Effect of diet and breed on milk composition and rennet coagulation properties

The effect of diet on the chemical characteristics and rennet coagulation properties of milk from Brown and Friesian cows was examined with three feeding levels (normal, +7 or +14% of INRA requirements) and three forage:concentrate ratios (65:35, 57:43 and 44:56). The experimental period was between the 9th and 20th week of lactation for all the animals. The increase in feeding level led to an increase in milk protein (+0.13 and +0.17%) and casein (+0.09 and +0.15%) and improved the cheesemaking properties of the milk, especially the rate of gel firming. The forage:concentrate ratio did not have any significant effect on milk 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 phosphorus, with positive effects on the cheesemaking quality and particularly on the gel firmness.