Effect of climatic environment on feed efficiency in swine

Since feed costs comprise about 60 to 70% of the total costs of production, efforts to reduce feed costs is then a major preoccupation for increasing competitiveness of the pig industry. Understanding the factors that affect feed conversion in pigs can enable producer to more effectively combine various inputs in order to achieve a low feeding cost. There are many factors involved in reaching good feed efficiency including genetic, diet, feed, management, housing and environment. Temperature is the single most important environmental factor affecting the global farm feed efficiency. In ad libitum fed animals, changes in metabolic heat production are essential mechanisms to maintain body temperature within a physiologically safe range under cold or heat stress. These adjustments have direct consequences on energy intake and/or maintenance requirements which in turn could reduce energy efficiency as conversion of feed to tissue or other products. However, the low level of performance related to a thermal challenge can also be attributed to a direct effect of ambient temperature (independent of feed intake) on reproductive physiology, health, and energy metabolism. Finally, thermal stress could also be a major cause of pig mortality at birth, during the nursing period or thereafter, and could predispose pigs to mortality or morbidity by other causes (starvation, diseases, etc.). High mortality rates in nursing piglets or in finishing pigs have a significant impact on overall farm feed efficiency. The chapter describes how climatic environment impacts feed efficiency in pigs and reviews solutions that can be used in order to attenuate the effect of environmental temperature on feed efficiency.