Effects of dietary protein concentration and amino acid supplementation on the feeding behavior of multiparous lactating sows in a tropical humid climate.

Forty-seven mixed-parity Large White sows were used to determine the effect of diets with reduced CP content or supplemented with essential AA on 28-d lactation feeding behavior under humid tropical climatic conditions. The study was conducted at the INRA experimental facilities in Guadeloupe, French West Indies (latitude 16 degrees N, longitude 61 degrees W) between February 2007 and January 2008. Two seasons were distinguished a posteriori from climatic measurements continuously recorded in the open-front farrowing room. The average ambient temperature and average daily relative humidity for the warm season were 23.6 degrees C and 93.8%, respectively. The corresponding values for the hot season were 26.1 degrees C and 93.7%. The dietary experimental treatments were a normal protein diet (17.3%), a low protein diet (14.1%), and a normal protein diet supplemented with essential AA (17.6%). No interaction between season and diet composition was found for all criteria. Average daily feed intake was less (P < 0.01) during the hot season (4,559 +/- 161 vs. 5,713 +/- 204 kg/d). Meal size was reduced during the hot season (542 +/- 37 vs. 757 +/- 47 g/meal; P < 0.01). Daily ingestion time (45.5 +/- 3.2 vs. 55.8 +/- 4.0 min/d; P < 0.05) was less in the hot season. Meal size was reduced during the hot season at night (P < 0.01). In both seasons, daily feed intake, feed ingestion, and rate of feed intake were less (P < 0.01) during the nocturnal period than during the diurnal period. The number of meals per day was not affected (P > 0.10) by season or diet composition. Daily feed intake was greater for the sows fed the low protein diet when compared with normal protein treatments (P < 0.05). Duration of standing was not affected by diet or season (P > 0.05), and averaged 126 +/- 35 min/d. This study confirms that feeding behavior variables of the lactating sow are affected by seasonal pavariations of the tropical climate. Irrespective of season, the reduction of CP content improved feed consumption under tropical conditions.