by Kai Yuan PhD, Senior Technical Advisor
*Summary of Dr. Mike Van Amburgh’s webinar on strategies to improve milk protein
The value of milk protein has been very attractive in the past two months, in the range of $4 to $6 per pound. Many dairy producers and nutritionists are looking into strategies to maximize milk protein and profits. Recently, Dr. Mike Van Amburgh from Cornell University gave an excellent webinar on a few dietary strategies to increase milk protein. Below is the summary of a few key points he presented:
1) The most effective way to drive rumen microbial protein is to feed adequate level of fermentable sugar. According to Dr. Mike Van Amburgh, feed at least 6 to 7% fermentable sugar to cows to maximize microbial protein synthesis and fiber digestion. Feeding sugar increases the population of protozoa in addition to bacteria. Protozoa are often overlooked but some recent data showed that protozoa can contribute up to 20% of the microbial protein yield. Sugar is especially beneficial on diets where NDF digestibility is not optimal. During the Q&A session, Dr. Van Amburgh mentioned that current version of Cornell model ration software may not fully characterize the value of sugar on growing microbial protein due to not predicting protozoal yield, so the next model release will likely improve that aspect. Mike also emphasized that all sugars are not created equal, and the most effective types of sugars on microbial protein responses are sucrose, glucose, and fructose.
2) Make sure there is adequate DCAD level in the lactating cow diet. Cows typically respond to higher dietary DCAD with higher DMI, fiber digestibility, and milk components. This could be due to improved K or improved rumen buffering capacity. Typically, DCAD level at 35 mEq/100 g of DM or more is recommended. Studies consistently showed increased milk protein and fat yield with higher DCAD. Mike mentioned that improved milk protein is most likely due to enhanced fiber digestibility.
3) Balance methionine and lysine relative to metabolizable energy. Always calculate methionine first based on the energy, than calculate lysine otherwise the 2.7:1 Lys:Met ratio will provide incorrect values. For example, if the ration has 60 Mcals ME, then methionine required is 60 Mcal x 1.19 g/Mcal = 71.4 g methionine. Next, calculate lysine using the methionine value times 2.7, which is 71.4 g x 2.7 = 193 g Lys.
Some other points Dr. Van Amburgh presented include: a) the importance of properly characterizing cows appropriately (such as correct BW) into ration formulation software; b) how to properly implement high byproduct diets; c) effects of different fatty acid supplementation on improving energetic efficiency and possibly milk protein.
Note: this webinar was organized by Balchem Corp. The link to the recording: https://youtu.be/Leue8fpkQ3o