Most universities explain feed formulation in a session or two, and then only superficially as any in-depth analysis requires hands-on experience; feed formulation laboratories are a rare thing! As such, most graduates with a degree in animal or veterinary sciences have but a vague idea how a feed is formulated. It is by bitter experience, the so called trial-and-error method, that most professionals get to know eventually the ins and outs of feed formulation.
Of course, learning feed formulation on your own is not an impossible task. There are some books on the subject, and the internet offers much valuable information. But, without a mentor, or a course on feed formulation, it is difficult — but not impossible — to acquire those skills that differentiate someone who understands how feed is formulated from someone who can actually formulate a successful product. This may sound like a paradox, given the number of nutrition professionals who formulate animal feeds on a daily basis. In my experience, like in any profession, there are multiple levels of expertise, and whereas most can formulate basic feeds, when it comes to special products or significant changes, the majority will stop short from attempting anything out of the norm.
Successful formula designs by purpose
Here it merits to mention two real cases that have happened in my career. As a professional nutritionist, with almost 30 years in formulating feeds now — I developed my own feed formulation program in my first undergraduate college year using an IBM code — I keep relating these extraordinary instances as an indication of how the animal nutrition industry views feed formulation.
Feed formulation is not magic but rather the outcome of study and experience.
The first case was about a piglet feed formula I designed for a national feed company to replace an old product that was no longer relevant to their market. When the CEO saw how the new product worked, she immediately locked the formula and prohibited even me to change it. Only when things got difficult with ingredient availability did she ask me to modify the initial formula, and not without little apprehension regarding my capabilities — she even had the new formula tested before releasing it for production.
The second case was about an organic acid blend for poultry I designed for another customer a long time ago. This customer keeps using it after many years and does so despite my pleads to allow me (free of charge) to update the blend applying new technology. Instead, he prefers to pay for the expensive (old) raw materials. Now, I am a true believer of the saying “if it's not broken, don't fix it” but these two examples help illustrate the almost reverent approach to successful formulas in our industry. I often get the impression some believe successful formula designs are by chance and not by purpose.
Most believe that having a feed formulation program is all you need to formulate feeds.
Thus, to explain that feed formulation is not magic but rather the outcome of study and experience, I have tried to outline below the whole process in six steps. This is done not to teach how to formulate, but rather to help understand the formulation process. The former requires a long interaction and relevant education. The latter (that is, understanding) is a must for all of us in order to discuss formulas with those who design or use them.
- Define the animals that will receive the formulated feed.
Asking a nutritionist to prepare a broiler formula is like asking an architect to design a house, that is, without any further qualifications. Animal species is never enough. We need to define animal weight or age — start to end — and even genetics. Thus, a formula designed for a Ross broiler to be fed between the age of two and four weeks is different from a Cobb broiler feed of the same age. Likewise, even within the same genetic line, a starter feed is markedly different than a finishing feed. Furthermore, specialty feeds require even more qualifications, but this is rather advanced for the purposes of this discussion.
- Select the right source of nutrient specifications.
Quite often genetic companies publish their own estimates of nutrient requirements for each age or phase to be used along with their products. Experienced nutritionists will consider such information as the starting base and provide adjustments to suit individual farm needs. For example, a broiler farm experiencing early deaths among the fastest growing birds will need to feed diets with a lower energy/nutrient levels than normally recommended. There is a myriad of such cases, most of them commonplace, but some rather “exotic.” When genetic companies do not publish their own nutrient requirement tables — or when the nutritionist considers them inadequate — then there is a great number of scientific bodies that provide similar information. Picking the right one remains one of the hottest topics of debate among nutrition professionals.
- List available ingredients with their characteristics and prices.
Animals will receive energy and nutrients through the medium of wholesome ingredients. Thus, a commercial nutritionist has ingredients to work with and not purified nutrients. A list of available ingredients and their prices is often all that is available, but in most cases, further information is required. Wheat is an ingredient that will provide a very interesting example. Wheat is never just wheat. There is soft and hard wheat with a great disparity in crude protein levels. There is wheat from national or international trade; the former is easier to characterize, the latter almost impossible. Even wheat of the same genetic stock can differ markedly in nutrient composition depending on the area and climate under which it was grown. All such information will help the nutritionist pick or prepare a nutrient matrix for the exact ingredient at hand; not doing so will run the risk of under- or over-feeding animals, both of which are not profitable outcomes.
- Decide on the maximum and minimum allowances.
Not all ingredients can be used without limits. Corn and soybean meal are two ingredients that are seldom limited in most feed formulas. Other ingredients require a maximum level because they are too expensive or contain too many anti-nutritional factors. Fish meal is an example: too much, and the feed becomes too expensive. Animals can be turned off by the feed containing fish oil, and their products (eggs, milk) can be tainted by its smell. In a few cases, a minimum is required, as is with diets for young animals that require sensitive and expensive ingredients. Although there are tables that list the maximum-allowed levels for most unconventional materials, these figures often change based on new research and improvements in plant breeding or manufacturing of resulting feed ingredients. Thus, it remains at the discretion of the nutritionist to lower such maximum limits (for example, when by-products of unknown origin are to be used) or raise them (for example, when a different plant variety is used that is known to contain less anti-nutritional factors).
- Use a feed formulation software to prepare the formula.
Some believe that having a feed formulation program is all you need to formulate feeds. They assume, erroneously, that the above data are already pre-entered and they are correct; nothing further from the truth. Most companies that sell feed formulation programs cannot assume the responsibility required, and if they provide such data, it is only for training purposes or to test their demo software. But even without the data required to run a feed formulation software, picking the right program is a daunting experience. Free, stand-alone, feed formulation programs abound, but they often crash. Cloud-based programs come with better support and becoming increasingly more available — basic versions are free but they have limited capabilities, often a step above a free demo. A spreadsheet program like Excel from Microsoft with a Solver add-on function can be used to create one’s own least cost feed formulation program, but this requires advanced spreadsheet knowledge. Finally, a professional software can be obtained at various prices giving different capabilities. Here, a user-friendly interface is the most important as most programs focus on capabilities, often being crude transfers from old DOS operating systems, forgetting that Windows users require a different interface experience.
- Review and adjust the formula to production limits.
Thinking that all is now done? Unfortunately, feed formulation in earnest begins only now. Never was a feed formulated with just one run alone. The first draft needs to be reviewed. Often a low-cost ingredient, like salt or calcium carbonate, is pulled in at excessive levels because some nutrient specification had no lower limit to force a more expensive ingredient to price into the formula. And, even after fixing these irregularities, one has to look at the formula from a feed manufacturing point of view. For example, is 0.15 percent wheat (1.5 kg per metric ton) something that needs to be there when most feed mixing facilities have a minimum loading allowance of 5 kg? Or, will the mixer handle 10 percent soybean oil, or will the pelleting machine handle 40 percent dried whey? These questions require an understanding of the feed manufacturing process at the exact place where the formula will be converted into a tangible product. These are the things you learn in the field!
I often receive questions regarding the right feed formulation software program. I refuse to answer them, and I hope it is clear why now. Feed formulation is a highly responsible task. In my very first job, there was a requirement for three Ph.D. nutritionists to review and sign off every single formula change — one of them being the person who made the changes. This early lesson imprinted on me the need to be extremely careful with every formula I design and never give out anything before I am confident all of the above steps have been followed. Anything less would be a disservice to clients, animals, the environment, consumers and my own mentors.