Influence of seasonal changes on physiological variables, haematology and serum thyroid hormones profile in male Red Sokoto and Sahel goats

Abstract

The aim of this study was to evaluate the physiological responses of adult male Red Sokoto goats (n = 10; indigenous to the Guinea Savannah climate) and Sahel goats (n = 10; indigenous to the Sahel climate) at the peak of the cold-dry (CDS), hot-dry (HDS) and rainy seasons prevailing in the Guinea Savannah zone of Nigeria. Results revealed that Red Sokoto goats had significantly higher rectal temperature (RT), PCV, red blood cell (RBC), Hb, thyroxin (T₄), but lower respiratory rate (RR) and total leucocyte count (TLC) than Sahel goats during the CDS. Comparison within breeds for the three seasons showed that both breeds exhibited the highest (P < .05) PR, RT, neutrophil-lymphocyte ratio (N:L), but lower mean corpuscular volume and triiodothyronine (T₃) during the HDS. In addition, Red Sokoto goats showed higher (P < .05) RR and T₄, but lower RBC, Hb, lymphocyte counts and T₃:T₄. However, Sahel goats exhibited higher (P < .05) PCV, RBC, erythrocyte osmotic fragility, but lower circulating T₄. It was concluded that the cold and hot seasons exerted different physiological effects on the two breeds of goats with marked variation in RT, composition of blood cellular components, thyroid physiology and erythrocyte membrane integrity.