2011 Volume 16 Issue 1 Pages 21-22
Use of fostering technique is common in commercial breeding herds. Using fostering technique makes it possible to be a higher number of pigs weaned by a sow (PW) than the pigs born alive to that sow at farrowing (PBA). The objective of the present study was to compare the relationship between reproductive performance of sows and sow groups based on the difference between PBA and PW (PBA-minus-PW) by parity and herd groups that were performing differently.
The present study included 164,407 parity records of 61,135 sows farrowed during 2007 and 2008 in 113 Japanese commercial herds. Sows were classified into two PW groups on the basis of PBA-minus-PW:namely Increased-PW (PBA<PW) and Decreased-PW (PBAPW) groups. Herds were classified into three groups on the basis of upper and lower 25th percentiles of pigs weaned per mated female per year:high-, intermediate- and low-performing herds. Two-level analysis was applied using a herd at level 2 and an individual record at level 1. Parity 1 and parity 2 or higher sows were separately analyzed.
Of 164,407 parity records, 24.8% had more PW at weaning than PBA at farrowing. Means (±SEM) of PBA-minus-PW in Increased-PW sows in parity 1 and parity 2 or higher were -2.8±0.02 and -2.7±0.05 pigs, respectively. High-performing herds had more Increased-PW sows than low-performing herds (24.9 vs. 20.1%; P < 0.05).
Increased-PW sows had fewer PBA at farrowing and higher PBA-minus-PW than Decreased-PW sows in any parity groups (P<0.05). Increased-PW sows had heavier adjusted 21-day litter weight than Decreased-PW sows (P<0.05). Increased-PW sows in parity 1 had 0.5 days longer WMI than those in the Decreased-PW group (P<0.05), but there was no such difference in parity 2 or higher sows (P=0.62). Additionally, Increased-PW sows had lower farrowing percentage and fewer subsequent PBA in any parity sows (P<0.05).
In summary, Increased-PW sows had heavier adjusted 21-day litter weight than Decreased-PW group. However, Increased-PW sows in parity 1 appear to have longer WMI, lower farrowing percentage and fewer subsequent PBA than Decreased-PW sows.
