The amount of straw for growing-finishing pigs considering the reduction of time spent in manipulative behavior

The behavior of rooting and digging is highly motivated in the pig. The motivation to perform this exploratory behavior is not reduced even after the dietary requirement has been fulfilled through feeding. The aim of this study was to identify the minimal amounts of straw needed to satisfy pig motivation for manipulation and reduce to a minimum the manipulating behavior of pigs directed toward pen mates. To determine the minimal amount of straw needed for conventional growing-finishing pigs, a study using 168 pigs provided with 7 different amounts of straw (20, 40, 60, 80, 100, 200 or 300 grams/ pig/ day) was performed. The straw was provided either once or four times per day. Behavior observations were made using focal animal sampling and continuous recording for one hour between 9 and 10 am and between 3 and 4 pm. The time spent by the pigs manipulating straw increased over 10% ranging up to 27% in all the pens receiving over 200g of straw per day compared to the range from 4-22% in pens receiving 20-100g of straw. Meanwhile, the time spent in redirected behavior decreased below 5% in all the pens receiving over 200g of straw per day. No significant differences were found when comparing pens provided with straw once or four times per day.