Why the Liver and Bioavailable Minerals Matter So Much in Horse Nutrition

When we talk about horse nutrition, I think a lot of people naturally focus on what they are feeding - the supplement, the vitamin mineral, the herb, the ration balancer, the add-on. But one thing that matters just as much is this:

Can the horse actually use what we are putting into the body?

Because at the end of the day, it is not just about what goes in. It is about what gets digested, absorbed, processed, stored, and actually utilized.

And that is where the liver deserves a whole lot more attention.

The liver is one of the hardest working organs in the horse’s body. It plays a major role in metabolism, processing nutrients, storage of certain vitamins and minerals, and handling all kinds of substances that move through the body. It is deeply involved in what happens after nutrients are absorbed from the digestive tract and sent into circulation. That is a big reason why I often think of the liver as one of the true powerhouses behind how the body handles what we feed.

Now, to be clear, absorption itself begins in the digestive tract, not the liver. But the liver is still a huge part of the bigger picture. Once nutrients are absorbed through the gut, the liver helps regulate, transform, store, and distribute many of them. So when we are thinking about overall nutritional efficiency, the liver absolutely matters.

It is not just about how much is in the feed

This is where bioavailability becomes so important.

Bioavailability basically means how available a nutrient is for the horse to actually absorb and use. Two feeds or supplements can list the same mineral amount on paper, but that does not automatically mean the horse will utilize them the same way. The form of the mineral matters.

This is especially important with trace minerals like zinc, copper, and manganese.

You will often see minerals in a few different forms on feed tags or supplement labels. Some are more traditional inorganic forms, like oxides or sulfates. Others are what we often call more bioavailable or organic forms, such as chelated minerals, proteinates, or amino acid complex minerals. In simple terms, these minerals are bound to organic molecules like amino acids or peptides, which can help protect them and may improve how they are absorbed and retained by the body.

What are chelated, proteinate, and amino acid complex minerals?

These terms can sound fancy, but the general idea is pretty straightforward.

Chelated minerals are minerals that have been chemically bound to an organic carrier, often an amino acid. Proteinates and amino acid complexes are similar in that they are also attached to organic compounds, rather than existing only as simple inorganic salts. These forms are often used because they may be more stable in the digestive tract and may compete less with other minerals during absorption.

That does not mean every single organic mineral source is automatically perfect, and it does not mean inorganic minerals are useless. But it does mean that form matters, and it is one of the reasons why two supplements that look similar on a label may not perform the same in the horse.

Why this matters in real life

This matters because horses are not eating nutrients in a vacuum.

They are eating forage-based diets with natural antagonists, varying mineral levels, possible imbalances, stress, workload, age-related changes, and sometimes digestive issues on top of all of that. So when you are trying to support hooves, topline, immune health, skin, coat, connective tissue, recovery, or overall resilience, you want the minerals you are feeding to have a better chance of actually being used by the body.

This is one reason why better-formulated feeds and supplements often include at least some minerals in more bioavailable forms.

For example, research in horses has shown differences in absorption and retention when comparing oxide, sulfate, and organic-chelated sources of copper, manganese, and zinc. Organic-chelated forms showed advantages in retention in that study, which supports the idea that source matters, not just dose.

There is also equine research showing that complexed trace mineral supplementation can influence antioxidant capacity and muscle-related oxidative stress markers in young horses under training. That does not mean it is a magic fix, but it does reinforce the idea that mineral form may have meaningful physiological effects.

Why I pay attention to liver health too

When I think about nutrition, I do not just think about deficiencies on paper. I think about the horse’s ability to handle nutrition well.

That includes the digestive tract, of course, but also the liver. If the liver is central to processing, storing, converting, and distributing nutrients, then it makes sense that this organ deserves more appreciation in the overall nutrition conversation. The body cannot do as much with poor inputs, poorly balanced minerals, or nutrients that are hard to utilize.

To me, this is why quality matters so much.

Not just flashy labels.Not just big claims.Not just “this supplement has zinc” or “this one has copper.”

What form is it in? How available is it to the body? Is it balanced properly? Is it designed with the horse’s actual physiology in mind?

Those are the questions that matter.

What I want you to takeway from this is

Feeding a nutrient is not always the same thing as nourishing the horse.

The liver plays a major role in helping the body process and manage nutrients after absorption, and the form of the minerals we feed can make a real difference in how effectively those nutrients are used. That is why bioavailable minerals - such as chelated minerals, proteinates, and amino acid complex minerals - are worth paying attention to when building a nutrition program.

Because sometimes the conversation should not just be about what is in the bucket.

It should be about what the horse can actually do with it.

References

Kienzle E, Zorn A. Bioavailability of Minerals in the Horse. In: Advances in Equine Nutrition III. 2006.

Wagner EL, Feaster JP, Staniar WB. Absorption and Retention of Trace Minerals in Adult Horses. Journal of Equine Veterinary Science. 2005.

Latham CM, Coverdale JA, Arnold CE, et al. Complexed trace mineral supplementation alters antioxidant status and reduces indicators of oxidative stress in young horses entering training. Journal of Animal Science. 2021.

Ralston SL. Clinical Nutrition of Adult Horses. Veterinary Clinics of North America: Equine Practice. 1990.

Merck Veterinary Manual. Nutritional Requirements of Horses and Other Equids. Updated 2026.