Association of Cortisol with Litter Size and Lamb Weight in Awassi Sheep
Association of Cortisol with Litter Size and Lamb Weight in Awassi Sheep
Layth H. Merzah, Tamadhur H. Hussein, Tahreer m. Al-Thuwaini*
ABSTRACT
Reproductive performance is influenced by various factors, including litter size, nutrition, and stress. Stress could contribute to economic losses in the sheep farming industry by decreasing the lambing rate and litter size. Therefore, this study investigated the association of cortisol hormone with litter size and lamb weight in Awassi ewes. The study evaluated 100 sexually mature and healthy ewes aged between 3 and 4 years. Body weight and age were recorded for each animal. Serum samples were collected to measure cortisol hormone levels using ELISA kits from ELK Biotechnology. The study revealed that litter size significantly (P ≤ 0.05) influences the body weight and cortisol hormone levels of Awassi ewes. Twin-born ewes were heavier and had higher cortisol hormone levels, as determined by an ANOVA test. However, they had lower lamb weights at birth and weaning compared to ewes with single births, as indicated by the t-test. The highest Pearson correlation (P ≤ 0.05) was found between cortisol hormone levels, litter size, and body weight, as confirmed by univariate regression analyses. In conclusion, cortisol hormone levels increased in Awassi ewes with twin births. Study findings reveal a valuable connection between cortisol levels and the economic impacts on sheep farming in terms of litter size and lamb weight. Consequently, cortisol may be a promising candidate for further research in sheep breeding and reproduction to enhance prolificacy.
Keywords | Growth traits, Pregnancy, Sheep, Stress hormone, Twinning rate, Weaning
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November 2024
Vol. 12, Iss. 11, pp. 2062-2300
