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Beware of grain bloat in self-fed cattle

Feed roughage and avoid very fine grain particles

Beware of grain bloat in self-fed cattle

Self-feeders are both a blessing and a curse. A handful of self feeders makes life a lot easier by augering in tonnes of creep or grower ration into each one for growing beef cattle. They can also be a curse when a few cattle become victims of grain bloat.

Since nobody wants to lose animals to grain bloat, those who raise cattle on high-grain diets and feed them in this way learn to take necessary precautions. These measures pay for themselves almost immediately — it’s a low-cost way of feeding cattle, which in turn helps generate optimum revenue.

However, I know of two extreme cases of grain bloat where cattle in Saskatchewan were fed high-grain diets in self-feeders and a few bloated animals died.

In the first case, the producer backgrounded a couple of hundred five-cwt steers to 900 lbs. using a series of old wooden self-feeders. The regular diet was hammered 50:50 oats-barley, a medium-level protein supplement and a bit of chopped straw. Bales of free-choice alfalfa-grass hay were provided in addition to the concentrate ration in the self-feeder.

The small hammer mill to his own admission was old and created a lot of grain fines, which he had planned to replace. Unfortunately, it should have been replaced a long time ago, because this year, it literarily was a “dust-” making machine. After a few days of feeding this diet to a group of cattle, this producer drove down to his small feedlot one morning and found a half-dozen animals bloated and a couple that had died overnight.

In the second case, the producer was feeding a group of 50 replacement heifers by using a mobile metal self-feeder. For weeks this winter, the producer was cleaning out grain bins and wanted to use up its last bushels. I understand that this grain had a lot of chaff and was musty, but the producer thought it was still viable to feed it to cattle.

On the unfortunate day, the hired man made the heifer ration as usual: rolled barley, a few 25-kg bags of protein supplement, plus some chopped grass (bales of the same grass hay were provided separately).

However, he ran out of chopped hay about half-way through, so that week’s diet was almost all grain. As a result of this major diet change, low-forage diet and questionable grain quality, within a day or so three animals had distended left sides and one animal died. Other animals looked like they had a hard time breathing.

Hard lesson learned

Both producers chalked up their sick and dead cattle as a lesson learned. However, the first producer had his veterinarian examine some of the survivors and it was confirmed to be frothy grain- or feedlot bloat.

Frothy bloat in cattle is often caused by a sudden increase in the consumption and subsequent digestion of large amounts of readily available grain starch by the rumen microbes. This starch digestion is so rapid that fermentation gases get unnaturally mixed with rumen fluid into a mass of slimy green foam (slime produced by specific types of rumen bacteria).


Awareness and prevention are the real keys to avoiding sometimes-fatal grain bloat in self-fed beef cattle. Here are some precautions:

1. Provide at least 10-15 per cent forage in your self-fed beef diets. I realize mixing chopped forage with grain ration isn’t particularly practical, and separation is a big problem. However, it is warranted.

2. Feed palatable free-choice forage. Self-fed grain is usually the preferred choice versus free-choice forage by cattle.

3. Avoid significant diet changes. Keep a good inventory of forages, grain and other feeds. Whether cattle are self- or bunk-fed, it’s never a good idea to make forced feed changes in a short period.

4. Avoid feeding “too fine” grain, one of the biggest culprits in grain bloat in self-fed cattle. If grain particle size is too fine, it creates a readily available surface area for starch digestion. I recommend that barley kernels are hammered into quarters for optimum rumen digestion.

5. Manage your self-feeders. I advocate grain self-feeders with adjustable panels to limit grain filling the trough. The opening can be narrowed or widen depending on how much grain ration that cattle should be eating.

6. Avoid adding feed additives to control bloat. Adding monensin sodium to reduce bloat in cattle is not recognized by the Canadian Food Inspection agency.

About the author


Peter Vitti is an independent livestock nutritionist and consultant based in Winnipeg. To reach him call 204-254-7497 or by email at [email protected]



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