Diet formulas include corn, soybean meal, poultry meal & antibiotics
The first set of broiler formulas (BR01) in the Animal Feed Formulations Library describes what the majority of the world, and especially the United States and many Latin American countries used before the advent of the antibiotic-free era.
Notes on feed ingredients
These formulas are based on corn as the main energy source, supplemented by soybean oil. Of course, other cereals such as sorghum and wheat are available, and a plethora of other oils and fats are used. The end result remains the same, but it requires some further refinement and more attention to ingredient quality when we depart from classic ingredients. As such, corn and soybean oil remain the standard ingredients used to describe typical U.S. broiler formulas.
The same applies to soybean meal, which here is of the 44% crude protein variety — although many nutritionists prefer the 48% crude protein variety for the starter feed. Not many exotic vegetable protein sources are available, except for dried distillers grains with solubles (DDGS), and canola (Canadian rapeseed) that is used in Canada and certain northern United States.
Regarding animal-derived ingredients, poultry byproduct meal has long replaced fishmeal, which is too expensive now and not as available as in the past, and of course meat and bone meal (beef and/or pork). This is because poultry integrators have a surplus of poultry byproducts from their slaughterhouses. As such, this ingredient (and poultry fat, too) has become a staple source of protein and fat (unless defatted) for broiler diets (and other animal feeds). Depending on its quality, the inclusion level can be higher, but here we opted for a conservative number to illustrate its use and presence only.
Downloadable PDF: Traditional US broiler starter feed formulation
The rest of the ingredients require little discussion. Perhaps, some exception can be made for the vitamins and trace minerals. First, the two premixes are always advised to be used separately, and almost always are used mixed together. At least, choline chloride — a very reactive vitamin — is now almost universally added separately. Whether one uses a constant level of premix(es) throughout the life of a commercial broiler, a separate premix for each phase, or a phase-down approach of a universal mix (such as shown here) depends on the nutritionist designing each program.
Finally, although a corn-soy diet contains enough natural choline, most nutritionists prefer to add a bit extra of this vitamin because established requirements are several decades old. Perhaps, the greatest need for this precaution is for the starter feed. Incidentally, poultry byproduct meal is a super-rich source of choline (more than 6,000 ppm compared with about 500 ppm in corn).
In this set of formulas, antibiotics and anticoccidials are included, but their exact inclusion rate depends on manufacturer instructions. The inclusion rates indicated, also in the case of additives, are nothing more but a placeholder. Regarding all other additives, the most common additive that could have been used in this type of formula is phytase, something that could be explored in another set of formulas designed to illustrate this specific concept. Then, of course, each nutritionist has a specific array of additives that prefers to use.
Downloadable PDF: Traditional US broiler grower feed formulation
Notes on nutrient specifications
In order to round up the ingredients, to show easily how their concentrations decline gradually (except for corn, which always takes up any slack in formulation space) as birds grow, nutrient specifications have been allowed to deviate by relatively small fractions. In fact, this is often the decision of the nutritionist; that is, whether to prepare the final (production) formula on exact nutrient levels or rounded up ingredient figures to accommodate the needs of the feed plant.
For example, in many feed mills, corn cannot be weighed in increments of less than 5 kg.
In general, nutrient specifications also decline (except for energy) as birds grow heavier and, in fact, they can be made to differ for birds housed by sex, as females and males have different growth rates, hence different nutrient requirements. In the case at hand, we opted for relatively conservative energy and protein levels to reflect modern practice (even though antibiotics are being used in this case).
This is to avoid the sudden-death syndrome of heavy birds due to overeating, and a host of other metabolic disorders associated with rapid ingestion of nutrients and energy early in life. Nevertheless, the protein profile has been kept constant (some nutritionists will have a different opinion, but this is a simple exercise and not a commercial or scientific project), whereas the absolute amino acid levels have been kept quite high (even for the most demanding genetic lines).
A question can be raised regarding the dietary electrolyte balance, as some nutritionists might prefer a higher number, but this is refined nutrition beyond the scope of this discussion. Finally, other nutrients, such as linoleic acid, arginine and other amino acids could have been monitored, but given the commonality of the ingredients, it is rather assured that such secondary issues are sufficiently covered.
As a side note, it should be reminded that even when we formulate on exact nutrient levels, laboratory analyses invariably fail to return such exact numbers. This is because actual ingredients are not always as we describe them to the formulation program, and even laboratory analyses have their own acceptable degree of error.
This is why many nutritionists do not worry about a point up or down but insist on certain ingredient levels. This might make feed a bit more expensive, but it ensures animal performance in the absence of a vigorous analytical program. All of these will be discussed elsewhere.
Downloadable PDF: Traditional US broiler finisher feed formulation
Notes on feeding
These formulas have been designed for a feeding program lasting 42 days from hatching until market, which is the most common program worldwide — at least for the year 2020.
A final withdrawal feed is not included here as it is a local decision. Quite frequently for such feed, the finisher is used without the antibiotics and coccidiostats. The withdrawal period is determined by the veterinarian and the processing plant to ensure compliance with applicable laws and regulations.
Otherwise, this is can be quite a flexible program that can be modified in several ways. The most frequent one is that of 1-2-3 weeks, meaning the starter is fed for one week, the grower for two weeks, and the finisher for three weeks — for a total of six weeks or 42 days. Or, another more expensive variation is that of 2-2-2 (two weeks for each feed), but this is used only when the birds receive a super pre-starter during the first four days post-hatch, so the starter, if fed, for only 10 days.
Adjustments are required and are made frequently based on chick quality, season, feed quality and animal health.
Finally, the holding size of a feed silo that serves each broiler house plays an important role. Birds consume a known (more or less) amount of feed each day and, based on this number and the capacity of the silo, one can determine how much of each feed should be ordered and fed to each broiler house to roughly coincide with the required feeding days. Of course, matters are easier when operation size increases, but then other problems of logistical nature arise.
Broiler feed formulations in the series and related analysis:
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