Researchers at two universities are examining the feed value of glycerin. Monty Kerley, professor of ruminant nutrition at the University of Missouri-Columbia, is researching the effectiveness of glycerin as cattle feed. The six-month study, which started in May, will determine the impact of glycerin on calves’ growth performance and meat quality. Over a period of 160 to 180 days, 60 calves from various breeds will consume differing percentages of glycerin in their diets: 0 percent, 5 percent, 10 percent or 20 percent.
Meanwhile, researchers at Iowa State University (ISU) and the USDA Agricultural Research Service (ARS) are researching glycerin in swine and poultry feed. Brian Kerr, an ARS research leader and collaborating associate professor of animal science, recently concluded a nine-month metabolism study, in which nursery and finishing pigs were given feed with glycerin levels of 5 percent, 10 percent or 20 percent. The study found that glycerin is readily used by pigs. Preliminary data suggests glycerol has approximately 3,500 kilocalories per kilogram, Kerr said. He is also finalizing the data on a four-month growth study, in which 5 percent and 10 percent glycerin was fed to pigs from weaning to market weight. Results showed equal growth performance between the glycerin-supplemented diet and a more conventional corn/soy meal diet. Kerr’s glycerin was provided by Ag Processing Inc. in Sergeant Bluff, Iowa. Next, Kerr would like to see if biodiesel feedstocks affect the feed quality of the glycerol.
A poultry study conducted by Kristjan Bregendahl, assistant professor of poultry nutrition at ISU, trialed four levels of crude glycerin: 0 percent, 5 percent, 10 percent and 15 percent. It found the energy was used with high efficiency by 48 laying hens with no adverse effects. Other studies at ISU are in the works to further examine the use of crude glycerin in diets for nursery and finishing pigs, sows, broilers, and laying hens.