Abstract
The cortisol and triiodothyronine (T3) concentrations of West African Dwarf (WAD) goats purchased from a local market in Abeokuta, indigenous to the humid climate of West Africa and progenies of parent stock of the Kalahari Red (KR) goat introduced to the humid zone of South-Western Nigeria from the semi-arid sub-tropical zone of South Africa were investigated in the rainy season. Twelve goats consisting of 6 WAD and 6 KR goats of healthy status free of internal and external parasites, aged between 8 and 9 months were housed in a well ventilated concrete-floored pen. The animals were raised semi-intensively throughout the duration of the experiment. They were allowed to graze on pasture mainly (Chloris gayana kunth) and supplemented with concentrate feed at 4 % body weight, on a dry matter basis daily for six months in the rainy season (May – October). Blood was collected twice a month via jugular venipuncture to determine cortisol and triiodothyronine (T3) concentrations. Breed, season and breed by season interaction had no significant effect (P > 0.05) on cortisol. Also, breed had no significant effect (P > 0.05) on triiodothyronine (T3) concentration. However, season and breed by season interaction had a highly significant effect (P< 0.001) on triiodothyronine (T3) concentration, with triiodothyronine (T3) concentration higher in the West African Dwarf goats (128.36 ± 7.64 ng/dl) than the Kalahari Red goats (107.94 ± 9.08) in the month of August. It can be concluded from the study that there was no difference in the cortisol concentration in the West African Dwarf and Kalahari Red goat breeds in the rainy season while triiodothyronine concentration (T3) was higher in the West African Dwarf goats in the month of August in the rainy season.
