A study of the effect of a hot environment on productivity and the strategies to manage heat stress in Japanese Black fattening cattle

Abstract

This study was conducted to determine the effects of a hot environment on productivity and to consider the strategies for heat stress management of Japanese Black fattening cattle. First, we investigated the effect of a hot environment on feeding performance and feed digestibility in Japanese Black fattening steers. The results demonstrated that heat influenced the productivity of Japanese Black fattening steers to differing degrees based on the fattening stages, and it reduced feed digestibility during the late fattening stage. In order to improve feed digestibility in Japanese Black fattening steers during the hot season in the late fattening stage, the effect of restricted feeding on feed digestibility and growth performance was examined. It was determined that restricted feeding reduced the adverse effects of a hot environment on feed digestibility, especially crude protein digestibility and nitrogen retention. Furthermore, to enhance the effect of restricted feeding on feed digestibility of steers, we evaluated the use of wood kraft pulp (KP) as a replacement concentrate on feed digestibility and rumen properties of Japanese Black fattening steers. Subsequent feed digestibility, especially fiber digestibility, was higher in steers fed the KP diet than in the controls. Increased fiber digestibility could be attributed to a decreased proportion of starch in the diet.