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Lush pastures posing a gassy problem for cattle this spring

Lush pastures posing a gassy problem for cattle this spring

Lush pastures posing a gassy problem for cattle this spring

Published on Apr. 23, 2010

As picturesque as cattle grazing lush pastures on Kentucky rolling hills may be, a closer look reveals a problem producers are having to deal with this time of year – bloat.

University of Kentucky College of Agriculture Extension Forage Specialist Ray Smith said that recent good growing conditions have caused a lot of white clover to sprout in pastures and limited precipitation has slowed grass growth.

“Cattle are consuming greater quantities of white clover due to short grass and that’s promoting legume bloat or frothy bloat,” Smith said. “Similar conditions can also occur when cattle are grazing wheat.”

Frothy bloat is different from gaseous bloat, which happens more when cattle are consuming grain, and it’s also more difficult to relieve.

“Usually frothy bloat happens when cattle are grazing forages that are high in soluble protein combined with rapid fermentation,” said Jeff Lehmkuhler, extension beef specialist for the UK College of Agriculture. “It produces a stable foam in the rumen that blocks the normal escape of the gas from fermentation through eructation or belching.”

When the gas cannot escape, the cow’s rumen becomes distended similar to blowing up a balloon, and that can impact the animal’s ability to breathe normally because of pressure against the diaphragm, added Michelle Bilderback, UK College of Agriculture extension veterinarian.

Bilderback said that the stable foam has to be disrupted to allow the gas to escape.

“Saliva contains mucin which has been shown to be key in disrupting and preventing the formation of this stable foam,” she said. “Wet, lush forages reduce chewing activity and saliva production.”

Risk is greater during periods when the forage is wet such as when dew is present in the morning and evenings. Stimulating rumination by providing palatable, good quality grass hay is believed to help prevent frothy bloat. Some researchers, however, have not shown this to be effective means of preventing or reducing the severity of bloat.

So what can a producer do to help ensure that cattle don’t suffer from frothy bloat? UK researchers agree that a proactive approach works best, and if producers can strategize ways to prevent bloat in the first place, they won’t have to worry how to alleviate it after it occurs.

“We commonly use feed additives to prevent and reduce bloat severity,” said Roy Burris, extension beef specialist for the UK Research and Education Center in Princeton. “Using ionophores has been shown to be effective in preventing and reducing the severity of bloat.”

Lehmkuhler said poloxalene is a proven bloat-preventing feed additive; however, it can be costly to feed.  Producers commonly use poloxalene blocks for their convenience, but producers can also get poloxalene in a powder form to mix in supplements or mineral mixtures.  During periods of severe bloat risk, Lehmkuhler said the target intake level of poloxalene is 2 grams per 100 pounds of body weight. 

“You can reduce it to 1 gram per 100 pounds of body weight as the risk to bloat diminishes,” he explained.  “It is recommended that poloxalene be added 2 to 3 days prior to introduction into pastures that are at risk to promote bloat.  Poloxalene must also be consumed on a daily basis as there is no carry over protection.”

Producers can contact Burris, Lehmkuhler or a local Cooperative Extension agent for product recommendations. Most products are readily available from feed dealers who sell free-choice mineral mixtures. Some additives may be helpful but can also be costly to feed.

Other practical management strategies do exist, and they can reduce the incidence of frothy bloat.

“Ideally the legume content of a pasture should be below 50 percent to reduce the risk of bloat throughout the grazing season,” Smith said. “Allowing legumes to mature to late bud, early bloom stage will also reduce the bloat risk.”

Bloat risk is reported to be higher for vegetative pre-bud stages.

“Moving cattle to pastures with less legume content and returning to pastures when the legumes have advanced in maturity might be an effective strategy if such diversity exists on your farm,” Lehmkuhler said. “You do want to avoid moving cattle to new fields with high legume content when they are hungry. Attempt to fulfill their hunger with high quality hay if necessary before moving into legume pastures, and it’s important to monitor cattle frequently throughout the day.”

Sometimes producers will face an emergency case of frothy bloat, and Bilderback stressed the importance of quick action and prompt treatment.

“Death can occur in as little as one hour after grazing begins but is more commonly seen 3 to 4 hours after bloat starts,” she said. “If life threatening, your veterinarian may do an emergency rumenotomy (cutting a hole in the rumen) to relieve the pressure. If the animal is not in immediate danger, passing a stomach tube into the rumen and administering an antifoaming agent such as mineral oil may aid with the problem.”

For more information contact your county agricultural extension agent and your veterinarian.

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