Sheep In Africa Research Articles

Estimating net energy requirements of male Djallonke sheep

Context Energy requirements in sheep can vary significantly due to various factors, including age, breed, sex and environmental conditions. Genetic selection and crossbreeding further contribute to this variability. Although guidelines from the US and UK national research councils are commonly used for formulating sheep diets, they may not adequately account for the unique characteristics of sheep in Africa. Aims The study aimed to estimate the net maintenance energy requirement of male Djallonke sheep. This estimation will provide a basis for comparing the energy requirements of Djallonke sheep with national recommendations and recent estimates for other sheep breeds. Methods Sixteen entire male Djallonke sheep were selected and grouped by weight. They were then randomly allocated to four treatment groups in a 4 × 4 Latin square design. The sheep were fed to achieve intake levels ranging from 1 to 1.75 multiples of their maintenance energy requirement. Gas exchange data were collected using the GreenFeed system over a 3-day period at the conclusion of each treatment period. Heat production was calculated using the established Brouwer’s equation. A linear regression equation was developed to relate heat production to metabolisable energy intake scaled by metabolic bodyweight to calculate the net energy for maintenance. Key results The estimated net energy for maintenance for male Djallonke sheep was determined to be 0.354 MJ/kg BW0.75. This estimation indicated that the energy requirements of male Djallonke sheep exceeded the recommendations provided by the US National Research Council and the UK Agricultural and Food Research Council. However, it closely aligned with an updated estimate of 0.358 MJ/kg BW0.75. Conclusions Based on the study’s findings, male Djallonke sheep have higher energy requirements for maintenance than what is commonly recommended by existing guidelines. Therefore, it is advisable to update ration formulation software for male Djallonke sheep to better reflect their actual energy requirements for maintenance. Implications These results have practical implications for the formulation of diets and feeding management practices for male Djallonke sheep. Adhering to updated energy requirement estimates can help improve the efficiency and productivity of sheep production in the context of Djallonke sheep farming.

Dorper sheep in Africa: A review of their use and performance in different environments

Abstract The Dorper breed developed in South Africa is used either as a pure breed or crossbred with existing indigenous breeds by many countries across the African continent to improve sheep production. This article presents documented information on the adoption, use, and performance of Dorper sheep across the continent of Africa and opportunities for their more sustainable production under the changing climatic conditions in Africa. Apart from the well-documented information on the Dorper sheep in South Africa, published information on the performance of the sheep is mainly from Eastern Africa. Most countries initially retained purebred Dorpers in nationally owned institutions for multiplication and crossbreeding trials with different indigenous breeds prior to distributing the crossbreds to diverse livestock keepers. The offspring produced through crossbreeding programs with the Dorper have better growth rates than indigenous breeds in the different countries; however, the performance of Dorper sheep in South Africa has not been achieved in any of the other countries. Genomic studies including Dorper sheep have identified regions of interest for resistance to brucellosis and Mycoplasma ovipneumonia that imply adaptability to challenging environments within Dorper sheep. Unfortunately, limitations in systems for guided breeding and monitoring of sheep productivity in Africa have resulted in haphazard crossbreeding of the Dorper. Targeted efforts are required across the different countries to develop breeding programs for improving locally adapted Dorper sheep populations and their crosses with indigenous breeds. New science and technologies need to be innovatively packaged and used to identify and propagate more productive and resilient Dorper and Dorper-based breed-types for the increasingly challenging tropical African range environments.

The Prevalence and Determinants of Taenia multiceps Infection (Cerebral Coenurosis) in Small Ruminants in Africa: A Systematic Review

Cerebral coenurosis is a fatal parasitic neurological disease affecting the brain and spinal cord of goats and sheep. Despite the large population of sheep and goats in Africa, there is very little awareness about the scale or effects of the disease. A systematic review was conducted to bridge the gap in the current understanding of the epidemiology of Taenia multiceps coenurosis in Africa. A detailed literature search was conducted in EBSCOhost, Google Scholar, Research4life (AGORA), and PubMed for studies in T. multiceps coenurosis in goats and sheep in Africa for the period spanning January 2000 to December 2019. The search identified 574 publications, of which only 11 studies were eligible, highlighting major gaps in reporting of this disease in Africa. Data were extracted and evidence synthesized in relation to prevalence and determinants for T. multiceps coenurosis. The descriptive summary statistics revealed a median (IQR) prevalence of coenurosis of 22.3% (range: 18.3–26.4 percent) for community based and 14.8% (range: 3.8–45.6) for abattoir-based studies. This high prevalence indicates that Taenia multiceps coenurosis is an important disease for small ruminant productivity in Africa. Knowledge of the determinants of prevalence could be used to inform preventive measures, including behaviour change among livestock keepers and those involved in livestock slaughter to break cycles of transmission between small ruminants and dogs.

