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Abstract Background The Gobra zebu and N'dama taurine cattle breeds are important genetic animal resources for Senegal. For several decades, genetic breeding programmes have been devoted to them at the Centre de Recherches Zootechniques de Dahra and Kolda. Since then, these animals have been subjected to mass selection, mainly in closed selection nuclei. Objective This study aims to assess the genetic diversity within these selection nuclei in order to orient future selection strategies. Material and methods The study was carried out on the Gobra zebu and N'dama taurine populations from selection nuclei of Dahra and Kolda respectively, which were compared to 5 other populations of the main cattle breeds in Senegal. One hundred eighty (180) animals were genotyped with 21 microsatellite markers recommended by the Food and Agriculture Organisation. Results All populations were found to be polymorphic with a PIC of over 55%. However, animals from the CRZ‐Dahra (indigenous) and CRZ‐Kolda stations had the lowest mean heterozygosity (0.643 and 0.591 respectively). The other populations had an average heterozygosity between 0.650 and 0.737. Conclusion The cattle populations maintained at the different CRZs show a lower genetic diversity than the other populations described in our study. The main reasons for this are reproductive isolation and selection pressure on these populations.

In order to investigate the trypanotolerant indices in cattle breeds, haematological parameters were determine in 12 N'Dama (ND), 13 Muturu (MUT), 11 White Fulani Cross (WFX) and 14 White Fulani cattle (WF). The packed cell volume (PCV), haemoglobin (Hb) and red blood cell (RBC) values of all the breeds of cattle were within the normal reference interval. MUT had significantly higher PCV, Hb and RBC values than the WFX. No significant difference (p>0.05) in the PCV, Hb and RBC was observed among the other breeds. No significant difference (p>0.05) in mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) was observed in all the breeds of cattle. However, ND had significantly higher (p<0.05) mean corpuscular haemoglobin concentration (MCHC) compared to MUT, WFX and WF. The trypanotolerant cattle (ND and MUT) had significantly higher (p<0.05) Hb and MCHC than the more trypanosusceptible cattle (WFX and WF). There was no significant difference (p>0.05) in the white blood cell (WBC) count among the breeds of cattle. However, WF cattle had significantly lower (p<0.05) lymphocyte count than WFX, MUT and ND. ND cattle had significantly higher (p<0.05) eosinophil count than WF, MUT and WFX. The results suggest that MCHC, lymphocytes and eosinophils are considered as possible trypanotolerant indices in the trypanotolerant breeds of cattle. [ABSTRACT FROM AUTHOR]

Blood proteins play a significant role in immunity. In order to assess the role of blood proteins in trypanotolerance, blood samples were collected from fifty cattle of four different breeds (12 N'Dama (ND), 13 Muturu (MUT), 11White Fulani Cross (WFX) and 14 White Fulani (WF)) that were reared predominantly under the extensive system of management. Blood samples were analyzed for the levels of plasma proteins, fibrinogen and serum proteins (ie total protein, albumin, globulin and albumin-to-globulin ratio (A:G)). Plasma protein and fibrinogen were significantly (p<0.001) higher in the trypanotolerant cattle (ND and MUT) than the susceptible (WFX and WF) (8.01±0.45 g/dL, 7.03±0.78 g/dL and 275.0±44.4 mg/dL, 170.8±85.9 mg/dL, respectively). However, no significant difference was observed in the albumin levels among the breeds of cattle. N'Dama (4.18±0.39 g/dL) had significantly (p<0.001) higher globulin level than White Fulani (3.94±0.31 g/dL). No significant difference was observed in the serum total protein, albumin, globulin and A/G ratio between the trypanotolerant and trypanosusceptible cattle. Conclusively, plasma protein, globulin and fibrinogen are seen to play a vital role in trypanotolerance. [ABSTRACT FROM AUTHOR]

Background: The Gobra zebu and N'dama taurine cattle breeds are important genetic animal resources for Senegal. For several decades, genetic breeding programmes have been devoted to them at the Centre de Recherches Zootechniques de Dahra and Kolda. Since then, these animals have been subjected to mass selection, mainly in closed selection nuclei. Objective: This study aims to assess the genetic diversity within these selection nuclei in order to orient future selection strategies. Material and methods: The study was carried out on the Gobra zebu and N'dama taurine populations from selection nuclei of Dahra and Kolda respectively, which were compared to 5 other populations of the main cattle breeds in Senegal. One hundred eighty (180) animals were genotyped with 21 microsatellite markers recommended by the Food and Agriculture Organisation. Results: All populations were found to be polymorphic with a PIC of over 55%. However, animals from the CRZ‐Dahra (indigenous) and CRZ‐Kolda stations had the lowest mean heterozygosity (0.643 and 0.591 respectively). The other populations had an average heterozygosity between 0.650 and 0.737. Conclusion: The cattle populations maintained at the different CRZs show a lower genetic diversity than the other populations described in our study. The main reasons for this are reproductive isolation and selection pressure on these populations. [ABSTRACT FROM AUTHOR]

