Long-term effects of straw blocks in pens with finishing pigs and the interaction with boar type

This study verified the effect of straw blocks on the behavior and growth of finishing pigs and possibleinteractions with the genetic background (boar type). A total of 359 finishing pigs, which were offspringfrom different boar types, were housed in gender-mixed pens with slatted floors. Half of these pigsdescended from sires selected for better carcass traits and lower growth rates (type C) and the other halffrom sires selected for better growth and poorer carcass traits (type G). The offspring of these two boartypes were spread equally over control (only a chain) and treatment groups (chain and straw blocks in adispenser). Direct individual behavioral observations were carried out once a week and the presence oflesions on the body was verified every two weeks. Individual weights were recorded at different weighingmoments. Lesions on organs and carcass traits were obtained after slaughter.A lower frequency of pen mate manipulation was observed in pens with access to straw blocks in typeG pigs. For type C pigs however, no significant difference was present in pen mate manipulation betweengroups with or without straw. It has been shown that pigs selected for high lean tissue growth rate showhigher frequencies of tail biting behavior and in this study, providing straw blocks does not seem to besufficient to decrease this behavior. These pigs also showed more pen manipulation, which might reflectan increased foraging motivation or motivation to explore. Mounting and fighting were recorded morefrequently at the start of the finishing phase and in this period significantly more in pens with strawblocks, which might be related to both competition for straw and introduction in a new environment.Growth was not significantly affected by the presence of straw blocks. Type G pigs however reachedhigher slaughter weights compared to type C pigs, but no interaction with the presence of straw wasseen.It can be concluded that in general, straw blocks decreased the manipulation of pen mates in finishingpigs, but this effect was only seen in pigs selected for better growth. Pigs predisposed to a higher leanmeat percentage showed in general higher frequencies of this behavior and in these pigs, straw blocksdid not reduce pen mate manipulation compared to more barren environments. In general, the presenceof the straw blocks seemed to be associated with more competition related behavior in the beginning ofthe fattening period. The presence of straw did not affect growth or carcass traits.

Publication year:2016

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Authors from:Higher Education

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