Respostas fisiológicas de bovinos e bubalinos recebendo dietas com diferentes níveis de concentrado

Abstract

The objective of this work was to investigate the physiological responses of cattle and buffaloes to warm temperatures is affected when fed diets with different proportions of forage and concentrate. The experiment was conducted in the Animal Science Department at the Federal Rural University of Pernambuco, from February to June 2006. Four male buffaloes and four steers were fed diets with increasing levels of concentrate, on dry matter basis (DM). Animals were housed in individual pens with cemented floor and covered with asbestos-cement tiles. It was used a split-plot arrangement in a complete randomized experimental design. The experiment lasted for 114 days. The environment was monitored bya meteorological station installed at the experimental area. Thermoregulation was evaluated by measures of rectal temperature (RT), respiratory rate (RR), skin temperature (TP), and sweating rate (TSUD). Average air temperature ranged from 25.6 to 31.0 ºC, the temperature and humidity index (THI) from 76.0 to 81.6 the black globe temperature and humidity index (BGHI) from 77.7 to 84.8, and Radiant Thermal Charge (RTC) from 480.1 to 538.4 watts/m².Higher levels of concentrate in the diet of cattle and buffaloes increased RT, RR, and TP of animals, but these values remained within the normal physiological range.