Effect of Trypanosoma vivax infection on body temperature, feed intake, and metabolic rate of West African dwarf goats.

Thirty-two mature dwarf goats weighing between 16 and 30 kg (22.7 +/- 3.7, SD) were used to study the effect of Trypanosoma vivax infection on rectal temperature (RT), feed intake (DMI), and metabolic rate. Sixteen of the goats were infected intravenously with 14 X 10(6) T. vivax each; the 16 others served as controls. Animals were fed at about 1.1 times maintenance. Heat production was measured from 1 wk preinfection to 6 wk postinfection. From data on successive 9-min periods, heat production was calculated per 24-h period and separately for 0700 to 2000 (day period) and for 2000 to 0700 (night period). Rectal temperature was measured twice weekly. Compared with controls, animals infected with T. vivax developed and maintained a 1 degree C higher RT and a higher metabolic rate. After the prepatent period of 5 to 7 d, during which RT remained normal, all infected goats had a period of about 7 d with constant high temperatures. After that initial episode, RT fluctuated. Heat production of infected animals was increased by 15.6 kcal.d-1.kg-.75, or about 16%. This increase in heat production was greater during the night (22 kcal.d-1.kg-.75) than during the day (14 kcal.d-1.kg-.75). After T. vivax infection, large differences in DMI among animals were apparent. In four animals, a clear relation between DMI and RT was noted, but in 12 animals no such relationship was apparent.