Thermoneutral temperature and thermal stress of sheep creole: physiological and ingestive behaviour

This research aims to evaluate the physiological variables of native sheep raised in a controlled environment with different temperatures. Twenty-four entire male sheep of the Santa Inês (SI), Morada Nova (MN), no defined racial pattern (NDRP) and Soinga (SO) breeds were used. Rectal temperature (RT), respiratory rate (RR), heart rate (HR) and surface temperature (ST) were collected twice a day, during the last 5 days of each experimental phase. The HR (P = 0.001) showed a significant effect for the breed and temperature interaction. RT (P = 0.002) and HR (P < 0001) showed a significant effect of breed, where RT presented the highest value in the SI and NDRP breeds and similar to the SO, the MN presented the lowest value for RT. The RT, RR, HR, ST and SKT showed a significant effect (P < 0.0001) in relation to temperature. The STRT and SKTRT thermal gradients showed a significant difference (P < 0.0001) as a function of temperature. The groups were similar in terms of adaptation, even MN presenting low values for RT and HR, which changed abruptly considering the temperatures evaluated and from 28°C onwards the physiological variables are altered.