Effects of dietary protein levels during lactation to first-litter sows fed a fortified corn gestation diet.

Abstract

Two experiments were each conducted at two locations to determine the efficacy of feeding varying dietary protein levels to first-litter lactating sows that had been fed a fortified corn diet (8.2% C.P.) during gestation. Gilts at both locations were limit fed the corn diet approximately 30 days prebreeding and throughout pregnancy at the rate of 1.82 kg/day. Lactation diets were fed after parturition on a restricted basis the first week postpartum then ad libitum until weaning (28 days). Creep feed was not supplied to the pigs. Lactation diets containing from 12 to 20% protein were formulated by altering the ratio of corn and soybean meal. Litter size was equalized to eight pigs in the first experiment but not in the second. Total protein concentrations in milk and blood serum were determined on days 14 and 28 postpartum of the second experiment. Although there were differences between locations, overall gestation performance was satisfactory. Sow weight loss was greatest and feed intake, litter gain and pig weight at weaning were lowest when the lower protein level was fed. Sow feed intakes and pig gains increased by 14 and 28 days as sow dietary protein levels increased. The number of pigs weaned per litter was not affected by lactation protein level (Experiment II). Milk protein concentrations on days 14 and 28 were somewhat indicative of pig performance but was not significantly correlated. These results suggest that sows fed a corn gestation diet may have a higher dietary amino acid requirement during lactation than sows fed higher gestation protein levels.