Impact of alfalfa maturity and preservation method on milk production by cows in early lactation

Ninety-six cows in early lactation were used in two experiments to measure the impact of alfalfa maturity (early or midbud vs. early or midbloom) and method of forage preservation (silage vs. hay) on DMI and milk production. Silage diets were fed as TMR, and hay was fed separately from grain. All diets contained 60% alfalfa (dry basis) and were balanced for 19% CP. Maturity had little effect on milk production in either experiment. Adjusted milk production for early cut silage, late cut silage, early cut hay, and late cut hay were 33.6, 33.4, 30.7, and 32.1 kg/d for Experiment 1 and 38.1, 37.0, 35.0 and 35.0 kg/d for Experiment 2. Increased alfalfa maturity tended to reduce DMI. Cows fed the silage diets consumed 1.2 kg more DM and produced an average of 2.1 kg more milk daily in Experiment 1 than those fed the hay diets. All treatment groups consumed similar amounts of DM in Experiment 2; however, cows fed silage produced 2.6 kg/d more milk than those fed hay. Preserving alfalfa as silage and feeding in a TMR to cows in early lactation resulted in greater milk production via increased DMI or improved feed efficiency compared with preserving alfalfa as hay and feeding grain separately.