Simple Summary: Climate change is increasing the risk of spreading vector-borne diseases such as African Animal Trypanosomiasis (AAT), which is causing major economic losses, especially in sub-Saharan African countries. Mainly considering this disease, we have investigated transcriptomic and genomic data from two cattle breeds, namely Boran and N'Dama, where the former is known for its susceptibility and the latter one for its tolerance to the AAT. Despite the rich literature on this disease, there is still a need to investigate underlying genetic mechanisms to decipher the complex interplay of regulatory SNPs (rSNPs), their corresponding gene expression profiles and the downstream effectors associated with the AAT disease. The findings of this study complement our previous results, which mainly involve the upstream events, including transcription factors (TFs) and their co-operations as well as master regulators. Moreover, our investigation of significant rSNPs and effectors found in the liver, spleen and lymph node tissues of both cattle breeds could enhance the understanding of distinct mechanisms leading to either resistance or susceptibility of cattle breeds. African Animal Trypanosomiasis (AAT) is a neglected tropical disease and spreads by the vector tsetse fly, which carries the infectious Trypanosoma sp. in their saliva. Particularly, this parasitic disease affects the health of livestock, thereby imposing economic constraints on farmers, costing billions of dollars every year, especially in sub-Saharan African countries. Mainly considering the AAT disease as a multistage progression process, we previously performed upstream analysis to identify transcription factors (TFs), their co-operations, over-represented pathways and master regulators. However, downstream analysis, including effectors, corresponding gene expression profiles and their association with the regulatory SNPs (rSNPs), has not yet been established. Therefore, in this study, we aim to investigate the complex interplay of rSNPs, corresponding gene expression and downstream effectors with regard to the AAT disease progression based on two cattle breeds: trypanosusceptible Boran and trypanotolerant N'Dama. Our findings provide mechanistic insights into the effectors involved in the regulation of several signal transduction pathways, thereby differentiating the molecular mechanism with regard to the immune responses of the cattle breeds. The effectors and their associated genes (especially MAPKAPK5, CSK, DOK2, RAC1 and DNMT1) could be promising drug candidates as they orchestrate various downstream regulatory cascades in both cattle breeds. [ABSTRACT FROM AUTHOR]

L’étude a été menée à l’ouest de la Côte d’Ivoire dans le district des Montagnes sur 120 vaches et 96 veaux mâles et femelles de races N’Dama et croisées (Montbéliarde x N’Dama) pendant 36 mois afin de déterminer leurs performances de reproduction et de croissance. Les résultats ont révélé que le taux de gravidité et la durée de lactation des vaches croisées (demi-sang Montbéliardes) étaient plus élevés que ceux des N’Dama. De même, l’intervalle entre vêlages des vaches croisées (428 ± 16,6 jours) a été inférieur à celui des N’Dama (452 ± 12,8 jours). Le poids à la naissance des veaux croisés (23 à 25 kg) a été supérieur à celui des N’Dama (17 à 19 kg). Le gain moyen quotidien sur toute la période a été de 356,8 ± 47,7 g pour les mâles et de 324,8 ± 47,1 g pour les femelles chez les croisés, contre respectivement 291,7 ± 57,6 g et 266,6 ± 49,1 g chez les N’Dama. Enfin, le poids adulte a été de 370 ± 1,7 kg pour les mâles et 300 ± 2,3 kg pour les femelles chez les croisés, contre respectivement 235 ± 1,6 kg et 230 ± 2,1 kg chez les N’Dama. Les performances de reproduction et de croissance des croisés ont été significativement plus élevées (p < 0,05) que celles des N’Dama.

Many breeding programs have been implemented in developing countries, many of which have been unsuccessful. To better understand the failure of these breeding programs, it is proposed to analyze their adequacy with innovations that are actually adopted by smallholders. The proposed methodology takes account of these innovations, the reasons for their adoption and the objectives of livestock keeping. The N’Dama cattle-breeding program in Senegal was used as a case study. Surveys were carried out among 54 farmers: 27 breeders who participated in this program, 17 of whom recently resigned, and 27 breeders who have never participated. Feeding was the most frequently cited area of innovation, followed by infrastructure. Genetics, animal health and reproduction held the third rank. Milk production appeared as an important objective of breeders, although the context remains one of strong multifunctionality. Principal component analysis highlighted three categories of breeders according to the innovations they adopted: institutional, modernizing, and integrating innovators. The groups of institutional and modernizing innovators dominate, gathering each 41% of the farmers. In the first category, breeders have organized themselves in an association and use N’Dama sires, livestock aiming at an insurance objective. In the second category, artificial insemination with exotic breeds and other technical innovations (cowshed, vaccination, urea treatment of straw) are used to improve production of milk and meat. The third group is termed ‘integrating innovators,’ since their innovations aim at integrating livestock and crop production. Gathering 18% of the sampled breeders, this group presents intermediate features between the two previous groups, using animals as draught power and for manure production. These results indicate that a process of intensification is at play and that the genetic improvement through the selection of N’Dama cattle for production criteria does not meet the breeders’ demand. However, the N’Dama’s adaptive traits justify its use as part of the breeding strategy of farmers, either in pure-breeding or in crossbreeding. The study thus tends to show the interactive link between genetic improvement and other innovations. It suggests that the success of a breeding program depends on its adequate positioning within the set of innovations adopted by breeders and proposes a method to inform breeding programs accordingly.

