Effects of Cold-Dry (Harmattan) and Hot-Dry Seasons on Daily Rhythms of Rectal and Body Surface Temperatures in Sheep and Goats in a Natural Tropical Environment

摘要: Studies on daily rhythmicity in livestock under natural conditions are limited, and there is mounting evidence that rhythm patterns differ between chronobiological studies conducted the laboratory pronounced seasonality. Here, we investigated influence of cold-dry (harmattan) hot-dry seasons rectal (RT) body surface temperatures (BST) indigenous sheep goats light-dark cycles. The RT BST animals, ambient temperature (AT) relative humidity (RH) inside pen, were measured every three hours for a period two days, twice separate days during harmattan seasons, respectively. AT RH had minimum values 16°C 15% recorded maximum 32°C 46% season, A trigonometric statistical model was applied to characterize main rhythmic parameters according single cosinor procedure. result showed exhibited different degrees rhythmicity, their oscillatory differed with (larger amplitude season than season). displayed greater (p < 0.05) all seasons. acrophases restricted light phase cycle. mesor not affected by but mesors both species significantly higher season. more robust (70%) as compared (56%). Overall, results demonstrated seasonal changes influenced considerably Awareness these may be useful improvement diagnosis, treatment prevention diseases, welfare productivity conditions.