Epsilon Archive for Student Projects

Abstract

The objectives of this experimental study were to investigate if a strategic method to supply loose housed sows with large quantities of straw 2 days before expected farrowing and if the sow’s body condition had any effect on the occurrence of shoulder lesions 5 weeks after farrowing. Data came from a study conducted on four commercial piglet-producing farms in southwest Sweden between March and December 2009. At each farm one batch of sows was followed during two consecutive lactations. The sows were randomly assigned to two different treatment groups and the sows that remained in the batch during the second lactation switched treatment group. In the treatment group (n=163 farrowings) sows were provided with 15–20 kg of chopped straw 2 days before expected farrowing. Sows in the control group (n=161 farrowings) received 0.5–1 kg of chopped straw on a daily basis plus 2 kg for nest building when the stockperson judged that the sow was about to farrow. After the sows was moved to farrowing pens (0-9 days before actual farrowing), body condition was measured with ultrasound equipment and a back-fat thickness of ≤12 mm was denoted “low body condition” (n=41 farrowings) while higher values were denoted “high body condition” (n=283 farrowings). Shoulder lesions were recorded on a 5-point scale (score 0-4) after the sows was moved to farrowing pens and approximately 5 weeks after farrowing. Data were analysed using z-tests for proportions. The provision of 15–20 kg of straw 2 days prior to expected farrowing could not be shown to affect the prevalence of shoulder lesions. On the other hand, the sows’ body condition before farrowing had a strong effect on the development of shoulder lesions. The percentage of shoulder lesions after farrowings with a low and high body condition score was 71 and 39 percent, respectively (z=4.20, p<0.001). In sows with a low condition score, the difference in the prevalence of shoulder lesions of scores 3-4 between treatment and control groups (15 and 33 percent, respectively) indicates that large quantities of straw can reduce the risk of severe shoulder lesions in lean sows. In conclusion, piglet producers should keep their farrowing sows in good body condition to prevent shoulder lesions. Strategic supply of large quantities of straw before farrowing can be effective in reducing the risk of severe lesions, but further research is needed.