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Genetic Analysis of Elevated Mastitis Risk Based on Mastitis Indicator Data
A mastitis detection model was used on online SCC (OCC) from automatic milking systems for establishment of elevated mastitis risk (EMR), a continuous variable where values close to 0 and 1 indicate healthy and mastitic cows, respectively. A total of 876,260 EMR and OCC records and mastitis treatments from 2,374 first parity cows were used for estimation of genetic parameters in 30 days intervals across the lactation. Using repeated measurements of ln(EMR), heritabilities were h2=0.06-0.15 and were slightly larger than heritabilities of repeated ln(OCC) measurements, h2=0.06-0.14. Repeatabilities of ln(EMR) were 0.57-0.70, whereas they were 0.37-0.50 for ln(OCC). Combining ln(EMR) values into a mean ln(EMR) value for each period did not decrease heritabilities. However, with the data availability for this study it was not possible to get reliable results for genetic correlations between EMR and mastitis treatments.
Keywords:
mastitis
somatic cell count
genetics
