Grazing Management Is Critical During Drought

LEXINGTON, KY.
   Much of the state has been behind on rainfall since spring began, but the drought has been exceptional in Western Kentucky with some cities 8 and 9 inches below normal rainfall totals. With some of the state’s historically driest months ahead, good pasture management is critical for livestock producers, said forage extension specialists from the University of Kentucky College of Agriculture.
   One of the easiest things producers can do to ensure their animals get the most use of their forages is to practice rotational grazing. In a rotational grazing system, livestock graze in one area for a limited time before being moved to another area. This gives forages time to recover from grazing and ensures that the animals are utilizing a greater percentage of the available forage.
   “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,” said Garry Lacefield, UK forage extension specialist.
    Many of Kentucky’s pastures are full of coolseason grasses including tall fescue, orchardgrass and Kentucky bluegrass. These pastures are the least productive during hot, dry weather. If producers install some pastures with warmseason perennial grasses into their rotational grazing system, it can help ensure their cattle have quality forages during the summer months. Examples of native warm-season perennials include Eastern gamagrass, switchgrass, big bluestem, Indiangrass and little bluestem. These grasses are normally planted in late May to early June and take a full growing season to become established. While it may be too late to install these grasses this year, producers may want to think about establishing them in the future.
   Another option for producers is to incorporate pastures containing alfalfa or alfalfa-grass mixes into their grazing system. Alfalfa tends to have a deep root system, which makes it more drought tolerant than other cool-season legumes and grasses, and alfalfa will continue to produce while other cool-season grasses go dormant during periods of extreme drought, Lacefield said.
   Many producers may be worried about coming up short on pastureland if the dry conditions continue. Those producers can plant late-season summer annuals such as sudangrass, sorghum-sudangrass and pearl millet, to provide emergency pasture for their animals. However, these grasses should be planted after a rain and will need moisture to get established, which may be difficult in areas already in a drought.
   These forages are only a short-term fix. UK forage extension specialist Ray Smith said many producers tend to avoid planting these forages because sudangrass and sorghum-sudangrass have the potential to cause prussic acid and/or nitrate poisoning. Pearl millet only has the potential for nitrate poisoning. But these summer annual forages are high yielding and high quality forages. The potential for toxicity problems is low when these forages are carefully managed. Producers should watch that animals do not graze them at an early growth stage or immediately after a frost or during a severe drought.
   To help prevent prussic acid and nitrate poisoning, animals should only be allowed access to enough pasture for one to three days, only graze warm-season annuals that are at least 18 inches tall, and avoid grazing these grasses during or shortly after droughts when stand growth is severely reduced.
   UK extension publications on rotational grazing, summer annuals and extending the grazing season are available under the publications section on the UK forage website, http://www.uky.edu/Ag/Forage. Δ