Tip of The Day - October 4, 2016

Photo by Tom Semadeni

Finch hiding

1987 Aggressive Behaviour of Sows

Hein van der Steen was a visitor from the Netherlands in 1987 and later became employed by PIC in the USA.

Sows, especially primiparous, may show aggressive behaviour at parturition against their own piglets, resulting in wounding or death of the piglets. The frequency, environmental influences, and heritability of aggressive behaviour were studied in two data sets. The first was based on 923 first litters collected on an experimental farm in Wageningen from 1976 to 1984. The other was 925 first litters from a nucleus herds of a Dutch breeding company.

The frequency of aggressiveness ranged from 7 to 12% of the litters. Fixed effects of year, season and feeding levels during the rearing period did not affect the frequency of aggressiveness. A less favourable environment might predispose aggressive behaviour if the sow has to carry a large litter.

Heritability of aggressiveness on the underlying normal scale (threshold model analysis) were 0.12 for the first data set, and 0.25 for the second. Heritabilities estimated by daughter-dam regressions were 0.49 and 0.87, respectively, and might indicate the existence of significant maternal effects.

On a practical basis, boars and gilts should be selected from litters of non-aggressive sows only. Response to selection would be slow due to the low frequencies of the problem. Otherwise, estimated breeding values should be calculated and utilized to combine performance of the sow itself, and data from relatives.

Photo by Tom Semadeni

Foggy morning