African Animal Trypanosomiasis (AAT) is a neglected tropical disease and spreads by the vector tsetse fly, which carries the infectious Trypanosoma sp. in their saliva. Particularly, this parasitic disease affects the health of livestock, thereby imposing economic constraints on farmers, costing billions of dollars every year, especially in sub-Saharan African countries. Mainly considering the AAT disease as a multistage progression process, we previously performed upstream analysis to identify transcription factors (TFs), their co-operations, over-represented pathways and master regulators. However, downstream analysis, including effectors, corresponding gene expression profiles and their association with the regulatory SNPs (rSNPs), has not yet been established. Therefore, in this study, we aim to investigate the complex interplay of rSNPs, corresponding gene expression and downstream effectors with regard to the AAT disease progression based on two cattle breeds: trypanosusceptible Boran and trypanotolerant N’Dama. Our findings provide mechanistic insights into the effectors involved in the regulation of several signal transduction pathways, thereby differentiating the molecular mechanism with regard to the immune responses of the cattle breeds. The effectors and their associated genes (especially MAPKAPK5, CSK, DOK2, RAC1 and DNMT1) could be promising drug candidates as they orchestrate various downstream regulatory cascades in both cattle breeds.

Many local livestock breeds in developing countries are being replaced by exotic breeds, leading to a loss of genetic resources. In southern Mali, for the past two decades, a trend towards increasing crossbreeding between the trypanotolerant N’Dama cattle and the trypano-susceptible Fulani Zebu cattle has been taking place. A survey with 160 farmers owning a cattle herd was carried out in southern Mali to investigate their production objectives, as well as trait and breed preferences and correlated socio-economic determinants in order to understand farmers’ breeding decisions and to identify comparative advantages of three breed groups (N’Dama, Fulani Zebu and crossbreds) raised in the study area. Data were analyzed using an exploded logit model. The reasons for raising cattle, as well as trait and breed preferences reflected the multiple objectives of the farmers. Draught power and savings were the most important production objectives. Productive traits were ranked highest; farmers reported large body size as the most preferred trait, followed by fertility, draught ability and milk yield. Crossbreds were the favored breed group. Breed preferences were mainly explained by ‘resistance to disease’ for N’Dama cattle and ‘high market price’ for Fulani Zebu and crossbred cattle. Production objectives, trait and breed preferences were mainly influenced by farmer group (local farmers and settled transhumants). Local farmers put comparatively more emphasis on livestock functions linked to crop production such as draught power. They had a higher preference for traction ability as a selection trait and preferred N’Dama over Fulani Zebu cattle. Settled transhumants emphasized milk yield as a selection trait and preferred Fulani Zebu over N’Dama. The results indicate that the trend towards more crossbreeding will continue putting the N’Dama breed under high risk of genetic dilution in southern Mali. The N’Dama cattle remain a valuable breed due to their adaptive traits such as disease and drought tolerance and their good traction ability, fulfilling the diverse objectives of local farmers. Crossbreeding was found to be a promising breeding strategy, which might contribute to the maintenance of the local breed, provided that breeding schemes are thoroughly planned and organized.

Many breeding programs have been implemented in developing countries, many of which have been unsuccessful. To better understand the failure of these breeding programs, it is proposed to analyze their adequacy with innovations that are actually adopted by smallholders. The proposed methodology takes account of these innovations, the reasons for their adoption and the objectives of livestock keeping. The N'Dama cattle-breeding program in Senegal was used as a case study. Surveys were carried out among 54 farmers: 27 breeders who participated in this program, 17 of whom recently resigned, and 27 breeders who have never participated. Feeding was the most frequently cited area of innovation, followed by infrastructure. Genetics, animal health and reproduction held the third rank. Milk production appeared as an important objective of breeders, although the context remains one of strong multifunctionality. Principal component analysis highlighted three categories of breeders according to the innovations they adopted: institutional, modernizing, and integrating innovators. The groups of institutional and modernizing innovators dominate, gathering each 41% of the farmers. In the first category, breeders have organized themselves in an association and use N'Dama sires, livestock aiming at an insurance objective. In the second category, artificial insemination with exotic breeds and other technical innovations (cowshed, vaccination, urea treatment of straw) are used to improve production of milk and meat. The third group is termed 'integrating innovators,' since their innovations aim at integrating livestock and crop production. Gathering 18% of the sampled breeders, this group presents intermediate features between the two previous groups, using animals as draught power and for manure production. These results indicate that a process of intensification is at play and that the genetic improvement through the selection of N'Dama cattle for production criteria does not meet the breeders' demand. However, the N'Dama's adaptive traits justify its use as part of the breeding strategy of farmers, either in pure-breeding or in crossbreeding. The study thus tends to show the interactive link between genetic improvement and other innovations. It suggests that the success of a breeding program depends on its adequate positioning within the set of innovations adopted by breeders and proposes a method to inform breeding programs accordingly. [ABSTRACT FROM AUTHOR]

