Maintaining a consistent flow of good quality weaned pigs should be the
principal goal of a commercial swine operation, and to achieve this, producers
must consistently meet weekly breeding targets. PG600 (400 IU eCG and
200 IU hCG; Intervet, USA, De Soto, KS) has been proven to induce a
synchronized estrus in weaned sows. The primary objective of this study was
to determine effects of PG600 treatment at weaning on the percentage of
sows bred and subsequent litter sizes.
Primiparous crossbred (PIC C22 and C29) sows from a 5,000 sow commercial
farrow-to-wean facility were initially allocated to experiment by farrow weight
and genetics to 1 of 2 treatments: 1) PG: PG600 (n = 189) administered
intramuscularly in the sow’s neck on the morning of weaning or 2) CON (n =
218): no treatment at weaning. Sows were bred according to herd protocol,
depending on the day estrous was first detected. It was found that although the performance of PG and CON were similar in the
current study, the advantage PG600 at weaning was realized in a tighter and
more synchronous breeding “week” of 2-3 days, which in turn, focuses heat
stimulation, heat detection and breeding into a narrower time window resulting
in a decrease in the spread of time at farrowing of the subsequent litter and
thus age at weaning.