Grazing subirrigated meadow regrowth influences subsequent‐year plant production and nutritive value

Abstract

AbstractSubirrigated and mesic meadow ecosystems are an important forage resource for livestock operations, being used for hay production, grazing, or a combination of both. Our study evaluated how timing and intensity of grazing meadow regrowth following a summer hay harvest influenced subsequent‐year plant production and forage nutritive value. Cattle grazed within established meadow paddocks during prefreeze (fall) or postfreeze (late‐fall/early‐winter) time periods at two utilization rates, moderate (53.0% ± 4.9%) or heavy (66.1% ± 4.9%), from 2018 to 2020 in four randomized compete blocks. Meadow regrowth available for grazing was 24% less between the prefreeze and postfreeze grazing periods, and forage crude protein (CP) decreased from 136 to 84 g kg−1 over the same period (p < 0.01). Prefreeze grazing reduced (p = 0.03) subsequent‐year graminoid production by 11.2% compared to grazing occurring during the postfreeze period and 10.5% (p = 0.08) compared to a non‐graze control; however, subsequent‐year total live plant production (graminoids and forb/legumes) did not differ among the grazing time and intensity treatments. Subsequent‐year forage nutritive value was variable by year and grazing treatment, but tended to follow the amount of forb/legumes present in total plant biomass (CP, R2 = 0.72; p < 0.01). Grazing meadow regrowth during the prefreeze period provides opportunities to better utilize greater forage quantity at a higher nutritive value, but periodically rotating grazing timing from prefreeze to postfreeze could limit negative effects of grazing during the prefreeze period on subsequent‐year graminoid biomass.