Reproductive performance of sows bred in different days after weaning their litters

The authors studied the reproductive performance of sows bred in different days after weaning their litters in eight commercial farms. Results showed that the sows had an average parity of 3.53 litters. These sows were bred as they come in heat or they were culled as normally practiced in the farms. Of the 8,519 sows, 13.28% were culled at weaning or were not bred anymore to farrow the next litter for various reasons. Of the 7,388 sows (86.72%), 5,665 (76.68%) farrowed, 1,092 (14.78%) were repeat breeders and 631 (8.54%) were culled for various reasons. The repeat breeder sows had 77.75% farrowing rate. In five of the eight farms, majority of the sows were bred in day 5 after weaning, whereas, in the remaining three farms, majority of the sows were bred in day 4. Altogether, almost the same number of sows was bred in 4 and 5 days after weaning, comprising 62.74% of all sows. On the average, 88.55% of the sows were bred within 14 days postweaning. Farrowing rate was highest for sows bred on day 1 (85.19%), followed by sows bred in the fourth week postweaning. Most farms had higher farrowing rates for sows bred in day 4 than those sows bred in day 5 postweaning. There were drastic drops in farrowing rates for sows bred in 6 and 7 and on the second and third week postweaning. The average total litter size at birth and at weaning, pig birth weight, and 30-day weaning weight of the pigs were apparently not affected by the day of breeding and sows postweaning. However, the relatively larger litter size at birth and at weaning and the slightly heavier pigs at weaning for sows bred on the fifth recommendation of culling sows at 30 days postweaning if they are not yet bred maybe modified to 35 days to take advantage of this new information. Of the 1131 sows, 401 were culled due to old age and 194 due to low production equivalent to 52.61% combined. Another 194 sows (17.15%) were culled due to long dry period and 115 sows (10.17%) due to leg problems. Of the 631 sows, 408 sows or 64.66% were culled for failure to conceive and 130 or 20.60% due to abortion and premature farrowing. The sows culled for failure to conceive ranged from 40 to 85.56% on a farm basis; abortion and premature birth ranged from 10 to 40%. These two causes of culling bred sows resulting to 85.26% of the listed cause of culling should not be taken for granted