, Issue 3

Author(s): Cassandra Olds , Stephen Mwaura , David Crowder , David Odongo , Monique van Oers , Jeb Owen , Richard Bishop , Claudia Daubenberger

Commercial vaccines based on the tick gut protein Bm86 have been successful in controlling the one-host tick Rhipicephalus (Boophilus) microplus and provide heterologous protection against certain other non-target ixodid tick species. This cross protection, however, does not extend to the three-host tick R. appendiculatus, the vector of the protozoan parasite Theileria parva. When transmitted to cattle, T. parva causes the often fatal disease East Coast fever. Here, we used insect cell-expressed recombinant versions of the R. appendiculatus homologs of Bm86, named Ra86, to vaccinate cattle. We measured multiple fitness characteristics for ticks that were fed on cattle Ra86-vaccinated or unvaccinated. The Ra86 vaccination of cattle significantly decreased the molting success of nymphal ticks to the adult stage. Modeling simulations based on our empirical data suggest that repeated vaccinations using Ra86 could reduce tick populations over successive generations. Vaccination with Ra86 could thus form a component of integrated control strategies for R. appendiculatus leading to a reduction in use of environmentally damaging acaricides.

Designing bovine T cell vaccines via reverse immunology

2013-05-18T10:07:33Z

Publication date: June 2012
Source:Ticks and Tick-borne Diseases, Volume 3, Issue 3

Author(s): Vishvanath Nene , Nicholas Svitek , Philip Toye , William T. Golde , John Barlow , Mikkel Harndahl , Soren Buus , Morten Nielsen

T cell responses contribute to immunity against many intracellular infections. There is, for example, strong evidence that major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTLs) play an essential role in mediating immunity to East Coast fever (ECF), a fatal lymphoproliferative disease of cattle prevalent in sub-Saharan Africa and caused by Theileria parva. To complement the more traditional approaches to CTL antigen identification and vaccine development that we have previously undertaken we propose a use of immunoinformatics to predict CTL peptide epitopes followed by experimental verification of T cell specificity to candidate epitopes using peptide–MHC (pMHC) tetramers. This system, adapted from human and rodent studies, is in the process of being developed for cattle. Briefly, we have used an artificial neural network called NetMHCpan, which has been trained mainly on existing human, mouse, and non-human primate MHC–peptide binding data in an attempt to predict the peptide-binding specificity of bovine MHC class I molecules. Our data indicate that this algorithm needs to be further optimized by incorporation of bovine MHC–peptide binding data. When retrained, NetMHCpan may be used to predict parasite peptide epitopes by scanning the predicted T. parva proteome and known parasite CTL antigens. A range of pMHC tetramers, made “on-demand”, will then be used to assay cattle that are immune to ECF or in vaccine trials to determine if CTLs of the predicted epitope specificity are present or not. Thus, pMHC tetramers can be used in one step to identify candidate CTL antigens and to map CTL epitopes. Our current research focuses on 9 different BoLA class I molecules. By expanding this repertoire to include the most common bovine MHCs, these methods could be used as generic assays to predict and measure bovine T cell immune responses to any pathogen.

Worms in smallholder livestock systems: Technologies and practices that make a difference

2013-05-18T10:07:33Z

Publication date: 4 May 2012
Source:Veterinary Parasitology, Volume 186, Issues 1–2

Author(s): G.D. Gray , J.G. Connell , V. Phimphachanhvongsod

Australian scientists, in partnership with Asian, African and Pacific nations have longstanding interests in applied research on helminth parasite control. Many technologies and practices have been successfully developed to control the parasite problems of smallholder and emerging farmers. This wide range extends from simple herbal remedies to complex, integrated use of chemicals, feeding and breeding. In many cases widespread adoption has been limited by lack of technical support, poor access to input markets and lack of incentives for poorer farmers to seek out and pay for innovations. A further new approach may be required that encompasses the wider production and market environment.

The biological, social and economic context of each ‘emerging farming system’ is different and the matching of technologies to each system requires sound understanding of farmer needs and requirements. Thus, it is essential that farmers, extension workers, and scientists jointly decide what technologies to try, what results mean and, if successful, how to sustain their use.

In one Asian example a range of technologies were considered for pig, large ruminant and goat production and parasite control through a participatory process which was also used to agree on what determines sustainability beyond testing. The criteria use to screen technologies and practices were (a) continued availability of inputs including dewormers, (b) dependence on related innovations (e.g. weaning or fencing) and (c) degree of community organisation required (e.g. control of breeding or communal grazing). On this basis deworming with chemicals, especially for Toxacara infection in cattle and buffalo calves following on from supplementary feeding with forages were the most feasible entry points. Further interventions were dependent on changes to the production system, including the introduction of weaning and controlled breeding. Further, the incentives for these production changes could not exist without improved market access and market signals for improved weight and condition. Examples such as this point to the need for stronger multidisciplinary and participatory approaches to parasite control.

