Hey, Doc, come out and look at the calves," the dairy owner said anxiously over the phone. 

When he arrived at the farm, veterinarian Craig Meadows found that about 50 percent of the young calves between five and 10 days of age were affected. Some had died suddenly. Others looked pathetic, their bodies showing grotesque enlargement. The producer had no idea what was causing the problem, but Meadows, of Turlock, Calif., had seen it before on other farms — abomasal bloat syndrome.

Sure enough, the farm had recently changed milk replacers on the advice of its feed company.

Often, the problem is related to the use of milk replacer. And, the cure often involves switching back to a high-quality milk replacer or feeding whole milk until the problem has a chance to resolve itself.

Prevention is the key. Although the veterinary community doesn't understand all there is to know about abomasal bloat syndrome, here are some things you can do to minimize your chances of an outbreak.

1.Do your homework before changing milk replacers. 

Using a cheap milk replacer may bring on the problem.

Be cautious when changing milk replacer — especially when switching from a high-quality milk replacer that relies primarily on milk proteins to a cheaper brand that relies primarily on plant-based protein sources. The label may not tell you everything you need to know, so be sure to check with your supplier. Ask him if milk protein is the primary protein source.

Optimal proteins include:

  • Dried whey protein concentrate.
  • Dried skim milk.
  • Protein-modified soy flour.
  • Dried whey product.
  • Dried whey.
  • Dried milk protein.

If you do experience a problem with bloat on your dairy, consider switching to a higher-quality milk replacer or whole milk for calves less than 10 days of age.

2. Avoid over-feeding milk replacer.

Meadows says the problem may be related to the volume of milk replacer the calves ingest at one time. "When a calf is able to take in a large volume quickly, that seems to cause more of a problem," he adds.

Brad DeBey, diagnostic pathologist at Kansas State University, agrees that over-feeding may be a factor. He has studied abomasal bloat syndrome in dairy calves, beef calves and goat kids, and has written about his studies in scientific journals. 

"Based on what I know in beef calves, the people generally tell me it is the best-growing calves that are affected, which would mean if they grow faster, they eat more," DeBey says. "So, I think a large volume (of milk replacer) could contribute to this."

For calves that are 10 days of age or younger, Meadows suggests restricting their intake of milk replacer to 2 quarts per feeding. If the calf manager is trying to push the calf by feeding more than 2 quarts, then it's probably better to raise the solids in the milk or feed more often than to raise the volume fed at once.

As a further precaution, avoid bucket feeding until the calves are 10 days old, he says.

3. Replace worn nipples.

Check the nipples on bottles. Replace worn nipples to ensure that the calf is receiving a controlled dose of milk replacer rather than too much at once.

4.Check the temperature of the milk replacer.

The temperature of the milk replacer should pretty much match the calf's normal body temperature of 101.5 degrees F.

Based on what we know about the organism that may be causing abomasal bloat syndrome (please see the sidebar on page 28), it may be a problem to feed milk replacer at temperatures significantly above body temperature. But, no one knows for sure what the exact danger threshold might be.

What is causing this problem?

No one knows for sure, but the likely cause of abomasal bloat syndrome is a gas-producing bacterium called Sarcina ventriculi.

Sarcina are soil-borne organisms. They are normally found in the cow's rumen, but not in another stomach chamber known as the abomasum. So, something must happen to create the right conditions for Sarcina to get into the abomasum and cause bloating.

Perhaps a large influx of warm milk replacer provides the bacteria with the needed substrate or food source on which to grow.  

Brad DeBey, diagnostic pathologist at Kansas State University, says Sarcina are the most likely cause because:

  • They are a gas-producing organism. Large volumes of trapped gas cause the calf's abomasum to dilate in size.
  • They ferment lactose. So, if there is a lot of milk in the environment, they are very happy organisms with a built-in food source. 
  • They can tolerate and grow in very acidic conditions — at pH levels as low as 2. Often times, it gets that acidic in the abomasum.
  • When veterinary diagnosticians take tissue samples from animals that died from abomasal bloat syndrome,  they find Sarcina organisms.