Respostas fisiológicas de caprinos nativos em ambiente controlado.

Abstract

The objective of this research was to detennine the physiological response of two caprine races from the Brazilian semiarid, submitted to a thermically controlled climatic chamber. Twelve male animals were used, 6 Canindés e 6 Moxotós, with average weight of 19,6 + 1,9kg e 20,4 + 1,6kg respectively, fed with a diet containing 43% of Tifton hay (Cynodon dactylon, (L) Pers) and 57% of concentrated. The animals were distributed into an entirely casualised delineation, in factorial scheme (2 x 4 x 6), two races, four temperature levels and six repetitions. In each repetition four temperatures were utilized (20,6, 24,8, 27,8 e 31,6 °C), with the average relative air humidity of 60 + 5%, and wind speed of 0,5m/s. Physiological parameters such as cardiac frequency, respiratory frequency, fur temperature, skin, rectal temperature and water and food consumption were analyzed. For each studied temperature the animals stayed four days in acclimation and three days for data collecting, being ten hours in confinement and fourteen hours for recomposition of physiological functions. The animals stayed within the thermic comfort zone for the FC and FR variables in environmental temperatures between 20,6 e 27,8 °C. The transition between the state of comfort and stress begins respectively at 28,1 e 28,3 °C. The environment temperatures between 20,4 and 31,6 °C did not alter significantly the animal's physiological TR, that was maintained in 39,5 + 0,18 °C, which is considered normal for the species. The FR and the FC are the most affected variables in the transitions from the state of comfort to thermic stress and proved to be the best indicated mechanisms as verifiers of thermic discomfort for Canindé e Moxotó caprines in controlled environment conditions. The food consumption capability is not significantly altered in ambient temperatures between entre 20,4 e 31,6 °C, if the experimental conditions of this research are maintained. Water consumption is maximized in the environment average temperature of 31,6 °C, having a positive correlation with the increase of FC and FR at this temperature.