Background: Animal trypanosomosis is a major cause of economic loss in livestock production in Africa. A suggested control measure is to use breeds with traits of trypanotolerance. The study examines the effect of natural Trypanosoma vivax challenge on haematological parameters in two trypanotolerant cattle [N’Dama and West African Shorthorn (WASH)] herds. Methods: Trypanosoma vivax-specific primers were used to diagnose T. vivax infection in an N’Dama herd at Cape Coast in southern Ghana and a WASH herd at Chegbani in northern Ghana from May to July 2011 in a cross-sectional study. Levels of haematological parameters comprising packed cell volume (PCV), haemoglobin (Hb) concentration and red blood cell (RBC) and total white blood cell (TWBC) counts; differential WBC counts (neutrophils, lymphocytes, eosinophils, monocytes and basophils); and RBC indices of mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were determined in blood samples and then compared between infected and uninfected cattle. Results: We found that haematological indices for infected and uninfected animals in both breeds were within the normal range. However, the mean PCV values for T. vivax-infected WASH and N’Dama were lower in infected compared to uninfected animals. The difference was significant ( p< 0.05) in N’Dama but not in WASH. Conclusion: Despite the presence of infection by T. vivax, N’Dama and WASH cattle maintained their haematological parameters within acceptable normal ranges, which confirms their trypanotolerant trait. This highlights the need for low-input traditional African farmers in medium, high and severe tsetse challenge areas to be educated on the advantages of N’Dama and WASH breeds to increase their utilization in integrated tsetse and trypanosomosis control programmes.

Background: Animal trypanosomosis is a major cause of economic loss in livestock production in Africa. A suggested control measure is to use breeds with traits of trypanotolerance. The study examines the effect of natural Trypanosoma vivax challenge on haematological parameters in two trypanotolerant cattle [N’Dama and West African Short Horn (WASH)] herds. Methods: T. vivax-specific primers were used to diagnose T. vivax infection in an N’Dama herd at Cape Coast in southern Ghana and a WASH herd at Chegbani in northern Ghana from May to July 2011 in a cross-sectional study. Levels of haematological parameters comprising packed cell volume (PCV), haemoglobin (Hb) concentration and total red blood cell (RBC) and white blood cell (WBC) counts; differential WBC counts (neutrophils, lymphocytes, eosinophils, monocytes and basophils); and RBC indices of mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were determined in blood samples and then compared between infected and uninfected cattle. Results: We found that haematological indices for infected and uninfected animals in both breeds were within the normal range. However, the mean PCV values for T. vivax-infected WASH and N’Dama were lower in infected compared to uninfected animals. The difference was significant ( p< 0.05) in N’Dama but not in WASH. The RBC indices were higher in infected N’Dama compared to infected WASH with a significant difference in total RBC ( p < 0.05). Conclusion: We conclude from our findings that despite the presence of infection by T. vivax, N’Dama and WASH cattle maintained their haematological parameters within acceptable normal ranges, and this underscores the need for routine diagnosis and treatment so that such trypanotolerant cattle do not serve as potential reservoirs of trypanosome parasites.

African Animal Trypanosomiasis (AAT) is a disease caused by pathogenic trypanosomes which affects millions of livestock every year causing huge economic losses in agricultural production especially in sub-Saharan Africa. The disease is spread by the tsetse fly which carries the parasite in its saliva. During the disease progression, the cattle are prominently subjected to anaemia, weight loss, intermittent fever, chills, neuronal degeneration, congestive heart failure, and finally death. According to their different genetic programs governing the level of tolerance to AAT, cattle breeds are classified as either resistant or susceptible. In this study, we focus on the cattle breeds N’Dama and Boran which are known to be resistant and susceptible to trypanosomiasis, respectively. Despite the rich literature on both breeds, the gene regulatory mechanisms of the underlying biological processes for their resistance and susceptibility have not been extensively studied. To address the limited knowledge about the tissue-specific transcription factor (TF) cooperations associated with trypanosomiasis, we investigated gene expression data from these cattle breeds computationally. Consequently, we identified significant cooperative TF pairs (especially D B P − P P A R A and D B P − T H A P 1 in N’Dama and D B P − P A X 8 in Boran liver tissue) which could help understand the underlying AAT tolerance/susceptibility mechanism in both cattle breeds.

Cattle husbandry plays an important role in the livelihoods of many households in southern Mali where the endemic N’Dama and Fulani Zebu breeds and their crosses are raised by farmers. This study examines food security, its determinants and the coping strategies used among 258 households in southern Mali, with particular emphasis on the contributions of cattle keeping and different breed groups, i.e. N’Dama, Zebu, crossbreds and mixed herds, to food security. The main aim was to investigate whether the replacement of the endemic N’Dama breed threatens or improves household food security. A linear mixed model was used to analyze the effects of household characteristics on food security using the household dietary diversity score (HDDS), food consumption score (FCS), and a modified household food insecurity access scale (mHFIAS) as indicators. Results revealed that cattle ownership and breed group were important determinants of all household food security indicators. Households keeping Zebu and mixed herds had the highest FCS. HDDS and FCS were positively correlated with crop diversity and household wealth, while negatively correlated with cotton cultivation. During the period of food shortage, households raising Zebu were better off and had significantly lower mHFIAS than those keeping N’Dama, crossbreds or mixed herds. In times of food shortage, selling livestock was the main coping strategy for households with a cattle herd, while households without cattle relied mostly on borrowing cash. In conclusion, the ongoing displacement of native N’Dama cattle by Zebu cattle and their crosses is contributing to improved household food security in Mali. [ABSTRACT FROM AUTHOR]