Safety and Immunogenicity of Rift Valley Fever MP-12 and a Novel arMP-12?NSm21/384 Recombinant Vaccine Candidate in Native Breed of Black Head Sheep (Ovis aries) from Tanzania

Objective: Rift Valley fever (RVF) is a mosquito-borne zoonotic viral disease that affects humans and ruminants in Africa and the Arabian Peninsula. Efforts to develop effective vaccines have had limited success. Therefore, the aim of this study was to evaluate the safety and immunogenicity of RVF MP-12, and arMP-12ΔNSm21/384 vaccine candidates in sheep. Methods: One group of 6 sheep was vaccinated intramuscularly (IM) each with one ml of 1×105 PFU/ml of the RVF MP-12 and 9 sheep were inoculated IM each with one ml of the arMP-12ΔNSm21/384 vaccine candidate, and two control sheep received one ml each of only Eagle's Minimum Essential Medium. Blood samples obtained on days 14 and 0 before vaccination and on days 3, 4, and 5 post vaccination (PV) were tested for RVFV in Vero cells and by RT PCR assay, and samples collected at interval PV through day 87 and on days 7, 14 and 21 following revaccination on day 87 PV to test for RVFV neutralizing antibody response by the plaque reduction neutralization test. Results: All animals, including the controls remained in good health during the PV period as supported by normal body temperature, and the absence of clinical manifestations throughout this study. A viremia was not detected in any of the animals. Six of 6 animals that received the RVF MP-12 and 8 of 9 animals that received the arMP-12ΔNSm21/384 had antibody titers that ranged from 1:10 on day 5 PV to as high as 1:40 to 1:160 through day 87 PV. The antibody titers for these 15 animals following revaccination on day 87 PV with 1×104 PFU/ml of the MP-12 vaccine increased rapidly and by day 21 PV the titers for most animals ranged from 1:160 to 1:640. Conclusion: Overall, these findings based on a limited number of sheep indicated that both the MP-12 and the arMP-12ΔNSm21/384 are promising vaccine candidates for the prevention of RVF in sheep in Africa.

Genomic footprints of dryland stress adaptation in Egyptian fat-tail sheep and their divergence from East African and western Asia cohorts

African indigenous sheep are classified as fat-tail, thin-tail and fat-rump hair sheep. The fat-tail are well adapted to dryland environments, but little is known on their genome profiles. We analyzed patterns of genomic variation by genotyping, with the Ovine SNP50K microarray, 394 individuals from five populations of fat-tail sheep from a desert environment in Egypt. Comparative inferences with other East African and western Asia fat-tail and European sheep, reveal at least two phylogeographically distinct genepools of fat-tail sheep in Africa that differ from the European genepool, suggesting separate evolutionary and breeding history. We identified 24 candidate selection sweep regions, spanning 172 potentially novel and known genes, which are enriched with genes underpinning dryland adaptation physiology. In particular, we found selection sweeps spanning genes and/or pathways associated with metabolism; response to stress, ultraviolet radiation, oxidative stress and DNA damage repair; activation of immune response; regulation of reproduction, organ function and development, body size and morphology, skin and hair pigmentation, and keratinization. Our findings provide insights on the complexity of genome architecture regarding dryland stress adaptation in the fat-tail sheep and showcase the indigenous stocks as appropriate genotypes for adaptation planning to sustain livestock production and human livelihoods, under future climates.

