PASTURE MANAGEMENT STUDIES.: I. DAILY STRIP GRAZING VERSUS FREE RANGE GRAZING OF DAIRY CATTLE ON CULTIVATED PASTURE

摘要

Daily strip grazing was compared with free range grazing for dairy cows during three pasture seasons on replicated areas in a 5-year crop rotation. Seventy-two Holstein and Ayrshire cows in early lactation and twelve yearling heifers were used for the complete experiment.Pasture productivity was estimated by crediting the respective pasture plots with the T.D.N. required for the milk produced, for maintenance and gain, and for the estimated T.D.N. harvested as silage or hay. The T.D.N. fed in supplementary feed (silage, hay, and concentrate) and the T.D.N. equivalent of any body weight losses were deducted from the pasture production.Strip-grazing yields were 16.5 to 26.9 per cent higher than those from free range grazing. Surplus grass cut and supplement adjustment accounted for the major portion of these differences. While strip grazing appeared to maintain more persistent milk yields, total milk production did not differ significantly between the two systems. Milk composition (butterfat and solids-not-fat) did not differ significantly between the two systems of grazing and was not affected by the varying stages of pasture growth during strip-grazing cycles.