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Cover crops provide value for feedlot production systems

by Wyoming Livestock Roundup

Cover crops and feedlots don’t usually come up in a conversation together, but they both go hand-in-hand. Some feedlots are starting to implement cover crops in their systems to be able to place and grow calves before finishing them on rations.  

On a recent University of Nebraska-Lincoln (UNL) BeefWatch podcast dated March 25, Beef Systems Specialist Dr. Mary Drewnoski sits down to exemplify what she has experienced by adding cover crops into feedlot systems. 

Low-cost gain 

Performance in a feedlot setting is always top of the list, with concerns of calves performing well and feedlots still coming out on top. Cover crops can be an effective way to put gain on calves for a low cost.  

“This can be a great opportunity for feedlots to buy more calves in the fall when they’re at lower costs,” explains Drewnoski.  

This may possibly allow feedlots to buy beyond their capacity at a particular point in time, put calves on a low-cost gain and feed them into their yard throughout winter and into spring.  

Drewnoski adds, “Cover crops, especially coupled with corn residue, can be a great way to lower a feedlot’s incoming costs for calves.” 

Cattle at Drewnoski’s facility in eastern Nebraska graze oats mixed with rapeseed and are supplemented only with mineral.  

“We get an average of about 1.9 pounds of gain per day,” Drewnoski says. “On average, when we initiate grazing in early November, we get about 70 days worth of grazing when stocking one calf per acre.”  

Weather factors  

However, weather is a huge factor, and cattle on Drewnoski’s facility have seen gains anywhere from 1.3 to 2.4 pounds per day. The wet weather is extremely hard on the calves, regardless of the temperature. According to Drewnoski, cattle with wet hair end up using more energy to regulate body temperature, resulting in no gain.  

Drewnoski explains weather is the biggest variable of all and can also affect cover crops. The wet weather, paired with lack of freezes, leads to trampled crops and producers may see losses up to 70 percent. 

“We’ve ranged in grazing days from about 40 to 100 days if we have one calf per acre, and we’ve really seen a difference just depending on weather,” states Drewnoski.  

Types of crops  

Early harvested corn silage ground before Sept. 1 allows feedlots to plant a blend of forage for fall grazing.  

“My favorite mix at the moment is about 50 pounds of oats and three pounds of rapeseed per acre,” shares Drewnoski.  

This mix averages $15 per acre. Drewnoski’s facility has tried oats alone, but it was not beneficial.  

“The oats plus rapeseed lowers the feed cost by about five dollars per acre,” she notes. “We see about two-tenths of a pound of gain per day by adding the rapeseed.”  

Oats and rapeseed also do not produce bulbs, making it easier for calves to graze. Transitioning into more winter hardy grains, like winter wheat, cereal rye or winter triticale, is an option if corn silage was not harvested early.  

“If I can’t plant oats and rapeseed by Sept. 1, then I would plant winter hardy grains,” Drewnoski shares.  

Managing small cereals for spring grazing needs to be done more carefully. Rotational grazing is a great tool so cereals do not become too mature or grazed down.  

Drewnoski says she doesn’t let crops get taller than eight inches and doesn’t graze lower than two inches.  

“I think this is working really well in eastern Nebraska with dry land, while having three calves per acre on it,” says Drewnoski.  

Between fall and spring crops, the calves are pulled in and fed distillers’ until the spring crop is ready. 

Mid-May is when Drewnoski pulls calves from spring crops to prepare the field for planting corn or soybeans. They only see about 30 to 45 days worth of grazing.  

“The cost of gain is still economical when taking into account the seed cost, fencing and adding 10 cent yardages. We were still at about 30 cents per pound per gain,” explains Drewnoski. 

Risks with cover crops 

When calves that have never had a high-protein diet get switched to a hot ration, fog fever may present itself. According to Drewnoski, fog fever occurs when the amino acid tryptophan is converted into 3-methylindole by rumen microogranisms and enters the bloodstream, causing pneumotoxicity. This will present in cattle as respiratory distress, as this compound is toxic to the lungs.  

“The bottom line is, if producers are bringing calves in and turning them out on high-quality forage, they need to put calves on a high-quality diet beforehand or feed ionophores,” states Drewnoski.  

This is not a common risk, but feedlots should be prepared.   

There is also the risk of having to turn out sooner or later on the crops, so a backup plan is good to have. Feeding corn residue with some distillers’ is a low-cost system to have in place for sick calves and for periods between fall and spring crops.  

Delcy Graham is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to 

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