R. Bras. Zootec.01/Sep/1999;28(5):1133-40.
Influence of the season of year on the rectal temperature and breathing rate of rams
DOI: 10.1590/S1516-35981999000500032
This work was carried out to evaluate the effect of the season of the year, from March/96 to March/97, on the rectal temperature (RT) and breathing rate (RR) of rams from Bergamacia, Corriedale and Hampshire Down (Hd) breeds, with three-four years of age. Twenty-four rams, nine Bergamacia (Be) eight Corriedale (Co) and seven Hampshire Down (Hd), were used. The month of the year had a significant effect on RT for Hd breed. The observed rectal temperatures was higher in the summer (39.31ºC), decreased in the autumn (38.63°C) and in the winter (38,93°C) and increased again in the spring (39.15ºC). The RR in the Co e Hd breeds, under high temperature (31.8°C), was higher (130 and 120 breaths/min, respectively) than the Be breed (68 breaths/min), while under low temperature (21.2°C), values of 79.89 breaths/min for Co and Hd breed and 33 breaths/min for Be breed were observed, showing to be the respiratory tract the main mechanism used by the breeds Co and Hd to dissipate the heat.
Keywords: lamb; rectal temperature; respiratory frequency; year seasons