EFFECTS OF CLIMATIC CONDITIONS ON THE PERFORMANCE, METABOLISM AND HEALTH-STATUS OF WEANED PIGLETS - A REVIEW

This review discusses current information on the effects of climatic conditions on performance, metabolism and health status of weaned piglets raised in intensive conditions, and on the acclimation mechanisms of the piglets to cold environment. Ambient temperature is the predominant component of the climatic environment, and since weaning is associated with rapid changes in food intake, requirements for ambient temperature are examined in relation to food intake. The critical period immediately postweaning, corresponding to the time required to attain the preweaning level of food intake, is characterized by a loss of body fat and a decrease in thermal insulation. During this period current recommendations are for constant temperature of 26-28-degrees-C for piglets penned on perforated floors. During the postcritical period, i.e., once regular food intake is established, the ambient temperature can be reduced by 2-3-degrees-C per week until the temperature to be maintained in the finishing house is reached. Ways of reducing the heating cost, including provision of a microenvironment, reduction of the nocturnal temperature and of overall temperature are discussed. Effects of other thermal components including, air movement, relative humidity and type of floor are assessed by their effects on the lower critical temperature, performance and behaviour. Mechanisms of acclimation to cold environment are presented in terms of behavioural, physiological and metabolic adjustments. There is evidence that the increase in heat production in cold is associated with an increase in the turnover of both FFA and glucose and involves changes in thyroid hormones and catecholamines. Finally, diarrhoea is the most common clinical problem encountered in the first weeks after weaning. Data suggest a complex effect of weaning, level of food intake and non optimal climatic conditions on the health status of the weaned piglet.