Effectiveness of a novel method to reduce heat stress in broilers: A cool roost system

摘要

Effective and economical techniques to minimize production losses that result from heat stress are important in the broiler industry. Zone cooling, as opposed to whole-house cooling, during hot weather may be effective in relieving heat stress. The present studies seek to determine the effectiveness of such a practice. Two flocks (I and 2) were raised sequentially for 42 days. Studies were analyzed separately, and when the results of the two studies were consistent, a combined analysis was completed and reported. Means comparison tests were completed on production parameters at harvest (day 42). Cool roost birds showed greater live weight and roost use, lower mortality, and lower feed-to-gain ratios than ambient roost and floor birds, respectively. The parts yield analysis showed that wing weight was greater in the floor-raised birds than in either the cool roost or ambient roost raised birds in flock 1. In flock 2, the cool roost birds showed a greater breast meat weight than the ambient roost birds. The cool roost system appeared to be more efficient at relieving heat stress at temperatures below 30 degreesC than at temperatures above 30 degreesC. Heat loss through the feet of birds ranged between 0.65 and 5.09 watts per bird during week 6 in either flock (chamber air temperature varied from 29 degreesC to 37 degreesC). Moisture condensation on the cool roost system did not significantly increase the litter moisture content in the cool roost treatment beyond that of the ambient roost system.