Dakotafest goers learn how 'bale wrap' can harm cattle


MITCHELL, S.D. — The technology of using "bale wrap" for storing large round bales has become more popular, but it's created some health problems when cattle and other animals accidentally ingest it.

Taylor Grussing, a cow-calf field specialist with South Dakota State University Extension in Mitchell, S.D., gave a talk at Dakotafest about the importance of removing "bale wrap," before feeding ruminant animals. The wraps of various composition are becoming increasingly popular to preserve the bindings of various forages, but the wraps are sometimes not sufficiently removed and cleared from feed. She explained that when cows eat it, the wraps can accumulate in the rumen, eventually cutting feed intake and reducing health and performance of the animal.

This was a bigger problem during the 2017 drought when herds were fed for longer periods rather than being sent to pasture to forage for themselves.

"If you didn't grind it properly or take (the wrap) off, we're seeing some increase in problems. National surveys indicate it's a primarily for cattle, but also sheep and horses," Grussing said.

Grussing was among colleagues manning a booth that illustrated the problem with an actual preserved rumen.

Is that real?

Adele Harty, an SDSU Extension cow-calf specialist colleague at Rapid City who focuses primarily on beef nutrition preserved the rumen as a training device for Dakotafest and throughout the state.

The cow stomach was fully inflated and available with cut-outs to allow show-goers to see for themselves the physical features that make grass consumption possible for cattle and other four-stomached species. Even some experienced producers were surprised.

"They mostly say, 'Wow,' is that really how big it is?'" Grussing says. "When we think of a 1,400-pound cow, she has a lot of room in her middle, her gut area. When that's fully inflated, is full of feed, with 40 to 50 pounds of feed a day, they're holding it that long, and it's full of cellulose."

Grussing grew up on a cow-calf ranch near Kimball, just east of the Missouri River and 100 miles from Sioux Falls. She says she's seen plastic rumen models that mimic the vast size of the rumen but hadn't seen a preserved rumen before.

As a youngster, Grussing said she became ware of the malady called "bloating," a kind of indigestion resulting in a buildup of gas in the rumen. The malady is often treated by passing a stomach tube into the rumen, and inducing antifoaming agents. In some emergency cases, producers punch a hole into the rumen to remove the gas.

First sightings

Grussing and colleague Robin Salverson, SDSU Extension cow-calf specialist at Lemmon, started their spiel with the big rumen "vat," where microbes digest the cellulosic forage and mix it. The process creates volatile fatty acids, which enter the bloodstream where they add to cow health.

The top portion of the rumen is equipped with "papillae," hairy structures that increase the surface area of the rumen. Their presence indicates good rumen health and absorption of nutrients.

The second chamber, the reticulum, is equipped with honeycomb-like structures that catch foreign structures, such as wire pieces, and prevent them from going farther into the digestive system and creating more damage.

Digested forages then go to the omasum, which has many folds, and absorbs water from the upper two structures.

Finally, it goes into the abomasum, the "true stomach" which is more like the human single stomach and is surprisingly small. That is where starches are processed before material passes into the small and large intestines.

When asked again about the size of it, Grussing noted that when cows are in-calf, late in their gestation period, the calf takes up space in the body cavity and the rumen is pushed to the side. The cows have an ability to "move this organ around their body pretty efficiently" to make room for a calf or even twins.