title: Short communication: Genetic analysis of nonreturn rate and mastitis in first-lactation Norwegian Red cows.
abstract: Associations between clinical mastitis (CM) and nonreturn rate within 56 d after first insemination (NR56) were examined in Norwegian Red (NRF) cows. Records on absence or presence of CM within each of the intervals, -30 to 30, 31 to 150, and 151 to 300 d after first calving, and records on NR56 for 620,492 first-lactation daughters of 3,064 NRF sires were analyzed with a Bayesian multivariate threshold liability model. Point estimates of genetic correlations between NR56 and the 3 CM traits were between -0.05 and -0.02. Residual correlations were close to zero, and correlations between herd-5-yr effects on NR56 and CM in the 3 lactation intervals ranged from -0.15 to -0.17. It appears that CM and NR56 in first lactation are independent traits.
authors.affiliation: Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, N-1432 As, Norway. bjorg.heringstad@umb.no
authors.forename: B
authors.initials: B
authors.lastname: Heringstad
authors.forename: I M
authors.initials: IM
authors.lastname: Andersen-Ranberg
authors.forename: Y M
authors.initials: YM
authors.lastname: Chang
authors.forename: D
authors.initials: D
authors.lastname: Gianola
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D001947:Breeding / Q000706:statistics & numerical data; D002417:Cattle / Q000235:genetics* / Q000502:physiology; D003612:Dairying; D005260:Female; D005298:Fertility / Q000235:genetics; D007774:Lactation / Q000235:genetics*; D008297:Male; D008414:Mastitis, Bovine / Q000235:genetics*; D008957:Models, Genetic; D015999:Multivariate Analysis; D012008:Recurrence; D012641:Selection, Genetic; D013997:Time Factors