Submitted to: American Veterinary Medical Association Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/13/2002
Publication Date: N/A
Technical Abstract: Chickens were pedigree hatched from a commercial broiler breeder flock that had been identified by the company to have a relatively high incidence (20% - 60%) of subgroup J avian leukosis virus (ALV-J) infection. Unexpectedly, only one of 175 (0.6%) of chicks hatched at our laboratory tested positive for ALV-J at hatch; however, 55/97 (56%) of these chicks tested positive for endogenous ALV. At various ages, the incidence of viremia and cloacal shedding varied from 8% - 16% and from 1% - 13%, respectively. Only two of 157 (1.3%) of chickens developed tumors by 32 weeks of age. Results suggest that the virus had spread to 16% of the hatchmates, with only 5% persistently viremic. The relatively high incidence of ALV-J infection initially reported by the breeder company was likely due to the presence of endogenous ALV.