EFFECT OF DIET AND BREED ON MILK-COMPOSITION AND RENNET COAGULATION PROPERTIES

The effect of diet on the chemical characteristics and rennet coagulat ion properties of milk from Brown and Friesian cows was examined with three feeding levels (normal, +7 or +14% of INRA requirements) and thr ee forage:concentrate ratios (65:35, 57:43 and 44:56). The experimenta l period was between the 9th and 20th week of lactation for all the an imals. The increase in feeding level led to an increase in milk protei n (+0.13 and +0.17%) and casein (+0.09 and +0.15%) and improved the ch eesemaking properties of the milk, especially the rate of gel firming. The forage:concentrate ratio did not have any significant effect on m ilk composition or its cheesemaking properties. An analysis of all the experimental data revealed that the Brown cows produced a milk with a significantly higher content of protein, casein, calcium and phosphor us, with positive effects on the cheesemaking quality and particularly on the gel firmness.