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Be alert to bovines consuming ‘software’

Animal Health with Roy Lewis: Twine, plastic, rope — there is a good chance it could end up in an animal’s gut

During a necropsy on a calf, some of the material in its gut included this fairly large piece of tan-coloured plastic.

I just completed an autopsy on an older well-doing calf that got suddenly sick dehydrated and toxic-looking. My daughter, also a veterinarian, did an autopsy on a mature cow that was losing weight and going downhill, becoming emaciated and weak.

Even though both these clinical signs seem different, as well as the age difference between the patients, both had somewhat similar things on post-mortem. It is what we call ‘software disease’ — the opposite of ‘hardware disease’ — metal in the stomach. Plastic materials and other miscellaneous things can lead to digestive upsets, among other problems.

I hope I can shed some light on preventing these incidents. We must realize that every case we discover is the tip of the iceberg. There could be many other less-clinical signs and production losses. In these hard-to-diagnose situations, vets should be thinking of a potential software problem.

Calves are especially inquisitive so plastic junk such as twine, plastic, rope halters, grocery bags and silage plastic can easily be consumed. Similarly to cows eating placenta, cattle will chew away at all kinds of materials.

My daughter’s post-mortem revealed a huge twine ball that was lodged and blocking the exit to the rumen. This must have been building up for some time. The producer did not cut and remove the bale twines so one would assume that all the cattle in this herd could have twine balls to some degree. In these cases, cattle are initially ‘inappetant’ — not eating and off their feed. When a blockage occurs they go downhill very quickly and dehydrate so prognosis can be very poor, and these conditions seem to be accentuated when cows are heavy in calf. The calf takes up more room in the abdomen, making blockages more likely. These cases are also very hard to diagnose clinically as signs mimic many other diseases. Ultrasounds, bloodwork, palpation or other physical exams often fail to find anything substantial.

Hard to believe what you find

I know of one case where a very valuable dairy cow was off feed and a skilled veterinarian was able to palpate what he believed was a foreign object in the abdomen. On exploratory surgery, an entire intact rope halter was removed from the rumen. The cow recovered. Who would have thought a cow would eat an entire rope halter, but it did. These one-off things will happen, but trying to prevent access to these things is paramount in our management strategies..

We know it takes a multiple approach to reduce the risk of hardware disease. Producers minimize access to metal objects by keeping yards, pens and pastures as clean as possible. Sometimes they install heavy-duty magnets on feed wagons to catch metal objects. Magnetizing animals with a permanent rumen magnet also works wonders at prevention. Not all metals have ferric compounds so are not all are attracted to magnets but most are.

We also know to avoid lead poisoning by being ever-diligent about old vehicle batteries being left along fence lines, in junkyards or around old deserted vehicles. Licking or consuming battery parts can be fatal to many animals so don’t hesitate to warn your neighbour, or to pick up errant batteries and have them recycled. If changing batteries, never, ever get them close to the cattle-feeding equipment. In other words, treat batteries as a potentially massive poison for cattle and handle accordingly.

But also be on the watch for this new hazard — software disease — as plastics do not break down in the rumen or other stomachs. Over time they can gradually accumulate.

I believe some cattle are more prone to eat these things that can result in a poor-doing, poor-performing beef animal, and even lead to death. It would be interesting to find out at slaughter how many twine hair balls are found.

Bale shredders accumulate twine on their paddles, so burn them off regularly. No matter how good you are at picking up twines and silage plastic, some gets missed, so always check your feed bunks and remove any hardware and software. This prevention will pay dividends in healthier cattle down the line.

I know certain manure haulers will not work for people that leave twines on bales that end up in manure piles. Imagine how this material might affect the health of their cattle, not even thinking about the issues with twines wrapped around axles, and damaging shafts and bearings of equipment.

As a final plug for overall good management practices, watch the video ‘Raised with Care: Stewards of the Land.’ It’s focused on the antimicrobial resistance issue. It is a well-done production by the Alberta Veterinary Medical Association and is an easy watch. Get some popcorn and enjoy a half-hour documentary which helps everyone in the industry and educates the public.

About the author


Roy Lewis is an Alberta-based veterinarian specializing in large-animal practice. He is also a part-time technical services vet for Merck Animal Health.



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