IFM laboratory characterizes four U.S. dairy diet profiles

[LEXINGTON, Ky.] – More than 1,500 feed samples have been analysed at Alltech’s In Vitro Fermentation Model (IFM) laboratory in Brookings, S.D. since its inception in 2013, and with that data researchers have been able to put together four specific regional dairy diet profiles.

IFM is a practical diagnostic tool used to evaluate and troubleshoot total mixed rations (TMR) to achieve optimal rumen fermentation and utilization of feed. Utilizing IFM technology, feed samples are incubated within a standardized rumen fluid and a buffer system to mimic natural rumen fermentation in an oxygen-free environment. IFM then measures gas production, identifies TMR inefficiencies and provides 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 fibre,” 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) with 45 percent of total samples analysed, followed by the Southeast (SE), Northeast (NE) and West-Southwest (WSW) with 25, 18 and 13 percent, respectively. 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 fibre 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.
• Fibre 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.

Overall, researchers determined the nutritional value of TMR measured as in vitro dry matter digestibility is highest for MW samples followed by NE, WSW and SE (81-78 percent). Milk production from these samples ranged from 83.0 to 75.4 pounds between MW and SE TMR.

“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 said.

For more information on how to submit a TMR sample to the IFM Lab, please contact BrookingsIFM@alltech.com.