With advancements in bale binding technology, efficiency has increased. Today's net wrap increases baling efficiency by 75% over twine binding. "In addition, net wrap also increases water-shedding ability, resulting in less spoilage and outdoors storage losses," says Taylor Grussing, SDSU Extension cow-calf field specialist.
Due to these advantages, it's no surprise an estimated 90% of producers have converted from twine to net wrap over the last decade. However, says Grussing, producers need to remember that net wrap is not twine. So, although it was OK to leave twine on the bale when feeding or grinding, she does not encourage this practice with net wrap.
"Net wrapping is newer and the effects on cattle consumption are relatively undocumented," Grussing notes. "When net wrap is not removed prior to feeding whole bales or grinding, there is a potential risk for cattle to ingest the net wrap along with the forage."
Net wrap ingestion is potentially harmful
In a 2008 study, University of Nebraska veterinarians reported large volumes of twine accumulation in rumens upon postmortem evaluations of beef cattle.
North Dakota State University diagnosed net wrap ingestion as the cause of an unexpected death in a feedlot heifer in 2014. A follow-up study looked at net wrap digestibility compared to sisal and biodegradable twine. After 14 days of incubation in rumen cannulated steers, 70% of sisal twine disappeared while none of the net wrap and biodegradable twine was degraded.
"Since net wrap does not appear to be digested in the rumen, it can accumulate, which may have implications on production efficiency and animal health if the digestive system is compromised," Grussing says.
TUMMY ACHE: This photo shows net wrap accumulation found in a steer’s stomach at a packing plant.
The highest risk occurs when whole net wrapped bales are offered on cow-calf operations; however, there is also potential for net wrap to accumulate even if particle size is decreased when used as tub-ground hay.
"Risk of loss is likely related to how much opportunity cattle have to consume net wrap," Grussing says. "Cows fed exclusively long hay in net-wrapped bales from bale feeders would likely be at the greatest risk." Feedlot cattle fed a high-concentrate diet would have much less exposure, but could still accumulate significant amounts of net wrap.
Take the net wrap off before feeding bales
While it may not be possible to remove all the net wrap, Grussing says it's important to try, especially when feeding whole bales.
Net wrap removal can be done using a simple pocket knife or hot knives, which are available for the more tangled mess. "Hot knives are especially handy in the winter when net wrap can freeze onto bales making it more difficult to remove," she notes.
When grinding bales, cattle producers likely won't be able to cut off net wrap as they go, so Grussing encourages them to prepare for the grinder a couple days ahead by removing net wrap from a few bales each day. "This method may allow you to get half of the net wrap off bales to be ground, which will result in less accumulation in the pile," she says.
If producers choose not to remove net wrap prior to feeding, Grussing suggests they at least pick it up and throw it away after the bale is gone. "Cattle get bored and like to chew on things so they will eat net wrap if it's lying around," she says. "Taking the time to pick up net wrap in and around bale feeders is a simple way to reduce the chances of ingestion."
If you have questions on net wrap ingestion or how to conduct postmortem evaluations, contact your herd veterinarian or an Extension field specialist.
Source: South Dakota State University