Turning livestock onto pastures as soon as forages begin to green up in the spring can be tempting. Research has shown that most cool-season grasses produce two-thirds of their season long yield during the spring of the year. Growth of these grasses slows as temperatures rise above 75°F. Properly managing stocking density during the rapid spring growth can help extend the stand of your grass. Being proactive in the spring will give positive results all year long.

Why Should You Prevent Cattle from Overgrazing?

Forage Considerations - Grazing forages too early can reduce stand productivity and longevity. Allowing plants a sufficient growth period after breaking dormancy in the spring, and prior to grazing, allows plants to develop photosynthetic capacity and restore some depleted root reserves. Grazing too short early hurts future forage production, stand persistence, and damages the tillers that produce new growth.

Animal Considerations - Young forage is high in water and low in highly digestible fiber. High water content of plants can limit dry matter intake. Low levels of highly digestible fiber can increase risk to foundering cattle on pasture, though rare in occurrence. Allowing access to hay may help cattle maintain dry matter intake and adequate fiber to prevent foundering. Often, when pastures are grazed too early, available forage is sparse, which increases traveling distance and reduces intake. Increased traveling and reduced bite mass leads to reduced gains for growing cattle, and increased body condition loss and lower production for lactating cows.

Rotationally Graze

Rotational grazing can be an effective method to utilize this rapid spring growth. This method will give cattle access to new forage every few days and provide an adequate rest period for regrowth of the forages. Under-grazing can be a problem when trying to use too few cattle to manage spring growth. Often, when stocking density is not adjusted, the number of livestock on the farm cannot graze cool-season grasses fast enough in the spring to prevent them from becoming overly mature. Increasing animal numbers to match spring growth rates can lead to overgrazing during the summer months when forage growth rate is much lower. Finding a balance is key to maintaining vegetative forage during the grazing season.

Ways to Manage Rapid Spring Forage Growth

Shorten grazing rotation in spring - Shortening a normal 4 week rotation down to 2 weeks in the spring will provide enough forage for animals while not stunting grass growth. Using a shortened rotation period by moving livestock quickly allows animals to only graze a few inches of the grass, often referred to as top grazing. In the spring, a producer can begin grazing cool-season grasses before the recommended height (begin around 3-6 inches depending on forage species), as a result of the limited forage removal and fast regrowth. This will allow a producer to get through all pastures before seedhead development and start back on the first paddock with enough regrowth to adequately support animals. Consider an eight paddock system where cattle are normally held for four days in the paddock, allowing for 28 days of rest. In 28 days, forages can rapidly go from vegetative to mature during the spring. Reducing the grazing duration to two days allows for the cattle to be back in the first paddock in 14 days. Utilizing cool-season grasses, such as tall fescue, while it is young will provide a higher quality forage. Also, seedheads from mature forages can scratch and irritate the eyes of cattle, increasing the risk of pinkeye.

Make hay now and use fewer acres for grazing in spring vs. later - One method to adjust stocking density in the spring is to allocate certain paddocks for hay production. Once the paddocks have had time to recover from being harvested for hay they can be added back into the grazing schedule as forage growth slows during the remainder of the grazing season and additional forage production is needed.

Graze more cattle in spring - Another method, often used by stocker operations, is adding more animals to the herd in the spring and leaving pasture acreage the same. When grass growth begins to slow, a stocker operator can adjust animal numbers by selling some and keeping others. Keep in consideration that if stocking density is not adjusted accordingly, overgrazing can occur.

Traditionally, cow/calf operations will keep similar number of livestock on farm each year. Purchasing additional animals to adjust stocking density for spring growth may not be feasible for such operations. However, fall calving herds may retain calves longer to utilize additional spring grass growth. Extra acreage can be used for hay production.

Provide Adequate Mineral

Be sure that cattle are supplied with proper type and amount of minerals at all times. In early spring, a high magnesium, or high “Mag” mineral (to provide 20g magnesium) should be available for cows 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. 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.

Ideal grazing heights can vary depending on forage species. The following table shows recommended grazing heights for forages common in Kentucky.

Table 1. Grazing Heights for Forages Common in Kentucky

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Spring
Extending the Grazing Season