Understanding broiler feed formulation pressure points

A typical broiler formula can be constructed easily using only a handful of ingredients. Knowing the three most expensive nutrients in any feed, one can start understanding where the main pressure points are in feed formulation.

Experience, paired with deep knowledge, can lead to the formulation of a commercial feed with a purpose. (Rido | Dreamstime.com)
Experience, paired with deep knowledge, can lead to the formulation of a commercial feed with a purpose. (Rido | Dreamstime.com)

A typical broiler formula can be constructed easily using only a handful of ingredients: a major cereal, like corn or wheat; a major protein source, such as soybean meal; and no more than a few well-known sources of minerals and vitamins. Throwing them together in any feed formulation software along with a set of dietary specifications — those provided by major genetics companies will suffice for this discussion — will provide a least-cost formulation. In fact, such was my first attempt in learning feed formulation principles, and I even built my first feed formulation software using a broiler diet as the backbone of testing.

Expensive nutrients

One of the first things we learn in nutrition courses is that there are three expensive nutrients in any feed: energy, protein and phosphorus. If we want to be 100 percent correct, we must emphasize that energy is not a nutrient but a property of nutrients like glucose, and we end up calling it a nutrient for convenience. Likewise, animals do not require protein, per se; instead, they need protein building blocks, the well-known amino acids of which some are more limiting than others. Finally, phosphorus is not only expensive, it can be of very variable quality in terms of its digestibility or availability.

Pressure point is a novel term that describes the point at which the feed formulation program provides a solution that can no longer be made less expensive.

Knowing these three most expensive nutrients in any feed, one can start understanding where the main pressure points are in feed formulation. It merits mentioning that in absolute amounts, any formula will spend the most money in covering its energy specification, then protein and the least for phosphorus.

Pressure points

This is a rather novel term that describes the point at which the feed formulation program provides a solution that can no longer be made less expensive. Anything below such a pressure point and the formulation becomes infeasible — that is, it cannot meet all specifications we requested. Anything above this point and the formulation becomes unnecessarily more expensive. Naturally, the first three pressure points are the above mentioned most expensive nutrients.

Let us see what happens when we include the major sources of these three nutrients: corn for energy, soybean meal for protein and dicalcium phosphate for phosphorus. We shall ignore the rest of the nutrients for now. Setting only minimum requirements for these three nutrients will yield a solution (formulation) that will meet the minimum requirement first for phosphorus, then for protein and the rest will be corn. In other words, the feed formulation software will use the least possible amounts of dicalcium phosphate and soybean meal and ignore the minimum specification for energy, as it needs to bring the total to 100 percent by using the remaining ingredient: corn.

Relative cost of nutrients

In the above-described scenario, the first pressure point is phosphorus. This might appear as a paradox considering the fact that it is the third most expensive nutrient. But it makes absolute sense when one considers the cost per unit of required nutrients. Indeed, in such terms, phosphorus is most expensive, followed by protein, followed by energy. Thus, energy, the least expensive per unit required, is used as the filler.

Had we included an indifferent ingredient, such as salt (without setting a requirement for it or for its nutrients: sodium or chlorine), the feed formulation program would have used this as filler instead of corn. In this last scenario, we assume salt is less expensive per unit weight (kg or lb) compared to corn or else the feed formulation program would have continued to use salt. This example helps explain why some times we see low-cost ingredients like salt and limestone entering formulas at very high levels, creating a most undesirable feed — something that needs to be fixed by the nutritionist by setting a maximum for the respective nutrients.

Europe vs. U.S.

In the U.S., energy remains the least expensive nutrient per unit required. Formulas seldom balance on energy — in other words, energy never creates a pressure point. Corn in the U.S. (and other major producing regions of corn or wheat) remains relatively less expensive than protein (soybean meal). As such, energy research and education remains behind, whereas research and education on protein have reached the highest possible levels. The opposite is true for many parts of Europe where the availability of agro-industrial by-products rich in protein and the lack of extensive cereal arable land make energy more expensive than protein. This explains why more research and education are available on energy in Europe compared to the U.S. Of course, phosphorus remains expensive everywhere so it is a major concern for all.

Relieving pressure in feed formulas

Now that we understand what a pressure point is — and we described only the major ones and how they come about — we must start thinking how to relieve such pressure. Why should we do that? The reason is simple, yet hidden. By reducing, say, phosphorus from 0.50 down to 0.49 percent in a diet, one can expect but a very small reduction in feed cost, and perhaps one that is too risky as animal performance might suffer. The latter is especially worrying when dietary nutrient specifications are very close to animal requirements without margins of safety.

Understanding where pressure points come from is the first step toward advanced feed formulation techniques.

In such cases, we risk nutrient deficiencies for trivial savings. Such would be the case in the example scenario above using only three major ingredients. But, in real life feed formulation exercises, there are dozens of possible ingredients that can be used. In some, but not all cases, a small pressure relief at a critical point will cause a new ingredient to enter the formula; perhaps an ingredient that carries more nutrients than the required phosphorus. This then can cause a complete rearrangement of all feed ingredients being used resulting in a significant feed cost reduction that goes far beyond the savings in phosphorus. When this happens, a qualified nutritionist will have to make a decision whether it is safe or worth keeping this new formulation solution.

What is the value of a small savings?

Let us assume then that the above exercise yields a new formula with a final cost reduced by USD$1, that the nutritionist in charge deems that the reduction in phosphorus levels are insignificant — one might say even hard to determine in routine laboratory analyses — and that the overall new formula looks interesting enough to use. If we were to consider a broiler farm with 1,000,000 birds per year, we could then extrapolate easily to any real farm capacity.

Using the most recent national performance figures from the National Chicken Council (2016) in the U.S., we find that these birds will grow to 2.81 kg body weight requiring 1.87 kg feed per kg gain (apologies if you are reading this in the U.S.; just multiply kg by 0.454!). So, in a year, there will be 5,254 metric tons of feed coming through such farm. A single dollar saved from feed cost would then bring USD$5,254 to profit instead of expenses. Perhaps not a significant amount for some broiler enterprises, especially seen as a figure of USD$0.005254 per bird — that is, less than a red U.S. cent per broiler! But do also consider that in the U.S. there were 8.8 billion broilers raised last year. Now the math becomes really interesting as the potential profit is slightly above USD$46 million. I will let you find out the global effect of this single dollar.

Small savings are possible in relieving pressure points in broiler feeds. Such exercise must be performed by the most qualified nutritionists to ensure animal performance will not be affected — or if it does, then profitability keeps increasing. Understanding where pressure points come from is the first step toward advanced feed formulation techniques. This demonstrates clearly that feed formulation software is a tool that cannot replace the nutritionist.

 

Read more: Animal feed formulation principles: A crash course

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