Hoof Nutrition Intelligence is a twice-a-month web segment that is designed to add to the education of footcare professionals when it comes to effectively feeding the hoof. The goal of this web-exclusive feature is to zero in on specific areas of hoof nutrition and avoid broad-based articles that simply look at the overall equine feeding situation.
Below you will find Part 1 of the latest question and answer installment that you can share with your footcare clients.
Q: Does iron play a role in hoof growth and quality?
By Eleanor M. Kellon, VMD
A: From pregnancy to performance with the horse, nothing happens without iron. Essential for all forms of life, iron is a mineral that has no substitute and powers key life-sustaining reactions in your horse's body. However, iron also has an insidious dark side.
The most well know role of iron is in red blood cells, where iron forms the active center of hemoglobin, the pigment that carries oxygen in the red cells. It performs a similar function in the muscle pigment myoglobin, which gives muscle its red color. Iron is also needed for thyroid hormone production. Iron containing enzymes are also used inside the cell's nuclear powerhouses, the mitochondria.
Iron has many functions because chemically it is extremely reactive — in fact almost too reactive. Unfettered iron can do a tremendous amount of damage to the tissues. In a normal horse, there is virtually no free iron. It is all securely bound to carrier and storage proteins until well controlled and sequestered reactions free it up for use.
Because of the important jobs iron performs, and the fact that deficiency is common in humans, iron finds its way into equine vitamin and mineral supplements and fortified feeds. Iron is a common ingredient in “blood builders” and widely recommended for any horse that is anemic.
However, more is not necessarily better for iron and the truth is that equine diets contain more than enough (sometimes much more) iron than the horse needs. There has never been a documented case of iron deficiency anemia in an adult horse — ever. Still, since it's so important it can't hurt to supplement anyway, just in case, right? Actually, no.
Because free iron is so dangerous to the body, there is an intricate system to keep it under control. Iron can be absorbed through the gaps between intestinal cells, a process that is increased in the fermentation of hay/forage. Otherwise, iron is absorbed into intestinal lining cells in the small intestine. From there, its release into the body is controlled by hormones/regulators that can block movement out of the cell and control the electrical charge of the iron, which in turn determines if it can be picked up by its carrier protein, transferrin.
Once iron is in the body, it is basically there to stay. Unlike other minerals, the body has no avenue for getting rid of iron other than tiny amounts in sweat. This iron accumulates over time. While a high enough dose all at once can kill a horse (foals are especially susceptible), toxicity is more likely to build up over time.
Unsupplemented diets often contain considerably more iron than the horse needs and levels in the body will rise over time. It makes no sense to add to the burden with the horse's supplements. Look for the words iron and ferrous in both the analysis and the ingredients list.
Dr. Eleanor Kellon, a staff veterinary specialist for Uckele Health & Nutrition, has been an established authority in the field of equine nutrition for over 30 years. The owner of Equine Nutritional Solutions in Robesonia, Pa., she is a founding member and leader of the Equine Cushing’s and Insulin Resistance (ECIR) group, whose mission is to improve the welfare of horses with metabolic disorders via integration of research and real-life clinical experience. Prevention of laminitis is the group’s ultimate goal.
Click here to read part 2 of the Oct. 1, 2020 installment of Hoof Nutrition Intelligence: Should I be concerned about laminitis when grazing my horses in the fall?