Effects of coccidiosis vaccination administered by in ovo injection on the hatchability and hatching chick quality of broilers1,2,3.

Effects of the in ovo injection of a commercial coccidiosis vaccine on the hatchability and hatching chick quality variables of Ross × Ross 708 broilers were examined. Four treatment (TRT) groups were represented on each of 7 replicate tray levels of a single-stage incubator (28 TRT-replicate groups). Each TRT-replicate contained 63 eggs (1,764 total eggs). On d 18.5 of incubation, eggs were subjected to one of 4 TRT using a commercial multi-egg injector. Three control groups (non-injected, dry-punch, and diluent-injected) and one TRT group (injected with diluent containing Inovocox EM1 vaccine) were used. On d 18.5 of incubation, the site of injection and stage of embryo development were determined. On d 21.5 of incubation (d zero post hatch), hatchability of injected eggs (HI), chick BW, and yolk sac, intestine, and liver weights were determined. On d zero post hatch, 20 chicks from each of the 28 TRT-replicate groups (560 total birds) were placed in corresponding isolated wire-floored battery cages. On a daily basis, from d zero to 14 post hatch, pooled fecal samples from each individual replicate cage were collected for oocyst output determination. There was no significant difference among TRT for HI or chick BW on d 21.5 of incubation. In the non-injected control and vaccine-treated groups, mean HI was 93.1 and 89.4%, respectively, and chick BW were 43.4 and 43.8 g, respectively. The mean embryonic stage score was 2.09, and 84.8 and 15.3% of in ovo injections were in the amnion and embryo, respectively. Oocyst shedding began 4 d post hatch (d 6 post injection), and reached a peak at d 7 post hatch (d 10 post injection). It was concluded that the in ovo injection of Inovocox EM1 vaccine did not have a significant detrimental effect on broiler embryogenesis or hatching chick quality.