Genetics of milk coagulation properties predicted by milk mid infrared spectrometry analysis of Irish dairy cows

Milk coagulation properties (MCP) are important traits for profitable dairying. To improve MCP through animal breeding large quantity of routinely available data on MCP as well as existence of heritable genetic variation in these traits is required. Objectives of this study were to i) develop prediction equations for MCP through mid-infrared spectroscopy (MIRS) ii) apply equations to a spectra dataset of Holstein-Friesian cows, and iii) estimate variance components. Data for MCP and MIRS were available on 324 samples. Proportion of variation in external validation for RCT, k20, and a30 explained by equations was 0.45, 0.41 and 0.27, respectively. Heritability for MCP estimated from 9,867 spectra on 1,104 cows varied from 0.06 to 0.20; coefficient of genetic variation for MCP varied from 5.99 to 10.07, while genetic correlations between MCP and milk quality traits demonstrated positive relationships between MCP and milk composition.