Effects of Short-Term Fasting and Diurnal Heat Stress on Broiler Performance and Behavior

Abstract

Experiments were conducted to test the effect of short-term (2-day) fasting and diurnal heating of the rearing environment on the performance, carcass yield, and behavior of 49-day-old broilers. In Experiment 1, female broilers were used. Birds in the heated environment were exposed to air temperatures that were above 35 C for 1.2 h and above 32 C for 4.7 h/day. Neither heated environment nor fasting alone significantly affected body weight gain, water consumption, or carcass yield parameters. However, the combination of heating and fasting resulted in the greatest reduction of body weight gain. Heating the environment resulted in consistently reduced feed consumption. In Experiment 2, male broilers were used. Heat-stressed birds had rearing environment temperatures above 35 C for 4.4 h and above 32 C for 6.1 h/day. Both heating the environment and fasting resulted in losses in body weight, although the difference for the unheated and fasted group did not differ significantly, from the unheated and fed group. However, full-fed birds that were heat stressed had significant body weight losses when compared with unheated/fed birds. Heating of the environment significantly reduced daytime feed consumption by 67 g/bird. Total feed consumption was significantly affected by both heating and fasting. Treatments affected daytime and overnight water consumption values. Analysis of behavioral data suggested that fasting of birds exposed to high daytime temperatures stimulated behaviors better suited to survival than behaviors of fed birds.