In recent decades, there has been a rapid shift in livestock breeds used in developing countries, leading to a loss of local genetic resources. The introduction of high-performing livestock breeds might, however, offer opportunities to improve the income of poor livestock keepers. In southern Mali, where cattle play an important role in farmers’ livelihoods, the endemic trypanotolerant N’Dama cattle breed is increasingly being crossbred with the improved Fulani Zebu breed. Thus, the N’Dama cattle face serious threats of genetic erosion, despite their adaptive attributes. This study aims to evaluate and compare the productive and economic performance of endemic N’Dama, Fulani Zebu and their crossbreds in southern Mali in order to assess the comparative advantages of these breed groups for farmers. Data collection methods comprised of interviews with 34, 31, 34 and 61 households keeping N’Dama, crossbreds, Fulani Zebu and mixed herds respectively, and a cow progeny history and body condition scoring (BCS) (n = 770). Data were analyzed using linear mixed models and a non-parametric test. Results on cow individual performances showed a higher body condition for N’Dama compared to Fulani Zebu and crossbred cattle, while cow milk offtake was higher for Fulani Zebu herds. Calving and offtake rates were higher for the Fulani Zebu and crossbred herds. The gross margin/cattle and the benefit-cost ratio were highest in the Fulani Zebu herds, followed by the crossbred herds, whereas the net benefit/cattle, including non-market benefits, such as traction, manure, insurance and home consumption, was similar between the herd categories. The N’Dama cattle remain a valuable breed for subsistence-oriented crop-livestock farmers for whom non-market benefits from cattle play a considerable role. Fulani Zebu and crossbred cattle were the most favorable options for market-oriented local and settled transhumant farmers, given their higher price and increased profitability. [ABSTRACT FROM AUTHOR]

Many local livestock breeds in developing countries are being replaced by exotic breeds, leading to a loss of genetic resources. In southern Mali, for the past two decades, a trend towards increasing crossbreeding between the trypanotolerant N’Dama cattle and the trypano-susceptible Fulani Zebu cattle has been taking place. A survey with 160 farmers owning a cattle herd was carried out in southern Mali to investigate their production objectives, as well as trait and breed preferences and correlated socio-economic determinants in order to understand farmers’ breeding decisions and to identify comparative advantages of three breed groups (N’Dama, Fulani Zebu and crossbreds) raised in the study area. Data were analyzed using an exploded logit model. The reasons for raising cattle, as well as trait and breed preferences reflected the multiple objectives of the farmers. Draught power and savings were the most important production objectives. Productive traits were ranked highest; farmers reported large body size as the most preferred trait, followed by fertility, draught ability and milk yield. Crossbreds were the favored breed group. Breed preferences were mainly explained by ‘resistance to disease’ for N’Dama cattle and ‘high market price’ for Fulani Zebu and crossbred cattle. Production objectives, trait and breed preferences were mainly influenced by farmer group (local farmers and settled transhumants). Local farmers put comparatively more emphasis on livestock functions linked to crop production such as draught power. They had a higher preference for traction ability as a selection trait and preferred N’Dama over Fulani Zebu cattle. Settled transhumants emphasized milk yield as a selection trait and preferred Fulani Zebu over N’Dama. The results indicate that the trend towards more crossbreeding will continue putting the N’Dama breed under high risk of genetic dilution in southern Mali. The N’Dama cattle remain a valuable breed due to their adaptive traits such as disease and drought tolerance and their good traction ability, fulfilling the diverse objectives of local farmers. Crossbreeding was found to be a promising breeding strategy, which might contribute to the maintenance of the local breed, provided that breeding schemes are thoroughly planned and organized. [ABSTRACT FROM PUBLISHER]

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Background: Trypanosomosis, a protozoal disease affecting livestock, transmitted by Glossina (tsetse) flies is a major constraint to agricultural production in Sub-Saharan Africa. It is accepted that utilization of the native trypanotolerance exhibited in some of the African cattle breeds to improve trypanotolerance of more productive but susceptible breeds, will offer a cost effective and sustainable solution to the problem. The success of this approach is based on the premise that quantitative trait loci previously identified under relatively controlled situations confer useful trypanotolerance under natural field situations. As part of a study to authenticate this hypothesis, a population of 192 cattle, consisting of six batches of N'Dama and Kenya-Boran backcross animals [(N'Dama x Kenya-Boran) x Kenya-Boran] born over the period 2002 to 2006 was constructed. Some of the batches also included pure Kenya-Boran cattle, or N'Dama x Kenya- Boran F1 animals. Each batch was exposed as yearlings to natural field trypanosomosis challenge over a period of about one year; the entire challenge period extending from December 2003 to June 2007. Performance of the animals was evaluated by weekly or biweekly measurements of body weight, packed blood cell volume (PCV), parasitemia score, and number of trypanocide treatments. From these basic data, 49 phenotypes were constructed reflecting dynamics of body weight, packed cell volume (PCV) and parasitemia under challenge. Results: Females were distinctly more trypanotolerant than males. F1, backcross and pure Kenya- Boran animals ranked in that order with respect to trypanotolerance. Overall batch effects were highly significant (p<0.001) for most traits, and were generally more significant than the gender or genetic type effects. The superior trypanotolerance of the F1 animals was expressed in all three components of animal defense strategies against pathogens: Avoidance resistance, and tolerance. Conclusions: The results show that trypanotolerance derived from the N'Dama is expressed under field conditions; and that the trait is primarily additive in nature, being expressed in heterozygous condition and in a three-quarters Boran genetic background. The results further, underscore the complexity of the trait in the field manifesting all three host disease-control strategies, and show the importance of gender and local environmental conditions in determining response to challenge. [ABSTRACT FROM AUTHOR]

