Effect of the botanical composition of hay and casein genetic variants on the chemical and sensory characteristics of ripened Saint-Nectaire type cheeses

Forty-two multiparous dairy cows of 3 different breeds (Holstein, Montbelia rde and Tarentaise) were divided into 2 groups (A and B) according to beta- and kappa-casein genetic variants, and were fed 3 floristically different types of hay (cocksfoot, rye-grass-rich and native mountain grassland hay) according to a 3 x 3 Latin-square design. The milk produced by these cows w as used to make Saint-Nectaire-type cheese, using identical and controlled cheesemaking techniques. The cheeses made from cocksfoot diet milk had high er pH (P < 0.01), lower fat in dry matter (P < 0.05), more elastic texture and a strong cellar odour (P < 0.1). The cheeses produced from the milk of cows fed native mountain grassland hay exhibited a slightly gritty and yell ower body, and had a pronounced vinegar and cabbage odour. Rheological anal ysis confirmed the beneficial effect of the B variant of beta- and kappa-ca seins on milk rennet clotting ability. This effect did not seem to affect t he cheeses because they could not be distinguished by any of their sensory characteristics.