Pasture growth, production, and quality under rotational and continuous grazing management

Management intensive rotational grazing (MIRG) is an expanding practice amo ng dairy farmers in the Upper Midwest. Despite the high productivity associ ated with MIRG pastures, many acres of unmanaged, continuously grazed pastu res still exist. Our goal was to document relationships between forage grow th, production, and quality in rotational and continuous grazing systems an d to evaluate the role that management plays in the productivity of these p astures. Forages were monitored under farmer management on three MIRG dairy farms and on three continuously grazed pastures (CON) on conventional live stock farms in 1994 and 1995. Evaluation of the results was complicated by the range of conditions and management practices that characterized the stu dy's participants. As is typical for this region, CON pastures in this stud y were unmanaged. In contrast, MIRG pastures were monitored daily by their owners and sward health was maintained through movement of the herd and suc h practices as interseeding legumes. Forage mass for MIRG pastures was grea ter than CON every week of the 24-wk grazing season, averaging 1763 lb/acre for ready-to-graze MIRG paddocks vs. 850 lb/acre for CON. Crude protein av eraged 16.6% for MIRG vs. 15.3% for CON. Seasonal average ADF values were 3 4.2% for MIRG and 34.1% for CON. Average NDF values were 53.4% for MIRG and 56.8% for CON. Forage mass between 1300 and 1900 lb/acre appeared to provi de a balance between yield and quality on MIRG pastures. Cooperating farmer s most often chose to graze paddocks at this level. For CON, forage quality decreased as forage biomass increased. Ready-to-graze MIRG paddocks had si gnificantly higher quality than CON pastures at equivalent levels of forage biomass. It was not possible in this study to isolate individual managemen t practices and test them separately, so no one factor can be viewed as res ponsible for the differences we observed. Indeed, these differences probabl y are the result of the interaction among several management practices on M IRG farms and the lack of pasture management on CON farms.