Editor’s note: The following information was provided by Rock River Laboratory in Watertown, Wis.
Energy for gains or milk production hinges on TMR Total Digestible Nutrient (TDN). Nutritionists measure feed nutrient contents then multiply by predicted digestibilities to predict TDN. Measuring nutrient content is relatively straightforward, but predicting feed and diet digestibilities (for troubleshooting or use in our nutrition models) is not. Historically, we’ve used ADF-based equations, lab-bench (in vitro), fecal starch, and even rumen incubation (in situ) estimates to formulate diets or troubleshoot nutrition challenges. We’re constantly striving for a more accurate approach.
Universities have demonstrated the most accurate approach: measuring digestion through cows using TMR and fecal samples with indigestible marker techniques. These digestion measures are very meaningful; however, they are costly and have not been routinely viable. Scientists use expensive markers that laboratories cannot measure quickly or cost- effectively. This changed, however, with a novel commercial-marker approach based on work published by Professor Randy Shaver’s group at the University of Wisconsin.
In September 2012, Rock River Lab’s team co-authored a paper in the Journal of Dairy Science describing a way to routinely measure indigestible markers and measure digestion through commercial dairy cows. The paper described how using an alternative marker, indigestible NDF measured using Combs-Goeser approach, can be used to accurately calculate digestion. To our knowledge, this is the first commercial-digestion approach that has been directly related to milk production.
The technique as described in the Journal of Dairy Science is now available commercially for your herds. This new analysis package, titled TMR-D, is available exclusively through Rock River Laboratory and Rock River Laboratory-West. Using TMR and fecal samples you collect, we’re able calculate digestion through commercial high-producing cows and return results in a short period of time. Results can be used proactively to benchmark diet performance during great performance or find new margin opportunities. Results can also be used reactively to troubleshoot poor performance and react to forage or ingredient changes faster by identifying the poor performing nutrient.