Effect of the temperature of the rearing house on subsequent productivity of hens during the laying period

Abstract

An experiment was carried out to study the effects o o of one of two environmental temperatures (22 C and 32 C) during the rearing period on the productivity of two strains of birds kept at one of two environmental temp- eratures(22°C and 32°C) during the laying period. Thirty- two pullets of each strain were used. They were subdivided equally into four treatment groups. The treatments were combinations of high (H) and low (L) environmental temperatures during the rearing period and high (H) and low (L) environmental temperatures during the rearing period (i.e. H H, H L, L H, L L,). The rearing period began when the pullets were one week old and lasted until they were 20 weeks old. The laying period began when the pullets were 20 weeks old and was terminated when they were 28 weeks old.

The acclimatization of pullets to the high temperature during rearing was sufficient to prevent a delay in age at sexual maturity normally associated with high environmental temperatures during rearing. Temperature treatment during the rearing period had no effect on subsequent egg production. Growth rate during the rearing period was apparently modified by the effects of environmental temperature on food intake. There was a slight apparent effect of rearing treatment on cloacal temperature in both the high and low temperature environments of the laying period. Environmental temperature during the laying phase had marked effects on productivity. High environmental temperatures during the laying period resulted in an increase in cloacal temperature and daily water intake and a reduction in food intake, body weight, egg production, egg weight and shell thickness. Efficiency of food utilization was similar in all treatments.

There was no evidence that the rearing treatments had no significant effect on productivity in the subsequent laying period. It was therefore concluded that rearing birds in a high temperature environment did not result in any marked acclimatization that would have beneficial effects for laying pullets in a hot environment.