Age-related changes in hormonal profiles and testicular diameter of West African Dwarf buck treated with gonadotropin-releasing hormone

Abstract

This study aimed to investigate the impact of age-related peripheral and Gonadotropin Releasing Hormone (GnRH)  -stimulated hormonal profiles on testicular size in West African dwarf bucks. Twelve 3-month-old bucks were randomly  divided into two groups: the GnRH- treated group (n = 6) and the control group (n = 6). Over the course of 10 months,  from month 3 to month 12, the testicular diameter of all bucks was measured monthly, and blood samples were  collected monthly for hormone analysis. The results showed that testicular diameter increased with age and higher  concentrations of Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH) and Testosterone (T). The GnRHtreated  group reached its peak testicular diameter (28.36±1.44 mm) earlier at 8 months compared to the control group  (30.50±1.44 mm) at 10 months, aligning with the peak concentrations of FSH, LH, and T. While the GnRH stimulation led  to higher FSH, LH, T, and estrogen levels in the treated group, it didn't significantly affect the final testicular diameter  (p<0.05). It can be concluded that hormonal levels rise with age and increasing testicular size, and GnRH stimulation can  accelerate this process. Testicular size is an important factor in breeding soundness and is influenced by LH, FSH, and  testosterone concentrations. These hormones can reliably indicate the reproductive capacity of the buck. Therefore,  hormonal profiling should be an integral part of the breeding soundness examination.