Effect of diet quality on the suitability of mid-lactation bovine milk forcheddar cheese manufacture

The influence of diet quality on the suitability of milk for cheddar cheese manufacture was investigated. Milk was collected from two spring-calving h erds, each of 16 Friesian-Holstein cows. The herds were offered either a re stricted diet, consisting of a restricted grass supply, or a supplemented d iet, consisting of a standard grass supply with a daily supplement of 3 kg concentrate. The herds were maintained on these diets for a 28-week period. On five occasions, over a 17-day period in mid lactation, bulk milks from each of the herds were converted to cheddar cheese, which was matured for 1 50 days, Milk from the herd on the supplemented diet had significantly high er concentrations of protein, casein and whey protein and superior rennet c oagulation properties, compared to milk from the herd on the restricted die t. The supplemented diet milk resulted in a significantly higher cheese yie ld and milkfat recovery compared to the restricted diet milk. Diet had no s ignificant effect on the gross composition of the cheese. although the cont ents of moisture and fat-in-dry matter were numerically lower and higher, r espectively, with the high-quality diet milk. While cheese firmness and pro teolysis over the 150-day ripening period were not significantly influenced by diet, cheese from the supplemented diet milk had a numerically lower le vel of pH 4.6 soluble N. Cheese from the supplemented diet milk also had a significantly lower fracture stress than that from the restricted diet milk .