Genetic analysis of reproduction, body weight and mohair production in South African Angora goats

Abstract

Abstract Genetic parameters for South African Angora goats were estimated from body weight, mohair production and reproduction data collected from birth on ram and ewe kids, as well as on the adult ewes in three herds from 2000 to 2015. Medium heritabilities were estimated for body weight from birth until 12-month of age and adult body weight, while a high heritability was estimated for 16-month body weight. Heritability for fibre diameter and spinning fineness was high, while a low heritability was estimated for standard deviation of fibre diameter along the length of the staple and for staple length. Medium heritabilities were estimated for fleece weight and the remainder of the fibre traits. Low heritabilities were estimated for all reproductive traits. Heritability estimates of lifetime number of kids born and weaned were higher than the heritability estimated on the individual records. Expressing lifetime number of kids weaned per kidding opportunity further increased the heritability. There were favourable significant genetic correlations of total weight of kids weaned (TWW) with adult body weight and fibre diameter, but significant unfavourable genetic correlations of TWW with adult fleece weight. Fleece weight was, however, unfavourably correlated with fibre diameter. Early fleece weights were genetically favourably correlated with all the adult traits, except with adult fibre diameter. The opposite is true for early fibre diameter, which were genetically unfavourably correlated with all the adult traits, except with adult fibre diameter. Early body weights were also genetically favourably correlated with all the adult traits, except with adult fibre diameter. Maiden ewe reproductive performance at the first parity was favourable genetically correlated with lifetime reproductive performance. Different selection strategies are proposed for ram and ewe selection, where ewe selection should focus on improving reproduction, while the fleece traits should be accommodated under ram selection. Selection of young ewes should be based on early body weight and TWW at the first parity. Too much selection pressure on early fleece weight and fibre diameter should be avoided in the selection of young ewes.