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.