Effects of high ambient temperatures on the metabolism of West African dwarf goats. II

Abstract

32 West African dwarf goats were exposed in respiration chambers to temperature treatments of 20, 25, 30, 35, 35, 35, 30, 25, 20°C. Each treatment lasted three days. 16 goats were kept in individual pens (“I”); the others in two group pens of eight animals each (“G”). During each treatment, heat production and activity were recorded continuously over 48 hours. In addition, feed and water intake, rectal temperature, skin temperature and respiratory rate were measured during each treatment.

Compared to 20°C, at 35°C rectal temperature increased from 39.0°C to 39.9°C, respiratory rate from 30 to 260 times. min⁻¹ and skin temperature from 37.1°C to 39.5°C. Hay intake decreased by 40%; concentrates (30 g. kg^−0.75. d⁻¹) were always completely consumed. Heat production was higher for the “G” animals at 20°C and higher for the “I” animals at 35°C. These differences in heat production between the two groups were reflected in differences in rectal and skin temperature and in respiratory rate but only very slightly in differences in hay intake.

Tissue insulation was 0.014 K. m². W⁻¹ at 30°C and 35°C and 0.022 K. m². W⁻¹ at 20°C.

It is concluded that the reactions of these dwarf goats to high ambient temperatures are not different in principle from those of other domestic ruminants and that they do not exhibit a specific suitability or unsuitability for ambient temperatures as prevailing in West Africa.