PLASTIC DISEASE: The New Hardware Disease in Cattle
You’re out feeding your cows on a winter day when you notice a cow that just doesn’t look right. She’s big bellied, doesn’t seem to have much appetite, yet her nose is wet and eyes are clear. You can see by her tag that she’s a six-year-old, right in the prime of her life. There are no real symptoms that you can doctor her for, so you decide to just keep an eye on her. Days pass and she gets thinner and thinner, until finally you put her in the corral to give her a little extra help. In a few weeks, despite ample good feed, she dies. You have a couple more cows that are losing weight and acting similarly, so you call the vet out to do a necropsy, hoping to prevent any more losses if you can learn what you’re dealing with.
The vet opens the cow up and in the rumen is a sodden mass of what turns out to be netwrap or plastic twine, all mixed with the little bit of hay that she had eaten in her last days. The other cows with similar symptoms, plus that bull you spent so much on several years ago, are headed down the same road, and you can’t do anything about it.
This is the new “hardware disease,” which should be called “plastic disease,” due to the volume of plastic twine and netwrap that are used in baling hay. Even the biodegradable twine that some have started using as an alternative will cause the same problem once it’s ingested. It only breaks down in ultraviolet light, so once it’s out of the sunshine, it stops dissolving. It will, however, break down and no longer be a threat if it is on the ground, unlike plastic twine and netwrap, which remain in the environment indefinitely.
Pulling netwrap or twine off of round bales is time consuming and difficult, especially in country where it will become iced onto the bales. Sometimes yards of it will be frozen to the hay and is left on the ground under the hay when it is rolled out. The theory is that the cows will eat the hay off of it, but, if you can’t pull it loose with your fingers, they can’t pull the hay loose with their tongues. When that happens, they get large pieces of netwrap ingested due to the surface area and length. Once they get it in their mouth and swallow once, they can’t spit it out.
Feeding in bale feeders is another place that twine and netwrap either are left on the bale to prevent waste, or not all of it is removed for various reasons. The bale feeder gets moved and the plastic is left on the ground in the lots, where cattle can try to pick hay out of it, eat weeds growing up through it, or baby calves just have to pick it up to taste it, and it’s in them.
People who use bale processers often times don’t remove the netwrap or twine, believing that the beaters will peel it off as the hay is fed. That gets a lot of it, but certainly not all of it, as the netwrap is often shredded in the process. Walking the feedground after it’s fed will turn up pieces several feet long, even if only a few inches wide. It can go right into the cow when she takes a bite of hay and she’ll chew it and swallow it.
Bale processing and feeding without the removal of the net wrap can lead to a high incidence of free-gas bloat caused from concretions of pieces of plastic wrap blocking the cow’s esophagus. It likely floats in the rumen until the cow belches and the wad of plastic becomes lodged in the esophagus, the cow can’t belch, and the gas buildup rapidly causes a fatal bloat. Even nursing calves will pick up a small piece of netwrap, and when mixed with the grass they graze, can have the same sudden onset bloat and death.
Veterinarian Dr. Jim Myers, Belle Fourche Veterinary Clinic, Belle Fourche, South Dakota, says “I’ve done necropsies of the second stomach and it looks like a piece of burned plastic. It stops the advancement of feed on through the digestive process. It’s not possible to remove anything from the second stomach, so there’s nothing we can do to save the animal.”
Rumen microbes can’t break it down, so it stays in the rumen, unable to pass on through via the small intestine. Cattle that have “mysteriously” died on pasture, when the carcass breaks down and the rumen contents are revealed, can have a ball of plastic twine, some as big or bigger than basketballs, left within the ribcage. The netwrap will also be revealed in a similar mass.
“Even grinding it can lead to impaction and isn’t safe,” says Dr. Myers. “It still can’t pass through to the small intestine.”
Grinding hay has become a popular way to utilize lower quality forage by mixing with better feed for rations. Feedlot cattle receive a lot of ground feed, and even though there are incidents of impaction, they are usually slaughtered before the netwrap or twine becomes an issue. Mother cows and bulls, however, due to their longer lives, have the most incidents of blockage or impaction due to the years they are fed ground or processed hay.
Midwest Ag and Veterinary Services, with locations in Watertown and Aberdeen, South Dakota, have had experience with the netwrap and plastic twine losses in customer cattle in that area, according to owner Chris Bartelt. “In 2018, Dr. Rink found an 18-pound piece of netwrap in an eight-year-old cow. In 2019, Dr. Whitlock did a post mortem on a bull and found a complete blockage. It’s a serious problem.”
With the welfare of livestock being so important to producers, plus the sheer cost of losing cattle, it’s imperative that people review their methods of feeding and management of the twine and netwrap that are used. The extra time it takes to remove it will pay off in the long run with fewer problems of poor doing cattle or cattle that simply don’t make it.
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