Grazing livestock on cover crops

Grazing cover crops accomplishes one of the soil health principles of integrating livestock into crop rotations. The other principles of soil health are to keep the ground covered, increase biodiversity, keep a root in the soil at all times, and minimize disturbance.

Until livestock are integrated back into the cropping rotation, soil health is not fully optimized. Hauling stored manure to the field does not have the same impact as a grazing animal assisting directly in nutrient cycling in the soil.

When grazing livestock are managed properly on crop fields, their manure, hoof impact and grazing of plants stimulate soil biology, improving nutrient cycling and water infiltration in turn.

Benefits to soil

Cover crop grazing studies have shown that soil organic carbon (SOC), microbial biomass carbon, and potassium concentrations are greater when grazing cover crops compared to not grazing cover crops. Additionally, researchers found that increased SOC was associated with decreased soil bulk density and increased water-stable soil aggregates. These factors possibly translate to minimizing soil erosion and increasing water infiltration.

Conversely, it is not hard to find studies that demonstrate detrimental cover crop grazing impacts on soil health. But often, these studies do not detail how the livestock were managed and how much cover crop biomass was removed by grazing livestock. This gap in detailing which livestock management methods were used casts doubt on any conclusions about livestock impact.

Benefits to your budget

Economically, cover crops are a livestock feed opportunity. If livestock are already being grazed on perennial pastures, cover crops can extend the grazing season in the spring or fall. The savings acquired from grazing cover crops instead of feeding stored feed can often cover the expenses of planting the cover crop.

The fencing and labor costs of grazing cover crops can be traded for the manure hauling and forage harvesting costs of housing cattle in a drylot. For example, using winter grazing of stockpiled grass legume mixtures or even corn crop residues for two months before hay feeding leads to hay savings of 1,382 to 2,357 lbs per cow for the season compared to cows in a drylot.

A South Dakota study of a corn, soybean, rye and cover crop rotation found that integrating cover crop grazing increased farm profitability by $17.23 per acre in the first year and $43.61 per acre in the second year. Of course, any number of variables in your specific farm’s context can alter the profitability of grazing cover crops.

Benefits to livestock nutrition

In Minnesota cropping systems, late summer corn silage harvest allows planting a diverse cover crop mix. Depending on weather conditions and cover crop species selected, this timing should allow for adequate cover crop growth to graze cattle in the spring.

Using small grains in your cropping rotation can provide an even larger window for cover crop planting, growth and fall grazing after small grain harvest.

Often, cover crop mixes provide more than adequate nutrition for sheep, heifers, steers or dry cows. Supplementation of dry hay may be needed when turning livestock out onto high protein cover crops initially to prevent digestive upset.

Read Extension research on cover crops for grazing systems and use the Midwest Cover Crop Council selector tool for more information about cover crop species' nutritional value and agronomic properties. 

Apply soil health principles to grazing livestock

There are many benefits to grazing cover crops, yet concerns remain. For example, what if grazing cover crops on cropland decreases subsequent cash crop yields? 

There is a potential that livestock can have detrimental effects to the soil or subsequent cash crops if they are not managed properly. The same soil health principles should be applied to grazing livestock.

• Minimize disturbance by taking livestock off the field if conditions are too wet or keep them moving to a new paddock at least once a day.
• Maximize soil cover by controlling how much of the cover crop the livestock eat.
• Do not over-graze.

Other concerns may be that grazing leads to greater water pollution and runoff. However, keep in mind that grazing the above-ground biomass affects the below-ground root structure of cover crops. As long as cover crops are not overgrazed, this root structure and soil cover should remain in place to prevent erosion and water pollution.

Whether grazing livestock for increased soil health benefits or to fill gaps in the forage chain, consider what opportunities are available for increasing farm resiliency and profitability.