Researchers compared options for utilising the by-products of cotton (whole cotton seed) and canola (canola oil) production in terms of greenhouse gas emissions. The alternative uses for the by-products were:
Feeding canola oil (as canola meal) to cattle was estimated to result in a net increase in GHG. However, there was an overall reduction in GHG from the combination of converting canola oil into biodiesel and feeding the canola meal to cattle.
The net reductions in GHG emissions from converting cottonseed oil into biodiesel were generally greater than the reductions in emissions from feeding the oil as a supplement to cattle. However, the distances that the oil feeds fed to cattle, or that the biodiesel were required transporting to end use was a major determinant of whether there was a net reduction in GHG, with the breakeven estimated at 381 km.
Ludemann CI, Howden SM, Eckard RJ (2016). What is the best use of oil from cotton (Gossypium spp.) and canola (Brassica spp.) for reducing net greenhouse gas emissions: biodiesel, or as a feed for cattle? Animal Production Science, 56, 442–450, http://dx.doi.org/10.1071/AN15453.