COMBATING HEAT STRESS IN LAYING HENS A REVIEW

Abstract

Pakistan is located in the subtropical zone of the world where the ambient temperature remains higher most of the year and causes significant economic losses in commercial laying hens. The ambient temperature of some parts in Pakistan reaches up to 52 °C whilst, the ideal temperature for efficient performance for laying hens is 19-22°C. Yet, ambient temperature particularly on the higher side is very disruptive, therefore; heat stress during summer is a major problem of poultry producers in most regions of Pakistan. Several studies have investigated the biohazards of heat stress on production performance, physiology, immunology, digestibility of nutrients, hematology, serology, welfare, behavior and livability of commercial layers. During summer production at farms decreases drastically, thus adversely affecting the economics of layer farms, which might add to a number of culled birds. The key strategies to alleviate heat stress in laying birds are feeding practices and management practices. New innovative approaches such as exploiting and incorporating genes for heat tolerance and genetic marker assisted selection for genotypes with improved heat tolerance should also be explored. Therefore, this review article intends to discuss the effects of heat stress on layer birds’ health and production and various management and nutritional approaches to coping with it.