Genetic parameters of cellular immune traits in UK Holstein-Friesian dairy cows (Bos taurus)
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A previous study in dairy cows identified associations between a number of cellular immune traits within the blood and important health traits, including CD4:CD8 T cell ratios and subclinical mastitis, % CD8 T cells and fertility, and % NKp46+ cells and lameness. The purpose of the present study was to determine the genetic parameters of these cellular immune traits, and explore their relationships with health traits in a larger independent dataset. Blood samples were collected from 279 Holstein-Friesian dairy cattle at 2- monthly intervals and analysed by flow cytometry for 7 cellular immune traits, including T cell subsets, B cells, NK cells and granulocytes. Data were modelled using a repeated measures mixed linear model. Heritability estimates and the variance components were calculated using univariate analyses, and ranged from 0.083 (% peripheral blood mononuclear cells) to 0.340 (%CD4+ T cells). The heritability estimates for %CD4+, %CD8+ and %NKp46+ cells were 0.340, 0.282 and 0.239, respectively and were all statistically greater than zero (P < 0.05). These traits also had the most significant estimates of repeatability (0.650, 0.715 and 0.239, respectively). Associations between the cellular immune traits and lactation traits were investigated with bivariate analyses. The strongest statistically significant (P < 0.05) genetic correlation obtained was between %CD8+ and somatic cell count (0.6857), a measure of subclinical mastitis. The CD4:CD8 ratio was also genetically correlated with somatic cell count ( 0.5698). In conclusion, these results suggest that genetic selection for cellular immune traits may be a useful tool in improving resistance to disease.
Other Titles/Title of Conference
British Society for Immunology Annual Congress
John Wiley & Sons Ltd.
Journal Title/Title of Proceedings
Immunology - Special Issue: Abstracts of the British Society for Immunology Annual Congress