25 December 1998

No damage from stone swallowing

CONCERN that stone chewing by outdoor sows leads to an increase in tooth damage, stomach laceration and ultimately premature death have been quashed by researchers.

According to CAMBACs Tracy Jones, an inspection of 150 stomachs from outdoor sows and 50 stomachs from indoor sows found no difference in stomach damage relating to stone swallowing.

During the study, researcher Zoe Davies extracted up to 1.2kg of stones from sow stomachs, although the average stomach contained just 170g of stones of 2cm – 4cm (0.75in – 1.6 in) in length. An average sample of outdoor sow dung commonly contained 204g of stones while stone retained in the mouth amounted to 35g a sow. Tooth wear also differed. The study looking at 50 heads from outdoor sows and 25 heads from indoor sows found that outdoor sows had more wear to the upper and lower molars caused by grinding stones. Indoor sows had more wear on lower incisors. But researchers were unable to draw any firm conclusions from this, explains Ms Jones.