Ofori S A, Hagan J K
Department of Animal Science, School of Agriculture, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana.
Trop Anim Health Prod. 2020 Sep;52(5):2577-2584. doi: 10.1007/s11250-020-02276-9. Epub 2020 May 23.
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.
开展了一项研究,以分析影响西非矮山羊生长性能的遗传和非遗传因素的作用。使用了该养殖场2011年至2017年259只母羊所生836只羔羊以及8只公羊的繁殖记录。所研究的生长性能性状包括出生体重、断奶体重、6月龄体重、9月龄体重、周岁体重以及断奶前和断奶后的生长速率。确定了羔羊性别(雄性或雌性)、产羔季节(主要季节、次要季节和旱季)、产羔年份(2011 - 2017年)以及出生类型(单胎、双胎或三胎)对生长性能的固定效应。还估计了遗传力和性状间相关性等遗传参数。使用GenStat(Discovery Edition 12)的通用线性模型程序对获得的非遗传数据(固定因素)进行分析。所获得的生长性状遗传力估计值分别为0.45±0.15、0.57±0.29、0.04±0.05、0.74±0.59、0.49±0.35、0.55±0.39和0.54±0.36,表明这些性状间存在较高的遗传变异(6月龄体重除外)。这可用于羊群内的遗传改良。性状间的表型相关系数范围从低到高(0.04 - 0.95),表明山羊身体性状间存在线性关系,这可能由遗传或环境相关因素导致。遗传相关性也为中等至高度(0.30 - 0.96)。总体而言,在品种改良计划中对这些生长性状中的任何一个进行选择,都会对其他性状同时产生相当大的积极影响。所获得的总体出生体重、断奶体重、6月龄体重、9月龄体重、周岁体重以及断奶前和断奶后的生长速率分别为1.48千克、5.35千克、6.56千克、8.30千克、10.00千克、32.26克/天和19.39克/天。发现这些生长性能受到所研究的非遗传因素的显著影响。因此,有必要在未来的品种改良计划中考虑这些因素,以确保计划的成功。