Morphological and Genetic Characteristics of Bos indicus Indigenous Cattle of Eritrea

Abstract

Indigenous cattle production plays important socio-economic roles at households and national levels. An improvement would therefore be desirable in enhancing household incomes, food and nutrition security. This can only happen in structured cattle breeds genetic improvements whose initial phase is determination of the genetic resources inventory. This study was therefore aimed at establishing the morphological and genetic differences that exist within and between indigenous cattle populations. The data was on 243 animals found in 27 sampling populations found in the three agro-ecological zones (AEZs) spread throughout Eritrea. Data for morphological classification of cattle populations was collected from 12 body characteristics, and analysis done by cluster and discriminant analyses. Analysis for genetic diversity study was used to compare variabilities among/within cattle populations. Structure analysis was done to infer the current number of different cattle populations. Analysis of Molecular Variance (AMOVA) was used to test the significance variability between and within cattle populations. Analysis of production data indicated that the average milk yield from Barka breed was 3.48 litres per day compared to Arado breeds at 1.98 litres. Irrespective of the farming system, most farmers selected bulls based on body size criterion as their first choice, and cows based on milk yield performance. Morphologically, indigenous cattle resources of Eritrea clustered into two groups (breeds; Barka and Arado). Generally, the mean morphometric measurements of Arado breed were lower in all body measurements. In molecular analysis, a total of 16,388 polymorphic autosomal SNPs were produced following the filtering and used for diversity, structure and signature analysis. Average allele frequency (AF) of 0.157 was found for all cattle populations. The expected heterozygosity (HE) per population ranged between 0.192 to 0.343. The cluster analysis was carried out and resulted three distinct groups. The signature analysis produced nine candidate genes which were significantly annotated for Gene Ontology (GO) terms. The genomic regions under positive selection harboured genes of facial morphology, skeletal and muscle system development, mineral homeostasis and immune systems. This association could have effect on characterization of ICPs and need to be considered in setting breeding program.