"Gasto energético para deslocamento em bovinos"

Abstract

The objective of this study was to evaluate the heat production of Holstein heifers in continuous or intermittent exercise. The experiment was conducted between June and August 2016, with the first two months of training. Four Holstein heifers with a mean body weight of 302.75 ± 67 kg were used in a completely randomized design. The oxygen consumption was measured using a respirometric mask of a closed circuit, and the animals remained with the mask throughout the evaluation time. The respirometric mask was connected to two exhaust tubes to continuously circulate the air between the mask and the container and the muzzle of the animal, so that all breathing air circulated through the container. Three treatments were evaluated: rest, continuous and intermittent locomotion. In the continuous treatment the animals walked continuously for four cycles and in the intermittent treatment, the animals stopped walking at the end of each cycle, again walking again at the time of the exits closing. The displacement was performed in circular circuit with 15.4 m distance, noting the time of each turn and the number of turns in each cycle. The oxygen consumption was determined by the difference of the initial and final oxygen concentration inside the container obtained by the oximeter. The heat production was calculated by multiplying the oxygen consumption, assuming 4.89 kcal / L O2 consumed. The speed of the animals in continuous and intermittent exercise had no effect. With regard to oxygen consumption, no effect was found when comparing exercise types. When compared to rest with exercise, effect was observed. Heat production had no effect between the types of exercise, only between rest and exercise. The increase in heat production had no effect between continuous and intermittent exercise. No effect of the type of exercise was observed in the heat production of Holstein heifers.