Genetic study of immunological parameters in periparturient Holstein cows
Is Version Of
Immunological assays were evaluated in 137 Holstein cows during the periparturient period. Results for all immune assays were altered around calving time. Heritability estimates were obtained before, at, and after immunosuppression. Significant genetic variability was found in the periparturient changes for neutrophil chemokinesis, assays measuring neutrophil respiratory burst (cytochrome C reduction, chemiluminescence, and iodination), serum concentration in IgG[subscript]1, IgG[subscript]2, and IGM, and serum hemolytic complement activity;Genetic factors affecting mastitis indicators (somatic cell score, clinical cases, bacteriological status) and retroviral infections (bovine leukosis virus, bovine immunodeficiency virus) were studied. Heritabilities for all mastitis indicators averaged 0.10, but differences were seen among mastitis indicators. Heritability estimates for retroviral infections were close to zero. The genetic correlation between the number of quarters infected with minor and major pathogens was negative;We examined the genetic effects on the disease indicators of our immunological assays and of the alleles at the BoLA-DRB3 locus, at the IgG[subscript] 2a locus, and at the locus for the mutation responsible for the bovine leukocyte adhesion deficiency syndrome. Negative genetic associations were found between all mastitis indicators and the presence of BoLA-DRB3 alleles b12 and b11, various neutrophil assays, the number of blood mononuclear cells, and the presence of IgG[subscript] 2a allele A1. BoLA-DRB3 allele b3 was negatively associated with infection with bovine immunodeficiency virus. No genetic effect of any of the immunological parameters on infection with bovine leukosis virus could be demonstrated.