Feeding to minimise heat stress

摘要

Broilers and layers perform less efficiently during periods of hot weather. Minimise these ill effect by making changes to the diet specification and to feeding practices. Animals are subject to stress from a number of sources, among them management/husbandry practices, nutrition and environment. For poultry in tropical countries, environmental temperature is one of the major stressors because this can range from -5 up to 35-43 deg C for prolonged periods. The ideal temperature for broilers is 10-22 deg C for optimum body weight and 15-27 deg C for feed efficiency. Layers will produce eggs constantly in the temperature range of 10-30 deg C. Above 30 deg C, performance will be depressed in terms of growth, feed intake, egg production, egg size andeggshell quality. Nutritional imbalances can also result from poor quality control and lack of regulations for feeds, feed ingredients and feed additives. Furthermore, mycotoxins develop very quickly in hot and humid conditions, leading to loss of production, immunosuppression and higher mortality. Routine management practices, e.g. medication, vaccination, beak-trimming etc, also add to the stress.