Impact of amount of straw on pig and pen hygiene in partly slatted flooring systems

BACKGROUND: Straw is a beneficial enrichment material for pigs, shown to improve welfare through reducing tail biting. Straw has previously been identified as one of the means of how to raise pigs without tail docking, through improving natural exploratory behaviour. Straw has however been linked to poor pen hygiene, making farmers reluctant to use straw and has largely not been implemented in commercial farming worldwide. Straw is a beneficial enrichment material for pigs, shown to improve welfare and reduce abnormal behaviour such as tail biting. RESULTS: This study investigates the impact of straw on pig and pen hygiene in pens with partly slatted floor in three grower and four finishing pig batches on five commercial farms (2329 pigs, 211 pens) in Sweden which were providing straw daily. Each batch was divided into two treatments; Control: 50-600 g straw/pen/day based on the farm normal straw ration; and Extra straw; (=doubled Control ration). The pens were scored based on cleanliness of the pigs, solid and slatted pen floor every second week. The pig and pen hygiene were mostly scored as clean in both treatments, overall around 1% of the observations were considered dirty/soiled. CONCLUSIONS: As very few pens or pigs were considered dirty, it was concluded that straw provision is possible without risking poor pig and pen hygiene. Few observations in this study were considered dirty regardless of amount of straw that was provided, and had likely to do with other factors in the production rather than straw ration. These results implies that straw could be used in partly slatted pens in order to improve pig environment but more research is needed to quantify the impact of other external factors related to climate (e.g. temperature, humidity, velocity).