Abstract
A total of 191 crossbred sows were used to determine the effect of energy intake during one lactation on (1) sow and pig performance and (2) the percentage of sows in estrus by 7, 14, 21 and 70 d postweaning. Sows received 8 (Lo) or 16 (Hi) Meal of metabolizable energy (ME)/d (Exp. 1 and 2) and 8 (Lo), 12 (Md) or 16 (Hi) Meal of ME/d (Exp. 3) during a 28-d lactation period. All sows were fed an equal amount of crude protein, vitamins and minerals that met or exceeded the recommendations of the National Research Council. Each day after weaning, sows were fed 1.8 kg of a 14% crude protein diet and checked for estrus using boars. Serum samples were obtained weekly from sows not detected in estrus by 15 d postweaning for progesterone analysis. In Exp. 1 sows fed Lo lost more (P<.01) weight and backfat, and weaned lighter weight (P<.01) pigs than sows fed Hi. Fewer sows fed Lo exhibited estrus (P<.1) by 7, 14, 12 and 70 d postweaning than sows fed Hi. In Exp. 2, sows fed Lo lost more (P<.01) weight and backfat than sows fed Hi, but pig weaning weights did not differ. Fewer sows fed Lo expressed estrus by 7 d (P<.01) postweaning than those fed Hi. In Exp. 3 sow weight and backfat loss decreased (P<.01) linearly as energy intake increased. Pig weaning weights were not affected by energy intake. Fewer sows fed Lo expressed estrus (P<.05) by 7, 14, 21 and 70 d postweaning than those fed Md and Hi. There was no difference in the percentage of sows fed Md or Hi that exhibited estrus by these time periods. Blood samples collected on d 110 of gestation and d 14 and 26 of lactation, indicated that energy intake did not influence hematocrit values, total serum protein or albumin concentrations. A significant energy intake by time interaction was observed for serum blood urea N. Three of the 25 sows bled for progesterone analysis had luteal tissue activity suggesting ovulation had occurred even in the absence of a detected behavioral estrus. Copyright © 1982. American Society of Animal Science . Copyright 1982 by American Society of Animal Science.