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Art, science of formula tweaking

Art, science of formula tweaking
There are many reasons for nutritionists and feed formulators to tweak feed and diet formulas, but there's both an art and a science to it.

*Dr. John Foley is formulation portfolio manager for Feed Management Systems Inc. focused on feed formulation, ration formulation and related software solutions. Foley can be reached at [email protected]

CHANCES are, if you are a nutritionist or feed formulator, you are a tweaker — and even though neither an online dictionary nor a spellchecker recognizes the term tweaker, I think you know what I mean.

Just to clarify, though, I'm not talking about the tweaking that involves pinching and pulling with a sudden jerk and twist. If you acknowledged that you are, indeed, a tweaker and that's the type of tweaking you were thinking about, well, I'm not one to judge. However, I'm referring to tweaking that involves making small adjustments in or to (in this case) a feed formula or animal diet.

So, regardless of whether you've tweaked by the first definition, you've certainly tweaked according the second one, haven't you?

There are a number of legitimate reasons for tweaking feed and diet formulas, including:

* To achieve a specific feed or diet cost suitable for the market or customer;

* To maintain or establish a reasonable margin for a specific feed;

* To improve or re-establish animal performance that is currently unsatisfactory;

* To achieve economical rather than optimal animal performance under difficult market conditions;

* To establish, maintain, improve or recover physical characteristics of a feed or diet (color, pellet quality, texture, density, etc.);

* To test a new animal model or challenge an existing model, and

* To design a new feed or diet and achieve that just-right balance of nutrition, palatability and appearance.

Tweaking isn't just a common practice among nutritionists and feed formulators; it's more like a must-have core competency, and there's both an art and a science to it.

I realize that some nutritionists bristle at the implication that what they do is anything but science, but the definitions here are quite instructive.

Science is a system of knowledge related to general truths or the application of general laws, especially those obtained and tested via scientific method. By that definition, nutrient requirement equations based on animal feeding experiments come to mind: a method for obtaining practical results from the application of scientific laws.

Now, let's turn to art — skill acquired by experience, practice, study or observation. One way to think about this is that art enables the creative application of science. In a way, it goes a step beyond science to allow the skills, knowledge and experience of the nutritionist or feed formulator to nuance the application of that science.

Science provides the base for what we do, while tweaking expresses the art of our craft and, frankly, often allows us to better serve our customers and their animals. In fact, sometimes, art is forced to overcome a shortage of science.

Here's an example of how this science-first, art-second thing works in practice: A laboratory-based analysis of the nutrient content of feed ingredients fits the definition of science as the application of general laws obtained and tested via scientific method. We might receive a lab analysis that covers moisture, crude protein, crude fat, neutral detergent and/or acid detergent fiber, ash and some measure of non-fiber carbohydrates like starches and sugars. We can add another layer of science if we have science-based equations that take those six or so nutrients and, by specific ingredient, use science-based equations to calculate many more nutrients, perhaps hundreds more.

Using soybean meal as an example, we can calculate a host of species-specific digestible amino acid specifications, crude protein, all of the key individual minerals from ash, etc. However, if we base our calculations on one sample of soybean meal from one soy processing plant — or, worse yet, on a book value — the rigor of our science breaks down. If the scientific rigor of our ingredient analysis is lacking, then tweaking becomes a murkier proposition.

Here are some things we know about feed ingredients based on current science:

* Each processing plant — flour mill, oilseed crushing plant, ethanol plant, etc. — is distinct from all others, as is the feed ingredient it produces. ("Soybean meal is not soybean meal is not soybean meal.")

* Book values just don't cut it anymore.

* Establishing a meaningful level of confidence in a feed ingredient's nutrient content requires persistent testing and statistical analysis to assess the mean and variation of a specific processing plant's output.

* If the six or so analyses routinely received on lab reports have changed in relation to our ingredient library, then so have many more nutrient specifications used in formulation.

How are you doing on the science side of things? Are you confident about the nutrient specifications of the ingredients you use to formulate your feeds and diets? Does it affect your ingredient supplier selection?

How are you doing with the artful side of formulation? The baseline for effective tweaking is sound science. Without knowing precisely the base from which you are tweaking, you can end up tweaking in the dark.

The next time you attempt to apply the same tweak, it may not work because the specific nutrient content of the feed or diet has changed, and you may not realize it — and that can earn you an unwanted and unfriendly tweak-on-the-cheek from an unhappy customer.

Volume:85 Issue:22

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