During this gift-wrapping season, perhaps it’s apropos to discuss our use of bale-wrapping options, specifically those for round bales since plastic twine is used almost exclusively on other bale types.
I’m old enough to have experienced the evolution of sisal twine to plastic twine to net wrap for round bales. Net wrap now dominates the market for the following reasons:
Improved baling efficiency: Spinning plastic twine on bales necessitates 20 to 30 turns of the bale chamber compared to 1-1/4 to 2-1/2 turns with net wrap. This improves baling efficiency by 30% to 35% and translates to more bales per hour and a reduction in machinery time, labor, and fuel.
Reduced leaf loss: Because the bale spins fewer times in the chamber, fewer leaves are lost in the field. University of Wisconsin research documents about 1% dry matter loss with net wrap compared to nearly 3% for twine.
Superior outdoor storage: Dry matter losses for outdoor storage are 20% or more for sisal twine, 11% for plastic twine, and 7% for net wrap. Net-wrapped bales are superior at shedding water and keeping moisture from infiltrating the outside of the bale.
Greater marketability: Although more subjective in measure, net-wrapped bales tend to hold their shape, integrity, and color better than twine-bound bales. Net wrap won’t rot or be subject to rodent damage.
Although net wrap dominates the market, it still has some detractors. For those who farm in more arid regions, the rain infiltration issue is less of a selling point. Some frugal-minded hay producers cite the additional cost of net wrap and a so-equipped baler. Finally, some farmers find it far more difficult and time consuming to remove net wrap when compared to twine. The difficulty scale heightens when the net wrap is iced and frozen to the bale.
Feed hay, not plastic
As a well-wrapped Christmas gift is more difficult to open than a poorly wrapped one, the same can be said for round bales. Perhaps this is why some farmers forego the unwrapping ritual, especially those who chop or grind the hay.
It’s not natural to force-feed plastic to cattle. The rumen microbiome contains a lot of bacteria, but none of them can break down plastic. Multiple research trials have documented the buildup of plastic net wrap in the rumen when it is not removed from the bale.
In one South Dakota State University study, six cows were fed grass hay that was ground through a 5-inch screen. After only 140 days, these cows retained a ball of plastic about the size of a softball. The researchers determined that about 50% of the plastic net wrap consumed was still in the rumen. The weight of the net wrap ranged from 0.8 to 1.1 pounds. That amount of net wrap could have a significant impact on rumen capacity and function.
Keep in mind, this study was only run for 140 days. If this feeding regimen continued for the life of a cow, the resulting plastic accumulation and negative impact on animal health can be significant. More than one veterinarian has found this to be the case.
For now, net wrap is here to stay. It offers advantages in terms of hay quality and marketability, even if it’s not a perfect binding solution. That’s the conundrum.
