According to this New Scientist article, feeding rapeseed (canola) oil to cows can produce butter with a better balance of unsaturated fats.
Apparently the proportions in the feed have to be handled delicately, as the cow’s rumen (forestomach) contains bacteria that don’t respond well to the presence of so much canola oil.
I wonder if this would have any effect on bovine methane production … one of my student groups is doing a research project on livestock methane production and greenhouse gases in the southern hemisphere. Better butter and less gas might be asking for a lot, but … strive for it!
It’s a compared to what type of deal. The oils of rapeseed are better oils, like olive or sunflower, than the oils in maize so switching from maize to rape improves the milk fats used for butter. Quality pasture is better than any of them though production is lower. Pastured cattle are also healthier and live longer.
Methane is produced by rumen bacteria that digest cellulose. There is little cellulose in either maize seed or rape seed so there is an apparent reduction in methane from cattle when these foods are substituted for normal pasture grasses and green forage. But the maize and rape plants from which the seeds are harvested contain cellulose which will release methane when it rots. The saving is illusory, an artifact of looking at only part of the system.
If the maize and rape plants are aerobically composted different bacteria do the digestion and produce more co2 than methane. Burning is similar. Oxygen makes a difference in how cellulose is broken down. But aerobic composting uses fossil energy to turn the piles and keep them moist and aerated. One way or another you pay, GHGs can’t be removed from the process, they can only be shifted to another account.
The smartest use of both the plants and the seeds is to feed it to cattle since you get the full food value and economic benefit. This is usually what happens but the green portions are fed to less valuable animals that don’t need the concentrated energy of seeds. These cattle are young, old or dry – not currently lactating – or beef cattle that don’t need such high energy diets.
When you look at the whole system – from plowing the land to grow crops to churning the butter – there is little change in the methane/co2 balance and it costs fossil fuels to accomplish the minor shift. The hurrier they go the behinder they get.