The research was conducted on three management intensive rotational grazing (MIRG) dairy farms, and continuously grazed pastures (CON) on three conventional dairy farms in Wisconsin in 1994 to 1995. Continuous pastures in this study averaged 41.1% Kentucky bluegrass (Poa pratensis) cover. Although species composition surveys showed that the more productive, taller-growing species were present in relatively high proportions, these pastures tended to be shorter and denser than MIRG, in which the tall-growing species tended to be more dominant. The seasonal mean height of the densest part of the sward was 3.6 in. for CON and 5.9 in. for MIRG. Forage mass for ready-to-graze MIRG paddocks averaged 1736 lb/acre, more than twice as much as forage on offer for CON at 850 lb/acre. The data suggest that, under management common in this region, forage mass is lower in continuously grazed pastures than in rotationally grazed pastures at similar stocking rates. It can be predicted that forage mass during the growing season and forage quality declines in response to increasing availability for CON pastures, particularly for fiber content. For the pastures in this study, as CON forage mass approached levels considered ready-to-graze for MIRG, forage quality declined linearly. Overall, this study documented that overall forage yields of rotationally managed pastures are considerably higher than those of unmanaged, continuously grazed pastures.
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