Livestock producers with limited pastures supplies should adopt rotational grazing and consider planting a late-season summer-annual forage crop, say University of Kentucky (UK) Extension forage specialists.

“During a drought, we can’t afford to waste pasture, and rotational grazing permits us to use more of what we grow and waste less,” says Garry Lacefield.

If the dry conditions continue, summer annuals such as pearl millet, sudangrass and sorghum-sudangrass can supply a significant amount of high-quality forage, adds Ray Smith. However, he says they need moisture to get established and are only a short-term fix.

Producers tend to avoid planting them because pearl millet has the potential to cause nitrate poisoning and sudangrass and sorghum-sudangrass also can cause prussic acid poisoning. But he says the risk is low when the forages are carefully managed.

To help prevent prussic acid and nitrate poisoning, only give animals access to enough pasture for one to three days, don’t graze warm-season annuals less than 18” tall, and avoid grazing them during or shortly after droughts when growth is severely reduced, Smith advises.

In the future, producers may want to establish pastures with warm-season grasses such as eastern gamagrass, switchgrass, big and little bluestem and indiangrass, says Lacefield. Many Kentucky pastures are full of cool-season grasses like tall fescue, orchardgrass and Kentucky bluegrass, which are least productive during hot, dry weather. Adding warm-season species can help ensure that cattle have quality forages during the summer months, he says.

Another option is to add pastures containing alfalfa or alfalfa-grass mixes. Alfalfa tends to have a deep root system, which makes it more drought tolerant than other cool-season species, and it will continue to produce during periods of extreme drought, says Lacefield.

UK Extension publications on rotational grazing, summer annuals and extending the grazing season are available under the publications section on the UK forage Web site.