Updated: Feb 26, 2021
There is no shortage of supplements for horses. Sometimes I think it's just another way the feed companies try to get us to spend money! Especially since most supplements on the market are high in sugar, not balanced nor necessary to your horses' overall health.
How to properly supplement? Test your hay!! Blood and hair testing is not an accurate way to figure out how much to supplement of what. An imbalance in minerals in the diet can cause a deficiency somewhere, but simply supplementing what is deficient is missing the big picture. You will continue to chase your (or your horse's) tail until you properly balance the minerals to the forage your horse is consuming.
Suggested Feeding Program
Surprisingly, you don't need to purchase 30 different supplements to have a healthy horse. In fact, less is more, because we are trying desperately to keep things balanced. This is the basic feeding program that I recommend for a full size horse:
20-30lbs low sugar hay, offered free choice in small holed nets
1/3c ground flax seed
1000-2000iu Vitamin E (human gel caps are best)
5g-10g Magnesium Oxide (can taste bad, start slow)
2Tbsp plain white Salt
1-2mg Selenium, if you are in a low Selenium area
Use a low sugar hay pellet, such as Haystack Low-Low, (or rinsed and soaked beet pulp) as a carrier for your minerals, amino acids, and vitamins. I've found that California Trace and Vermont Blend both satisfy the recommended amounts of trace minerals. You will still have to add vitamin E, flax, and salt (and magnesium if you use California Trace).
It's All About Balance
What's the most important nutrient for healthy feet? All of them! Fatty acids, amino acids, proteins, vitamins and minerals. The most important part is balance. Too much is just as detrimental as too little. For example, too much iron will crowd out the uptake of zinc, copper, and calcium. Commercial ration balancers and balanced feeds are NOT what I'm talking about when I say it's all about balance. I'm talking about making sure the ratios of minerals in their diet are balanced and that there isn't too little or too much of anything. Many companies out there try to fool us by using buzz words like "balance", "support", "health", growth", "power", "gain", "hoof" and the list goes on, but this is purely marketing. Even feeds and supplements marketed towards IR horses have sugar and grains in them, which is absolutely NOT OK for an IR horse!! You need to be the advocate for your horse, and help to shield them from greedy companies trying to profit off of your good intentions. Every feed label and every supplement label should be read with a magnifying glass, as they like to sneak in grains, sugar, starch, and they like to hide iron in different forms.
Whoa There, Iron!
The reason we try to cut out any added iron in the horses' diet, (aside from iron overload contributing to IR) is because we are trying to keep it balanced with the other minerals.
The correct ratio for iron:copper:zinc is 4:1:3. If there is too much iron in the diet, copper and zinc do not get absorbed properly. If zinc doesn't get absorbed properly, calcium cannot be utelized. All the hay I have tested has been high in iron and low in copper and zinc. Your horse is getting all the iron it needs from the hay and water it consumes, we do NOT need to supplement it! What we do need to supplement is copper and zinc. Look at all labels with scrutiny, any supplement that has added iron is a waste of money, and should not be purchased. Manganese acts like iron, so watch out for added Manganese as well. Too much iron long term causes iron overload and with it a litany of health issues, it can be identified by:
"Bleached" red ends of the mane and tail
Black livers are often found in horses with iron overload at necropsy. This is caused by long term iron deposits called hemosiderin. Late stage iron overload causes liver damage and failure, earlier stages have been observed to have joint pain/arthritis, lethargy, and often metabolic issues such as Insulin Resistance.
(photo source: https://forageplustalk.co.uk/iron-overload-in-horses-by-dr-kellon/#/ )
The Importance of Zinc
Zinc is not to be overlooked, it is absolutely critical to building strong, healthy cells in the horse's body. If the cells are not built strong in the first place, they will eventually break down. Weak cells can not be fixed topically, that is why it is so important to focus on nutrition! Zinc deficiency can actually be observed through the condition of the hooves:
Slow hoof growth
Brittle, dry, thin "shelly" hoof walls
Weak connections (flaring, laminitis)
Weak horn material
Another reason to make sure Copper and Zinc are adequately supplemented, is the Copper Zinc superoxide dismutase enzyme, which protects against oxidative damage to the fats and oils present in the hoof. The fats and oils create the protective seal in the hoof, filling the spaces between the keratin cells. Making sure to keep proper moisture levels in the hoof, and keeping out dirt and microbes. This enzyme protects the fats and oils within the hoof, and without this protection the seal is broken on the cellular level. These micro breaks in the structure will allow microbes in, and cause the hoof to dry out and crack. Microbes such as thrush can get in to the weakened hoof, and have free rein. (photo source: https://proteopedia.org/wiki/index.php/Copper%2C_Zinc_Superoxide_Dismutase )
But What About Calcium?
