Trego's Mountain Ear

About a dozen years ago – just as I was starting to look into retiring – hog production facilities in Minnesota began blowing up. I had moved from Extension to the department, so it wasn’t really my topic – but it was interesting. The first correlation I heard was the change in feed – from the total grain to dried distiller’s grains. Folks were looking for an explanation, for the Pig Bang Theory. Some of the explosions killed 1500 pigs in a single incident. It was pretty easy to figure out what was exploding – something in the hog wastes was creating natural gas and hydrogen sulfide. But it was a problem.

The Smithsonian covered the topic ((https://www.smithsonianmag.com/science-nature/mysterious-exploding-foam-is-bursting-barns-124424083/ ) back in 2012. “Why these explosions happen is well understood. As manure ferments, it releases methane gas, which bubbles to the surface of the pit. Normally this methane doesn’t pose a risk. The gas seeps out of the pit, and the barn’s ventilation fans carry it away. But when thick, gelatinous foam covers a manure lagoon, the methane can’t rise. The foam acts like a sponge, Jacobsen says, soaking up the gas. Jacobsen and his colleagues have collected foam samples that are 60 percent methane by volume. When a farmer disturbs the foam by agitating the manure or emptying the pit, the methane gets released all at once. In barns without adequate ventilation, the concentration of methane can quickly reach the explosive range, between 5 percent and 15 percent. A spark from a fan motor or a burning cigarette can ignite the gas. An explosion in southeastern Minnesota raised a barn roof several feet in the air and blew the hog farmer, who was on his way out, 30 or 40 feet from the door.”

Nautilus (https://nautil.us/the-curious-case-of-the-exploding-pig-farms-234669/ ) explained the solution: “With no known cause for foaming manure, there’s no going at the root of the problem. The best short-term solution farmers have come up is antibiotics. Rumensin 90, an antibiotic normally used to prevent bloating in cattle, has been repurposed to prevent gas in pig manure pits. It works, though no one knows why. Scientists have hypothesized that shifts in the microbial community—either from DDGS feeding or from another cause—may have a role in foaming manure as well.”

So near as I could understand it, the shift to feeding dried distillers grains created a situation where the natural gas could build up, and adding the equivalent of cow tums to the ration stopped the explosions (or I moved further from Minnesota, Iowa and swine production and quit hearing about it).