Rumen fluid collected from three rumen fistulated N'Dama and three crossbred animals fed three different diets at medium supplementation level, was used to compare the plant cell wall degrading community of the two breeds of cattle. In vivo digestibility was also examined and compared using 12 animals (six of each breed) fed the same diets. The microbial community of the rumen was analyzed by 16S rRNA hybridisation, using phylogenetic probes of different levels: a universal probe, domain-specific probes for Bacteria, Eukarya and Archaea, and probes targeting cellulolytic organisms: Chytridiomycetes, Fibrobacter spp., Ruminococcus albus and Ruminococcus flavefaciens. In vivo, organic matter (OM) and neutral detergent fibre (NDF) digestibility were significantly higher in N'Dama compared to crossbred animals when they were fed either baby corn stover and concentrate, or groundnut hay and moringa. In contrast, when the animals were fed groundnut hay and concentrate there was no difference in OM and NDF digestibility between the two breeds. Results of the microbial community analysis showed that RNA concentration of total Bacteria and Archaea was not affected by the breeds of animal, but were significantly affected by diet. The eukaryotic RNA concentration was higher in crossbred animals compared to the N'Dama and was not affected by the diet. Fibrobacter and R. flavefaciens RNA concentrations (μg/mL) were significantly dependent on diet and breed. Ruminococcus albus and Chytridiomycetes RNA concentrations were neither affected by the breed, nor by the diet of the animals. This suggested that the differences between breeds observed in digestibility could be partially explained by the composition of the cell wall degrading community. [ABSTRACT FROM AUTHOR]

Abstract: Forage from three sweet potato cultivars (A = TIS-87/0087; B = TIS-8164; C = TIS-2532.OP.1.13 at 30% daily dry matter intake), dried brewers'' grains (DBG) and cottonseed meal (CSM) each at 2.5 kg were supplemented to Guinea grass (GG) to form four diets: Diet A=GG+TIS-87/0087; Diet B=GG+TIS-8164; Diet C=GG+TIS-2532.OP.1.13, and Diet D=GG+DBG+CSM (as control). Treatments were assigned as 4×4 Latin squares design over 60 days (10-day adaptation and 5-day sampling) using Bunaji and N''Dama cows in early lactation. The 48-h rumen dry matter (DM) degradation ranged (P <0.01) from 407 g kg−1 DM for GG to 791 g kg−1 DM for sweet potato cultivar TIS-87/0087. Bunaji dry matter intake varied (P <0.05) between 7.1 kg day−1 in Diet B and 8.9 kg day−1 in Diet D, but was similar (P >0.05) among diets for the N''Dama cows. The metabolisable energy (ME) intakes were higher for Diet D although, it recorded the least efficiency of ME utilization for milk production. Milk yields were significantly (P <0.01) higher in the Bunaji than the N''Dama cows, which is typical of their true breed differences. Total solids, ash, protein, fat, and sugar contents of the milk were similar among diets for both cow breeds, except Bunaji ash contents that ranged (P <0.05) from 0.77 g 100 g−1 for Diet B to 0.83 g 100 g−1 for Diet D. The results suggest that sweet potato forage could be utilized as whole or partial replacement for DBG and CSM to save cost under smallholder farming systems. [Copyright &y& Elsevier]

In central and sub-Saharan Africa, trypanosomosis is a tsetse fly-transmitted disease, which is considered as the most important impediment to livestock production in the region. However, several indigenous West African taurine breeds ( Bos taurus) present remarkable tolerance to the infection. This genetic capability, named trypanotolerance, results from numerous biological mechanisms most probably under multigenic dependences, among which are control of the trypanosome infection by limitation of parasitemia and control of severe anemia due to the pathogenic effects. Today, some postgenomic biotechnologies, such as transcriptome analyses, allow characterization of the full expressed genes involved in the majority of animal diseases under genetic control. One of them is serial analysis of gene expression (SAGE) technology, which consists of the construction of mRNA transcript libraries for qualitative and quantitative analysis of the entire genes expressed or inactivated at a particular step of cellular activation. We developed four different mRNA transcript libraries from white blood cells on a N'Dama trypanotolerant animal during an experimental Trypanosoma congolense ( T. congolense) infection: one before experimental infection (ND0), one at the parasitemia peak (NDm), one at the minimal packed cell volume (NDa), and the last one at the end of the experiment after normalization (NDf). Bioinformatic comparisons in bovine genomic databases allowed us to obtain more than 75,000 sequences, among which are several known genes, some others are already described as expressed sequence tags (ESTs), and the last are completely new, but probably functional in trypanotolerance. The knowledge of all identified named or unnamed genes involved in trypanotolerance characteristics will allow us to use them in a field marker-assisted selections strategy and in microarrays prediction sets for bovine trypanotolerance. [ABSTRACT FROM AUTHOR]

Abstract In Africa, trypanosomosis is a tsetse-transmitted disease which represents the most important constraint to livestock production. Several indigenous West African taurine (Bos taurus) breeds, such as the Longhorn (N'Dama) cattle are well known to control trypanosome infections. This genetic ability named "trypanotolerance" results from various biological mechanisms under multigenic control. The methodologies used so far have not succeeded in identifying the complete pool of genes involved in trypanotolerance. New post genomic biotechnologies such as transcriptome analyses are efficient in characterising the pool of genes involved in the expression of specific biological functions. We used the serial analysis of gene expression (SAGE) technique to construct, from Peripheral Blood Mononuclear Cells of an N'Dama cow, 2 total mRNA transcript libraries, at day 0 of a Trypanosoma congolense experimental infection and at day 10 post-infection, corresponding to the peak of parasitaemia. Bioinformatic comparisons in the bovine genomic databases allowed the identification of 187 up- and down- regulated genes, EST and unknown functional genes. Identification of the genes involved in trypanotolerance will allow to set up specific microarray sets for further metabolic and pharmacological studies and to design field marker-assisted selection by introgression programmes.

