'Pig Bang' Theories Elude Scientists
Pork producers are dealing with a mysterious, and potentially explosive, situation this time of year - foaming manure that has been the cause of 30 to 40 flash fires over the last several years. An explosion in Iowa was so powerful it destroyed a barn, killed 1500 pigs, and severely burned a worker.
Some pork producers use pits under their barns to collect manure throughout the year, which is later pumped out and used to fertilize crops in the fall. By this time of year, those pits are getting pretty full. Sometimes, for reasons that are unclear, the manure starts foaming and causes methane gas bubbles to rise up. If the highly flammable gas comes into contact with sparks of any kind, such as from a heater or lighter, it can explode. The foaming also reduces storage space, sometimes pushing up above the slats in the pens and resulting in a very nasty home for the pigs.
Researchers have been trying to pinpoint the cause of the problem since they first started getting reports in 2008, without much luck so far. In 2009, farmers were trying to reduce the foam by agitating the pits or spraying them down with water. Unfortunately, that ‘bursts’ the bubbles in the foam and releases the methane at an even faster pace, and it was at that point that reports of flash fires and explosions really escalated.
Steven Hoff, a professor at Iowa State University, is now heading up a three state research project. He says that around 25% of producers that they’ve talked to have some sort of foaming. Now nine months into the three year study, it’s been very hard to find a clear connection between cases. Producers with multiple barns - all with the same type pigs, feed, management and facilities - would have the foaming manure in one but none of the others.
For a while, scientists thought it might be a bacteria that’s been found to cause a similar problem at wastewater management facilities. Scientists did find it in some samples, but not all of those were foaming. In some cases that were foaming, the bacteria wasn’t found at all. Scientists have now turned to a new theory - long-chain fatty acids. A likely source of these would be the addition of DDGS into the pigs’ diets and could possibly be causing incomplete digestion of the oils, in turn helping to form the bubbles.
Still, researchers have not been able to make a definitive connection. For now, farmers are using a couple of different additives used in cattle feed. One is monensin, an antibiotic used to promote weight gain. Monensin decreases acetic acid, a precursor for methane buildup. Another ‘band-aid’ to control the foaming is Rumensin 90, an antibacterial that reduces bloating in cattle. Obviously, the additional feed additives are costing farmer’s a lot of money while they wait for someone to find out what is causing what’s been dubbed ‘pig bang’.