Technological properties of cow's milk: correlations with milk composition, effect of interactions of genes and other factors.

We analysed the correlations of milk fermentability (yogurt test acidity), renneting (time to rennet coagulation of milk protein) and results of ethanol tests (indirect indicator of milk thermostability) with the percentages of the milk components. The correlations of the milk component percentages with renneting were mostly weak, while the correlations with the ethanol test were even poorer. The CSN3 and LGB genotypes did not show a significant interaction in their influence on milk fermentability, renneting or ethanol test results. For the ethanol test, many significant interactions were observed between the DGAT1, LEP, FASN, SCD1, CSN2, CSN3 and LGB genotypes. DGAT1 interacted significantly with all genes for milk fermentability. For renneting that was measured instrumentally, CSN3 interacted significantly with DGAT1, FASN, SCD1, CSN2 A/B, CSN2 A1/A2; SCD1 interacted significantly with LEP and FASN. The breed and genotypes did not show any interactions. Farm and genotypes interacted significantly for all the technological properties studied; similar results were observed for the protein percentage and the genotypes, except that no interactions influenced the ethanol test results. [ABSTRACT FROM AUTHOR]