Some West African Bos taurus cattle breeds such as the N’Dama and a number of West African Shorthorns are resistant to tsetse fly-transmitted trypanosomosis. The trait is termed trypanotolerance, for which changes in packed red cell volume percent (PCV) and growth rate following infection are generally considered to be indicators. An F22 population was created with the N’Dama and the Kenyan Boran (a trypanosusceptible breed). Two hundred and fourteen F2N’Dama×Boran cattle were infected by the bites of tsetse flies infected with the cloned parasite Trypanosoma congolense IL1180. Body weight, PCV, and parasite counts were recorded on a weekly basis for 150 days post infection. Seventeen derived traits were defined based on the data recorded; seven derived from bodyweight, seven from PCV, two from parasite counts recordings and survival. Average values among the F2 animals were intermediate between those of N’Dama and Boran control animals for all traits. The highest and lowest responders in the F2 group, when selected on maximum decrease in PCV or on maximum decrease in body weight, were equal to the averages of the Boran and N’Dama animals, respectively. The most trypanotolerant F2 animals followed similar courses to N’Dama controls and the most susceptible animals followed similar courses to the Borans. There were moderate to low phenotypic correlations (0.00–0.32) between average log(parasite count) or number of times an animal was detected parasitaemic, and the PCV and body weight derived traits. There were low to moderate phenotypic correlations (0.02–0.74) between and within (0.01–0.96) PCV and body weight derived traits. Most of the traits defined in this study were heritable. Heritabilities ranged from 0.01 for PCV recovery, to 0.88, for initial PCV. Some F2 animals seemed to be able to control anaemia and have a higher average body weight and body weight gain than the pure-bred N’Dama. Overall, in this study body weight change following infection seems an appropriate and easy to measure indicator of trypanotolerance. [Copyright &y& Elsevier]

In a 90-day study, the feed conversion efficiency of three cattle genotypes was tested on non-conventional feed resources with a view of widening the feed resource base for peri-urban dairy production in The Gambia. Eighteen growing bulls in three breed groups comprising of six bulls each with a mean starting weight of 157±14 kg; 230±31 kg and 194±26 kg kg for N’Dama (ND), N’Dama×Holstein–Freisian (NHF) and N’Dama×Jersey (NJ), respectively, were used in the study. Experimental diet was a composite ration based on horticultural residues consisting of 667 g/kg baby corn stalk and 333 g/kg bean vines collected from commercial farms of the Greater Banjul Area. Cattle genotype had a significant effect on in vivo dry and organic matter digestibility. NHF had a lower (P<0.01) digestibility coefficient compared with NJ and the pure ND with 559, 602 and 615 g/kg for NHF, NJ and ND bulls, respectively. The voluntary feed intake of the experimental diet ranged between 25 and 27 g/kg L.W. across genotypes resulting in a positive nutrient retention in the experimental animals. Data on live weight showed that the feed allowance was good enough not only to maintain the animals but also allowing for generous average daily gains (ADGs) of 510, 640 and 680 for ND, NJ and NHF, respectively. Although the ND had the least (P<0.05) ADG, it recorded the highest mean body condition score. In conclusion, the horticultural resides proved to be a feed resource of high biological value in terms of feed conversion to animal products if harnessed judiciously especially for the peri-urban dairy sub sector. [Copyright &y& Elsevier]

This study compared the changes in the bone marrow (BM) of five trypanotolerant N'Dama cattle with those of four trypanosusceptible Boran cattle during trypanosome infection. In the early parasitaemic phase, from 12 to 21 days postinfection (DPI), tsetsetransmitted primary Trypanosoma congolense IL 1180 infection induced parasitaemia, slight depression in packed cell volume (PCV), marked leucopenia due to lymphocytopenia and eosinopenia, and thrombocytopenia which were of similar intensity in Boran and N'Dama cattle. However, from 28 DPI until the end of the experiment on 112 DPI, the parasitaemia was higher in the Boran than in the N'Dama. Severe anaemia and leucopenia characterised by lymphopenia, neutropenia, eosinopenia and monocytopenia persisted in Boran cattle. In contrast, the PCV values dropped gradually in N'Dama cattle and from 77 DPI recovered slowly to values just below preinfection levels by 112 DPI. The total and differential leucocyte counts of the N'Dama cattle stabilised at approximately two-thirds of preinfection values between 28 and 112 DPI, and were double those of the Boran. Marked thrombocytopenia occurred in both breeds. The anaemia was initially macrocytic hypochromic but terminally became microcytic hypochromic in both breeds. Light and electron microscopic studies of sequential biopsies of the BM of these animals showed that the BM response was the key to these differences between the N'Dama and Boran. The biopsies of the BM of the N'Dama cattle were hypercellular (scored 4.5±1.0 compared to 4.0 for controls) with mild hyperplasia of erythroid cells and mild hypoplasia of myeloid cells from 28 to 112 DPI, endowing the animals with higher haemopoietic potential that enabled them to replace most lost cells. In contrast, the Boran cattle had hypocellular (scored 2.4±1.1) BM biopsies with relative erythroid hyperplasia and myeloid hypoplasia, resulting in low capacity of cell replacement manifested as severe unremitting anaemia and leucopenia. The BM of both breeds showed moderate hyperplasia of cells of the mononuclear phagocyte system. Therefore, this study showed, for the first time, that BM response is a key determinant factor of trypanotolerance as it determines the animal's capability for blood cell regeneration. [ABSTRACT FROM AUTHOR]

