Plastic netting has mostly replaced natural twine for wrapping large hay bales but the material can cause health problems when cattle ingest it. Melissa Koesler, Extension Director for Garvin County Oklahoma, says around 90% of producers now use plastic wrapping instead of biodegradable sisal twine. Some producers leave the material in their pastures when feeding, or they grind or shred bales with the bale net in place.

 Plastic bale netting offers a number of advantages in terms of baling efficiency and preservation of hay quality, Koesler says. However, she encourages producers to remove plastic netting or twine from bales and pastures whenever possible, and veterinarians to watch for health problems possibly associated with plastic materials accumulated in an animal’s rumen. Koesler notes that necropsies have found accumulations of plastic twine or netting materials in cattle digestive tracts.

North Dakota State University Extension beef cattle specialist Carl Dahlen, PhD, has studied the issue after the NDSU diagnostic laboratory diagnosed a case of acute tympany (bloat) associated with excessive net wrap ingestions. Dahlen and his team designed a test in which they placed samples of five different baling materials and hay samples as a control into rumen-cannulated steers. They placed the samples in Dacron bags, incubated them in the rumen for 14 days and measured disappearance of the baling materials. The materials tested included three types of net wrap, natural sisal twine and biodegradable twine.

After 14 days of incubation in the rumen of forage-fed steers, none of the three types of net wrap evaluated or the biodegradable twine samples disappeared from the Dacron bags. During the same period, more than 80% of the hay sample and more than 70 percent of the sisal twine disappeared.

The researchers concluded that plastic baling materials have the potential to build up in the rumen over time and possibly lead to associated complications. The risk of complications probably depends on the volume of material consumed and the size of the particles ingested. Netting that has been through a hay grinder, for example, probably passes through the digestive tract more readily than large pieces of netting left in a pasture.

Read more about the NDSU study on digestibility of baling materials.