Beating Bloat in Calves

Within hours, bloat in dairy calves can go from serious to deadly.

Geof W. Smith, Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, says modern dairy practices may contribute to the problem—especially as they relate to abomasal emptying and its contributions to bloat.

But the good news? Producers can take steps to reduce the risks and the losses.

Bloat in calves is different from that in cows.

"When adult cows bloat, free gas becomes trapped in the rumen and they become distended on the left side," Smith says. "Bloat in young calves is caused by excessive gas accumulation in the abomasum."

Smith says affected calves are often 5 to 10 days old—sometimes up to 21 days old.

"We see a lot of abomasal bloat, caused by free gas in the abomasum, and often the calves will bloat and die within 12-24 hours," Smith says. "Many vets call this clostridial bloat, which is caused by a bacterial infection. But in many cases other factors are also involved."

Smith says more aggressive feeding programs may lead to problems within calves' digestive systems.

"The dairy industry has moved toward more liberal feeding systems that permit calves to express their genetic potential for growth, reduce age at first calving and improve milk production," he says. "This trend in calf feeding has many benefits—and we absolutely are not saying an aggressive feeding plan should be avoided. But it could promote abomasal diseases including bloat."

The longer the milk or milk replacer stays within the stomach, the more opportunity for bacteria to grow and bloat to develop, Smith says.

Therefore, two factors should be considered when feeding larger volumes to calves: the volume fed at one feeding, and the osmolality or the concentration of particles in a solution.

"We need to pay close attention when mixing milk replacers, to ensure they contain the proper amounts of water," Smith says. "Cows' milk normally has an osmolality between 280 and 290 mOsm/L.

However, recent research has shown that calves fed an oral electrolyte solution with high osmolality have a much slower abomasal emptying rate as compared to calves fed a solution with a lower osmolality."

This high osmolality can delay gastric emptying, leading to increased gas and bloat.

Smith advises producers to avoid feeding milk replacers or oral electrolyte products with an osmolality greater than 600 mOsm/L. A brix refractometer can help to ensure proper osmolality of feedings.

Feeding frequency is also a critical factor in calf digestive health.

"When a producer feeds larger volumes in one feeding, those larger volumes can empty more slowly from the abomasum," Smith says.

A beef calf will often nurse its mother seven or eight times per day, at 1 or 1 ¬Ω liters per feeding, Smith says.

"Of course, that's not practical in a dairy system," he says. So how can a dairy producer continue with a more aggressive feeding program, while maintaining digestive health in calves?

One option, Smith says, is moving from two feedings per day to three.

"Automated feeders can help a producer move to smaller, more-frequent feedings," Smith says.

As well, during high-stress times of year, one additional feeding per day can help promote greater GI health in calves, he says.

Regardless of the feeding system used, Smith says, consistency is critical.

"Calves do well when the feeding schedule is consistent," he says. "So feed at the same times each day, and be consistent with the milk or milk replacer used."

By following these guidelines and keeping abomasal emptying in mind, your calves can experience greater GI health, and hopefully, cases of bloating can be few and far between.

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