Individual variation in thermotolerance and expression of HSP70 in sheep

Abstract

The main objective is to assess the physiological responses of sheep raised on pasture with natural shade and shelter. The work will be held at the Faculdade de Zootecnia e Engenharia de Alimentos FZEA/USP, located in Pirassununga, SP. Fifty Santa Ines females will be studied. In the first phase, rectal temperatures will be recorded for the evaluation of heat tolerance, indicating thermolysis capacity. The temperatures will start at 1:00pm (T0) and 2:00pm (T1: one hour after sun exposure) and other at 2:45pm (T2), 45 minutes of rest in the shade with food and water restriction. A record will be made six hours before the test to measure the baseline (7:00am). At the same time of rectal temperature samples, will be measured for sweating rate, respiratory rate, and surface temperature, and also blood will be taken for measurement of HSP70. At the end of the work, it could be possible to determine the relationship between the ability of thermoregulation and the individual gene expression of HSP70. From the characterization of the animal by the findings of physiological responses to the environment in which animals are exposed it may be made beneficial to improve their welfare, thus maximizing their production. The statistical analyzes will be performed using UNIVARIATE, CORR, and GLM procedures, (SAS).(AU)