| Summary: | The heat tolerance index (HTI) of 16 light colored and 15 dark colored pelage of Santa Inês breed was evaluated. This study was carried out on hot days with BGHI greater than 90. In order to calculate HTI (10 – (RT2 - RT1)) rectal temperature (RT) was recorded at 01:00 p.m. (RT1) after two hours of rest in the shade. Later they were exposed to direct sun light for one hour and then they rested one more hour under shade, when the RT2 was recorded at 03:00 p.m. A completely randomized design was used to analyze hair length (HL), coat thickness (CT), skin temperature (TS) and coat temperature (TC). No differences on RT were observed between light colored and dark colored hair coat ewes, but all of them raised their temperatures (P<0.05) after heat stress. No differences on HTI, CT, HL, and TS were observed between groups, but the black colored hair coat ewes had the highest TC (P<0.05). No effect on heat tolerance between dark colored and light colored hair coat Santa Inês breed in heat conditions is observed.<br>Objetivou-se avaliar o índice de tolerância ao calor (ITC) em ovelhas da raça Santa Inês, 16 de pelagem clara e 15 de pelagem negra, na época do calor, com ITGU superior a 90. Para o cálculo do índice foram registradas as temperaturas retais (TR) às 13 h (TR1), após duas horas em descanso na sombra; em seguida, os animais ficaram expostos ao sol por uma hora e, depois, à sombra por mais uma hora, quando se registrou a TR2, às 15 h (10 – (TR2 – TR1)). Utilizou-se o delineamento inteiramente ao acaso para avaliar comprimento do pelo (CP), espessura do pelame (EP), temperatura da pele (TPele) e do pelame (TP). Não houve efeito da cor do pelame na TR das ovelhas Santa Inês. Todas as ovelhas aumentaram a TR após o estresse (P<0,05). Não houve diferença entre as ovelhas quanto ao ITC, EP, CP e TPele; as ovelhas de pelame negro tiveram maior TP (P<0,05). A cor do pelame não interfere na tolerância ao calor em ovelhas Santa Inês nas condições de calor do local.
|
|---|
