Articles on forages, animals, and grazing systems
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Extension Forage Specialist
University of Kentucky
Phone: (859) 257-3358
Fax: (859) 323-1952
It is tempting to turn livestock back onto pastures as soon as forages start to green up and produce new growth. Harvesting forages too early or grazing down too low can reduce stand productivity and longevity. Allow plants sufficient growth time prior to grazing as well as during rest periods to maximize forage quality, yield, and stand persistence. Increased chance of overgrazing is another issue when grazing short forages. Grazing too early not only hurts future forage production but can also reduce livestock performance. Loose stools are common when grazing this young forage that is highly digestible and low in fiber content. Often, during this time, available forage is sparse which may increase traveling distance and reduce intake. Increased traveling and reduced bite mass may lead to reduced gains and reduced production.
Ideal grazing heights can vary depending on forage species. The following table shows recommended grazing heights for forages common in Kentucky.
|Species||Start Grazing||End Grazing|
|Other Cool-Season Grasses/Legumes||8-10”||3-4”|
|Warm-Season Annual Grasses||20-24”||8-10”|
|Warm-Season Native Grasses||18-22”||8-10”|
While it is important not to overgraze pastures, when cool-season forages are growing rapidly in the spring, livestock may not be able to keep up with grazing. Too keep forages from becoming too mature, one possible option is to harvest some fields for hay while using others strictly for grazing. If not harvesting for hay, pastures should be mowed to keep forages from becoming too mature and to control weeds. Moving livestock more quickly may be another option. It is important for each individual to consider all costs when deciding to harvest pastures for hay.
Another consideration in the early spring is the livestock’s change in diet. Mixing dry hay into the diet when shifting to lush pastures can allow animals to become accustomed to the change. Also, be sure that livestock are supplied with adequate minerals at all times. Keep in mind that in early spring, a high magnesium, or high “Mg” mineral should be available to reduce the risk of grass tetany and fed until daytime temperatures are consistently above 60°F.
The beginning of the grazing season is a time to be very aware of both pasture and animal health. Start the grazing season off right by adapting your system to the current conditions. Turning livestock out on pastures before the forages are allowed adequate growth may decrease forage production for the remainder of the year. On the other hand, livestock may not be able to keep up with forage growth in the spring when forages are growing rapidly. Harvesting this forage for hay, mowing pastures, or moving animals more quickly are options to keep forages from becoming too mature and to control weeds. Early spring management of livestock and pastures can help to maximize success and production for the remainder of the grazing season. For more details see Rotational Grazing.