The influence of cattle breed on susceptibility to bovine tuberculosis in Ethiopia

2013-05-18T10:07:33Z

Publication date: May 2012
Source:Comparative Immunology, Microbiology and Infectious Diseases, Volume 35, Issue 3

Author(s): Martin Vordermeier , Gobena Ameni , Stefan Berg , Richard Bishop , Brian D. Robertson , Abraham Aseffa , R. Glyn Hewinson , Douglas B. Young

Bovine tuberculosis in domestic livestock such as cattle is an economically important disease with zoonotic potential, particularly in countries with emerging economies. We discuss the findings of recent epidemiological and immunological studies conducted in Ethiopia on host susceptibility differences between native zebu and the exotic Holstein–Friesian cattle that are increasingly part of the Ethiopian National herd, due to the drive to increase milk yields. These findings support the hypothesis that native Zebu cattle are more resistant to bovine tuberculosis. We also summarise the results of experimental infections that support the epidemiological data, and of laboratory experiments that suggest a role for the innate immune response, and in particular interleukin-6, in the outcome of bovine tuberculosis infection.

Prevalence of livestock diseases and their impact on livelihoods in Central Equatoria State, southern Sudan

2013-05-18T10:07:33Z

Publication date: 1 May 2012
Source:Preventive Veterinary Medicine, Volume 104, Issues 3–4

Author(s): A.K. Malak , L. Mpoke , J. Banak , S. Muriuki , R.A. Skilton , D. Odongo , J. Sunter , H. Kiara

A participatory epidemiological (PE) study was conducted in Kajo Keji and Yei Counties, Central Equatoria State, southern Sudan to assess the impact of livestock diseases on livelihoods. A serological survey of tick-borne diseases was conducted to supplement the PE study. PE data collection tools consisted primarily of focus group interviews and key informant interviews supplemented by observation. Information was collected on the social context, history and species of livestock kept. Constraints in livestock keeping were explored through description and probing. Proportional piling on the importance of different diseases and relative incidence scoring were also conducted. 243 sera were collected from cattle and tested for antibodies to Anaplasma marginale, Babesia bigemina, B. bovis, Theileria mutans and T. parva by ELISA. Additionally, 173 blood samples were collected for a PCR assay of T. parva. Livestock diseases were ranked as the most important constraint to livestock keeping. While East Coast fever was ranked as the most important disease in Kajo Keji, diarrhoea in small ruminants was reported as the most important disease in Yei. Serological analyses of the sera indicated that A. marginale, B. bigemina, T. mutans and T. parva were most prevalent. Prevalence of B. bovis was found to be low (4.0% and 7.4% in Kajo Keji and Yei, respectively). 35% of the samples screened with the T. parva p104 gene nested PCR assay were positive. The study concludes that while ECF is the most important disease in Kajo Keji, it was not the case in Yei. Additional epidemiological studies are proposed before control strategies are recommended.

Conflict Management, Decentralization and Agropastoralism in Dryland West Africa

2013-05-18T10:07:33Z

Publication date: April 2012
Source:World Development, Volume 40, Issue 4

Author(s): Matthew D. Turner , Augustine A. Ayantunde , Kristen P. Patterson , E. Daniel Patterson III

This paper reports on a four-site study conducted in the Sahelian zone of Niger. The study takes a novel mixed methods approach for understanding conflict management from the perspective of rural peoples by not only describing past highly publicized conflicts but also by analyzing the steps rural peoples follow to management disagreements that arise in their everyday lives. This “bottom-up” approach reveals both a capacity and preference among our informants to manage disagreements informally without involving village or extra-village authorities. Decentralization initiatives, by reworking the authority and responsibilities of authority-based systems, affect the role that these informal mechanisms, as mediated by social norms and relations, play in conflict management.

Effect of land use change, cropping systems and soil type on earthworm cast production in West and Central Africa

2013-05-18T10:07:33Z

Publication date: March–April 2012
Source:European Journal of Soil Biology, Volume 49

Author(s): Stefan Hauser , Lindsey Norgrove , Damian Asawalam , Steffen Schulz

Data on earthworm surface cast deposition in undisturbed, cropped and recovering sites from West and Central Africa were compiled to assess the effects of land use system (LUS) change and if casting can be used to indicate soil quality.

Annual cast deposition in undisturbed systems was significantly higher on Alfisols (49,000 kg ha⁻¹) than on Ultisols (25,000 kg ha⁻¹). Vegetation clearance had significant detrimental effects on earthworm activity. With an increasing length of continuous cropping, cast deposition declined. In young fallows, cast production exceeded levels attained in previously un-cropped controls on Alfisols, yet, on Ultisols, it depended on the previous LUS and length of the previous cropping phase. Recovery was highest after agrisilviculture and after clearing bush fallow. After forest clearance, burning and one year cropping, cast deposition did not recover within three years. On Alfisols, cast production was higher under planted tree fallow and natural fallow than under herbaceous fallow. On Ultisols, fallow type had no effect.

