Why Energy is Blunt and Protein is Crude

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Some new ideas from Professor Mike Vande Haar, Michigan State University.

Some of you may have been fortunate enough to attend the Australian Dairy Conference in Adelaide in February, and hear a fantastic presentation by Professor Mike Vande Haar from Michigan State University.  Mike’s presentation challenges a lot of misconceptions on how farmers might purchase feed, and the Reid Stockfeeds team was fortunate enough to spend some time with Mike, both on farm and in the classroom.

Professor Vande Haar challenged the common notion of how many people purchase feeds (both concentrates and forages), suggesting that ME (Metabolisable Energy) and CP (Crude Protein) by themselves are not representative of nutrients our cows actually need, so looking at cents/MJ of ME, while not irrelevant, should not determine a purchasing decision.

L to R: Dominic Conheady, Mike Vande Haar, Nick Reid, Daniel Bacon, Claire Templeton, Daniel Espinosa

The first point we were reminded of was that ME is not a measured nutrient, but a calculation, and depending on which calculation you use (there are several), the reported “energy” of a feed can vary significantly.

But this was not the big point of Mike’s presentation with regards to energy.  Potentially the most important point is that the nutrients derived from a given feed cannot be predicted without knowing the other feeds in the diet, and importantly, both their feeding order, and how they are likely to react with all other ingredients will have an impact on the true value of a given ingredient.

A powerful example of this was how we consider the energy contribution of protein.  That’s right, we get energy from protein!  But importantly, we get a lot more energy from True Protein (think Canola Meal) than we do from NPN (Non-Protein Nitrogen), which our lush green ryegrasses are full of (no, not now, but the autumn break is coming… we hope!)

The killer is, none of those energy equations we mentioned earlier take this into account, which means many (probably all) of our pasture and silage forage tests are overstating ME.

All this means that we need to carefully balance diets to ensure the available ingredients balance together, to get as close to the “reported” value (read potential) as we can, and that the feeds we choose really do provide the nutrient we are choosing them for.

Sander absorbing, Mike defending.

So that’s energy, what about Crude Protein?

“Put simply, the cow does not care about the CP value of the feed!” stated Professor Vande Haar.  “Crude Protein is easy to measure, but the cow has no direct requirement for it.”

Crude Protein is simply measured by total Nitrogen x 6.25, because Nitrogen is easy to measure via NIR, and True Protein is 16% N.  But, as we mentioned before, what about all that NPN in our forages?  It negatively affected energy, what about the Protein the cow needs?

To answer that, first we need to discuss what protein the cow needs.

Cows want Metabolisable Protein (MP), which is essentially the amino acids which are available for digestion in the small intestine, either coming as True Protein or Microbial Protein (MCP).

One of the many great things about cows is that they make their own MCP, which is perfectly matched to the protein they require to make milk.  However, to make really good MCP, we really need fermentable carbohydrates (grains), Rumen Degradable Protein (RDP – we have heaps and heaps and heaps in our forages), and True Protein, in that order, but given our oversupply of RDP, true Protein probably steps forward.

Mike was able to show how high producing cows could have a 15% CP diet, and have her MP needs met, but the same cow could be fed a 22% CP diet, and be deficient in MP… it’s all about the balance of the diet, and the level and type of ingredients we provide to make MP.

Ian Sawyer consults with Rodney Bakker and RSF nutritionist Claire Templeton during a day out with Mike Vande Haar

The key message here is that feed and forage analysis should indicate the quality of the proteins in our feeds, not just the CP, as the CP is in no way indicative of what the cow is getting in the way of MP.  It also means that despite those really high pasture CP numbers, we should probably keep the canola meal in all year, as it is our only real option for true protein.

Also consider products like Diamond V, which show a potential uplift in MP of around 100 grams, which is huge, and great value for money given its other benefits.

Does this all sound complicated?  Well in many ways it is, which is why Reid Stockfeeds are committed to exposing our great team to people like Professor Vande Haar.  No one feed can provide balance to a range of farms, which is why we customise our feeds to suit your needs, and with the support of our technical team, match the right ingredients, to the right situation, for the best possible outcome.

Professor Vande Haar was proudly brought to Australia by our valued partners Feedworks, who support Reid Stockfeeds through great brands such as AcidBuf, Diamond V, and Elitox, matched with great technical support.

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