By late August, much of the available grass is limited and brown. It's too early to start feeding hay and many ranchers look to cover crops as a grazing supplement in the late summer months. While sudan grass and millet are often the first cover crops producers think of, USDA Natural Resources Conservation Service Rangeland Management Specialist, Brent Woods, recommends grazing Brassicas as affordable cover crops for grazing.

A Brassica is a group of closely related plants, which include cabbage, cauliflower, kale, rape, radish, winter canola, turnip and swede. Brassicas have been used extensively in Europe as livestock forage for over 600 years. Brassicas can be used as cover crops for supplemental grazing. A cover crop is any crop that is planted between periods of regular crop production to prevent soil erosion and provide organic matter and nitrogen.

Simple, affordable economics

Woods is confident that planting Brassicas as cover crops is an incredibly affordable option for producers to consider. In a recent scenario of 141 cow/calf pairs on a 72-acre field of turnips for 17 days, Woods proved the economic advantages. He said that on average, calves gained 52 pounds for the 17 days, for 3.1 pounds average daily gain/calf. That calculates to 7,332 total pounds gained and for $1.09 sale price/pound, that results in $7,992 total income. For the 72 acres field, that's $111.00/acre gross return.

So, what are the expenses for these gains? For this scenario, Woods said the seed cost was $20, seeding was $13 and $12 for the herbicide chemicals and application. With gross income/acre at $111 and expenses/acre at $45, the net income/acre is a solid $66.

“Grazing cover crops pans out economically, but the real value is the recovery time on grazing land and the improved soil health,” said Woods, of Parkston, SD. “With cover crops, it's best to try and get them planted by August 1. These plants are easy to plant and quick to establish, as well.”

Woods said that these cover crops typically germinate three days after a rain. Producers can plant them using broadcast methods with a planter that can plant small grains such as wheat and alfalfa. These cover crops can be used for early winter grazing, usually until Thanksgiving time.

Will cows really eat this stuff?

While the economics of using cover crops as supplemental grazing seem pretty tempting, many producers worry that the cows will not like their newly introduced diets of turnips, radishes or rapes.

“A lot of producers ask me if the cows will actually eat these cover crops, or will they dislike or choke on the big radish and turnip bulbs?” said Woods. “Last year, a group of Nebraska cattle were introduced to turnips in paddocks. The first three weeks in the introductory paddock, the cattle didn't know what to do and a trail was made around the fence, as they didn't really graze in the turnips. The second three weeks in a new paddock, the cows started nibbling at the turnip tops. By the third paddock, the cows were pulling the turnips out of the ground, and there wasn't much left in the field after the three weeks.”

Brassicas are high in protein and energy but low in fiber, so grass or hay should be fed in conjunction with the cover crops. Bloat can be an initial problem, so Woods said to make sure the cows are full before entering cover crops for the first time. Strip grazing is recommended to reduce trampling and allow the livestock to learn how to graze Brassicas. Finally, producers should be careful of grazing stunted plants from early frost, wet conditions or inadequate fertilizer. Stunted plants could result in poisoning problems.

Consider cover crops

According to a recent NRCS study, data reports from central South Dakota are showing that cover crops are an excellent tool for storing nitrogen in the soil for next year's crop. The use of cover crops has benefits for both the soil and the subsequent crop. A number of cover crop species will utilize nutrients, especially nitrogen, which would otherwise be lost to leaching or denitrification before the next cash crop could capture them.

“I truly believe that cover crops have great potential in the area for cattle producers to utilize as a low-cost forage option for late fall,” said Woods.

Interested producers should visit with an agronomist or their local NRCS staff for science-based information on cover crops and for networking contacts to help producers at any point in their soil conservation efforts.