Effect of dietary arginine supplementation and environmental temperature on sow lactation performance

The objective of this study was to investigate whether supplemental dietary arginine increases lactation performance in sows subjected to a hot enviro nment. A total of 66 multiparous sows were allotted in a 2 X 3 factorial ar rangement, consisting of two environments and three dietary treatments. Sow s were maintained in a thermoneutral environment of 20 degreesC (TN) or hea t-stressed in a hot environment of 29.4 degreesC (HS), starting on day 95 o f gestation. From day 110 of gestation to weaning, sows were provided one o f three corn-soybean meal based dietary treatments formulated to contain 0. 96% arginine (1:1 arginine:lysine), 1.34% arginine (1.4:1 arginine:lysine), and 1.73% arginine (1.8:1 arginine:lysine), for control (C), medium (ME), and high (HI) dietary treatments, respectively. Respiration rate and rectal temperature increased in HS sows compared to TN sows (P < 0.01) and heart rate decreased in HS sows (P < 0.05) compared to TN sows. Arginine suppleme ntation did not affect heart rate and respiration rate; however, it tended to decrease rectal temperature (P < 0.10) in sows fed the ME diet in the th ermoneutral environment. Litter weight gain (P < 0.05) and voluntary sow fe ed intake (P < 0.01) decreased and sow weight loss increased (P < 0.01) in the hot environment. Dietary arginine supplementation did not improve litte r weight gain (P > 0.10) for either HS or TN sows. Arginine supplementation reduced feed intake (P < 0.05) and tended to reduce body weight loss (P=0. 06) during lactation. In conclusion, supplemental arginine in lactating sow diets in a hot environment did not improve litter performance but reduced sow weight loss and increased sow feed efficiency. (C) 2001 Elsevier Scienc e B.V. All rights reserved.