Epsilon Archive for Student Projects

Abstract

Differences in breeding goals in pig production have led to maternal breeds have a higher selection pressure on reproductive traits and paternal breeds have been focused on meat quality. In maternal breeds, this has led to an increase in the number of born piglets, but this is not something that all farmers desire as this put pressure on both the sow and the farmer. As a result of increased litter size, the number of piglets that die before weaning has also increased.
This study was part of a research project aiming at investigating crossing strategies with sire breeds in the maternal lines, as a strategy to achieve a more optimal litter size and thereby improve survival and growth in the litters. This pilot study investigated whether crossbreeds with sire breeds (Duroc and Hampshire) have any impact on the sow’s behavior, mainly during nursing in relation to her piglets, compared to the maternal crossbreed (Landrace and Yorkshire). Three crossbreeds were examined, where all had Yorkshire-genes and were crossed with either Duroc (YxD), Landrace (YxL) or Hampshire (YxH). The study has focused on examine lactation behavior from 9 sows and their litters (three of each crossbreed) by examine video material during the lactation. Analysis of activity from 18 sows around farrowing was also examined and the mean birth weight, litter size was examined from 38 litters and the mean growth rate from 37 litters.
The maternal behavior of the sow is a decisive factor for the survival of the piglets, especially during the very early life of the piglets. Within the next few days after farrowing, piglet mortality has been seen to be the highest, where low birth weight and crushing damage has been shown to be major contributing factors. Earlier studies have shown that sows may have some non-functioning teats, and this creates competition for teats to access nutrition between the piglets in the litter.
This study shows that there are some differences between the crossbreeds. Longer nursing times was seen in the maternal crossbreeds (YxL), compared to the paternal crossbreeds (YxD and YxH). The maternal crosses did not only have larger litter sizes, but they also had a higher average birth weight and daily growth. Furthermore, even though it was not significant, the maternal crosses can be seen to have a lower activity around farrowing compared to paternal crosses. The nursing frequency was slightly higher in the paternal crossbreeds (not significant) compared to the maternal crossbreed. Even if crossings with sire breeds result in smaller litters, it was not clear that this leads to better litter performance. This may be explained in part by inferior maternal ability in sire breeds.