EFFECT OF THERMAL ENVIRONMENT ON WATER AND FEED INTAKES IN RELATIONSHIP WITH GROWTH OF BUFFALO CALVES

Abstract

Eight buffalo calves, of six months of age with an average weight of 118 kg, were used to compare and assess their water and feed intakes and the average daily weight gain in response to constant heat stress (40 °C) and comfort (25 °C) conditions in thermo-controlled labs. The calves were divided into two groups in two labs, 4 calves under 40 °C and 87.5 % relative humidity (group, A) and 4 calves under 25 °C and 64 % relative humidity. Two stages were studied, each of one month interrupted by 15 days outdoors interval between the two stages. The mean values of daily water (WI) and feed (FI) intakes were computed for weekly intervals during the experimental stages. The animals were weighed initially and finally at each stage to calculate the average daily gain (ADG). The daily WI during the 1 st stage was greater under 40 °C by 20% than that under 25 °C, whereas the contrary occurred during the 2 nd stage. On the other hand, the FI was distinctly reduced by the effect of heat stress during the two stages in both concentrates and roughage. This effect of heat stress was great during the 1 st stage. The ADG in group (A) showed clear decrease (-0.49 kg/day) in BW during the 1 st stage while in the 2 nd stage there was almost maintenance of BW. In clear contrast, group (B) showed great increase in BW (1.11 kg/day) during the 1 st stage however the increase in the 2 nd stage was lower (0.45 kg/day). This study revealed that the major effect of temperature on growth is through control of FI. Under comfort temperature, in the 1 st stage the ADG increased positively with the increase in WI and FI, while in the 2 nd stage the calves showed less increase in spite of the increase in FI.