Anemia is one health issue that nearly everyone understands because we’re so familiar with it in people. However, the causes and corrections for anemia in people are different than in horses, especially on the nutritional end. There are many supplements being billed as ”blood builders,” but most are really formulated more appropriately for a human than a horse.
Needing Blood Builders
Blood builders are used for two general reasons: 1) In horses that are actually anemic, and 2) In hopes of boosting the red blood cell count to get better performance. The performance horses aren’t necessarily anemic, but their red-cell counts may be at the lower level of normal, and trainers know better red counts means more oxygen delivery and better performance.
Whether the horse has a true anemia or just a suboptimal red count, no blood-building product is going to have an effect if the horse already has an adequate intake of the nutrients in the supplement.
Most people immediately think iron when they hear anemia (and equine supplement manufacturers, too, apparently!), but iron deficiency has never been seen in adult horses and neither has anemia caused by iron deficiency. Studies have unequivocally shown that you can’t improve the red cell count of a horse by giving more iron. Equine diets have plenty of iron already, often way more than the horse needs.
B vitamin deficiencies, particularly pyridoxine, folic acid and vitamin B12 (cyanocobalamin) may also cause anemia in people, especially if they are undernourished. But this just is not a problem for most horses.
As with iron, no cases of B vitamin deficiency-related anemia have been reported in horses. Hays and grasses are good sources of B vitamins. That said, horses with less than optimal intestinal-tract function (older horses, horses with chronic gastro-intestinal problems) might have borderline bacterial B vitamin production, or be unable to utilize the B vitamins in their diet well. It is also recognized that horses on hay have lower levels than horses at pasture, and horses being heavily worked are known to have higher requirements for B vitamins. This leaves the door open for suboptimal B vitamin intake to contribute to some anemias.
Although we don’t know how often this happens in horses, copper deficiency can cause anemia by interfering with production of the iron-carrying protein ceruloplasmin, which is needed to get copper from the intestinal cells to the bone marrow to be used to make hemoglobin. Copper deficiency is common in equine diets. Even when the overall level of copper should be adequate, high levels of other minerals or sulfates in water may be interfering with its uptake.
High-performance horses, horses with chronic infections, allergies (especially lung), older horses in general and horses with insulin resistance have higher oxidative stress than otherwise healthy and less intensely active horses do. The red blood cell membranes can be damaged by oxidative stress, which results in those cells being taken up in the spleen and destroyed. If production keeps pace, there won’t be a problem. If it doesn’t, the red count will start to drop. Many common deficiencies can contribute to this including magnesium, zinc, vitamin E, selenium, possibly vitamin C with lung allergies.
Deficiencies of iodine or selenium may interfere with thyroid function. This can lower metabolic rate and red cell production.
Some infections can cause anemia directly, like Leptospirosis and Ehrlichia. Chronic infections can cause suppression of both red and white blood cell counts. Lyme is the most familiar example here. Severe illness can lead to an anemia from chronic disease, even without an active infection. This includes extensive and slow-to-heal surgical wounds or injuries, organ disease, chronic conditions like Cushing’s.
Very low normal to just below normal range red counts and hemoglobin are commonly found in older horses even when they are otherwise healthy. This is likely due to them being less active and to a general slowing of their metabolism. You should make sure the diet does not have any deficiencies or imbalances, but otherwise this doesn’t require any particular treatment and the horse will not have any symptoms.
Equine blood-builder products focus on iron and B vitamins, two things that most horses are not likely to need and least likely to be involved with anemia or borderline red cell counts. Unless you know for a fact, by a blood test, that your horse is iron-deficient we would not advise using any high-iron blood builder (200 mg or higher per dose).
Although not advertised as a blood-builder per se, we included the B-Plex from Horse Tech as an iron-free B supplement for high-performance horses or horses that may have gut issues. If you need more concentrated Bs for a performance horse, we still like the concentrated formula in Ultra Fire, a previous Horse Journal top B-vitamin pick with lower iron than most.
However, if you just need a blood builder, we like Su-Per Antioxidant Concentrate. It doesn’t appear to be marketed as a blood builder, but 1 oz. covers multiple bases in likely factors contributing to anemia in horses. Levels of trace minerals are excellent and appropriate for most hays. Iron is low. Antioxidant levels are good, and it has better levels of B vitamins than in many other products. Note: The manufacturer’s suggested dosage is 2 oz., however, for our recommendation as a blood builder, we think 1 oz. is adequate for most horses.
Horse Journal staff report.