June is often a transition time for pasture management. Generally in early June moisture and temperature are still favorable for good cool season grass growth. If seed heads have not been clipped off then grasses are in reproductive growth and rapidly maturing. As seed heads mature, forage quality declines. Clipping is used to set the plant back to vegetative growth and provide higher quality forage for livestock. If seed heads were clipped off earlier there can still be more seed head formation through the later part of June. The emphasis in pasture management systems at this time should be on quick rotations through pasture paddocks to try to keep up with grass growth and to try to keep seed heads grazed and/or clipped off. Another strategy may be to drop some paddocks out of the grazing rotation and use them for hay production.
As we get past mid-June and into later June our weather pattern often changes. Summer has arrived. It generally becomes warmer and drier. Cool season grass growth slows down. Plants clipped in late June remain in vegetative growth. The emphasis on pasture management now must shift to reflect this change in cool season grass growth. Pasture rotations should be slowed down. Paddocks that were dropped or left out of the spring rotation can now be worked back in to the rotation.
Keep in mind the two important "R's" of pasture management: Residual leaves and Rest period. Do not overgraze pastures as the transition is made from spring to summer. Make sure that leaf cover is left after a grazing pass. In beginning level grazing schools, we generally talk about leaving a residual of at least 4 inches of plant leaves. That leaf cover will provide the plant with a photosynthetic base to continue growing and recover more quickly from defoliation caused by grazing. The residual leaf growth will also provide shade for the soil. Shading will help to keep the soil temperature cooler as compared to exposed soil and it will help to reduce moisture loss due to hot temperatures. Cooler soil temperatures and retained moisture will help cool season grass to grow better longer into the summer period.
Rest period is simply the time it takes the cool season plant to recover or grow back to the target grazing height. Rest period is what dictates how soon a pasture paddock can be grazed again. In our beginning grazing schools we talk about an 8-10 inch beginning grazing height for most cool season pasture mixes. An endophyte infected fescue stand is an exception; and the recommended beginning grazing height of that forage is 6 inches. The rest period between grazing passes increases with our cool season grasses as the transition is made from spring to summer. Those slower growing cool season grasses need a longer rest period to recover after grazing. The exact amount of time needed is related to the residual leaf cover that remains after a grazing pass. Less residual leaf cover translates into longer rest periods.