title: Estimating genetic and phenotypic parameters of cellular immune-associated traits in dairy cows.
abstract: Data collected from an experimental Holstein-Friesian research herd were used to determine genetic and phenotypic parameters of innate and adaptive cellular immune-associated traits. Relationships between immune-associated traits and production, health, and fertility traits were also investigated. Repeated blood leukocyte records were analyzed in 546 cows for 9 cellular immune-associated traits, including percent T cell subsets, B cells, NK cells, and granulocytes. Variance components were estimated by univariate analysis. Heritability estimates were obtained for all 9 traits, the highest of which were observed in the T cell subsets percent CD4+, percent CD8+, CD4+:CD8+ratio, and percent NKp46+cells (0.46, 0.41, 0.43 and 0.42, respectively), with between-individual variation accounting for 59 to 81% of total phenotypic variance. Associations between immune-associated traits and production, health, and fertility traits were investigated with bivariate analyses. Strong genetic correlations were observed between percent NKp46+and stillbirth rate (0.61), and lameness episodes and percent CD8+(-0.51). Regarding production traits, the strongest relationships were between CD4+:CD8+ratio and weight phenotypes (-0.52 for live weight; -0.51 for empty body weight). Associations between feed conversion traits and immune-associated traits were also observed. Our results provide evidence that cellular immune-associated traits are heritable and repeatable, and the noticeable variation between animals would permit selection for altered trait values, particularly in the case of the T cell subsets. The associations we observed between immune-associated, health, fertility, and production traits suggest that genetic selection for cellular immune-associated traits could provide a useful tool in improving animal health, fitness, and fertility.
authors.affiliation: Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, United Kingdom. Electronic address: scott.denholm@sruc.ac.uk.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Denholm
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, Scotland, United Kingdom.
authors.forename: Tom N
authors.initials: TN
authors.lastname: McNeilly
authors.affiliation: Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, United Kingdom.
authors.forename: Georgios
authors.initials: G
authors.lastname: Banos
authors.affiliation: Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, United Kingdom.
authors.forename: Mike P
authors.initials: MP
authors.lastname: Coffey
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, Scotland, United Kingdom.
authors.forename: George C
authors.initials: GC
authors.lastname: Russell
authors.affiliation: Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, United Kingdom.
authors.forename: Ainsley
authors.initials: A
authors.lastname: Bagnall
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, Scotland, United Kingdom.
authors.forename: Mairi C
authors.initials: MC
authors.lastname: Mitchell
authors.affiliation: Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, United Kingdom.
authors.forename: Eileen
authors.initials: E
authors.lastname: Wall
mesh_terms: D000818:Animals; D002417:Cattle; D005260:Female; D005298:Fertility / Q000235:genetics*; D007774:Lactation / Q000235:genetics; D008892:Milk; D010641:Phenotype
keywords: dairy cow; heritability; immune-associated trait; variance