Trypanotolerant Breeds Research Articles

Current population size and risk status of the indigenous endangered Sheko cattle breed in south-west Ethiopia

This study assessed the current population size and risk status of the indigenous endangered Sheko cattle breed in four zones of South West Ethiopia. The Sheko cattle breed, known as the last remnants of Africa’s original Bos taurus cattle and the only trypanotolerant breed in Ethiopia, is facing a decline in their effective population size. The estimated population size of Sheko cattle is approximately 7252, with varying levels of genetic purity based on physical observations. The distribution of genetic purity levels of Sheko cattle indicates that there are approximately 4073, 2934, and 1145 individuals at the 1st (>80% pure), 2nd (>60% pure), and 3rd (>40% pure) levels, respectively. The breed is at risk due to factors such as aggressive behavior, interbreeding with zebu breeds, lack of pure Sheko bulls, and lack of awareness creation. To conserve the Sheko cattle breed, measures such as backcrossing to purebreds, genetic monitoring and evaluation, molecular characterization, assessment of genetic admixture and inbreeding, and collaboration among stakeholders are essential. Overall, this research emphasizes the urgent need for coordinated efforts to safeguard the genetic diversity and population size of the Sheko cattle breed.

Management practice of the Sheko cattle breed in Ethiopia: A review

The great diversity of agroecological conditions and production systems present in Ethiopia contributes to the country’s large livestock population and makes it suitable for various forms of livestock production. The Ethiopian livestock sector provides significant economic and social benefits at household levels and to the national economy. Ethiopia has 32 recognized indigenous cattle breeds, of which the Sheko is a known trypano-tolerant breed found in the southwest of the country. However, in recent times, the Sheko population has been declining mainly due to interbreeding with local Zebu cattle and to a shift in the production system. This paper aims to review and illustrate the current status and management practices of the Sheko cattle breed towards conserving and improving the breed, and the production system. The feed resources in the Sheko home area are natural pasture and crop residues, with limited utilization of cultivated improved forage. Husbandry practices such as feeding, watering, housing and veterinary services are priority areas where improvements are needed. Enhancing the conservation and improvement of the breed would greatly benefit from the active improvement of various stakeholders, including governmental policymakers and non-governmental organizations. Therefore giving special attention to enhancing the management systems in the breed’s home area is crucial. This involves the direct engagement of research centres, extension workers; and higher learning institutions in proximity to the area all aimed at the conservation and improvement of the Sheko cattle breed.

Whole blood transcriptome profiles of trypanotolerant and trypanosusceptible cattle highlight a differential modulation of metabolism and immune response during infection by Trypanosoma congolense

Animal African trypanosomosis, caused by blood protozoan parasites transmitted mainly by tsetse flies, represents a major constraint for millions of cattle in sub-Saharan Africa. Exposed cattle include trypanosusceptible indicine breeds, severely affected by the disease, and West African taurine breeds called trypanotolerant owing to their ability to control parasite development, survive and grow in enzootic areas. Until now the genetic basis of trypanotolerance remains unclear. Here, to improve knowledge of the biological processes involved in trypanotolerance versus trypanosusceptibility, we identified bovine genes differentially expressed in five West African cattle breeds during an experimental infection by Trypanosoma congolense and their biological functions. To this end, whole blood genome-wide transcriptome of three trypanotolerant taurine breeds (N’Dama, Lagune and Baoulé), one susceptible zebu (Zebu Fulani) and one African taurine x zebu admixed breed (Borgou) were profiled by RNA sequencing at four time points, one before and three during infection. As expected, infection had a major impact on cattle blood transcriptome regardless of the breed. The functional analysis of differentially expressed genes over time in each breed confirmed an early activation of the innate immune response, followed by an activation of the humoral response and an inhibition of T cell functions at the chronic stage of infection. More importantly, we highlighted overlooked features, such as a strong disturbance in host metabolism and cellular energy production that differentiates trypanotolerant and trypanosusceptible breeds. N’Dama breed showed the earliest regulation of immune response, associated with a strong activation of cellular energy production, also observed in Lagune, and to a lesser extent in Baoulé. Susceptible Zebu Fulani breed differed from other breeds by the strongest modification in lipid metabolism regulation. Overall, this study provides a better understanding of the biological mechanisms at work during infection, especially concerning the interplay between immunity and metabolism that seems differentially regulated depending on the cattle breeds.

