LUCENA, L. F. A.; http://lattes.cnpq.br/1440845732483551; LUCENA, Luiz Felipe de Almeida.
Résumé:
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.