Influence of sex-linked feathering phenotypes of parents and progeny upon lymphoid leukosis virus infection status and egg production.

Data were collected on egg production, livability, lymphoid leukosis virus and antibody incidence, and hemagglutinin response to sheep red blood cells for slow- and fast-feathering female progeny from slow- and fast-feathering dams with known lymphoid leukosis virus infection status. Analyses of these results indicate that when the offspring or the dams are of the slow-feathering type, the offspring experience an increased rate of horizontal infection. This infection seemingly leads to an immunologically tolerant condition with an inability to produce specific lymphoid leukosis virus antibodies, thereby allowing the viremia to persist. This immunologically tolerant condition, which also occurs in the progeny of virus positive dams due to congenital transmission, is associated with depressed egg production performance. However, a hypothesized lack of immunological competence was not found in the hemagglutinin response to sheep red blood cells late in life. Our results suggest that fast-feathering progeny of slow-feathering dams may also be adversely influenced by increased congenital infection from their dams.