Analysis of the Genetic Diversity and Population Structure of Four Senegalese Sheep Breeds Using Medium-Density Single-Nucleotide Polymorphisms.

Simple SummaryThis paper reported genetic parameters of four Senegalese sheep breeds, in relation to inbreeding, diversity and genetic proximity. The results provide informations on genetic conservation and adaptability of the breeds in the Senegalese context.In Senegal, sheep breeds have adapted to their environment and play a key socio-economic role. This study aimed to explore the genetic diversity and structure of four Senegalese sheep breeds (Peul-peul, Djallonke, Touabire, and Ladoum) and their relationships with global sheep breeds. To that end, forty-seven sheep were genotyped using the OvineSNP50 BeadChip, and these genotypic data were analysed with those of 73 sheep breeds representative of worldwide ovine diversity (2729 animals). The average observed heterozygosity (Ho) ranged from 0.293 in Djallonke sheep to 0.339 in Touabire sheep. The estimated Fis values were low, ranging from 0.019 for Ladoum to 0.034 for Peul-peul sheep. The estimated Fst values were low (0.003–0.044) among the trypanosusceptible breeds (Peul-peul, Touabire, and Ladoum) but high between the previous breeds and the trypanotolerant Djallonke breed (0.075–0.116), indicating better genetic conservation of the Djallonke sheep. A principal component analysis revealed clustering of the Senegalese sheep breeds according to their geographic distribution. However, owing to genetic improvement practices, the introgression of Touabire sheep blood seems to have reshaped the genetic landscape of the trypanosusceptible sheep breeds in Senegal. The Senegalese sheep breeds showed lower genetic diversity than their presumed ancestral sheep breeds of the Middle East. They also presented some relatedness with Caribbean sheep breeds, which reveals their contribution to the global genetic diversity and to the development of Caribbean sheep breeds.

Upregulation of sialyltransferases ST3Gal1 and ST6Gal1 promotes stabilization of erythrocyte mass and recovery of anemia in Trypanosoma brucei brucei-infected pigs

The role of Sialyltransferases (STs) specifically subfamilies ST3Gal1 and ST6Gal1 tissue expression was investigated in the liver and kidney of Trypanosoma brucei brucei-infected and uninfected control pigs. The study was aimed to provide emerging target for treatment. Pigs were experimentally infected with 2 × 106 T. b. brucei (Federe strain); parasitemia was monitored by microscopy and tissue expression levels of ST3Gall and ST6Gall in the liver and kidney were assessed using quantitative real-time polymerase chain reaction (qRT-PCR). Parasitemia were undulating and anemia occurred significantly (P < 0.01) on day 13 in the infected pigs with an attempt to recover toward the termination of the study on day 21. The gene expressions for hepatic and renal ST3Gal1 and ST6Gal1 were significantly (P < 0.0001) upregulated 5–42 folds in the infected pig compared to the non-infected control group. It was concluded from the findings in this study that increased tissue expression of ST3Gal1 and ST6Gal1 in T b. brucei-infected pigs may play a pivotal role in the resialylation of desialylated red blood cells, thereby promoting recovery of the red blood cells and stabilization of erythrocyte mass in trypanosome-infected pigs. It is recommended that the expression of serum ST3Gal1 and ST6Gal1 be investigated further, in trypano-susceptible against trypano-tolerant breeds of animals to determine the role of these genes in trypano-tolerance.

