Diurnal Variations and Heat Stress: Physiological and Biochemical Resilience in White Fulani Cattle

Abstract

This study evaluated the effects of diurnal variations under heat stress conditions on physiological, biochemical and haematological parameters in White Fulani (Bunaji) cattle raised under semi-intensive system of management. Twenty (20) White Fulani cattle of mixed sexes were exposed to heat stress conditions with Temperature-Humidity Index (THI) and body temperature monitored both in the morning and afternoon. Blood samples were also collected to measure haematological, biochemical and antioxidant indices. The THI exceeded 80, indicating significant heat stress during both morning and afternoon periods. Elevated body temperatures were recorded in the muzzle, left ear, and neck, with significant differences (P < 0.05) between morning and afternoon readings. Biochemical indices showed elevated (but non-significant changes, suggesting physiological adaptation. Antioxidant and enzyme levels remained stable despite elevated heat stress. Haematological indices revealed a significant decrease in Red Blood Cell counts from morning to afternoon (P = 0.0001), while other parameters remained stable. Correlation analysis showed that temperatures at the left ear and neck significantly correlated with THI, indicating their sensitivity to heat stress. These findings highlight the resilience of White Fulani cattle's physiological and metabolic functions under prolonged heat stress conditions.