A five-year old Black Angus in the prime of her life. Productive. Raised a nice calf every year. Confirmed pregnant this year and due to calve in two months. If a cow herd was a baseball lineup, this one would be hitting in the middle of the order. This is the kind of cow that pays the bills for the rancher, and the kind he's proud to have in his herd.
But a couple weeks ago, she started wasting away. It was gradual. It began with her lagging behind the rest of the herd at feeding time. Eventually, feed no longer interested her. She became tucked up and reluctant to move anywhere. Her breathing became more labored, with low but audible “grunts.” She ran a slight fever and was treated by the rancher with penicillin, but to no avail. Several days later, she could no longer rise, and by the next morning, she was found dead.
The cause of this cow's demise was mysterious. Worse yet, others in the herd were starting to show signs of doing the same thing. The rancher and his veterinarian decided to send the next cows affected to the SDSU Animal Diagnostic Lab. As the rancher drove the animals to Brookings, terrible thoughts were running through his mind. Something in the feed? The water? A new infectious disease? Would this run through the whole herd?
The pathologists at the diagnostic laboratory found that it was not a new infectious disease. In fact it was a very old one, recognized ever since people started using things like nails and barbed wire-“hardware disease.”
Hardware disease happens because of some anatomical oddities within the bovine belly. One of the four stomachs, the reticulum, acts as a trap for foreign objects that cows indiscriminately eat. If that foreign object is sharp, like a nail or piece of wire, it can poke through the lining of the reticulum. This creates a path for bacteria (plentiful in the digestive tract) to escape into the surrounding tissue and create infection and pain. What's worse is that this part of the stomach also lies very close to the cow's heart. If the hardware pierces the heart muscle or one of its blood vessels, death can quickly ensue.
The particular hardware found in these cows was different from roofing nails or barbed wire. The culprit in this case was a four-inch-long thin, rigid wire that had poked through to the heart, resulting in a plentiful buildup of infection and fluid. The wire looked similar to electric fence wire, but thinner. The rancher and the veterinarian were puzzled: it wasn't anything they recognized.
As the rancher searched over the cow lot for the source, nothing resembling that wire turned up. But as he opened the gate to leave the lot, a nearby tire feeder caught his eye. The rim of the feeder-around the opening where the feed was deposited-had something sticking up from it, like a cow-lick on top of a boy's head. This was it. These exposed wires on the edge of these steel belted tractor-tires-converted-to-hay-feeders were the exact same thing found in the cows. As the edge of the tire became worn, the wires were exposed. The motion of cows going into and out of the feeder to eat would bend the wires back and forth until they would break off and drop into the feed below, ready to be taken in with a mouthful of feed. Subsequent inspection revealed many of these worn feeders in the lot.
There are many advantages to using recycled tires for cattle feeders. They decrease waste and keep the feed free from contamination, in addition to being a good way to make use of spent tires.
But as this true story illustrates, if the feeders become worn, they can prove deadly for cattle. If you're using tire feeders this fall, make sure you inspect them closely for wear. If wires are exposed, take those feeders out of commission and get new ones. Spending a few dollars for a new feeder is much better than risking long-term illness or death in one of your cows.
Russ Daly, DVM, is the Extension Veterinarian at South Dakota State University. He can be reached via e-mail at russell.daly@sdstate.edu or at 605-688-5171.
