Influence of PG600 at Weaning of the First Litter does not Affect Sow Lifetime Performance

R.N. Kirkwood and L.A. Goonewardene

Alberta Pork Research Centre; Alberta Agriculture food and Rural Development, 905 O.S. Longman Building, 6909-116 Street, Edmonton, AB, Canada T6H 4P2

In a recent study the use of PG600 at weaning of primiparous sows was shown to greatly facilitate the achievement of breeding targets. However, in this study, the second litter size was reduced. The present study employed the database from one of the study herds and is a retrospective analysis of relationships between the PG600 treatment and lifetime sow productivity, defined as either number of litters produced or total number of pigs produced. The experimental period was terminated at breeding to produce the sixth litter. Hypotheses tested were that PG600 would allow the breeding of infertile sows resulting in an overall reduction in sow longevity and pig production and that sows responding to PG600 promptly were inherently more productive.

Analysis of variance indicated no treatment effect on either total pigs born (36.6 vs 35.9; P=0.5) or on litters produced (3.3 vs 3.2; P=0.9) for control and PG600-treated, respectively. For PG600-treated sows, regression analysis of total pigs produced and total litters produced on the first wean-to-estrus interval revealed a positive relationship (P<0.02) for pigs born and no relationship for litter production (P<0.3). However, wean-to-estrus interval accounted for only 2% or the variation.

The data indicate that PG600 treatment of primiparous sows does not result in the breeding of otherwise infertile sows but that the response to PG600 will not be predictive of subsequent sow performance.

Implication: PG600 can be used to improve the management of primiparous sows without fear of long term consequences for breeding herd performance.