Trypanotolerance Sheko cattle: an option for sustainable control of bovine trypanosomiasis

Abstract Trypanosomiasis is an impediment to cattle production and other agricultural development in tsetse-infested areas. It is a severe parasitic disease that causes loss in the production and performance of cattle. Hence, the aim of this paper is to review trypanosomiasis control options with emphasis on the use of trypanotolerant Sheko cattle breed for sustainable management of bovine trypanosomiasis in tsetse infested areas. Several methods have been used to control trypanosomiasis through the use of trypanocidal drugs and the management of the vector, tsetse fly. Tsetse fly controls require expensive insecticides and have adverse environmental consequences. Trypanocidal drugs are commonly used and considered a practical trypanosomiasis control method. However, the rise in trypanocidal drug resistance has rendered this option ineffective. The possibility of developing and using a vaccine against trypanosomiasis currently remains out of reach as Trypanosoma periodically undergo antigenic variation. In the absence of a vaccine, presence of trypanocidal drug resistance, and the lack of sustainable tsetse fly control measures demand the need to use trypanotole-rant cattle breeds. The Sheko breed which is found only in southwestern Ethiopia displays considerable natural resistance to tsetse-transmitted trypanosomiasis. This genetic resource provides sustainable solution for challenges related to trypanosomiasis. These cattle have a low level of parasitemia and are able to maintain a good packed cell volume (PCV) compared to other indigenous breeds. As several trypanosomiasis control methods are ineffective, the use of trypanotolerance cattle like Sheko breed in tsetse-fly-challenged areas was suggested.

Whole genome characterization of autochthonous Bos taurus brachyceros and introduced Bos indicus indicus cattle breeds in Cameroon regarding their adaptive phenotypic traits and pathogen resistance

Background African indigenous taurine cattle display unique adaptive traits shaped by husbandry management, regional climate and exposure to endemic pathogens. They are less productive with respect to milk and meat production which has been associated with amongst others, small size, traditional beliefs, husbandry practices, limited feed resources, disease burden and lack of sustained breeding for trait improvement. This resulted in the severe dwindling of their population size rendering them vulnerable to extinction.The Namchi taurine cattle breed is referred to as [Namchi (Doayo)] and shows resistance traits against trypanosome infection and exposure to tick infestation. Nonetheless, the historically later introduced Zebu cattle are the main cattle breeds in Africa today, even though they suffer more from locally prevailing pathogens.By using a whole genome sequencing approach, we sequenced with high depth for the first time the genomes of five cattle breeds from Cameroon in order to provide a valuable genetic resource for future African cattle breeding: the Namchi, an endangered trypano-tolerant taurine breed, the Kapsiki, an indigenous trypano-susceptible taurine breed, and three Zebu (Bos indicus indicus) breeds: Ngaoundere Gudali, White Fulani and Red Fulani.ResultsApproximately 167 Gigabases of raw sequencing data were generated for each breed and mapped to the cattle reference genomes ARS-UCD1.2 and UMD3.1.The coverage was 103 to 140-fold when aligning the reads to ARS-UCD1.2 with an average mapping rate of ~ 99%, and 22 to 30-fold when aligning the reads to UMD3.1 with an average mapping rate of ~ 64%. The single nucleotide polymorphisms (SNPs) obtained from analysis using the genome ARS-UCD1.2 were compared with reference genomes of European Bos taurus Holstein, the Asian Bos indicus Brahman, and the African trypanotolerant N’Dama breeds.A total of ~ 100 million (M) SNPs were identified and 7.7 M of those were breed-specific. An approximately 11.1 M constituted of small insertions and deletions. By using only breed-specific non-synonymous variants we identified genes as genetic signatures and associated Gene Ontology (GO) terms that could explain certain cattle-breed specific phenotypes such as increased tolerance against trypanosome parasites in the Namchi breed and heat tolerance in the Kapsiki breed. Phylogenetic analysis grouped, except for Namchi, the Bos taurus breeds Kapsiki, N’Dama and Holstein together while the B. indicus breeds White and Red Fulani, Gudali and Brahman clustered separately. The deviating result for Namchi indicates a hybrid status of the selected animal with a recent introgression of Zebu genes into its genome.ConclusionsThe findings provide the first comprehensive set of genome-wide variant data of the most important Cameroonian cattle breeds. The genomic data shall constitute a foundation for breed amelioration whilst exploiting the heritable traits and support conservation efforts for the endangered local cattle breeds.

