Resting heat production in Bos indicus and their F1 crosses with exotic breeds at a thermoneutral environment.
Resting heat production, 18 h post-feeding, was studied in Hariana cattle (Bos indicus; Zebu) and in their F1 crosses with Jersey, Brown Swiss and Holstein Friesian, at 18.5 degrees ambient temperature in a psychometric chamber at different ages. There was no significant change in the resting heat production on a per kg body-weight (W) 0.75 per 24 h basis from 16-19 to 37-40 months of age in any of the genetic groups. The daily resting heat production, however, increased with increases in body-weight and age. The resting heat production in all three F1 crosses was higher than that in Hariana cattle. Among the crosses, the resting heat production was highest in the Holstein Friesian X Hariana and lowest in the Jersey X Hariana. Metabolizable energy (ME) intake per 24 h was significantly different between genetic groups and in different age groups. However, ME intake per kg W 0.75 was not significantly different between genetic groups.