[Trembling in slaughtering pigs--an analysis of Swedish swine stock monitoring].

The incidence of trembling symptoms among pigs in the Swedish pig progeny testing scheme was highest among Land-race pigs (11%), Tab. I). Yorkshire, Hampshire and Duroc pigs had an incidence below 1%. Data on the incidence of trembling symptoms among 1716 adolescent Land-race pigs from one Swedish pig progeny testing station were analysed. The results showed no statistically significant difference in occurrence between sexes. According to Table II there were some phenotypic relationships between trembling and production traits. Pigs with trembling symptoms showed a higher daily gain as piglets, had a longer carcass and more lean in the carcass than non-trembling pigs. The heritability for trembling symptoms was estimated to be around 0.4.