Productive and physiological characteristics of West African dwarf goats fed cassava root sieviate-cassava leaf meal based diet

Productive and physiological characteristics of West African dwarf goats fed cassava root sieviate-cassava leaf meal based diet

Genomic signatures of adaptive introgression and environmental adaptation in the Sheko cattle of southwest Ethiopia.

Although classified as an African taurine breed, the genomes of Sheko cattle are an admixture of Asian zebu and African taurine ancestries. They populate the humid Bench Maji zone in Sheko and Bench districts in the south-western part of Ethiopia and are considered as a trypanotolerant breed with high potential for dairy production. Here, we investigate the genome of Sheko cattle for candidate signatures of adaptive introgression and positive selection using medium density genome-wide SNP data. Following locus-ancestry deviation analysis, 15 and 72 genome regions show substantial excess and deficiency in Asian zebu ancestry, respectively. Nine and 23 regions show candidate signatures of positive selection following extended haplotype homozygosity (EHH)-based analyses (iHS and Rsb), respectively. The results support natural selection before admixture for one iHS, one Rsb and three zebu ancestry-deficient regions. Genes and/or QTL associated with bovine immunity, fertility, heat tolerance, trypanotolerance and lactation are present within candidate selected regions. The identification of candidate regions under selection in Sheko cattle warrants further investigation of a larger sample size using full genome sequence data to better characterise the underlying haplotypes. The results can then support informative genomic breeding programmes to sustainably enhance livestock productivity in East African trypanosomosis infested areas.

Factors affecting sustainable animal trypanosomosis control in parts of Kaduna State, Nigeria

This study examined the factors affecting sustainable trypanosomiasis control in parts of Kaduna State within the sub-humid savannah ecological zone of Nigeria. Focus group discussions were held with herdsmen and livestock owners (n=85). Questionnaire was administered to participants (n=25) and key-informants (n=5) were interviewed. Most respondents (80%) were Fulani by tribe who could read and write Hausa in Arabic text (ajami). Over 70% were permanent residents practicing transhumant animal husbandry. Animal trypanosomiasis (sammore), liverfluke (chiwon hanta), worm infestations (helminthosis), and foot and mouth disease (chiwon kafa baki) in Hausa and “boru” in Fulfulde were ranked in decreasing order of important livestock diseases mentioned. A trypanocide (in sachet) identified to be Berenil® was administered by livestock farmers themselves. Many livestock owners and some households had lost various numbers of cattle and herds because of animal trypanosomosis. Tsetse flies (kudan tsando) were said to be very common, yet many could not differentiate it from other haematophagous biting flies. During dry season, when forage and water shortage is imminent, there is migration to southern parts of Nigeria. Annual herd movement to rangelands in nearby Bauchi State was due to perceived increased tsetse fly population in wet season. In addition, about 80% of arable land was used for crop cultivation. More awareness and preference for pour-on and aerial spraying were higher than the use of traps, target or screens. Rearing of trypanotolerant breeds and zero grazing was never practiced. A private-public partnership in tsetse and animal trypanosomosis control using commercially available trypanocides and insecticide is feasible and should be effectively explored. Any sustainable control strategy envisaged should recognize the level of awareness of the disease and vectors and willingness of grassroots stakeholders to participate and adapt the control methods. Keywords: Awareness, livestock, indigenous knowledge, socio-economics, trypanosomosis control, tsetse fly

Assessment of animal African trypanosomiasis (AAT) vulnerability in cattle-owning communities of sub-Saharan Africa.

