Evaluation of the zootechnical parameters of vaccinating against swine enzootic pneumonia under field conditions

A field test was carried out in different production systems to evaluate th e effect of vaccination against swine enzootic pneumonia with an inactivate d vaccine. A total of 13,691 pigs of four different genetic origins were us ed, of which 7351 were vaccinated and 6340 were used as controls. The anima ls were housed in 16 fattening units, in which the 'one-site: 'two-site' an d 'three-site' production systems were represented. There were the followin g statistically significant differences in favour of the vaccinated animals : a 1.89 per cent lower mortality (P<0.001), a 0.09 lower feed conversion r atio (P<0.030), a 3.12 per cent lower cost per kilogram gained in fattening (P<0.031),a 4.02 per cent lower cost per kilogram of carcase (P<0.018), a 3.77 per cent lower cost of feed per kilogram gained in fattening (P<0.012) and a 56.75 per cent lower potential loss of profit per kilogram gained in fattening due to mortality (P<0.001). An analysis of variance of the effec ts of genetic origin, treatment and production system on the different para meters showed that only the treatment had any statistically significant eff ect on the percentage mortality (P<0.002), feed conversion ratio (P<0.030), cost per kilogram gained in fattening (P<0.019), cosa per kilogram of carc ase (P<0.020), cost of feed per Idiogram gained in fattening (P<0.015) and potential loss of profit per kilogram gained in fattening due to mortality (P<0.002).