Feeding value of grain sorghum for the lactating sow

Two experiments were conducted to investigate the effects of a corn-soybean meal (C-SBM) and a sorghum-soybean meal (S-SBM) diet on reproductive performance and nutrient utilization by sows. In Exp. 1, 75 sows (39 gilts; 36 primiparous) were fed either a C-SBM or a S-SBM gestation diet from breeding to d 109. On d 110, sows were assigned to lactation diets; half of the sows from each dietary treatment were assigned to a lactation diet based on the opposite grain. Sow weight change from d 54 to farrowing was greater (P less than .06) for sows fed S-SBM than for sows fed C-SBM. There was no difference (P greater than .50) in weight change of sows during lactation. Feed consumption during lactation was greater (P less than .01) for sows fed C-SBM than for sows fed S-SBM. Litter size at birth and d 21 did not differ between treatments (P greater than .13). Litter weights at birth were similar, but litters of sows fed C-SBM gained more weight (P less than .05) during the 21-d lactation than those fed S-SBM. There were no differences (P greater than .30) in the number of days from weaning to estrus. In Exp. 2, the energy and N metabolism of the two diets was compared in 12 lactating, primiparous sows from d 15 to 20 of lactation. Dry matter digestibility, DE and ME percentages were not affected by grain source (P greater than .46).