Should you be worried about cattle eating netwrap?
The short answer is, maybe. Like twine, cattle will eat netwrap and it can accumulate in the rumen and cause impaction and bloat. The buildup, even if not severe enough to cause noticeable health issues, can reduce voluntary feed intake by three to five pounds a day.
It’s best to remove all netwrap and twine, however, this can be challenging if the netwrap and twine are frozen to bales. Some producers using a bale processor may rely on the chopper to shred the netwrap or twine, but this may not chop it into small enough pieces to pass through the rumen without incident.
Dr. John Campbell from the University of Saskatchewan investigated such a case in a well-managed herd, where a number of pregnant cows died suddenly for no apparent reason. The bale processor the producer was using was not shredding the netwrap, but rather shooting it out in large pieces that were then eaten by the cows. A combination of being heavy in calf and an overly full rumen due to netwrap obstruction led to increased pressure on the cows’ lungs and death by suffocation.
North Dakota State University researchers measured the disappearance rates of hay, three different kinds of netwrap, biodegradable twine, and sisal twine from the rumen. After 14 days, the netwrap and biodegradable twine were still intact, but 70 per cent of the sisal twine had disappeared. Biodegradable twine requires UV light to break down, so it won’t break down in the rumen where there is no light.
When netwrap is frozen to the bale, dropping it once or twice before cutting or unwrapping it may help with removal. If removing netwrap and twine is not an option, ensure the bale processor has chopped the material into very, very small pieces. This will depend on the sharpness of the knives and how fast the processor is being run.