A Review on Indigenous Goats of East Africa: A Case for Conservation and Management.

Indigenous goats are important in the livelihoods of rural households in East African countries. This is due to their ability to produce and reproduce in different environments and climatic conditions. Even though these indigenous goats are important, there is little available information on the genetic characterization of these breeds in Africa and at the international level. This paper reviews the status of indigenous goats, highlighting their production systems, phenotypic and genetic characteristics, and genetic diversity, and proposes potential ways for sustainable improvement and conservation in East African countries. Most households use traditional production systems with various uncharacterized goat breeds and ecotypes, which are hence named after the tribe or locality in which they are found. Most of these goats are classified as small East African breeds, with significant variability in morphological features. Some of the challenges to goat production in this region are indiscriminate crossbreeding, lack of pedigree records, parasites and disease incidences, low-quality pastures, and low levels of management. There is a need for a collaborative approach amongst the actors in goat breeding value chains as well as integrating modern genomic tools into breeding programs to enhance selection. This will ensure the resilience and sustainability of these unique indigenous goat populations in East Africa.

Assessing the Genomics Structure of Dorper and White Dorper Variants, and Dorper Populations in South Africa and Hungary.

Dorper sheep was developed for meat production in arid and semi-arid regions under extensive production systems in South Africa. Two variants with distinct head and neck colors were bred during their development process. White Dorper have a white coat while Dorper have a black head and neck. Both variants have grown in popularity around the world. Therefore, understanding the genomic architecture between South African Dorpers and Dorper populations adapted to other climatic regions, as well as genomic differences between Dorper and White Dorper variants is vital for their molecular management. Using the ovine 50K SNP chip, this study compared the genetic architecture of Dorper variants between populations from South Africa and Hungary. The Dorper populations in both countries had high genetic diversity levels, although Dorper in Hungary showed high levels of inbreeding. White Dorpers from both countries were genetically closely related, while Dorpers were distantly related according to principal component analysis and neighbor-joining tree. Additionally, whereas all groups displayed unique selection signatures for local adaptation, Dorpers from Hungary had a similar linkage disequilibrium decay. Environmental differences and color may have influenced the genetic differentiation between the Dorpers. For their molecular management and prospective genomic selection, it is crucial to understand the Dorper sheep's genomic architecture, and the results of this study can be interpreted as a step in this direction.

An On-Station Analysis of Factors Affecting Growth Traits of Pure Red Maasai and Dorper Sheep Breeds under an Extensive Production System.

This comparative study aimed to evaluate genetic and environmental factors' effects on the growth traits of lambs in Dorper and Red Maasai (RedM) sheep breeds. The data analyzed contained the following measurements: birth weight (Bwt), weaning weight (Wwt), yearling weight (Ywt), birth type (single or twins), and details on each lamb's dam (dam ID and age) and sire. Except for the RedM, whose birth weight decreased with time, both breeds generally showed an increase in other growth weights across the study period, with yearly variations affecting both breeds. Additionally, analysis by a linear mixed model with restricted maximum likelihood (REML) showed that only breed as a factor significantly (p < 0.05) influenced birth weight; breed, sex, and birth type all significantly (p < 0.05) influenced weaning weight, whereas season, sex, and dam age significantly (p < 0.05) influenced yearling weight. The RedM breed outperformed the Dorper breed in post-weaning growth rate, demonstrating early resilience and adaptation to local environmental factors independent of maternal influence. Breed and non-genetic factors play a vital role in the growth of lambs, and the results of this study offer an opportunity for improved farm management under an extensive production system and selection for the conservation of the indigenous Red Maasai breed.

A review on the potential effects of environmental and economic factors on sheep genetic diversity: Consequences of climate change.

Climate change has a significant effect on the productivity of livestock including milk, meat, and reproduction. This could be attributed to the internal diversion of energy resources towards adaptive mechanisms. Among the climate change variables, thermal stress seems to be the major limiting factor in animal agriculture. A better understanding of the effects of climate change-influenced ecological factors on the genetic diversity of livestock species is warranted. Sheep is an ideal livestock species to be used in investigating environmental adaptation due to its wide range of agroecological habitats, genetic and phenotypic variability. There is a heavy reliance on sheep genetic diversity for future animal protein security, but the implications of climate change on their genetic diversity receive less attention. Here, the potential environmental factors influencing natural selection in sheep populations are presented. We argue that prolonged exposure to these factors plays a major role in influencing the development of adaptation traits in indigenous sheep breeds, consequently leading to the alteration of genetic diversity at specific loci. The factors discussed include hot temperatures (heat stress), insufficient water, low quantity and quality of forage, and prevalence of parasites, pests, and diseases. In addition, genetic diversity, some signatures of selection for adaptation and economic angles of selection are also briefly discussed. A better understanding of environmental factors influencing the genetic diversity of sheep populations will inform breeding and management programs and may offer an opportunity for greater production efficiency with low input costs.