EFFECTS OF IN OVO VACCINATION AGAINST MAREK’S DISEASE VIRUS AND REOVIRUS DURING LATE STAGES OF EMBRYONAL DEVELOPMENT ON HATCHABILITY, CHICKS DEGREE AND CHICK PERFORMANCE IN BROILER CHICKS.

A total number of 990 embryonated (fertile) chicken (Arbor Acers) eggs were used in this study. The present experiment was conducted to evaluate the influence of early inoculation Marek’s disease virus and Reo virus during late embryonic development on Hatchability, chicks degree and productive performance in broiler chicks.
The embryonated (fertile) eggs were obtained from a commercial Parent stock farm (Cairo Poultry Company, CPC) at 53 weeks of age. The parent hens were specific Pathogen free (SPF) for common diseases. All eggs were weighted before setting (Zero time) and randomly distributed into equal sex experimental groups (treatments).
The 1^st group didn’t receive any treatment and served as sham control. The 2^nd group drilled only without any injection and served as holed control. The 3^rd group drilled and injected with distilled water and served as injected control. The 4^th group drilled and injected with MD vaccine strain H.V.T. suspended in strilled water. The 5^th group drilled and injected with MD vaccine Respine suspended in strilled water. The 6^th group drilled and injected with Reovirus vaccine suspended in strilled water. At day 18 of incubation, when routinely eggs transferred from setter to Hatcher, the eggs were injected by EMBREX INOVOJECT machine against Marek’s disease virus and Reovirus vaccines as shown above.
The obtained results can be summarized as follows:
(1)   In ovo vaccination didn’t affect the percent of hatchability and embryonic mortality.
(2)   The values of hatchability and mortality were in the normal range: the hatchability percent according total setting eggs were 88.4% to 96.4%.
(3)   The total embryonic mortality ratios ranged between 4.27 and 4.85% for eggs injected with MD and reovirus, respectively.
(4)   Early embryos injection with MD, H.V.T., Respine and reovirus provide an early protection, this improve the performance of chicks such as growth performance. Also, activate the immune system more early than post-hatch inoculation.