BackgroundAnimal African trypanosomiasis (AAT) is one of the biggest constraints to livestock production and a threat to food security in sub-Saharan Africa. In order to optimise the allocation of resources for AAT control, decision makers need to target geographic areas where control programmes are most likely to be successful and sustainable and select control methods that will maximise the benefits obtained from resources invested.MethodsThe overall approach to classifying cattle-owning communities in terms of AAT vulnerability was based on the selection of key variables collected through field surveys in five sub-Saharan Africa countries followed by a formal Multiple Correspondence Analysis (MCA) to identify factors explaining the variations between areas. To categorise the communities in terms of AAT vulnerability profiles, Hierarchical Cluster Analysis (HCA) was performed.ResultsThree clusters of community vulnerability profiles were identified based on farmers’ beliefs with respect to trypanosomiasis control within the five countries studied. Cluster 1 communities, mainly identified in Cameroon, reported constant AAT burden, had large trypanosensitive (average herd size = 57) communal grazing cattle herds. Livestock (cattle and small ruminants) were reportedly the primary source of income in the majority of these cattle-owning households (87.0 %). Cluster 2 communities identified mainly in Burkina Faso and Zambia, with some Ethiopian communities had moderate herd sizes (average = 16) and some trypanotolerant breeds (31.7 %) practicing communal grazing. In these communities there were some concerns regarding the development of trypanocide resistance. Crops were the primary income source while communities in this cluster incurred some financial losses due to diminished draft power. The third cluster contained mainly Ugandan and Ethiopian communities which were mixed farmers with smaller herd sizes (average = 8). The costs spent diagnosing and treating AAT were moderate here.ConclusionsUnderstanding how cattle-owners are affected by AAT and their efforts to manage the disease is critical to the design of suitable locally-adapted control programmes. It is expected that the results could inform priority setting and the development of tailored recommendations for AAT control strategies.

Importance des infections à transmission vectorielle selon le système de production : trypanosomose bovine et dynamique d’innovation des éleveurs au Sénégal

In Senegal, a project has been undertaken to eradicate a population of tsetse flies (Glossina palpalis gambiensis) from a prime area for intensifying livestock production – the coastal region of Niayes. The project is intended to remove the constraint of trypanosomosis and allow the ecological intensification of cattle production. A cross-sectional analysis of ten case studies was the inductive phase of an assessment to gauge the impact of removing trypanosomosis on livestock production strategies. The methodology used was comprehensive analysis, with participatory epidemiology tools to understand farmers’ rationales. The authors analysed the strategies of three main types of livestock producer (agropastoralists, mixed crop/livestock farmers and intensive dairy farmers). The strategies were in line with the farmers’ goals and their ability to mobilise the socio-technical network. The risk management of trypanosomosis has been incorporated into livestock management practices through the use of trypanotolerant breeds, medical prophylaxis or placing livestock in low-risk areas. Removing the risk of disease would therefore have a major impact on decisions about the composition and strategic direction of herds. This change in the animal health environment would steer livestock production along different routes of intensification in a highly competitive environment. The indicators of innovation capacity revealed by this study will be used to quantitatively monitor various change scenarios, taking livestock producers’ reasoning into account, in order to assess the socio-economic impact of eradicating the tsetse fly population in this area. The methodology presented in the study can be used to understand the impact of controlling other vector-borne infections on the innovation dynamics of livestock producers.

