EFFECT OF HEAT STRESS AND FLOCK DENSITY ON PHYSIOLOGICAL AND IMMUNOLOGICAL RESPONSES OF BROILERS

Abstract

This work was carried out on 385 days old commercial Arbor­ Acres broiler chicks. The study included: field research carried out at the Poultry Research Center, Animal Production Department Faculty of Agriculture, Cairo University (from mid September until mid November 2000) and Laboratory investigations at the Faculty Laboratory and

Animal and Poultry Research Institute Laboratory, Dokki.

The study aimed to investigate the effects of early heat stress, flock density and heat + density on physiological response, immunological reactions and productive performance of broiler chickens raised under Egyptian environmental conditions.

The study included three experiments:-

Experiment 1: Early heat exposure.

I. 71, 3 days old chicks were exposed to heat stress at 42-43°C for four hours then moved to nonnal brooding temperature (I stgroup). 2. Another 96, 5 days old chicks were treated as in the first group

(2"ct group).

3. 68 chicks one day old were reared under nonnal brooding temperature without any treatment (3'ct group, control). 4. At 8 weeks of age, 30 birds from each of the three mentioned groups were heat challenged at 42-43°C for 3 hours.