title: Associations between CXCR1 polymorphisms and pathogen-specific incidence rate of clinical mastitis, test-day somatic cell count, and test-day milk yield.
abstract: The CXCR1 gene plays an important role in the innate immunity of the bovine mammary gland. Associations between single nucleotide polymorphisms (SNP) CXCR1c.735C>G and c.980A>G and udder health have been identified before in small populations. A fluorescent multiprobe PCR assay was designed specifically and validated to genotype both SNP simultaneously in a reliable and cost-effective manner. In total, 3,106 cows from 50 commercial Flemish dairy herds were genotyped using this assay. Associations between genotype and detailed phenotypic data, including pathogen-specific incidence rate of clinical mastitis (IRCM), test-day somatic cell count, and test-day milk yield (MY) were analyzed. Staphylococcus aureus IRCM tended to associate with SNP c.735C>G. Cows with genotype c.735GG had lower Staph. aureus IRCM compared with cows with genotype c.735CC (rate ratio = 0.35, 95% confidence interval = 0.14–0.90). Additionally, a parity-specific association between Staph. aureus IRCM and SNP c.980A>G was detected. Heifers with genotype c.980GG had a lower Staph. aureus IRCM compared with heifers with genotype c.980AG (rate ratio = 0.15, 95% confidence interval = 0.04–0.56). Differences were less pronounced in multiparous cows. Associations between CXCR1 genotype and somatic cell count were not detected. However, MY was associated with SNP c.735C>G. Cows with genotype c.735GG out-produced cows with genotype c.735CC by 0.8 kg of milk/d. Results provide a basis for further research on the relation between CXCR1 polymorphism and pathogen-specific mastitis resistance and MY.
authors.affiliation: M-team and Mastitis and Milk Quality Research Unit, Department of Reproduction, Obstetrics, and Herd Health, Ghent University, 9820 Merelbeke, Belgium. Joren.Verbeke@UGent.be
authors.forename: Joren
authors.initials: J
authors.lastname: Verbeke
authors.forename: Mario
authors.initials: M
authors.lastname: Van Poucke
authors.forename: Luc
authors.initials: L
authors.lastname: Peelman
authors.forename: Sofie
authors.initials: S
authors.lastname: Piepers
authors.forename: Sarne
authors.initials: S
authors.lastname: De Vliegher
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle / Q000235:genetics* / Q000502:physiology; D002452:Cell Count / Q000662:veterinary; D015331:Cohort Studies; D005260:Female; D005838:Genotype; D015994:Incidence; D008321:Mammary Glands, Animal / Q000382:microbiology; D008414:Mastitis, Bovine / Q000453:epidemiology / Q000235:genetics* / Q000382:microbiology; D008892:Milk / Q000166:cytology / Q000378:metabolism*; D008969:Molecular Sequence Data; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy; D023062:Receptors, Interleukin-8A / Q000235:genetics*; D016415:Sequence Alignment / Q000662:veterinary; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000235:genetics / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000472:pathogenicity
chemical_list: D023062:Receptors, Interleukin-8A