Annuals used for cover crops can sometimes be grazed, providing excellent feed for livestock, extra rest for pastures and possible enhancement of biological soil activity. If the annuals were planted to be a cover crop, then grazing should be managed appropriately to ensure the original purpose is not compromised, notes Vic Shelton, state agronomist and grazing specialist with the Natural Resources Conservation Service.
When you add a ruminant, such as a cow, you add a fermentation vat to the system, Shelton says. The rumen is an excellent microbe source, and increases the synergy of the system and the availability of nutrients that might not be available otherwise. Annuals, especially summer annuals, grow quickly and produce enormous amounts of carbon. The top growth, along with the abundance of roots, certainly can help increase soil organic matter.
Before you consider grazing cover crops, be sure you aren’t violating any farm program rules that might cause you problems down the road. Assuming that’s not an issue, here are five tips from Shelton to help make grazing cover crops a success:
1. Make sure you have the necessary infrastructure. The two main things you must have available are fence and water. External fence needs to be sufficient to make sure livestock stay on the property; good fences make good neighbors. Temporary fence for allocating smaller units of forage for higher harvest efficiency and more control is the best way to manage the grazing. Three sets of reels with polywire and sufficient step-in posts for strip grazing is ideal — one set for a back fence, one for the front fence, and one for moving forward for the next move.
2. Give careful thought to providing water for animals. The watering system needs to be flexible enough to match up with the grazing management used and provide sufficient water to meet livestock requirements, Shelton says. Portable systems that move with the livestock are best. Some annuals have very high moisture content and little additional water is needed, but it’s always best to make sure there’s enough available. Water intake is influenced by temperature and humidity, as well as animal species, type and weight. Animals that are lactating or growing need more water, and the amount increases even more as other factors kick in.
3. Don’t graze under wet conditions. Shelton explains that you need to be extremely aware of soil and weather conditions prior to and during grazing periods. You don’t want to add or cause any additional compaction problems. Ideally, soils should be dry enough before grazing that you could have planted into them. The more cover and root growth present, generally the more resilience the soil will have.
4. Don’t graze until the crop is ready. Don’t graze until adequate growth is available, and then maintain adequate growth for cover and regrowth. To reduce the chances of soil compaction even more, provide enough water where livestock are actually grazing to reduce trailing, and don’t feed concentrates or hay in the field.
5. Watch out for problems that could cause illness or death. Annuals can provide excellent feed for grazing livestock. However, be sure that vegetation used for livestock feed doesn’t have any ill-causing attributes, such as excess nitrates or prussic acid.