Cost comparisons are made difficult by numerous factors, not least the difference in the methods used to control the health of a pig unit. A report from Canada illustrates the point when it looks at measures tried on a large Canadian unit to combat porcine proliferative enteropathy (PPE), better known internationally as ileitis.

In their paper called 'Ileitis vaccination delivers efficacy and cost benefits over in-feed medication', authors Silvain Messier (Clinique Demeter, St-Nicolas, Quebec) and Ernest Sanford (Boehringer Ingelheim Canada Ltd, Vetmedica Division) describe attempts at controlling the disease in this herd either by antibiotic treatments or by vaccinating. The herd in this instance was in fact a multi-site enterprise of 23 250 sows in which the mortality from sporadic acute PPE had varied up to about 1%.

Its control before 2006 had been based on giving 22ppm of lincomycin in the pigs' feed from 21 weeks of age through to the end of finishing. But in 2006 the dosage was increased to 44ppm from 18 weeks old because the network still experienced ileitis problems. Furthermore, tylosin in the water at 10 mg/kg bodyweight and individual injections of lincomycin given intramuscularly were needed to treat outbreaks in up to 50% of batches in some pyramids.

This meant a cost of C$2.54 per pig for medication related to PPE control in the most clinically active pyramid, according to the producer. The same structure was selected for a trial comparing 44ppm lincomycin from 18 weeks with the use of Enterisol Ileitis vaccine given orally at about 77 days old, between 5-7 days after the pigs arrived in the finishing house.

Each group comprised 10 batches of 2100 pigs per batch. The Canadian authors say vaccination effectively prevented clinical signs of ileitis and the vaccinated pigs were numerically better on performance than their counterparts receiving the system's medication programme. The difference became statistically significant (p 0.05) in the case of pigs that went on to be in the ideal market grid for top price. Their economic advantage worked out to be C$1.90 per pig. When the operators of the network added measurements that were numerically but not statistically better, they calculated that their production system obtained a net gain of C$3.87 per pig from vaccinated versus medicated groups.  PIGI