Comparison of different models for the estimation of genetic parameters of wool traits in intercross sheep

IF 1.6 3区农林科学 Q2 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Small Ruminant Research Pub Date : 2025-02-17 DOI:10.1016/j.smallrumres.2025.107462

Abdul Rahim , K.S. Rajaravindra , Rajni Chaudhary , R. Pourouchottamane , Pallavi Chauhan , G.R. Gowane , Arun Kumar

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Abstract

The quality and yield of wool determine the economic value of the fine-wool sheep, therefore this study aimed to estimate the (co)variance components and genetic parameters for direct and maternal influences on greasy fleece yield (GFY), staple length (SL) and fibre diameter (FD) of Inter-cross sheep maintained at North Temperate Regional Station, Garsa, Kullu (Himachal Pradesh), India. Data file consisted of first six monthly shearing records of 1084 hoggets descended from 513 ewes and 153 rams over a period of 11 years (2012–2022). Univariate analysis was carried out by average information restricted maximum likelihood (AI-REML) procedure fitting six different animal models with various combinations of direct and maternal effects. Improvement of log-likelihood values were used to evaluate the best fit models for fibre traits. Analysis revealed that year of birth was significant (P < 0.05) on all traits, while sex and types of birth on GFY and SL only. It indicates specialized care and management of lambs across significant effects to avoid production losses. Model 3, incorporating direct additive genetic, maternal additive genetic and their covariance showed the maximum Log-Likelihood estimate for all traits. The direct heritability for GFY, SL and FD were 0.11 ± 0.06, 0.10 ± 0.06 and 0.06 ± 0.05 and corresponding maternal heritability for respective traits were 0.06, 0.03, and 0.08, respectively. The correlations between direct and maternal effects ranged from −0.47 ± 0.07 (GFY) to −0.89 ± 0.31 (FD) for wool traits, which have inflated the heritability estimate. The total heritability estimates were very low indicating very low additive genetic variance for these traits. Genetic correlations among various wool traits were low and positive. These results suggest little scope of direct selection for these traits, however care and management of lambs during critical phase of growth, that affects the wool production and quality may help in reducing wool production losses.

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杂交绵羊羊毛性状遗传参数估算模型的比较

羊毛的品质和产量决定了细毛羊的经济价值，因此，本研究旨在估计在印度加尔萨（Garsa）（喜马偕尔邦）北温带地区站饲养的杂交羊的直接和母系对含脂羊毛产量（GFY）、短绒长度（SL）和纤维直径（FD）的（co）方差和遗传参数。数据文件包括11年（2012-2022年）期间513只母羊和153只公羊的1084头猪的前6个月剪羊毛记录。采用平均信息限制最大似然（AI-REML）程序进行单因素分析，拟合6种不同的动物模型，具有不同的直接和母体效应组合。采用对数似然值的改进来评价纤维性状的最佳拟合模型。出生年份对各性状均有显著性影响（P <； 0.05），出生性别和出生类型仅对GFY和SL有显著性影响。这表明对羔羊的专门护理和管理对避免生产损失有重大影响。结合直接加性遗传、母系加性遗传及其协方差的模型3显示所有性状的最大对数似然估计。GFY、SL和FD的直接遗传力分别为0.11 ± 0.06、0.10 ± 0.06和0.06 ± 0.05，亲本遗传力分别为0.06、0.03和0.08。羊毛性状的直接效应与母系效应之间的相关系数为- 0.47 ± 0.07 （GFY）至- 0.89 ± 0.31 (FD)，这使得遗传力估计值过高。总遗传力估计非常低，表明这些性状的加性遗传变异非常低。羊毛各性状间的遗传相关均为低正相关。这些结果表明，这些性状的直接选择范围很小，然而，在羔羊生长的关键阶段，影响羊毛产量和质量的护理和管理可能有助于减少羊毛产量损失。

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来源期刊

Small Ruminant Research 农林科学-奶制品与动物科学

CiteScore

3.10

自引率

11.10%

发文量

210

审稿时长

12.5 weeks

期刊介绍： Small Ruminant Research publishes original, basic and applied research articles, technical notes, and review articles on research relating to goats, sheep, deer, the New World camelids llama, alpaca, vicuna and guanaco, and the Old World camels. Topics covered include nutrition, physiology, anatomy, genetics, microbiology, ethology, product technology, socio-economics, management, sustainability and environment, veterinary medicine and husbandry engineering.