20 March 2010

3 minute read

“Wheat pasture bloat – sometimes called Sudden Death Syndrome – is a frustrating problem, often killing the faster-growing calves that consume a greater amount of forage,” said Mr Greg Highfill, Oklahoma State University Cooperative Extension area livestock specialist.

Several factors related to plant growth and composition plus animal consumption play a role in this problem. As the wheat plants break winter dormancy, the proportion of forage components during this rapid growth phase can contribute to the rumen digestion producing a frothy foam. With rapid fermentation and conditions to produce a froth covering in the rumen, fermentation gas is trapped and bloat occurs.

“Numerous factors can contribute to bloat conditions specific to each season,” Mr Highfill said. “In some years, the major culprit can often be cattle engorgement or simply eating too much wheat forage too fast.”

Death usually trails engorgement within nine hours to 24 hours. In addition, weather fronts often disrupt normal cattle feeding patterns. Cattle often consume more forage when a weather change is about to occur.

The number of bloating cattle can increase rapidly in a few short days.

“Producers often feel helpless as the death loss number can be significant,” Mr Highfill said. “One logical management strategy that should help reduce frothy bloat would be to take steps to make wheat forage intake more uniform and prevent engorgement.”

A useful option may be to provide cattle with a feed supplement that contains monensin. Monensin has proven to be effective in reducing the incidence of bloat and should reduce forage intake as well.

“Stocker cattle should receive 150 milligrams to 200 milligrams per head per day of monensin to effectively reduce bloat,” Mr Highfill said. “Purchasing a supplemental feed with the targeted monensin dose and getting it into the cattle are the primary management challenges.”

Mineral mixes containing monensin also are available, although consumption typically will vary more from calf to calf.

“Herd managers should assess the bloat risk in their operation to determine the level of protection needed, and possibly consult with their local veterinarian, if appropriate,” Mr Highfill said.

Poloxalene is the generally recommended treatment for significant bloat outbreaks, although it is an expensive feed additive. While poloxalene reduces rumen frothiness, it must be consumed daily as it has no residual effects in the rumen.

Mr Highfill said the generally recommended rate of Poloxalene is one gram to two grams per 100 pounds of the animal’s body weight. The most common form of poloxalene is Bloat Guard®.

“The preferred delivery would be to have poloxalene commercially mixed into a feed supplement; however, it could be top dressed onto processed feed in the feed bunk,” he said. “Hand-feeding a supplement may not be possible, so providing poloxalene in a mineral may be the best option.”

If mineral blocks are used, producers should encourage daily consumption of the proper poloxalene amount by removing all salt and other mineral sources.

What about the common practice of feeding hay to cattle on wheat pasture, in the belief that low consumption may provide limited bloat control?

“It’s important to note that OSU studies have shown that feeding hay really has no significant effect on reducing bloat,” Mr Highfill said. “Some stocker cattle are just much more sensitive to bloat than others. If these animals survive the early part of an outbreak, they should be removed from wheat pasture as they will probably be susceptible to bloat the entire grazing period.”