I have had several cows that have consumed netting, plastic bags and other plastic such as string. The reason I know is they died. They will get thinner and thinner and finally die. When I look at the place I have dragged the cows to I would find the twine, netting and plastic bags after the carcass had decomposed.. They would be in several wads and each wad connected to each wad with a narrow string of the plastic. I think this gets into the digestive system and prevents them from bringing up a cud and they will eventual die. Also each wad may have been each of the several stomachs a cow has. I have been pretty careful with the net and remove it the best I can to prevent this. The plastic bags blow across the pasture from people throwing them out of their cars. I also make sure when I see one that I try to get it before the cows get it.