Legumes or clovers are recommended additions to tall fescue-based pastures. The inclusion of legumes dilutes the endophyte and its negative impact on performance. In addition, legumes improve forage quality as they tend to be higher in crude protein and digestibility. Legumes also provide an opportunity for bacteria attached to their root system to capture and use atmospheric nitrogen. This nitrogen fixation process lowers the need for fertilizer sources of nitrogen.
Sometimes clovers can pose a risk particularly when clover stands become greater than 50 percent of the plant population. Legumes can induce a rumen disorder called frothy bloat. This typically happens when cattle selectively graze legumes from the pasture in high proportions or when legumes dominate the stand.
In recent years, bloat losses were largely associated with white clover. In the past years, drought conditions and overgrazing led to a weakening of the grass stand, which lowered competition and provided an opportunity for white clover to establish and thrive.
Commercial feed additives can be used and were shown to be effective to reduce the severity and incidence of bloat. These feed additives must be consumed daily to be effective. Poloxalene is an effective bloat-prevention product available in feeds and blocks. Monensin was also shown to aid in controlling forage induced bloat, as well. Oklahoma researchers demonstrated monensin to be quite effective to prevent wheat pasture bloat, which is similar to that caused by legumes. However, the product label does not claim to lower the severity or incidence of bloat.
General management changes can be made to lower the risk of bloat, as well. Avoid turning cattle on to pastures with a high proportion of legumes when hungry. Allowing legumes to mature to flowering can lower the risk. When possible, avoid grazing legumes that have moisture on their leaves following rain or heavy dew. Offering a good-quality grass hay is recommended, as well. Routinely check cattle as bloat symptoms happens rapidly and death losses may happen as quickly as three to four hours after consuming a large amount of legumes.
Long-term, fall pasture renovation of cool season grass pastures may be required to establish grasses back into the stand. It may be necessary to eliminate the legume from the stand to lower the competition level and provide the grass an opportunity to reestablish. Once the grass has been reestablished, legumes can be introduced into the stand again.
If you have overgrown stands of clovers in your pastures, it might be a prudent to develop and implement management strategies to reduce problems. For additional information, contact your local Extension office.
For more information, contact the UT-TSU Extension Office in Wilson County at 615-444-9584. You can also find us on Facebook or visit extension.tennessee.edu/wilson. Ruth Correll, UT Extension-TSU Cooperative Extension agent in Wilson County, may be reached at 615-444-9584 or firstname.lastname@example.org.