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Offsetting Winter Supplementation With Pasture

By James Rogers, Ph.D.
Associate Professor

Posted Oct. 1, 2018

Feeding a beef cow herd through winter with stored feed and hay is time consuming and can make for a long winter feeding period and if you are overstocked it can make for a long feeding period. It is a common management practice to test hay for its nutritive value so you can properly supplement it or, in a best-case scenario with a high-quality hay, not supplement at all. What you may not be doing is testing the nutritive value of your pastures. If you are properly stocked and have a good bermudagrass fertility program, those bermudagrass pastures may be able to carry you a lot farther into the winter than you may think.

Tractor tines

Bermudagrass Nutritive value

Table 1. Nutritive value of bermudagrass pastures with a spring-only nitrogen application, stockpiled or interseeded with wheat compared to wheat only pasture.

 NovemberDecemberJanuaryFebruary
Treatment %CP %TDN %CP %TDN %CP %TDN %CP %TDN
Spring N 15.16 60.38 11.10 55.72 11.93 57.87 9.19 43.37
Stockpile 12.73 60.09 13.61 58.26 13.54 60.74 8.21 44.88
Interseed wheat 17.64 63.65 15.21 62.19 17.84 65.09    
Wheat 27.95 71.77 21.60 81.86 23.65 75.71    

Here at Noble, we have been looking at two methods in cow-calf production to extend the grazing season on bermudagrass-based pastures and reduce winter feeding of stored feeds. In our cow-calf study, all pastures receive 75 pounds of nitrogen (N) per acre (Spring N) in May as a base fertility treatment.

The first treatment is a combination of stockpiled bermudagrass (Stockpile) where 50 pounds of N per acre is applied to bermudagrass in August or September, with grazing deferred until after frost. To further extend grazing beyond the stockpile, wheat is no-till interseeded into bermudagrass in the fall (Interseed wheat) and fertilized with 50 to 60 pounds of N per acre. Both stockpiled bermudagrass and interseeded wheat are allocated at 1 acre per cow. The second treatment is wheat planted no-till as a winter pasture monoculture (Wheat) and fertilized with 50 to 60 pounds of N per acre and allocated at 0.7 acres per cow.

Study Results

To make grazing season extension work, you need to know the forage nutritive value. Since the study began in 2015, we have taken grab samples of these pastures from November through February and analyzed them for nutritive value so we can supplement the cow herd accurately and when needed.

Table 1 provides the nutritive value results of the bermudagrass pastures (Spring N, Stockpile) compared to wheat only (Wheat) or bermudagrass pastures interseeded with wheat (Interseed wheat). Note in Table 1 the quality of pasture that was available from November to February from our Spring N and Stockpile pastures and compare these values to the nutrient requirements for a 1,200-pound beef cow in Table 2. In our case, pasture quality was much better than the hay on hand that was tested and contained 7.0 percent crude protein (CP) and 57.0 percent total digestible nutrients (TDN). In our cow-calf study during winter 2017-18, we were able to feed some cows on a supplement of 30 percent range cubes and Spring N pasture with no hay.

Each Year Will Be Different

Grazing season extension takes good management and a favorable environment. Each year is different, and some years will work better than others; as a manager, you must have enough flexibility to adjust accordingly. In the Spring N pastures, rainfall was favorable during 2017 so the excess forage was produced at the right time and could be used through fall and winter 2017-18.

There are years where the pasture quality is there but the quantity or volume is not, and you have to feed to make up for the difference. It is during these instances where having some stockpile is a good option. Stockpile can provide quality forage (Table 1) and volume to gain extra grazing days past frost. Another part of this system is interseeding wheat into bermudagrass to contribute to the nutritive value and forage biomass, especially as you get in January and on into spring. By adding cereal wheat, we do increase the quality of forage available to the cows but incur additional costs with planting and seed. Interseeding wheat into bermudagrass has worked well in this system as we essentially double crop wheat with bermudagrass. We have been able to time graze cows on our Interseed wheat treatments beginning in January to meet protein needs, and then allow them to have full access to Interseed wheat in March as wheat continues to develop in the spring.

Concept Applies to Other Perennial Pastures

When properly managed, bermudagrass can have good nutritive value much later into the fall and winter than often is thought or realized. To know what you have, take and submit forage samples of the pastures you are considering using to extend your grazing season to the Noble Research Institute, your local extension office or other testing service. This concept does not limit itself to bermudagrass pastures. The same can be applied to other warm- and cool-season perennial pastures as well. Establish the nutritive value, determine how much you have available and utilize pastures to offset winter feeding demands, but keep an eye on cow response and body condition and be flexible and adjust as needed.

Beef Cow Nutrient Needs

Table 2. Diet nutrient density requirements for crude protein acow at the middle third, last third of gestation or first 90 days postpartum producing 25 pounds of milk per day.

Cow weightGestation Period%CP%TDN
1,200 lbs. Middle third 7.1 50
1,200 lbs. Last third 7.9 54
1,200 lbs. First 90 days after calving, 25 pounds per day milk 10.5 59

Source: Nutrient Requirements of Beef Cattle. Oklahoma State University publication E-974.

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