Search

The current project based on the hypothesis that environmental challenges contribute to genetic characteristics of west-African cattle breeds being associated with adaptation, robustness and heat tolerance. Furthermore, social-ecological transformations in the African context may initiate breeding processes towards improved productivity and product quality. For inferring the respective genomic mechanisms, 449 cattle of the local breeds Borgou, Pabli-Kerou, Lagune and Somba were genotyped using the 50K SNP chip. Based on the first two principal components, breeds could be clearly allocated to different clusters, displaying further sub-clusters for the respective historical populations. Obvious was the large genetic distance with high-yielding German cattle breeds such as HF. A particularity of the genomic studies addressing selection signatures was the possible contrasting with the respective historical populations to infer genetic processes of transformation by time. The annotated potential candidate genes contributed to physiological pathways and mechanisms inducing immunity and adaptation. The detected gene RNF220 has well-known effects on calving ease in HF. Genome-wide associations for measurements of morphological traits could be associated with heat tolerance and disease resistance. The quite large heritabilities for continuous body measurements in cm indicate potential for further optimizations of genetic evaluations for conformation traits. Whole-genome sequencing of the west-African breeds contributed to the detection of four novel milk protein variants, illustrating the importance of west-African genetic resources to improve product quality. [ABSTRACT FROM AUTHOR]

Endangered cattle breeds with a small population size are increasingly legging behind in competitiveness compared to intensively used cattle breeds with a large population size, especially concerning the use of genomic data and advances in genomic selection. Enhanced usage of genomic marker data can substantially contribute to the preservation of genetic diversity, to improved inbreeding management and breed competitiveness. The present article presents -- with the Black Pied cattle (DSN) as an example -- possibilities and benefits of genotype and sequence data for genetic improvement and improved competitiveness in breeds with a small populations size. Analyses of whole-genome sequence data in DSN showed a high genetic diversity in genomic regions playing a crucial role in immune recognition and disease resistance. So far, breed comparisons on a phenotypic scale have not shown any superiority of DSN for health traits, but reflected good adaption of DSN to grazing (e.g., improved heat tolerance). Although DSN is considered to be one founder breed of high-yielding Holstein Friesian cattle, both breeds differ significantly from each other in analyses of genomic data. Breed specific genomic characteristics in DSN were identified in genome-wide association studies (GWAS) and gene analyses for production and functional traits. Hence, we developed a novel SNP chip with breed-specific variants for DSN. This article presents results from GWAS and genomic breeding value estimations when implementing the DSN specific chip. Moreover, we present further approaches for genetic improvement, inbreeding management and maintaining genetic diversity in breeds with a small population size, e.g., including genotypes from other countries or specific cluster analyses to build herd types across national borders. [ABSTRACT FROM AUTHOR]