Protective efficacy of a live attenuated anticoccidial vaccine administered to 1-day-old chickens
2003
Crouch, C.F. | Andrews, S.J. | Ward, R.G. | Francis, M.J.
The efficacy of a live attenuated anti-coccidial vaccine, Paracox-5, administered to 1-day-old chicks was investigated by assessing protection against changes in weight gain following virulent challenge. Vaccinated birds were challenged independently 28 days later with each of the component species (Eimevia acervulina,Eimeria maxima, Eimeria mitis or Eimeria tenella), and protection was demonstrated against associatedreduction in weight gain and lesion formation. In addition, an improvement in bird performance, in terms of feedconversion ratio, was also observed following vaccination. Furthermore, under conditions designed to moreclosely mimic those in the field and using hatchery spray administration, protection against a mixed virulent challenge introduced by 'seeder birds' was demonstrated evenly across a flock of broiler birds within 21 daysafter vaccination. These data demonstrate that Paracox-5 vaccine will protect broiler chickens against the adverse effects on performance induced by Eimeria spp.
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