title: Association of BoLA-DRB3 alleles with mastitis resistance and susceptibility in Japanese Holstein cows.
abstract: In this study, 714 cows from 26 dairy herds were reclassified as healthy or mastitic cows on the basis of long-term somatic cell count (SCC) in milk. Cows with more than three consecutive lactation records of SCC from the first or second to fifth lactation, were selected, and their BoLA-DRB3 (DRB3) alleles were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Cows with an SCC of < 200 000 cells/mL in all monthly records were classified as healthy (n=91). Cows with an SCC of > 300 000 cells/mL in two consecutive tests or four non-consecutive tests or cows with an SCC of > 500 000 cells/mL in any one test during lactation, regardless of parity, were classified as mastitic (n=201). Mastitic cows (n=153) from another 40 herds were considered to be infected if bacteriological testing revealed mastitis pathogens in milk. Their DRB3 alleles were identified using PCR-sequence-based typing (PCR-SBT). The differences in DRB3 allelic frequencies between healthy cows and cows with various degrees of mastitis were re-investigated. Moreover, the associations of various amino acid motifs in DRB3 alleles with resistance or susceptibility to mastitis pathogens were re-examined. DRB3.2*8(DRB3*1201) and DRB3.2*16(DRB3*1501) alleles were found to be associated with susceptibility, while DRB3.2*22(DRB3*1101), DRB3.2*23(DRB3*2703), and DRB3.2*24(DRB3*0101) alleles were found to be associated with resistance.
authors.affiliation: School of Animal Science, Nippon Veterinary and Life Science University, Musashino, Tokyo. yoshidat@nvlu.ac.jp
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Yoshida
authors.forename: Hiroki
authors.initials: H
authors.lastname: Furuta
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Kondo
authors.forename: Harutaka
authors.initials: H
authors.lastname: Mukoyama
mesh_terms: D000483:Alleles; D000818:Animals; D002417:Cattle; D060467:Disease Resistance / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D007564:Japan; D008414:Mastitis, Bovine / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
chemical_list: C423282:BoLA-DRB3 antigen; D000949:Histocompatibility Antigens Class II