THE EFFECT OF VACCINATION AGAINST MYCOPLASMA-HYOPNEUMONIAE IN PIG HERDS WITH A CONTINUOUS PRODUCTION SYSTEM

An inactivated Mycoplasma hyopneumoniae vaccine was evaluated in five pig herds clinically infected with enzootic pneumonia and practising a continuous production system in the growing/finishing unit In each he rd, a vaccinated and control group of approximately 47 pigs each were individually monitored from birth until slaughter. Vaccinated pigs rec eived the first dose at about 1 week of age and the second approximate ly 3 weeks later. During ail production stages, an equal number of vac cinated and control pigs was present in the same pen. Both groups were compared with respect to zootechnical parameters (major variables) an d by means of serological, pathological, and bacteriological parameter s (ancillary variables). Daily weight gain was improved by 14 gr/day d uring the period from 8 days of age until slaughter (P = 0.0486) and b y 25 gr/day during the growing/finishing period (P = 0.0067). Mortalit y rate, and the costs for curative medication were not significantly i mproved by vaccination. The results of the ancillary variables are pre sented and discussed.