Large quantities of straw at farrowing prevents bruising and increases weight gain in piglets.

Two major welfare issues in current pig production are the lack of nesting material for farrowing sows and poor claw health in suckling piglets. Therefore, a strategic method to supply loose housed sows with large quantities of straw at farrowing has been developed by Swedish piglet-producing farmers. The objective of this cohort study was to estimate the effect of a large quantity of straw (15-20 kg) supplied before farrowing compared to limited daily amounts (0.5-1 kg) on bruising and growth performance in pre-weaning piglets. On each of four commercial piglet-producing farms in south-west Sweden, one batch of sows was studied during two consecutive lactations. At inclusion, sows were randomly assigned to two treatment groups, and sows remaining in the batch during the second lactation switched treatment group. In the STRAW group (n=181 litters) sows were provided with 15-20 kg of chopped straw 2 days prior to expected farrowing. Sows in the CONTROL group (n=182 litters) received 0.5-1 kg of chopped straw on a daily basis plus 2 kg for nest building when the stockperson judged the sow to be about to farrow. Piglets were individually weighed within 36 h after birth, at 3-7 days after birth and at weaning. On day 3-7, limbs and feet were clinically examined for the presence and location of lesions. In conclusion, the provision of 15-20 kg of straw 2 days prior to farrowing effectively prevents the piglets from developing skin abrasions (IRR=0.38) and soft heel/sole erosions (IRR=0.08-0.35). We also conclude that the strategic use of large quantities of straw has a positive effect on weight gain, increasing the expected mean body weight at weaning by 0.33 kg.