Mitochondrial DNA variation of domestic sheep (Ovis aries) in Kenya

The history of domestic sheep (Ovis aries) in Africa remains largely unknown. After being first introduced from the Near East, sheep gradually spread through the African continent with pastoral societies. The eastern part of Africa was important either for the first diffusion of sheep southward or for putative secondary introductions from the Arabian Peninsula or southern Asia. We analysed mitochondrial DNA control region sequences of 91 domestic sheep from Kenya and found a high diversity of matrilines from the widespread haplogroup B, whereas only a single individual from haplogroup A was detected. Our phylogeography analyses of more than 500 available mitochondrial DNA sequences also identified ancestral haplotypes that were probably first introduced in Africa and are now widely distributed. Moreover, we found no evidence of an admixture between East and West African sheep. The presence of shared haplotypes in eastern and ancient southern African sheep suggests the possible southward movement of sheep along the eastern part of Africa. Finally, we found no evidence of an extensive introduction of sheep from southern Asia into Africa via the Indian Ocean trade. The overall findings on the phylogeography of East African domestic sheep set the grounds for understanding the origin and subsequent movements of sheep in Africa. The richness of maternal lineages in Kenyan breeds is of prime importance for future conservation and breeding programmes.

First Molecular Identification and Genetic Characterization of Theileria lestoquardi in Sheep of the Maghreb Region.

Theileria lestoquardi is the most prominent Theileria species in small ruminants that causes malignant theileriosis of sheep in Africa and Asia. In the present survey, blood samples and ticks were collected in Kebili (southern Tunisia) from 166 Queue Fine de l'Ouest sheep. Giemsa-stained blood smears, immunofluorescent antibody test (IFAT) and PCR were performed. The DNA was extracted from blood and analysed by PCR targeting 18S rRNA gene of Theileria spp. and then sequenced. A total number of 140 ticks were collected from a total number of 166 sheep during the four seasons. The ticks belonged to two genera and 4 species; the most frequent tick was Hyalomma excavatum 84.3% (118/140) and then Rhipicephalus spp. 15.7% (22/140). Only two animals had positive Giemsa-stained blood smears, and they were also positive by IFAT. The amplicons had 99.3 and 99.6% homology with the BLAST published T.lestoquardi amplicons. To our knowledge, this is the first report of T.lestoquardi in small ruminants within the Maghreb region.

Visible genetic polymorphisms in domesticated animal species.

Abstract Visible genetic polymorphisms are very frequent in domesticated animal species. Historically, they were used very early on by breeders to create standardized breeds. If flocks or herds breed at random, polymorphic populations occur (usually variegated, because most of the viable visible alleles that were kept after domestication act on coat colour) in agreement with the laws of population genetics, using the relative value of genotypic fitness coefficients. Such populations became known as primary populations or primary breeds. Numerous descriptions of polymorphic, variegated populations are available, especially for goats and sheep in Africa. Of these, many are probably primary breeds, but records of random mating (panmixia) are scarce. It appears that, after domestication, primary breeds arose, and it was within those that hot spots of standardization appeared later, resulting in standardized breeds.

The characterization of African strains of capripoxvirus

Isolates of capripoxvirus collected from sub-Saharan Africa were compared in sheep, goats and cattle and by restriction endonuclease digestion of their purified DNA. Biochemical techniques were used to precisely identify strains of capripoxvirus for epidemiological investigations. Strains of capripoxvirus infecting cattle have remained very stable over a 30-year period and are closely related to strains recovered from sheep in Africa.

Sheep and Sheep-Herders in South Africa

Opening ParagraphIn a recent paper Mr. C. K. Cooke, F.S.A., discusses the questions of the introduction of sheep into Africa and their arrival in southern Africa (Cooke, 1965).Mr Cooke quotes Zeuner's conclusion (Zeuner, 1963) ‘that the first sheep in Africa were screw-horned hair sheep from Turkestan or Persia which reached lower Egypt about 5000 B.C. and Khartoum by 3300 B.C. This breed disappeared with the Middle Kingdom when it was replaced by a wool sheep and the fat-tailed sheep reached Africa only from the Roman period.’ Zeuner further asserts thatOne breed of sheep descended from the Egyptian hair-sheep had reached South-West Africa before the arrival of the Europeans. In these animals the profile is convex, the eyes are placed high on the skull and close to the drooping ears. The rams carry thick horns and a long ruff on the throat.

Urea and biuret as protein supplements for range cattle and sheep in Africa

The natural rangelands (veld) of Africa yield grasses that are notorious for their poor phosphorus and crude protein contents. Unless supplementary feed is given during the dry months, animals otherwise entirely dependent for their subsistence on veld grazing will suffer in growth, production and reproductive ability. The problem of range feeding that exists in Africa is vastly different from that found in Europe, where the average grazing or roughage feed is of good quality.