Cerebral dopamine metabolism and stereotyped behaviour in early-weaned piglets

The behavioural response to apomorphine in cattle, sheep and pigs resembles some aberrant, oral behaviour patterns or vices that can occur as the result of restrictive environmental conditions and suggests that central dopaminergic neuronal systems might be involved. This study of the function of central dopaminergic mechanisms indicates that, in early-weaned piglets showing stereotyped snoutrubbing behaviour, there is a reduction in the metabolism of dopamine in parts of the brain receiving a dopaminergic neuronal input. The change in the metabolism of dopamine appears to be associated with the separation of the piglets from the sow and provides further evidence for biochemical changes in the brain occurring as the result of early-weaning.