High resolution mapping of trypanosomosis resistance loci Tir 2 and Tir 3 using F12 advanced intercross lines with major locus Tir 1 fixed for the susceptible allele

BackgroundTrypanosomosis is the most economically important disease constraint to livestock productivity in Africa. A number of trypanotolerant cattle breeds are found in West Africa, and identification of the genes conferring trypanotolerance could lead to effective means of genetic selection for trypanotolerance. In this context, high resolution mapping in mouse models are a promising approach to identifying the genes associated with trypanotolerance. In previous studies, using F2 C57BL/6J × A/J and C57BL/6J × BALB/cJ mouse resource populations, trypanotolerance QTL were mapped within a large genomic intervals of 20-40 cM to chromosomes MMU17, 5 and 1, and denoted Tir1, Tir2 and Tir3 respectively. Subsequently, using F6 C57BL/6J × A/J and C57BL/6J × BALB/cJ F6 advanced intercross lines (AIL), Tir1 was fine mapped to a confidence interval (CI) of less than 1 cM, while Tir2 and Tir3, were mapped within 5-12 cM. Tir1 represents the major trypanotolerance QTL.ResultsIn order to improve map resolutions of Tir2 and Tir3, an F12 C57BL/6J × A/J AIL population fixed for the susceptible alleles at Tir1 QTL was generated. An F12 C57BL/6J × A/J AIL population, fixed for the resistant alleles at Tir1 QTL was also generated to provide an additional estimate of the gene effect of Tir1. The AIL populations homozygous for the resistant and susceptible Tir1 alleles and the parental controls were challenged with T. congolense and followed for survival times over 180 days. Mice from the two survival extremes of the F12 AIL population fixed for the susceptible alleles at Tir1 were genotyped with a dense panel of microsatellite markers spanning the Tir2 and Tir3 genomic regions and QTL mapping was performed. Tir2 was fine mapped to less than 1 cM CI while Tir3 was mapped to three intervals named Tir3a, Tir3b and Tir3c with 95% confidence intervals (CI) of 6, 7.2 and 2.2 cM, respectively.ConclusionsThe mapped QTL regions encompass genes that are vital to innate immune response and can be potential candidate genes for the underlying QTL.

Economic assessment of the performance of trypanotolerant cattle breeds in a pastoral production system in Kenya

Cattle are the major source of food security and income for pastoral farmers in sub-Saharan Africa. However, infectious and parasitic diseases remain a major constraint to improved cattle productivity in the region. The use of animal health economics to support decision-making on cost-effective disease control options is increasingly becoming important in the developing world. Trypanotolerant indigenous Orma/zebu cattle in a trypanosomosis-endemic area of Kenya were evaluated for economic performance using gross-margin analysis and partial-farm budgeting. Orma/zebu and Sahiwal/zebu cross-bred cattle were exposed to similar husbandry practices and monitored for growth rate, incidence of common infections (trypanosomosis, anaplasmosis, babesiosis, East Coast Fever and helminthosis) and the cost of treatment assessed. Interview questionnaires were also used to assess the preference rating of the 2 breeds. Results indicated that incidence of infection was trypanosomosis 3%, anaplasmosis 58%, babesiosis 11%, East Coast Fever 22% and helminthosis 28%, with no significant difference between breeds. The Orma/zebu and Sahiwal/zebu breeds had comparable economic benefits, hence a pastoralist in Magadi division is likely to get similar returns from both breeds. This study therefore recommends adoption of not only the Sahiwal/zebu but also the Orma/zebu breed for cattle improvement in trypanosomosis endemic areas and conservation of indigenous genetic resources.

Transcriptional profiling of cattle infected with Trypanosoma congolense highlights gene expression signatures underlying trypanotolerance and trypanosusceptibility.

