Don’t Forget to Unwrap
As we transition into winter feeding season, one of the recent concerns associated with feeding baled hay, especially round bales, is the potential hazards associated with ingested polypropylene twine or net wrap.
Termed “software disease” or “plastic disease,” recent investigations have shown that poly twine is virtually indigestible and is not broken down by microbes in the rumen. If consumed in large enough quantities, normal rumen contractions and mixing can cause both poly wrap and poly twine to bunch together, which creates large indigestible mats in the rumen.
The large mats limit hay consumption by the cow as they take up valuable rumen space. The poly mats can also block the digestive tract, virtually stopping the flow of feed through the rumen and into the intestine. These blockages typically only allow liquids to pass through, resulting in diarrhea-like symptoms. Cattle with blockages often go untreated or are misdiagnosed, as animals will show common clinical signs such as reduced appetite, weight loss, partial bloating and diarrhea.
Recent digestion studies at North Dakota State University evaluated several different types of polypropylene and nylon net wraps and twines, as well as sisal twine. The wraps and twines were placed in the rumen for four to 14 days. The preliminary study showed that by day 14, sisal twine is approximately 70 percent digested, while all other nylon and poly products remain completely intact. Even sun-biodegradable poly twines remain undigested.
Software disease has become a larger problem for beef producers, as more bales are wrapped with polypropylene net wrap or twine. Net wrapped bales transport more easily and typically store better, as the net wrap forms a more protective barrier around the bale.
However, there is an increased tendency for cattle to end up consuming the wrap. During cold weather, netting often freezes to the bale, which makes it very difficult to remove. Additionally, the speed and convenience of feeding multiple bales with bale processors also results in more netting ending up in the diet.
The common misconception is that if the netting is ground into small pieces, it is less of a concern. The reality is that, while the individual pieces of netting may be smaller, they tend to clump or accumulate in the rumen during normal rumen contractions and mixing.
Once an animal has consumed enough wrap or twine to impact their health, there are very few options. The only solution is to surgically remove the twine from the rumen.
The best solution is to take several precautions to dramatically reduce or eliminate the chance of ingestion of the poly twine and wrap. Use sisal twine whenever possible. Although sisal twine is more expensive and its tendency to degrade during storage makes handling and transport difficult, sisal fibers will break down in the rumen if ingested. Taking the time to remove all wrap and twine from the bales prior to feeding and continually monitoring the feeding area, picking up any twine, netting or plastic bags will help to prevent future cases of software disease.