This study determined the stress and metabolic potentials of 63 goat bucks of different breeds - Kalahari Red (KR), West African dwarf (WAD) and Kalawad (KW) with 21 animals each. They were assigned to three age groups – 11 - 24, 25 - 36 and 37 - 48 months and evaluated across four seasons (early/late rainy and early/late dry) in a 3 × 3 × 4 factorial design. Animals were managed under same conditions for one year. Bimonthly blood samples were collected to analyze hormonal profile on stress and metabolic indices. Three-way ANOVA was used for data analysis using SAS (1999). All determined hormones were significantly (p <0.05) influenced by breed, age and season. The cortisol level was highest (13.91±0.04 ng/mL) in the animals at age 37 – 48 months (p <0.05) and during early dry season (14.43±0.03 ng/mL) while thyroxine and triiodothyronine concentrations had least values (5.79±0.05 ng/dL and 1.75±0.04 ng/mL) but peaked (7.45±0.04 ng/dL and 1.76±0.04 ng/mL) respectively during early rainy season. The least cortisol value (9.42±0.03 ng/mL) was recorded in WAD. Breed, age and season exert influences on hormones considered in goats bucks. This information provides reference values for selection of these breeds in heat-stressed environments.
Odeyemi et al. (Thu,) studied this question.