Effect of forage conservation (hay or silage) and cow breed on the coagulation properties of milks and on the characteristics of ripened cheeses.

Forty-two multiparous dairy cows of three different breeds (Holstein, Montbéliarde and Tarentaise) were fed on the same type of forage (natural grassland) preserved in the form of either hay (H) or silage (GS), according to a changeover design (two 4 week periods). The proportion of concentrate in the diet and the energy and nitrogen contents were similar in both treatments. The milk produced by these cows was used for the manufacture of Saint-Nectaire type cheeses, under controlled and identical cheesemaking technological conditions. More cheese was produced with the H treatment milk. The cheeses made with the GS treatment milk were more yellow and tended to be more bitter. The other chemical and sensory characteristics did not differ much between the two treatments. Of the 51 volatile compounds identified, four were in significantly higher proportion in the GS than in the H cheeses. Cheeses produced from Tarentaise cows' milk were more yellow and their pH was higher than those made with the milk of Holstein or Montbéliarde cows. The cheeses from Montbéliarde and Tarentaise cows' milk were firmer, more melting and tastier than those made with the milk of Holstein cows. Although some trends were apparent, there were no significant differences in cheese volatile compounds for different breeds.