26 January 1996

Clear-out and clean-up keeps pig disease down

DEPOPULATING and disinfecting nursery units improves productivity in pig farms suffering chronic infections, such as porcine reproductive and respiratory syndrome, according to the Veterinary Record (Jan 13, 1996).

The process prevents spread of infection from older, previously infected piglets to younger animals entering the unit after weaning. Benefits in improved growth rates and lower mortality were recorded in small and medium-sized farms.

Researchers examined whether sequential depopulation had the same effects in a large US unit with five herds containing about 1000 breeding sows. Over four-weeks four nursery units were emptied and cleaned while the piglets were transferred to fattening facilities on the fifth. Their biological and financial performance during the 12 months before and after the process was then compared.

The authors estimate that the increase in the numbers of marketable pigs earned an extra $345 (£225) a sow. &#42