Increasing behavioral oestrus strength is expected to offer several economic benefits to producers. Strong visible symptoms of oestrus should result in reduced missed heat cycles, decreased non-productive sow days and increased pigs per sow per year. Additionally, easily detectable oestrus symptoms would reduce inappropriate culling for reproductive failure actually caused by missed heat detection.

Drs Joe Cassady and Todd See along with their collaborators conducted a study to develop methods for measuring oestrus in swine and to estimate variance components for genetic correlations among these variables and production traits.

They identified several indicators that could be incorporated into breeding programmes but felt that length of oestrus and/or age at puberty (or a similar trait, such as age at first mating or age at first farrowing) are the most promising of the oestrus traits they measured to incorporate into current selection schemes.

They do caution that before implementing selection programmes for oestrus traits, economic values should be calculated and correlations with sow reproductive performance should be estimated.

This research is reported in its entirety as Estimates of variance components for genetic correlations among swine oestrus traits in Journal of Animal Science, 2010. 88:2913–2919.

November 2010