Growing-finishing pig feed formulations

curtoicurto | iStock.com

In 2020, WATT Global Media and Ioannis Mavromichalis, Ph.D., decided to publish a series of animal feed formulas, the Animal Feed Formulations Library, as a general information resource material. The first set of diets is focused on broilers, whereas next sets will address more animal feeds, such as those for layers, pigs and dairy cattle.

Learn More: Broiler Feed Formulations, a downloadable Excel spreadsheet includes three broiler feed formulation variations for starter, grower and finisher broiler diets.

In the future, more specific examples may be presented depending on audience acceptance and general interest. To this end, feedback is essential for the success of this project.

First and foremost

Before we begin, it is important for everyone to read the disclaimer carefully, which can also be found in its entirety at the end of this document.

In brief, these formulas are not complete (finished) as crucial parts have been left out. The parts missing, such as additives and vitamin/mineral premix specifications, are either covered in other publications or will be published in the future as part of this library of feed formulas. For the moment, their absence does not distract from the informational purpose of these formulas as the basic aspects of nutrition are described in sufficient detail. Nevertheless, these formulas should not be used for any other purpose, commercial or otherwise.

As always, it is strongly advised to consult with a local nutrition professional before using any published information.

Ingredient database dilemmas

To formulate feeds, we need a list of ingredients. Although the ingredients used in these formulas are very common, their nutrient specifications can differ from region to region and even from batch to batch.

For the purpose of this project, we have used the INRA‘s 2004 publication titled, “Table of Composition and Nutritional Value of Feed Materials,” supplemented as needed by the NRC (1994) publication titled “Nutrient Requirements of Poultry,” along with supplier- or manufacturer-specific nutrient composition data sheets. The fact that we have relied on table value can only reinforce the informational role of these formulas as any nutritionist attempting to formulate commercial feeds would prefer local actual data and if possible such as those based on laboratory analyses over a long period of time. But, again, for the purposes of this project, these generic sources suffice.

Nutrients and values

Feeds and ingredients are described with a great number of parameters when it comes to their energy value and nutrient composition. For the broiler formulas, we have selected the nitrogen-corrected apparent metabolizable energy system (AMEn), because it remains the most commonly used universally.

For amino acids, we used the true digestible values (TD), whereas for phosphorus we opted for the well-known available phosphorus system (AvP). All other nutrients were used based on their total concentration.

Here, it should be noted that, for fiber, we continued to use crude fiber, despite all its shortcomings, not only because there is no other practical system for poultry, but also because, for those typical ingredients we used, there is very little scope in changing to another form of fiber description.

Feed formulation system and least-costing

All feeds were formulated on a least-cost basis using the Solver add-on feature of Excel on a spreadsheet designed for the personal use of Mavromichalis. Prices used were picked from a specific region at the time of formulation and, as such, these formulas will not be the least expensive formulations when one applies other prices. Still, the formulas remain balanced in terms of nutrition even if they become more or less expensive as the two are not related — or at least they should be not.

Although other software systems were available, the end result remains the same and, at the end this approach, favors no commercial feed formulation software system. In the end, it remains the personal preference of us all to pick the tools that we feel most comfortable using in our job. Afterward, the formulas were rounded in their ingredient concentration part to reflect industry practice and make them easier to describe in the accompanying text; some nutritionists prefer to leave this step up to the feed plant.

Which dietary specifications and genetics to use?

Any feed formula is a mix of ingredients that tries to meet specific dietary energy and nutrient requirements. These requirements are not fixed, but they change on a great number of variables, one of which is genetics. Despite the great uniformity in genetics, differences still exist and, although the latest nutrient specifications of the two major genetic lines, namely Ross and Cobb have been consulted, these formulas conform to neither.

First, this is because these two specification sets are not identical and favoring one over the other would not serve the purpose of this initial attempt. Second, there are many other genetic lines, albeit minor ones, and then, even within the two major genetic houses there are several different strains with different nutrient requirements. Thus, a middle-of-the-road approach has been chosen to illustrate what a generic broiler formula would look like.

Other local factors that affect further the genetic houses’ specifications make it even more imperative to consult a local nutrition professional to tailor specific feeds to specific needs.

Where is such-and-such additive?

Additives are not part of this project. This is because there is no consensus over which additives should be used routinely and which should be used occasionally — actually, there is not even a global consensus on which ingredients are additives and which are not.

The second reason is because such is not the purpose of this project, although some generic products have been included for the purpose of demonstrating the difference between a formula containing growth-promoting antibiotics and one that does not. Also, some ingredients considered as additives in a region are not in another and a decision had to be made to ensure completeness of presentation.

Third, some specific additives that could be used are described under each set of formulas, but they constitute no recommendation whatsoever. Again, this is the job of the local nutrition professional.

Fourth and finally, there is such plethora of additives and information on them that it would require an enormous library of formulas to accommodate all the possible combinations.

Having said all of the above, this does not exclude the possibility of publishing new formulas in the future with specific additives included to demonstrate other concepts.

What about vitamin and trace mineral premixes?

Vitamins and trace minerals should be used, but their exact composition for the moment remains outside the initial scope of this project. It is expected to provide such information in the near future, but for the time being, it is advised to look into other sources and consult with your local nutrition professional.

The inclusion level indicated for each premix is just a generic number and can vary depending on how concentrated a premix is, but in general, anything below an 1 kg/metric tone inclusion rate is difficult to incorporate without further premixing, at least under most practical conditions, due to machinery limitations.

Download as a spreadsheet

For those who feel adventurous enough, all formulas in the library are available as an Excel spreadsheet to download.

Please be advised that, although all information (energy and nutrients) used in the creation of these formulas will be included (in rather crude form) and the functionality of the cells recalculating dietary specifications as ingredient concentrations change will remain, the least-cost formulation ability will not be made available and the formulas will not be able to rebalance automatically to 100% if something is altered. In other words, the spreadsheets are not the feed formulation program used for the creation of these formulas. So, use them with even more caution and only if you know nutrition, formulation and Excel very well.

These downloads are provided without further follow-up service and the same disclaimers and copyrights appeal as the published version — and even extend to any alterations you decide to make, especially in the case of liability.