Reproductive hormones and their association with the litter size in Kreishi ewes

• Siraj Ali Hashim1, Tahreer Mohammed Al-Thuwaini1

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This study evaluated the reproductive hormonal profile of Kreishi ewes during pregnancy and examined its association with litter size. In total, 100 ewes from the Kreishi breed were examined during their fourth and fifth months of pregnancy (46 with single pregnancies and 54 with twin pregnancies) and weighed between 75 and 95 kg. The levels of progesterone (P4), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were measured and compared by litter size and age. The results revealed highly significant (P ≤ 0.05) differences in hormonal concentrations between twin and single lamb-producing ewes. Ewes with twins displayed significantly higher progesterone, FSH, and LH concentrations (9.14 ± 0.91, 37.24 ± 1.45, 35.62 ± 1.55) than those with singletons (7.98 ± 1.19, 25.04 ± 1.34, 22.17 ± 1.20), suggesting increased endocrine activity. Age-related differences in progesterone levels were observed in 2-year-old ewes, but not in FSH and LH levels. Additionally, hormonal concentrations differed between the fourth and fifth months of pregnancy, reflecting physiological changes associated with pregnancy progression. Based on these findings, progesterone, FSH, and LH may serve as useful physiological indicators of reproductive performance in Kreishi ewes. This study provides valuable baseline information that may help improve prolificacy and lamb production in this indigenous sheep breed through future breeding and selection programs.

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