Use of live and oil emulsion Newcastle disease vaccines on day-old broilers: report on two trials

Two trials were carried out using broilers to test the effectiveness of concurrent live and oil emulsion Newcastle disease vaccines at day-old. The first trial compared this system, using a Newcastle disease oil emulsion vaccine formulated for adult birds, with the conventional programme of live vaccine only. The second trial used an oil emulsion vaccine specially formulated for a day-old dose fo 0.1 ml. It also examined the effect of an additional dose of live vaccine at 14 days old. The results show that birds were as well protected and grew at least as well when vaccinated at one day old and that the special low-dose oil emulsion gave as good protection against Newcastle disease as the higher dose vaccine. The additional live vaccine treatment in the second trial did not appear to increase the beneficial effects.