BackgroundAfrican animal trypanosomiasis (AAT) caused by tsetse fly-transmitted protozoa of the genus Trypanosoma is a major constraint on livestock and agricultural production in Africa and is among the top ten global cattle diseases impacting on the poor. Here we show that a functional genomics approach can be used to identify temporal changes in host peripheral blood mononuclear cell (PBMC) gene expression due to disease progression. We also show that major gene expression differences exist between cattle from trypanotolerant and trypanosusceptible breeds. Using bovine long oligonucleotide microarrays and real time quantitative reverse transcription PCR (qRT-PCR) validation we analysed PBMC gene expression in naïve trypanotolerant and trypanosusceptible cattle experimentally challenged with Trypanosoma congolense across a 34-day infection time course.ResultsTrypanotolerant N'Dama cattle displayed a rapid and distinct transcriptional response to infection, with a ten-fold higher number of genes differentially expressed at day 14 post-infection compared to trypanosusceptible Boran cattle. These analyses identified coordinated temporal gene expression changes for both breeds in response to trypanosome infection. In addition, a panel of genes were identified that showed pronounced differences in gene expression between the two breeds, which may underlie the phenomena of trypanotolerance and trypanosusceptibility. Gene ontology (GO) analysis demonstrate that the products of these genes may contribute to increased mitochondrial mRNA translational efficiency, a more pronounced B cell response, an elevated activation status and a heightened response to stress in trypanotolerant cattle.ConclusionThis study has revealed an extensive and diverse range of cellular processes that are altered temporally in response to trypanosome infection in African cattle. Results indicate that the trypanotolerant N'Dama cattle respond more rapidly and with a greater magnitude to infection compared to the trypanosusceptible Boran cattle. Specifically, a subset of the genes analyzed by real time qRT-PCR, which display significant breed differences, could collectively contribute to the trypanotolerance trait in N'Dama.

Detection of selection signatures within candidate regions underlying trypanotolerance in outbred cattle populations

Breeding indigenous African taurine cattle tolerant to trypanosomosis is a straightforward approach to control costs generated by this disease. A recent study identified quantitative trait loci (QTL) underlying trypanotolerance traits in experimental crosses between tolerant N'Dama and susceptible Boran zebu cattle. As trypanotolerance is thought to result from local adaptation of indigenous cattle breeds, we propose an alternative and complementary approach to study the genetic architecture of this trait, based on the identification of selection signatures within QTL or candidate genes. A panel of 92 microsatellite markers was genotyped on 509 cattle belonging to four West African trypanotolerant taurine breeds and 10 trypanosusceptible European or African cattle breeds. Some of these markers were located within previously identified QTL regions or candidate genes, while others were chosen in regions assumed to be neutral. A detailed analysis of the genetic structure of these different breeds was carried out to confirm a priori grouping of populations based on previous data. Tests based on the comparison of the observed heterozygosities and variances in microsatellite allelic size among trypanotolerant and trypanosusceptible breeds led to the identification of two significantly less variable microsatellite markers. BM4440, one of these two outlier loci, is located within the confidence interval of a previously described QTL underlying a trypanotolerance-related trait. Detection of selection signatures appears to be a straightforward approach for unravelling the molecular determinism of trypanosomosis pathogenesis. We expect that a whole genome approach will help confirm these results and achieve a higher resolving power.

Does breed matter to cattle farmers and buyers?: Evidence from West Africa

World agriculture is based on a small number of animal species and a decreasing number of breeds within each species. Several breeds of West African shorthorn cattle ( Bos taurus brachyceros) are now at high risk of extinction due to interbreeding. The West African shorthorn breeds are particularly important resources because of their superior abilities to resist diseases, particularly trypanosomosis, and be productive under high humidity, heat stress, water restriction and with poor quality feed. An analysis of farmers' breeding practices and breed preferences in a sample area in southwest Nigeria confirmed a strong trend away from trypanotolerant breeds, especially Muturu, and identified the traits farmers find least desirable in these breeds relative to zebu ( Bos indicus) breeds. An analysis of cattle market prices found that buyers have preferences for specific breeds for specific purposes and that though in general price differences due to breed are small, in some cases, buyers pay significantly different prices for certain breeds consistent with their preferences. The best hopes for increased utilization of breeds at risk such as Muturu is likely in other areas of West Africa, for example in southeast Nigeria, where the Muturu is better suited to the farming systems and there is a large market for this breed to provide incentives.

