Animals instinctively consume biochar, when it’s available. Not only does it control intestinal parasites, it also reduces methane production (flatulence) in ruminants, such as cattle. The energy contained in methane is energy that would otherwise be available to the animals for their metabolism. Animals learned to eat biochar because it captures this energy, which confers an evolutionary advantage to them. In the case of dairy cattle, metabolism includes milk production.
Feeding biochar to dairy cattle—which is illegal in the United States—has nearly doubled milk production in Uganda, according to a recent post on biochar.groups.io/. When used in bedding, biochar reduces methane emissions even more—up to 84%—and this is not illegal. But the prohibition against its use in feed represents an economic loss to dairy farmers as well as biochar producers—at least until farmers start making biochar on their own. In Uganda, dairy farmers pay nearly $6 for a 30 kg bag of biochar that costs $1 to make.
Log from a Catholic parish in Northern Uganda. Each pair of numbers is a dairy farmer's estimate of average daily milk production in liters from all of their cows before and after biochar.
In permaculture we learn to recognize actions that accomplish more than one goal, and feeding biochar to cattle is a good example. When fed to cattle, biochar first improves milk production, then the same biochar improves crop yields when their composted manure is applied to the field.
Unfortunately, this can’t be done legally in the U.S., where it lacks regulatory oversight. The Association of American Feed Control Officials (AAFCO) officially banned it in 2012 due to concerns that it might contain contaminants such as heavy metals, dioxins, and furans. (Activated charcoal is permitted for treating poisoning or toxin ingestion in livestock under the USDA National Organic Program.) Thus your home-made biochar cannot legally be fed to your commercial livestock, regardless of whether you can vouch for its safety as a by-product of your own forest management and agricultural practices. Never mind that biochar immobilizes the contaminants! But chicken farmers have reported it being gobbled up quickly from bedding and mulch, which suggests a loophole for cattle farmers.
A week or so after one of my kiln burns four years ago, I noticed that the pile I left behind had a little indentation at the top. Later, I noticed that the indentation had gotten bigger. I left the pile to see what would happen. Now the pile is nearly gone. The suspect? Another ruminant—deer. This had been a particularly hot burn, done on a windy day in April. I suspect that the deer chose this pile to suppress intestinal parasites, because the other piles had not been consumed. Next time I’ll set up a wildlife camera!