Submitted to: Poultry Science Association
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/2000
Publication Date: N/A
Technical Abstract: Marek's disease (MD), a T cell lymphoma of chickens continues to be a problem in the broiler industry. Substantial increases in condemnations and mortality due to MD have been observed since 1992, and they are attributed to the presence of highly virulent Marek's disease virus strains, as well as to vaccine failures. This increased incidence of MD has re-emphasized the genetics of the broiler. In this study, two commercial broiler pure lines were crossed to generate an F1 population. Eight F1 males were randomly-mated with three to five females per male (31 dam families) to produce an F2 population. All F2 chicks remained non-vaccinated. At five days of age, chicks were challenged intra- abdominally with 3000 pfu of Marek's disease virus, RB1B. Chicks were observed for clinical signs and mortality to 8 weeks post-challenge. All birds that died during the challenge and remaining birds at the end of the eight-week challenge were necropsied and examined for gross lesions. Spleen, liver and nerve were collected for histopathology. This study represents the first comprehensive genetic evaluation of MD resistance/ susceptibility in a commercial broiler population; major histocompatibility complex (MHC, B), Rfp-gamma and non-MHC genes are the focus of this study.