Does Breed Matter to Cattle Farmers and Buyers? Evidence from West Africa

World agriculture is based on a small number of animal species and a decreasing number of breeds within each species. Several breeds of West African shorthorn cattle (Bos taurus brachyceros) are now at high risk of extinction due to interbreeding. The West African shorthorn breeds are particularly important resources because of their superior abilities to resist diseases, particularly trypanosomosis, and be productive under high humidity, heat stress, water restriction and with poor quality feed. An analysis of farmers' breeding practices and breed preferences in a sample area in southwest Nigeria confirmed a strong trend away from trypanotolerant breeds, especially Muturu, and identified the traits farmers find least desirable in these breeds relative to zebu (Bos indicus) breeds. An analysis of cattle market prices found that buyers have preferences for specific breeds for specific purposes and that though in general price differences due to breed are small, in some cases buyers pay significantly different prices for certain breeds consistent with their preferences. The best hopes for increased utilization of breeds at risk such as Muturu is likely in other areas of West Africa, for example in southeast Nigeria, where the Muturu is better suited to the farming systems and there is a large market for this breed to provide incentives.

The Muturu: A rare sacred breed of cattle in Nigeria

SummaryThe Muturu, a trypanotolerant cattle breed is probably one of the least known breed of cattle in West Africa. Little has been published on its distribution, management, morphological characteristics or biological performance.Early reports showed that the Muturu cattle were once widely distributed across the continent from Liberia, across the West African subregion, to Ethiopia. However, due to expansion of the Zebu population and rapid urbanization, the small bodied animal came under pressure and was found surviving in pockets of the savannahs and in the humid forest zones where it had the comparative advantage of trypanotolerance. The survival of the cattle in the humid and forest zones of Nigeria stems from the fact that the animal is still sacred in so many communities and its milk is widely used for medicinal purposes. In some states of Nigeria, the semi-feral Muturu are not tended but hunted when required for sacrifice.From a population size of 0.4 million heads in 1960, Akinwunmi and Ikpi, (1985) reported a decline in the population of the breed to 50–80 thousand in the late 1980s in Nigeria although RIMS (1992), reported a population growth to 115 172 heads. With limited data bank information on their adaptation and productivity, possible identification of genes that confer resistance to or tolerance of environmental stress in these animals will be of global significance.

Geographic distribution and frequency of a taurine Bos taurus and an indicine Bos indicus Y specific allele amongst sub‐Saharan African cattle breeds

We report for the first time, and for the whole of sub-Saharan Africa, the geographical distribution and the frequency of an indicine and a taurine Y specific allele amongst African cattle breeds. A total of 984 males from 69 indigenous African populations from 22 countries were analysed at the microsatellite locus INRA 124. The taurine allele is probably the oldest one on the continent. However, the taurine and the indicine alleles were present in 291 males (30%), and 693 males (70%), respectively. More particularly, 96% of zebu males (n = 470), 50% of taurine males (n = 263), 29% of sanga males (crossbreed Bos taurus x Bos indicus, n = 263) and 95% of zebu x sanga crossbred males (n = 56) had the indicine allele. The Borgou, a breed classified as zebu x taurine cross showed only the zebu allele (n = 12). The indicine allele dominates today in the Abyssinian region, a large part of the Lake Victoria region and the sahelian belt of West Africa. All the sanga males (n = 64) but only one from the Abyssinian region had the indicine allele. The taurine allele is the commonest only among the sanga breeds of the southern African region and the trypanotolerant taurine breeds of West Africa. In West Africa and in the southern Africa regions, zones of introgression were detected with breeds showing both Y chromosome alleles. Our data also reveal a pattern of male zebu introgression in Mozambique and Zimbabwe, probably originating from the Mozambique coast. The sanga cattle from the Lake Victoria region and the Kuri cattle of Lake Chad, cattle populations surrounded by zebu breeds were, surprisingly, completely devoid of the indicine allele. Human migration, phenotypic preferences by the pastoralists, adaptation to specific habitats and to specific diseases are the main factors explaining the present-day distribution of the alleles in sub-Saharan Africa.