Agriculture : News
DATE: June 13, 2010
HARDIN COUNTY COOPERATIVE EXTENSION SERVICE
201 Peterson Drive
Elizabethtown, Kentucky 42701-9370
BY: Doug Shepherd
County Extension Agent for Agriculture and Natural Resources
2010 Clover Explosion:
Seems everybody is wondering what factors contributed to the over abundance of white clover in fields and yards this year. This situation has raised concerns about bloat in cattle and a number of local livestock farmers have experienced death losses in their herds due to bloat. The following are some comments from Dr. Garry Lacefield and Dr. Ray Smith, UK Extension Forage Specialists on this serious issue.
There are several reasons for the high percentage of white clover this year. Ironically the drought years of 2007 and 2008 set the stage. During those years many pastures in Kentucky were over grazed due to restricted plant growth and they simply could not sustain the number of cattle on most farms. Even the pastures that were not over grazed had thin stands as many pasture plants died due to drought. Simply put, there just was not enough forage to support the normal number of cattle raised on Kentucky farms. When normal precipitation returned during the fall of 2008 and spring of 2009 white clover that had been dormant in the soil for years had bare soil and perfect conditions to germinate and grow. Throughout 2009 clover continues to germinate and grow leading to a higher than average abundance.
Additionally, the abnormally cool moist conditions during 2009 were perfect for white clover to spread due to aboveground runners or stolons. Ample precipitation continued during the fall of 2009 and spring of 2010 allowing additional seed to germinate and more spreading to occur and clover seemed to take over many pastures.
In short, the clover abundance of 2010 goes back 4 years with bare ground caused by drought in 2007 and 2008, and above average precipitation and cool growing conditions during 2009 and 2010. And although clover is very high quality and desirable as forage, too much clover can lead to bloat in grazing cattle.
How long will we be plagued with this over abundance of white clover - is a difficult question to answer and will vary from farm to farm. Droughty conditions and the extreme heat we’re expected to experience this week, definitely are two factors that shallowed rooted white clovers don’t like. However, timely rains will provide moisture for the clover to continue its rapid growth that we’ve experienced so far this spring. Most of our cool season grasses, fescue and orchardgrass have moved into the reproductive stage, and this advancing maturity will result in animals grazing lower in the canopy to find the succulent, lush forage below where the clover will be. This selective grazing can increase the risk to bloat, but keep in mind that the real culprit is the percentage of legumes in the stands. Pastures with 30-40% clover or less will not be of much concern as the cattle will have ample leaves from the grass plants to graze lower in the canopy and pose little risk to bloat.
Managing Bloat Risk:
Use of ionophores such as monensin (Rumensin) and surfactants such as poloxalene can reduce the incidence of bloat but these products too must be managed. Encourage consumption of bloat blocks by not limiting animal access. It is better to have too many blocks out than not enough. These products must be consumed on a daily basis as there is no carryover protection. Too few blocks will prevent more timid cows from consuming the needed levels to reduce the risk of bloat. Keep the mineral feeders fresh and accessible if using a product with monensin. You may consider providing access to mineral and/or bloat blocks in loafing areas and near water sources to promote intake.
Feeding of long-stemmed hay may assist by reducing the rate of fermentation. It lowers the amount of soluble nitrogen that can contribute to the formation of the froth promoting slime. The biggest challenge in feeding long-stemmed hay is the amount needed. Encouraging hay consumption can be a challenge on fresh lush pasture, but cattle will eat good quality hay when offered.
We may see some reoccurrence of abundant clover growth this fall. As the cool weather and rain returns, this can stimulate clover growth again. The highly digestible grass at this time is rapidly fermented and can contribute and when combined with high levels of clover in the stand, sets the stage for risk of frothy bloat.
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