Abstract

Clinical mastitis was analyzed with mixed linear models (LM) and survival analysis ( SA) using data from the first 3 lactations of > 200,000 Swedish Holstein cows having their first calving between 1995 and 2000. The model for both methods included fixed effects of year-month and age at calving, fixed regressions of proportions of heterosis and North American Holstein genes, and random effects of herd-year at calving and sire. For the LM, clinical mastitis was defined as a binary trait measured from 10 d before to 150 d after calving. For the SA, clinical mastitis was defined either as the time period from 10 d before calving to the day of first treatment or culling because of mastitis ( uncensored record) or from 10 d before to the day of next calving, culling for reasons other than mastitis, movement to a new herd, or to lactation d 240 ( censored record). The heritability estimates from SA (0.03 to 0.04) were higher than those obtained with the LM (0.01 to 0.03). Consequently, the accuracies of estimated transmitting abilities were also higher for the trait analyzed with SA. The difference between estimates from the 2 methods was greater for later lactations. This study reveals the potential of analyzing clinical mastitis data with SA

Published in

Journal of Dairy Science
2005, Volume: 88, number: 2, pages: 797-803
Publisher: AMER DAIRY SCIENCE ASSOC

SLU Authors

• Carlén, Emma

  • Department of Animal Biosciences, Swedish University of Agricultural Sciences
    

• Schneider, Maria Del Pilar

  • Department of Animal Biosciences, Swedish University of Agricultural Sciences
    

• Strandberg, Erling

  • Department of Animal Biosciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Animal and Dairy Science
Veterinary Science


Publication identifier

DOI: https://doi.org/10.3168/jds.S0022-0302(05)72744-2

Permanent link to this page (URI)

https://res.slu.se/id/publ/7418