Sow vaccination by combined oral and intramuscular antigen: a field study of maternal protection against neonatal Escherichia coli enteritis.

A field trial was conducted to test the efficacy of a vaccination programme which combines oral and parenteral antigen administration to produce IgM antibody in the colostrum of the sow. The trial involved 11 herds, each selected because of their history of neonatal Escherichia coli enteritis. Following more than 2300 farrowings, the progeny from vaccinated sows required 75 per cent less medication to maintain a good standard of health. The average neonatal mortality decreased from 13.8 to 7.0 per cent and the number of pigs weaned increased by 0.6 per litter.