The impact of heat stress on growth and resilience phenotypes of sheep raised in a semi-arid environment of sub-Saharan Africa

IF 1.9 3区农林科学 Q2 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Livestock Science Pub Date : 2025-08-06 DOI:10.1016/j.livsci.2025.105794

E. Oyieng , J.M.K Ojango , M. Gauly , C.C. Ekine-Dzivenu , R. Mrode , E.L. Clark , R. Oloo , S. König

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Abstract

Sheep production in Arid and Semi-Arid lands face immense heat stress with the changing climate. This study assessed the effect of heat stress on growth and developed resilience phenotypes of sheep raised in a semi-arid environment. Heat stress was measured by Temperature-Humidity Index (THI). Live body weight records of 4078 animals, belonging to pure Red Maasai (RRRR), pure Dorper (DDDD), and their crosses: 50%Dorper-50%RedMaasai (DDRR) and 75%Dorper-25%Red Maasai (DDDR) collected between 2003 and 2024 were analysed. Random regression models fitted with reaction norm functions were used to develop two resilience phenotypes: Response and Stability, at THI 70 and THI 85 representing varying heat stress. Animal mixed models were used to estimate genetic parameters. The THI breakpoints were 78.75, 78.71, 78.42 and 77.93 with a decline rate of 0.06 Kgs, 0.09 Kgs, 0.05 Kgs and 0.15 in live weight gain per unit change in THI for RRRR, DDDD, DDRR and DDDR respectively. The breed, sex, type of birth, dams’ parity and season of birth significantly (P<0.05) affected the stability of growth at low and high heat stress. The heritability estimates of resilience traits ranged from 0.12 to 0.16. Genetic correlations of resilience phenotypes at THI 85 with pre-weaning live weight gain were antagonistic and significant (P<0.05). With the changing climate, resilience phenotypes should be included in selection programs for sheep in the Arid and Semi-Arid lands for robust growth.

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热应激对在撒哈拉以南非洲半干旱环境中饲养的绵羊生长和恢复表型的影响

随着气候的变化，干旱和半干旱地区的绵羊生产面临着巨大的热应激。本研究评估了热应激对半干旱环境下饲养的绵羊生长和发育弹性表型的影响。采用温湿指数（THI）测定热应激。分析了2003 - 2024年收集的4078只纯红马赛（RRRR）、纯杜珀（DDDD）及其杂交品种：50%杜珀-50%红马赛（DDRR）和75%杜珀-25%红马赛（DDDR）的活体重记录。采用反应范数函数拟合的随机回归模型建立了两种恢复表型：反应和稳定，分别在THI 70和THI 85下代表不同的热应激。采用动物混合模型估计遗传参数。RRRR、DDDD、DDRR和DDDR的THI断点分别为78.75、78.71、78.42和77.93，THI单位变化活重增重下降幅度分别为0.06、0.09、0.05和0.15 kg。低、高热应激条件下，品种、性别、出生类型、胎次和出生季节对生长稳定性影响显著（P<0.05）。弹性性状的遗传力估计范围为0.12 ~ 0.16。THI 85的恢复力表型与断奶前活重增加呈拮抗且显著的遗传相关（P<0.05）。随着气候的变化，为了使干旱和半干旱地区的绵羊茁壮成长，应将适应力表型纳入选择方案。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Livestock Science 农林科学-奶制品与动物科学

CiteScore

4.30

自引率

5.60%

发文量

237

审稿时长

3 months

期刊介绍： Livestock Science promotes the sound development of the livestock sector by publishing original, peer-reviewed research and review articles covering all aspects of this broad field. The journal welcomes submissions on the avant-garde areas of animal genetics, breeding, growth, reproduction, nutrition, physiology, and behaviour in addition to genetic resources, welfare, ethics, health, management and production systems. The high-quality content of this journal reflects the truly international nature of this broad area of research.