Grazing Tips for Hot Weather

By Hugh J. Karreman, V.M.D.

If you are already committed to grazing in general, here are a few tips to keep in mind for the summer. During the hottest time of the year, regular cool-season grasses go dormant, more or less. One way to help them “jump” when a rain does come is to not let pastures be grazed down too short.


By keeping the grass and pasture height no less than three inches, there will be enough plant mass available for rapid regrowth when moisture comes along during the hot spell.

As crop insurance (nongovernmental kind), plant sorghum sudan grass for July and August heat. Sorghum sudan grass is a warm-season grass that loves the heat. For a forty- to fifty-cow herd, three to four acres is all that is needed. Plant it during the last two weeks of May, but not much past the first week of June (in southeastern Pennsylvania).

cattle-heat
Cattle resting in the shade to keep cool.

The soil needs to be about 60ºF, and you should drill it in no deeper than half an inch deep. If the soil is too cold or the grass is planted too deep, it won’t start out well. Try to “stagger” its planting: two acres one week and two acres in another ten days. Since it normally comes up so fast and lush, this will help to not let it get ahead of you and the cows. Generally no herbicide is needed if planted correctly because of its fast growth. It does not do well being planted into an existing crop. A seed­bed needs to be properly prepared and the sorghum-sudan planted into it. Graze it when it is about eighteen inches or higher to avoid any possibility of prussic acid (though that seems to have been bred out of this plant).

Sorghum-sudan can also be cut and ensiled and, if cut at the right time and ensiled properly, is at least equivalent corn silage in terms of energy content. It is also more digestible with more effective fiber than corn silage.

Source: Four-Seasons Cattle Care