The effect of a single anthelmintic treatment of cattle during the early dry season was studied. One hundred and sixty-six N'Dama cattle, 1-3 years old, were selected from five herds. There were 65 males and 101 females divided into two groups of 83 animals each. One group was treated with fenbendazole at 7.5 mg/kg body weight by mouth in November 1992; the other group remained as the untreated control. At monthly intervals from November 1992 to April 1993, each animal was weighed and the number of eggs/g of faeces (epg) was determined. The infective larvae (L3) were examined following culture of pooled samples from each group of animals. In April 1993, 6 animals (3 treated and 3 controls) from the herds under study were necropsied. The difference in the weight gains (4.6 kg) of the two groups was highly significant ( p<0.0001). The difference in the weight gains and the epg between the treated and control groups was influenced by the age of the animals. Of the treated animals, one contained no nematodes, one contained only 25 Oesophagostomum radiatum, and the third contained 25 Cooperia L4. The three untreated animals were all infected. It was concluded that the treatment in early dry season, with an anthelmintic effective against both adults and larvae, led to a significant reduction in egg counts, to elimination of adults and hypobiotic larvae and, consequently, to an increase in the body weight gain by the treated animals. [ABSTRACT FROM AUTHOR]

African Animal Trypanosomiasis (AAT) is a disease caused by pathogenic trypanosomes which affects millions of livestock every year causing huge economic losses in agricultural production especially in sub-Saharan Africa. The disease is spread by the tsetse fly which carries the parasite in its saliva. During the disease progression, the cattle are prominently subjected to anaemia, weight loss, intermittent fever, chills, neuronal degeneration, congestive heart failure, and finally death. According to their different genetic programs governing the level of tolerance to AAT, cattle breeds are classified as either resistant or susceptible. In this study, we focus on the cattle breeds N'Dama and Boran which are known to be resistant and susceptible to trypanosomiasis, respectively. Despite the rich literature on both breeds, the gene regulatory mechanisms of the underlying biological processes for their resistance and susceptibility have not been extensively studied. To address the limited knowledge about the tissue-specific transcription factor (TF) cooperations associated with trypanosomiasis, we investigated gene expression data from these cattle breeds computationally. Consequently, we identified significant cooperative TF pairs (especially D B P − P P A R A and D B P − T H A P 1 in N'Dama and D B P − P A X 8 in Boran liver tissue) which could help understand the underlying AAT tolerance/susceptibility mechanism in both cattle breeds. [ABSTRACT FROM AUTHOR]

Immune response to infections has been shown to be mediated by genetic diversity in pattern recognition receptors, leading to disease tolerance or susceptibility. We elucidated naturally occurring variations within the bovine CD14 gene promoter in trypanosome-tolerant (N'Dama) and susceptible (White Fulani) cattle, with genomic and computational approaches. Blood samples were collected from White Fulani and N'Dama cattle, genomic DNA extracted and the entire promoter region of the CD14 gene amplified by PCR. We sequenced this region and performed in silico computation to identify SNP variants, transcription factor binding sites, as well as micro RNAs in the region. CD14 promoter sequences were compared with the reference bovine genome from the Ensembl database to identify various SNPs. Furthermore, we validated three selected N'Dama specific SNPs using custom Taqman SNP genotyping assay for genetic diversity. In all, we identified a total of 54 and 41 SNPs at the CD14 promoter for N'Dama and White Fulani respectively, including 13 unique SNPs present in N'Dama only. The significantly higher SNP density at the CD14 gene promoter region in N'Dama may be responsible for disease tolerance, possibly an evolutionary adaptation. Our genotype analysis of the three loci selected for validation show that mutant alleles (A/A, C/C, and A/A) were adaptation profiles within disease tolerant N'Dama. A similar observation was made for our haplotype analysis revealing that haplotypes H1 (ACA) and H2 (ACG) were significant combinations within the population. The SNP effect prediction revealed 101 and 89 new transcription factor binding sites in N'Dama and White Fulani, respectively. We conclude that disease tolerant N'Dama possessing higher SNP density at the CD14 gene promoter and the preponderance of mutant alleles potentially confirms the significance of this promoter in immune response, which is lacking in susceptible White Fulani. We, therefore, recommend further in vitro and in vivo study of this observation in infected animals, as the next step for understanding genetic diversity relating to varying disease phenotypes in both breeds. [ABSTRACT FROM AUTHOR]