The horse feed labels are the first thing you look at to reassure yourself about what you are feeding your horse or to compare two feeds. However, these labels are full of traps for those who are not initiated to equine nutrition. Let’s try to see them more clearly.

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What do the regulations say about horse feed labels?

The first thing to understand is that horse feed labels are designed to effectively meet regulatory requirements and not to inform the consumer about the nutritional benefits of the feed. It must contain all the information required by the regulatory list to which the feed corresponds and which is defined according to the type of feed and the species of destination. All manufacturers are obliged to comply with this requirement.

It is important to distinguish it from the product card (often available on the Internet) which is not subject to any regulatory obligation. Except for the truthfulness of the information it contains, of course!
The construction is left to the manufacturer’s discretion, who only includes the information he deems useful. Moreover, he is not even obliged to provide it.

We must compare… comparable things!

To compare two nutritional values, you have to do it in the same unit (it seems obvious but in the field, it’s not always…): percent, grams, milligrams, IU (International Unit : not simple because it varies from one molecule to another) etc. 

Similarly, to compare effectively, we must be careful to use the same frames of reference. To illustrate this, let’s take two examples :

Example 1 : The Raw Matter (RM) versus Dry Matter (DM) reference

A horse feed is on average 12% water and 88% dry matter. Therefore, it is important to know whether, for a given constituent, we are talking in /kg RM (per kilo of raw matter) or /kg DM (per kilo of dry matter).

The ingredients on the label are always expressed in terms of raw matter. Instead, on the product card, the manufacturer may choose to use the dry matter reference even though this is rare.

For instance: The Destrier POWER SAVE contains 215g of starch/kg RM but if we change the reference frame, it contains 244 g of starch/kg DM (necessarily more since we exclude the water part of the calculation).

Example 2: The “additive” versus ” whole feed” reference 

Trace elements (iron, zinc, copper, selenium, etc.) can be added specifically to the feed. These are called “additives”. In this case, it is the regulatory value found on the label.

But in addition to those that are added, trace elements are naturally contained in the other raw materials that make up the feed (in alfalfa, in cereals etc.). Therefore, to calculate the amount of “total trace elements in feed”, it is necessary to add the “additive trace elements” with the “natural trace elements contained in the raw materials”. On the product card, the manufacturer can choose to use one or the other reference system.

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Avoidable traps of horse feed labels… if you know them

The Raw Protein vs. MADC Trap

The raw protein content of a food is a quantitative information that gives the total amount of protein in the feed. It is a regulatory requirement and is therefore included on the label.

Beyond this quantitative aspect, equine nutrition is also interested in more qualitative aspects. Indeed, to be interesting, a protein must be useful to the horse on the metabolic level. This is called “digestible” protein. It can also be qualified as a “good quality” protein. This is why INRA (French National Institute of Agronomic Research) has proposed a system for evaluating protein requirements and intakes in terms of MADC (Horse Digestible Nitrogenous Matter) expressed in g/kg RM.

This information is not regulatory: it is not on the horse feed labels. On the other hand, it is often indicated on the product sheet.

For example, let’s compare two feeds:

Feed 1 :
Raw Protein = 11,8%, which represents 118 g/kg RM
MADC = 90 g/kg RM
76% of the proteins in this food are therefore digestible. (90/118 = 76%)

Feed 2 :
Raw Protein = 12,5%, which represents 125 g/kg RM
MADC = 85 g/kg RM
68% of the proteins in this food are digestible. (85/125 = 68%)

Naturally, the consumer looking for a high protein feed will turn to Feed 2, which has a higher amount of total protein. However, there is a greater amount of “quality” protein in Feed 1, which makes it more metabolically useful to the horse.

The trap of trace elements in mineral vs chelated form

In nature, there are two forms of trace elements:

• The mineral form which has a low bioavailability (only 30% of trace elements in this form are effectively valued during digestion). The mineral form also induces numerous interactions between the different trace elements. For example, iron can limit the absorption of copper and zinc.
• The organic form, which has a good bioavailability (over 60% thanks to a coupling with biological molecules) and few deleterious interactions. It is in this natural form, present in grass, that the horse ingests most of these trace elements.

In order to mimic nature, and therefore to increase bioavailability and avoid interactions between the different trace elements, animal nutrition research has created what are called chelates, by associating the mineral forms of trace elements with proteins. Chelates are therefore highly available trace elements.

Given the major differences in bioavailability (ranging from simple to double), this must be taken into account when comparing two feeds, one with chelates and the other without.

For example, let’s compare two horse feed labels for Iron, added as an additive:

Feed 1 :
The label indicates 45 mg/kg of Iron, broken down into:
– Iron sulfate = 40 mg/kg with 30% absorption, so “useful” iron (because absorbed) = 12 mg/kg
– Iron chelate = 5mg/kg with 60% absorption, so “useful” iron = 3 mg/kg

So total “useful” Iron = 15 mg/kg

Feed 2 :  The label indicates 47 mg/kg of Iron
– Iron sulfate: 47 mg/kg with 30% absorption

So total “useful” iron = 14 mg/kg

Feed 1 provides more iron that will be effectively used by the body than feed 2, thanks to the higher bioavailability of chelates, even though the label seemed to indicate exactly the opposite!

NB: Remember that in addition, highly bioavailable iron is already naturally contained in the raw materials of the feed. As seen previously and to be exhaustive on the comparison, it must be added.

The trap of nutritional value vs nutritional benefit

A common trap is to consider the value rather than the nutritional purpose. To avoid this, it is important to ask yourself what nutritional benefit you are looking for, which ingredients act in synergy to achieve this objective and what are the profiles of the foods you wish to compare with regard to all these elements.

Here is an example with Vitamin E:

The Trap	What you should do
Looking at the amount of Vitamin E only	Ask yourself what the nutritional goal is: here, it is resistance to oxidative stress (anti-oxidant potential)
Not asking yourself why you want to have a high level of Vitamin E or what other ingredients could act in synergy for the desired effects	Consider what other ingredients complement Vitamin E to achieve this nutritional goal: -High micronutrient concentration -Trace elements (taking into account their bioavailability: mineral or chelate forms) -Omega-3 essential fatty acids -Titrated antioxidants (Vitamin C, Selenium) -Natural antioxidant complex (plant extracts, polyphenols, spirulina etc)
Comparing the profile of different foods on Vitamin E only	Compare the profile of different foods on all these elements
Concluding that one feed is more suitable than another based solely on the amount of Vitamin E	Conclude that one feed is more suitable than another considering all the parameters

To remember

Horse feed labels provide some information and gives an idea of the profile of the feed, but it contains too little information to make an effective comparison between feeds (even for an informed nutritionist). The product sheet (if it exists), more complete, brings an essential additional information and allows in general an effective comparison, provided not to fall into its traps…

In conclusion, comparing two feeds on the basis of one or more nutritional goals is much more relevant than comparing simple values taken out of their nutritional context.

Marine Slove
Destrier veterinarian and nutritionist