Earthworm surface cast production contributes to soil quality. However, its suitability as an indicator of soil quality is limited to rough assessments as it is dependent upon earthworm species composition, vegetation management and soil type, with more drastic changes on the poorer Ultisols than the more fertile Alfisols.

Highlights

► Earthworm surface cast deposition is depending on soil type and land use change. ► After forest slash and burn and cropping, casting did not recover over 3 fallow years. ► On Ulitsols any land use change caused declines in surface casting. ► Surface casting can be used as a rough indicator of soil quality.

Tactical treatment with copper oxide wire particles and symptomatic levamisole treatment using the FAMACHA© system in indigenous goats in South Africa

2013-05-18T10:07:33Z

Publication date: 28 February 2012
Source:Veterinary Parasitology, Volume 184, Issue 1

Author(s): A. Spickett , J.F. de Villiers , J. Boomker , J.B. Githiori , G.F. Medley , M.O. Stenson , P.J. Waller , F.J. Calitz , A.F. Vatta

Haemonchosis is considered to be the most economically important gastrointestinal disease of small ruminants in the tropics and subtropics. However, chemical anthelmintics, which were the mainstay of control, have been compromised by a high prevalence of resistance worldwide. Copper oxide wire particles (COWP) have been shown to have anthelmintic effects, but few studies have examined their use under field conditions. The use of COWP was therefore evaluated as a tactical anthelmintic treatment in indigenous goats raised under communal farming conditions in Bergville, KwaZulu-Natal Province, South Africa. At the beginning of the summer rainfall season (October 2007), the faecal egg counts of 172 female goats belonging to 15 farmers were determined and this sampling continued every four weeks until the second week of January 2008. The goats within each of the 15 herds were ranked according to their faecal egg counts for this week. The goats were sequentially paired off within each ranking starting with those goats with the highest counts. One goat from each pair was randomly allocated to a treated or control group. Two weeks later, a 4g COWP bolus was randomly administered to each goat in the treated group. Faecal egg counts were carried out on the goats two weeks following treatment, and the sampling of the goats then proceeded every four weeks until October 2008. Except for the six-week period prior to the administration of the COWP, the goats were examined according to the FAMACHA^© system and symptomatically treated with 12mg/kg levamisole when anaemic. The percentage reduction in faecal egg count due to the COWP treatment was 89.0%. Mean pre- and post-treatment faecal egg counts for the COWP-treated group (n =73) were 2347 eggs per gram of faeces (epg) and 264epg, respectively. The corresponding values for the untreated controls (n =66) were 2652epg and 2709epg. The prevalence of Haemonchus spp. larvae in pre- and post-treatment faecal cultures was 72% and 46%, respectively. Symptomatic anthelmintic treatments in combination with mid-summer tactical treatments with COWP appear to be useful strategies for the control of Haemonchus contortus in indigenous goats in this farming system and this approach could have application in other similar agro-ecological zones.

Cytotoxic T lymphocytes from cattle immunized against Theileria parva exhibit pronounced cross-reactivity among different strain-specific epitopes of the Tp1 antigen

2013-05-18T10:07:33Z

Publication date: 15 February 2012
Source:Veterinary Immunology and Immunopathology, Volume 145, Issues 3–4

Author(s): L. Steinaa , R. Saya , E. Awino , P. Toye

The protozoan parasite Theileria parva causes a usually fatal disease in cattle, known as East Coast fever. Cattle can be vaccinated by injecting live parasites simultaneously with long acting oxytetracycline (the infection and treatment method, ITM). The immunity induced by ITM is believed to be mediated by cytotoxic T lymphocytes (CTL). Although effective, the ITM vaccine has disadvantages such as the need for a liquid nitrogen cold chain and a complex production process, which may be overcome by the development of a subunit vaccine. However, the high level of antigenic polymorphism among different strains of T. parva may hinder the development of a subunit vaccine aimed at induction of a protective CTL response.

In this study, the CTL cross-reactivity among T. parva strains was examined. The Tp1214–224 epitope has previously been shown to be recognized by cattle of the A18 BoLA type. Three different variants of this epitope have been identified from different T. parva strains. Here, bulk CTL and CTL clones were generated from two animals using both the live sporozoite vaccine composed of three different strains and a Muguga strain for immunization. The cross-reactivity of these CTL with the three variant Tp1 epitopes was examined in interferon gamma ELISPOT assays and CTL killing assays.

CD8⁺ cells from both animals cross-reacted with the three variant CTL epitopes in interferon gamma ELISPOT assays, although the CD8⁺ cells from the Muguga-immunized animal showed a more epitope restricted response. Clones from the vaccine immunized animal showed diverse response patterns with clones responding to each variant peptide. Although some variability in the cytotoxic response was observed, overall strong cross-reactivity among the variant Tp1 epitopes was seen in both animals. Such epitope polymorphism does not, in this case, serve as a potential challenge in a putative subunit vaccine as it would be sufficient to only include one of the variant epitopes.