Calcium is also crucial to building strong hooves. It is required for activation of the transglutaminase enzyme which is involved in the transformation of skin cells into keratinocytes, that forms the hoof horn, as well as strengthening the bonds between the keratin fibers themselves. But, the process that allows Calcium to be used requires Zinc. Zinc regulates calmodulin, which is what binds calcium. Even if you supplemented Calcium, if there wasn't enough Zinc, it would not be able to be used. Here come some more ratios! Calcium to Phosphorus is 1.2:1 to 2:1, Calcium to Magnesium is 2:1
So when adjusting one mineral, be sure to keep them all balanced!
We can't overlook magnesium, it is such a powerful mineral. Over 300 enzymes require Magnesium to function! It is quite possibly the most important mineral to make certain is supplemented. I've found that irritable and sensitive to touch horses make a complete turn around when supplemented Magnesium. It also helps to regulate insulin levels, and is required for all genetic material to function and be transcribed. It is needed at all levels, even down to the DNA and RNA. What does Magnesium deficiency look like?
Sensitive to sound and touch
The only real way to be able to tell how much Magnesium (and any other mineral) to supplement is to test your forage. But, as a general rule of thumb, a daily dose of 5g-10g is recommended. Magnesium Oxide seems to be the form best absorbed by equines. California Trace sells bulk Magnesium, 5# bags, on their website. "Human" Magnesium supplements is not recommended as it is more expensive and not any more effective.
Do Horses need Oil and Fat?
Short answer? No. But.. There are essential and nonessential fatty acids. Horses can synthesize fat so they don't need oil for fat. Horses do need essential fatty acids such as omega-3 and omega-6 in their diet if they are not on grass. However, it needs to be in a ratio from 4:1 to 6:1, which is the same ratio found in grasses. When you're picking out a source of fatty acids, you want more omega-3 than omega-6. Flax seed (I recommend ground) fits these parameters, as does chia (also does need to be ground). Vegetable and corn oil do NOT fit these parameters and should never be fed to a horse.
The B Vitamins
The most famous B vitamin is Biotin. But it is not the only B Vitamin that should be getting our attention when it comes to hoof health, IR, and laminitis. Horses on pasture generally do not have deficiencies in B Vitamins. So, the B Vitamins most involved in protein should get our attention, since there is such a high concentration of protein in the hoof wall. Those B vitamins are Folic Acid, Pyridoxine, Biotin, and B12. Folic acid is involved in nitric oxide generation, and as such should be supplemented to horses in a laminitic episode. Nitric Oxide is a vasodilator, it opens up the blood vessels and increases blood flow, both of which are crucial in treating laminitis.
Pyridoxine (B6) deficiency has not really been studied in equines. What we do know, is that in humans pyridoxine deficiency causes a burning sensation in the feet. Anecdotal, but still interesting.
The only vitamin that is not supplemented through forage is the B12 Vitamin, it is synthesized through fermentation in the hind gut. Which means, it is possible for horses to have deficiencies, especially if they suffer from hind gut ulcers or leaky gut. There is no standard amount set for supplemental B12. However, it has been observed that calcium deficiency can be a contributing factor to B12 deficiency. But don't just run out and add calcium. Remember, if you add calcium, you have to supplement more Zinc and Magnesium. More Zinc means they will need more Copper. Balance. Horses on a tested and balanced diet do not seem to show an issue with B12 Deficiency, but it's not out of the realm of possibility.
Dr. Eleanor Kellon recommends supplementing 10-20mg Folic Acid, 20mg Biotin, and 100mg Pyridoxine.
Vitamin E is a major antioxidant, ridding the body of harmful free radicals. It is present in every cell of your horse's body, and is essential, meaning it is not synthesized in the horse's body, it comes from the grass. Dried hay is lacking in Vitamin E, so if your horse is not on pasture, they will need to have it supplemented. But again, be vigilant with your reading of labels. The best Vitamin E out there for horses, is actually the human version in the liquid gel caps. It has no added sugars or flavorings, and it has a great potency. Vitamin E is fat soluable, so it is best absorbed in it's liquid form, not the dry pills or powders. The VItamin E supplements made for horses often have added sugar, preservatives, flavoring and are often lower in potency that the gel caps made for humans.