Genetic associations between somatic cell score and pathogen specific subclinical mastitis in Norwegian Red cows


  • K Haugaard
  • B Heringstad
  • A C Whist


pathogen specific mastitis, subclinical mastitis, linear model


The aim of this study was to estimate heritabilites of and genetic correlations among pathogen specific subclinical mastitis (SCM) and lactation mean somatic cell score (LSCS) in Norwegian Red. Four binary pathogen specific SCM traits, Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis and coagulase negative staphylococci (CNS), were analyzed together with unspesific SCM and LSCS using a multitrait linear sire model. Estimated heritability was 0.139 for LSCS, 0.075 for unspesific SCM, and ranged from 0.002 (Streptococcus uberis) to 0.013 (CNS) for pathogen specific SCM. Genetic correlations were positive and high, ranging from 0.68 to 0.99. Most of the genetic correlations were significantly lower than 1, indicating that subclinical mastitis caused by different pathogens can be considered as different traits.