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cattle grazing on wheat pasture
Cattle may have been turned on wheat pasture for grazing a little later than normal this year, but bloat from the new growth is still a concern. (Photo by OSU Agriculture)

Beef specialists warn of bloat on wheat pasture

Thursday, March 16, 2023

Media Contact: Gail Ellis | Editorial Communications Coordinator | 405-744-9152 |

Varying degrees of drought across the state have caused cool-season grasses to grow a little later than usual this year, and Oklahoma State University Extension specialists have received reports of bloat in calves grazing wheat and other small grain pastures.

Growing conditions improved for these pastures, which have been grazed short this winter with regrowth that is all highly digestible leaf.

“We have also had some late winter frost events that can damage the cell walls in the new growth, releasing the cell contents for rapid availability in the rumen, said Paul Beck, OSU Extension beef cattle nutrition specialist. “These plant fractions are the most bloat provocative and can very quickly cause bloat in grazing calves.”

Death can occur rapidly from bloat, but so can relief. Calves can return to normal soon after supplements containing Bloatguard (Poloxalene 6.6%). Bloatguard is commercially available in blocks, mineral supplements and topdresses for concentrate supplements.

  • Don’t wait until the bloat outbreak occurs. Have some type of block, supplement or mineral on hand that contains Bloatguard. Not all feed stores carry this item. Ranchers may have to travel to another town to find it.
  • Feed calves a few days a week throughout the winter to keep them coming up to troughs so they can be easily gathered if bloat occurs.
  • Mineral or supplements providing ionophore monensin decrease the incidence and severity of bloat. This will make it more manageable to identify bloat outbreaks before they cause death losses and allow time to take corrective measures.

OSU Extension also offers the following guidelines in herd management this time of year.

Replacement heifers and spring breeding

  • Should be 14 to 15 months of age
  • Roughly at 2/3 of their mature weight
  • Over 90% of heifers at this age and weight will be fertile, ready to conceive and on schedule to calve at 2 years of age

“At this point in the year, typically if we’ve got normal wheat pasture in Oklahoma, it’s relatively easy to get those heifers to that target weight, but if we’ve been in a situation with limited hay and feed resources and we’ve not had any winter cool-season grass to graze, we might want to take inventory of those heifers,” said Mark Johnson, OSU Extension beef cattle breeding specialist. “If we’ve got some wheat pasture coming on or just need to adjust our feeding program, we’ve still got time to get those heifers to where they need to be to breed at 2 years of age.”

Body Condition score of cow herd

  • Heifers should be at about a 6
  • Cows should be at a 5 ½
  • Monitoring body condition scores is as important as it’s ever been this year because of the large amount of nontraditional hays that have been fed

“Different feeding programs that we consider are supplemental feed, mineral supplementation and protein supplementation,” Johnson said. “You could add in an ionofore to cows’ diets if we need to put on a little weight and body condition score going into calving season. That way, we can get prompt breed back and keep them on schedule for calving once a year.”


Deworming can be the least expensive way for cattle to maintain or add body conditioning. Johnson recommends checking records and analyzing the cost effectiveness of deworming the herd.

Read more about preventing bloat in the Feb. 6 issue of OSU Extension’s Cow-Calf Corner Newsletter.

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