Genetic and non-genetic factors influencing the performance of the West African Dwarf (WAD) goat kept at the Kintampo Goat Breeding Station of Ghana

Abstract

A study was conducted to analyze the effect of genetic and non-genetic factors influencing the growth performance of the West African Dwarf goat. Breed records of 836 kids born by 259 does, and 8 bucks from 2011 to 2017 at the station were used. Growth performance traits studied were birth weight, weaning weight, 6-month body weight, 9-month body weight, yearling weight, and pre-weaning and post-weaning growth rates. The fixed effects of sex of kid (male or female), season of kidding (major, minor, and dry), year of kidding (2011-2017), and type of birth (single, twins, or triplets) on growth performance were determined. Genetic parameters such as heritability and correlations among the traits were also estimated. The non-genetic data (fixed factors) obtained were analyzed using the general linear model procedures of GenStat (Discovery Edition 12). Heritability estimates obtained for the growth traits were 0.45 ± 0.15, 0.57 ± 0.29, 0.04 ± 0.05, 0.74 ± 0.59, 0.49 ± 0.35, 0.55 ± 0.39, and 0.54 ± 0.36, respectively, an indication of high genetic variation existing among the traits (with the exception of 6-month body weight). This could be harnessed and utilized for genetic improvement within the flock. The phenotypic correlation coefficients among the traits ranged from low to high (0.04-0.95), indicating that there is a linear relationship among body traits of the goats which may be caused by either genetic or environmental factors of correlation. The genetic correlations were also medium to high (0.30-0.96). The general implications are that selection for any of these growth traits in a breed improvement programme would have a considerable simultaneous positive impact on each other. The overall birth weight, weaning weight, 6-month body weight, 9-month body weight, yearling weight, and pre- and post-weaning growth rates obtained were 1.48 kg, 5.35 kg, 6.56 kg, 8.30 kg, 10.00 kg, 32.26 g/day, and 19.39 g/day, respectively. These growth performances were found to be significantly influenced by the non-genetic factors studied. There is therefore the need to factor these in future breed improvement programmes to ensure their success.

Keywords: Genetic correlation; Genetic improvement; Genetic variation; Heritability; Phenotypic correlation.