Abstract
Thirty-five litters were weaned at either 10, 21, or 56 days of age. Pig and sow feed costs, pig growth rate and sow reproductive behavior were obtained. The days required to exhibit the first post-weaning estrus were 9.4, 6.25, and 4.0 (P<0.05) for the 10, 21, and 56 day groups, respectively. Two sows (20%) in the 10-day group had cystic ovaries. The ovulation rate for the 10,- 21,- and 56-day groups was 12.8, 15.2, and 16.6 ova, respectively (P≅0.06). The percent of the recovered ova showing normal cleavage did not differ for the three groups. Pigs weaned at 10 days of age failed to survive under the conditions of this study. Sows whose litters were weaned at 56 days of age lost 15 lb. from the 21st to the 56th day and feed cost per pound of gain in the 21-day weaned pigs did not differ from those weaned at 56 days. Pigs weaned at 21 days of age and held in one large group gained significantly slower from the 21st to the 56th day of age than pigs weaned at 56 days (0.50 and 0.74 lb., respectively, P<0.05). Copyright © . .