Herbage mass accumulation in an intensive rotational grazing system at UNH's Organic Dairy Research Facility

摘要

Pasture-based animal management in the Northeast U.S. relies on the ability to efficiently estimate pasture production and animal intake. Accuracy and precision of a rising plate meter, NDVI meter, and height measurements for estimating pasture biomass were compared relative to hand-clipped samples. Pasture measurements were used to describe biomass accumulation, lactating dairy herd intakes, and re-growth patterns for intensively rotated pastures. Pastures were measured from May-September, 2009 at the UNH Organic Dairy Research Facility in Lee, NH. The rising plate meter provided the most robust estimates of biomass (R²=0.58, SEE=2.73). Forty-seven paddocks were measured for 82 total grazing events; grazing periods were 12-hours on 0.15 ha paddocks (0.37 acres). Biomass accumulation was comparable to expected values for rotationally grazed Northeast pastures (5663 kg/ha and 7101 kg/ha). Herbage utilization efficiency (86%) was higher than recommended values for maximizing animal productivity. Overgrazing pastures slowed the re-growth of adequate biomass for grazing.