Managing diet quality for Cheddar cheese manufacturing milk. 2. Pasture v.grain supplements

The effects of supplementing a basal diet of silage and hay with increasing amounts of harvested spring pasture, or with lupin and wheat, on the compo sition of milk and the consequent effects on cheese composition and yield w ere investigated in an indoor feeding study. Milk was collected from five g roups of eight cows in mid lactation offered different diets and manufactur ed into Cheddar cheese on a pilot scale. Milk from cows given the lupin-whe at (LW) and the high pasture level (HP) diets produced low moisture cheese. Cheese produced with milk from cows given the control diet was high in moi sture content compared with that made with milk from cows offered the LW di et. Cheese yields from the milk of cows offered the HP and LW diets were gr eater than from the milk of cows on the control diet, and were associated w ith the higher casein concentrations of these milks. Casein number was high er in milk from diets supplemented with pasture but was not an indicator of the functional properties of milk that affected cheese moisture. The propo rtion of beta-casein in milk from cows offered the HP diet was higher and t hat of gamma-casein lower than in milk from cows given the LW supplement, a lthough cheese moisture content was similar with both diets. Milk from cows offered the HP diet had a greater inorganic P concentration then that from cows given the LW diet, although the dietary intake of P was higher for th e LW diet. The significance of the effect of dietary P intake on the concen tration of inorganic P in milk and hence its suitability for cheesemaking w as apparent when dietary P intake was low, as shown in milk produced by cow s offered the control diet.