Effect of reducing daily herbage allowance during early lactation on composition and processing characteristics of milk from spring-calved herds

The study investigated the effects of reducing daily herbage allowance (DHA) from 15.0 to 11.8 kg dry matter per cow (>3.5 cm post grazing sward height) to a spring-calved herd during early lactation on the composition, rennet coagulability and heat stability characteristics of milk during early lactation (EL, 29e70 days in milk, DIM), mid lactation (ML, 78e183 DIM), and late lactation (LL, 205e267 DIM). Samples of milk were taken at approximate 10 d intervals during EL and at 1e3 week intervals during ML and LL. Reducing DHA led to reductions in milk yield, milk solids yield, and concentrations of protein (~0.22%, w/w) and casein (0.13%, w/w) during EL. Otherwise, it had little effect on milk composition or on the selected processing characteristics in ML, LL or overall lactation. Stage of lactation resulted in comparatively large changes in most compositional parameters, rennet gelation and heat stabilit