Bloat can be a prominent issue this time of year for cattle grazing small grains pasture. Environment, weather, forage growth stage and forage quality all play a role in the occurrence of bloat. Even though producers understand why it occurs, bloat can be difficult to predict.
Learn about frothy bloat
Frothy bloat refers to the digestion of high-quality forages and the formation of a stable matrix within the forage mat floating on top of the rumen contents. Frothy bloat is not only specific to wheat pasture. It can occur in cattle consuming alfalfa, legume type forage and other small grains. Due to fermentation occurring in a ruminant’s digestive tract, gases are a natural part of the digestive process. However, the nature of those forages creates conditions where excess gas can be an issue. When the gases work their way up through the liquid in the rumen and become caught in that matrix, a dense foam can develop. That foam blocks the gas from being released through the esophagus. Without treatment, cattle can expire quickly due to intense pressure on the lungs and heart.
Bloat is common in calves grazing small grains. Small grains forage is high in protein and low in fiber, which makes it highly digestible. Many other factors contribute to the high-quality feed playing a role in the occurrence of bloat.
An increase in growing degree days in February and March can cause bloat. Pastures grazed through December and January may be clipped down, and when temperatures increase and moisture is available, growth rate increases. That immature fast-growing stage of the plant is the main contributor to bloat. Consumption rates may also be great due to the level of water content within the plant.
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Frost is also a big factor. Frost disrupts the cells of the growing plant making those soluble nutrients even more available. This time of year, frequent frost may cause a large percentage of calves to exhibit signs of bloat just after their morning grazing session.
Intense bouts of bloat don’t typically last the whole grazing season, being limited to times when the forage is immature and growing quickly. As the forage matures, bloat will become less prevalent due to increased plant fiber content. More fiber in the forage will require more digestive activity therefore alleviating most bloat issues. Activity such as mastication, saliva production and muscle contraction of the rumen will break up the matrix and reduce the foam.
Know what can be done
Decades of research by Oklahoma State University animal scientists have provided the industry with tools to manage and treat bloat. The first line of defense is providing a basic free choice mineral. The mineral should contain 15 percent to 20 percent calcium, 0.5 percent to one percent magnesium, and minimal phosphorus. Calcium is needed for proper rumen muscle contraction during digestion making it the most important mineral to supplement on wheat pasture. The assumption that magnesium or “Hi-Mag” is crucial on wheat pasture should be limited to mature beef cows who are prone to grass tetany when grazing lush growing forages. Research shows a basic non-medicated free choice wheat pasture mineral manages bloat and can boost performance 0.25 pounds daily.
The second line of defense is the addition of monensin in free choice mineral or small package energy supplements. Research has proven that monensin reduces the severity of bloat in addition to improving efficiency and boosting weight gain.
The final defense is the treatment of bloat when it occurs. Severe bouts of bloat can be treated effectively with paloxalene, which can be found as a feed additive and in pressed blocks. It is good practice to have a supply of paloxalene on hand in case of severe bloat. The product is somewhat expensive and may be most cost effective to treat bloat rather than provide the entire grazing season.
The article is a summary of an episode of the Extension Experience Podcast.
Dana Zook is an area livestock specialist for the Oklahoma State University Cooperative Extension.