Looking at the additives that have built up in a layer feed formula over the last few years gives a long list: an enzyme blend, a probiotic, a plant extract, an organic acid blend, a mycotoxin binder and a pigment. Each was added after a supplier's presentation, a trial report or a period of trouble. Together the additives now cost hundreds of TRY per tonne of feed. But nobody can say for sure which of them still works.
What does it take to pay for itself?
The simplest and most useful way to judge an additive is to work out the smallest effect it needs to pay for itself. You find it by dividing the cost of the additive by the money value of the expected effect. The result is then compared not with the effect the supplier promises but with the effect that can realistically be expected in the field.
Take an example, with illustrative numbers. An additive costs 60 TRY per tonne of feed. The feed costs 14,000 TRY a tonne, and the additive is claimed to improve feed conversion. A 1 percent improvement in feed conversion means 1 percent less feed for the same output. That is worth about 140 TRY for every tonne of feed eaten. The improvement the additive needs to pay for itself is 60 / 14,000, about 0.43 percent.
The supplier may promise a 2 percent improvement. But that result may have been achieved under particular conditions, perhaps in a flock with a health problem. In a healthy, well-managed flock the effect can be much smaller. What matters is whether you can expect an effect above 0.43 percent in your own conditions.
Effects do not add up
The most common mistake in additive arithmetic is adding up their effects. If an enzyme gives a 2 percent improvement, a probiotic 1.5 percent and a plant extract 1 percent, the three together do not give 4.5 percent. Most of these additives work through similar mechanisms, such as improving digestion or supporting gut health. If gut health is already good, the room left for a second and third additive to improve is very small.
So as the additive list grows, the extra benefit of each new additive shrinks while its cost stays the same. If a formula contains two or three additives doing similar jobs, removing one often lowers cost without changing performance.
Defining the additive correctly in the formula
The effect of some additives can be measured directly as nutrients. Phytase and NSP enzymes are the best example. These additives go into the formula with matrix values, and OptiFormula decides whether to use them by comparing them with other ingredients. That means working out automatically, in every solve, whether the additive pays for itself.
The effect of additives such as probiotics, plant extracts and organic acids, on the other hand, cannot be turned directly into a nutrient. They are usually added to the formula at a fixed dose, and the decision has to be made outside formulation, by looking at performance data. Having these additives show as a separate cost item in the formula keeps the total additive cost in view at all times.
When prices change, so does the sum
The effect an additive needs to pay for itself changes with the price of feed. When feed is expensive, a small improvement in feed conversion is worth more and the same additive pays for itself more easily. When feed gets cheaper, the case for the same additive weakens. So rather than deciding on additives once and forgetting, the sum should be redone when feed prices change noticeably. The price of the animal product counts too. When egg or meat prices are high, an additive that protects performance is worth more.
Running a trial in the field
The only reliable way to know whether an additive works in your own conditions is a properly set-up trial. Comparing a single flock fed with the additive in one house with a single flock fed without it in another is not enough. Differences between houses, chick source, season and management can be much larger than the effect of the additive.
A sounder trial splits several houses or several flocks into two groups and compares them over the same period, under the same conditions. Where possible the groups are swapped over. The results are judged not on a single figure but by looking at how much the difference between groups varies from flock to flock. Knowing from the start that a small effect needs many flocks keeps expectations realistic.
Regular review
Additives go into the formula during a period of trouble, but often stay there after the trouble has passed. A mycotoxin binder was needed in a wet harvest year but may not be needed in a clean one. A plant extract added during a coccidiosis episode is just a cost once the problem is solved.
Reviewing the additives in every formula once a year, and asking why each one is there and whether it still pays for itself, is a good habit. In OptiFormula, each additive shows in the formula as a separate ingredient, and the cost archive shows how additive costs have changed over time. The enzyme matrix lets you see the real gain with the effect of dose and substrate taken into account.
Used in the right place and at the right dose, feed additives can lower feed cost and support animal health. But every additive is an investment that has to pay for itself. Doing that sum for each additive separately is the simplest way to clear a formula of items it does not need.
