title: Genetic trends for fertility, udder health and protein yield in Swedish red cattle estimated with different models.
abstract: The aim of this study was to estimate and compare genetic trends in Swedish Red cattle using a full multiple-trait (MT) model and trait-group-wise models for female fertility, udder health and protein yield. Field data for maiden heifers from 1989 and cows with a first and second lactation between 1990 and 2007 were included. (Co)variance components were estimated prior to prediction of breeding values. The estimated genetic trends were clearly favourable for protein yield and udder conformation, and in most cases neutral to favourable for clinical mastitis and calving to first insemination. In maiden heifers, the trends were neutral for number of inseminations per service period. Unfavourable genetic trends were estimated for number of inseminations in the first two lactations, but the trends seemed less unfavourable from evaluations within trait groups compared with when using the full MT model. Excluding maiden heifer data affected genetic trends less than using trait-group-wise analyses instead of a full MT model. Unfavourable genetic trends in functional traits may be missed unless the traits are evaluated in a MT model including traits under strong selection.
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: S
authors.identifier: http://orcid.org/0000-0003-3357-5065
authors.initials: S
authors.lastname: Eriksson
authors.affiliation: Växa Sverige, Uppsala, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Johansson
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Hansen Axelsson
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: W F
authors.identifier: http://orcid.org/0000-0003-0578-0184
authors.initials: WF
authors.lastname: Fikse
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D003612:Dairying; D005260:Female; D005298:Fertility; D007774:Lactation; D008321:Mammary Glands, Animal / Q000503:physiopathology*; D008414:Mastitis, Bovine / Q000235:genetics / Q000473:pathology; D008894:Milk Proteins / Q000378:metabolism*; D008957:Models, Genetic; D010641:Phenotype; D019655:Quantitative Trait, Heritable
chemical_list: D008894:Milk Proteins
keywords: clinical mastitis; dairy cattle; female fertility; maiden heifers; multiple-trait model