The Alltech’s In Vitro Fermentation Model (IFM) laboratory located in Brookings, South Dakota has characterized four regional U.S. diary diet profiles after analyzing more than 1,500 feed samples. IFM is a diagnostic tool used to evaluate and troubleshoot total mixed rations (TMR) to achieve optimal rumen fermentation and utilization of feed. Using standardized rumen fluid and a buffer system to mimic natural rumen fermentation, the tool incubates feed samples within an oxygen-free environment. From there, researchers measure  gas production, identify TMR inefficiencies and provids additional information on the nutritive value of the feed.

“The main feature of IFM is the ability to estimate the contribution of the different carbohydrate pools: a fast pool representing soluble carbohydrates—starches and sugars—and a slow pool representing available fiber,” said Dr. Kamal Mjoun, research scientist at the Alltech IFM lab in Brookings. “The balance and the specific rate of fermentation of these pools are crucial to the efficiency of the fermentation and the utilization of the feed by the animal.”

Most samples submitted to the lab originated from the Midwest (MW) followed by the Southeast (SE), Northeast (NE) and West-Southwest (WSW). Regional differences in feeding systems, available feedstuffs and their nutritional quality were reflected in the chemical composition and rumen fermentation profiles of the samples:

• Feeds from SE and WSW had more fiber and less starch than MW and NE feeds, likely because of higher forage and/or by-product inclusion rates.
• Lignin and total sugars were highest in feeds from WSW and comparable in those from other regions.
• Crude protein was high in MW and WSW samples, compared with NE and SE samples.
• In terms of fermentation parameters, feeds from the WSW states had the highest amount and percent of the fast pool and those from the NE states had the lowest, likely because of feeding high levels of corn silage and by-product feedstuffs.
• Fiber quality indicated by the size of the slow pool and its rate of fermentation suggests that samples from the MW and NE had the best quality forages followed by SE and WSW.

“These results can be used to suggest specific supplementation strategies to optimize the fermentation profiles of a TMR and maximize feed efficiency and dairy performance,” Mjoun added.