Serum paraoxonase-1 activity in neonatal calves: age related variations and comparison between healthy and sick animals.

Early detection of inflammation in neonatal calves allows early intervention, which may reduce mortality. Paraoxonase-1 (PON1) is a negative acute phase protein in humans. The aims of this study were to investigate age-related variability in serum PON1 activity and its clinical usefulness in neonatal calves. In healthy calves (n=9), PON1 activity increased with age from 2 to 21 days of age. There was no significant increase in PON1 activity in healthy calves from days 21 to 120 (n=15), but PON1 activity was significantly higher in adult cattle (n=45). In sick calves, serum PON1 was significantly lower in calves <7 days of age with diarrhoea (n=8) and in calves >28- to 120-days-old with respiratory disease (n=8) in comparison with age matched controls (n=20 and n=15, respectively). These results support the role of PON1 as a negative acute phase protein in cattle.