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: I know selenium is essential for hoof growth, but how do I know if my horses are receiving the proper amount?
By Kathleen Crandell
A: Finding just the right balance of nutrients can be challenging. For example, too much selenium causes alkali disease, or seleniosis, while too little may cause muscle problems or white muscle disease. But how do you know where your horse stands on the selenium front?
According to a presentation at this year’s Australasian Equine Science Symposium, some New Zealand horses maintained on pasture had selenium blood levels below the laboratory’s normal limit, yet appeared completely healthy.
Many parts of the world, including regions of the United States and New Zealand have low soil selenium levels. This translates into reduced levels in forage, which is the primary source of selenium for horses that are maintained on pasture or fed hay-based diets.
To determine selenium levels in horses maintained on pasture in New Zealand in healthy, adult horses, Erica Gee, a senior lecturer at Massey University, and colleagues measured monthly selenium levels for 1 year. They found:
All horses had low blood selenium concentrations over the study period. Average blood selenium levels were 342 nanomoles per liter, which was approximately 5 to 10 times lower than the normal levels.
All horses appeared healthy during the study period, despite low selenium levels.
The levels of selenium in pastures varied from month to month, and supplemental hay was also low in selenium.
According to the New Zealand researchers, it is possible that dietary vitamin E levels in green pasture may protect horses against the low dietary selenium levels found in pastures and forage. This is because the two nutrients are known to compensate for each other in times of low supply.
One point to ponder: The “clinically normal” appearance of the horses that were included in the study may not be a sufficient measure of what damage may be occurring on a cellular level from a lack of selenium, particularly on a long-term basis.
More in-depth studies on immune function and muscular integrity are needed to determine whether there are truly no detrimental effects of low selenium intakes in horses. The New Zealand scientists assure us that there is on-going research on this topic.
To combat potential dietary deficiencies in horses, commercial feeds frequently contain supplemental selenium. As always, consider all forages, feeds, supplements and mineral blocks when assessing your horse’s overall diet. This will ensure that dangerous nutrient excesses are not reached when attempting to only prevent deficiencies.
If selenium levels are a concern, feed a powdered supplement that contains a proven blend of antioxidants, including selenium and vitamin E. Because selenium nutrition is linked with vitamin E, consider a natural vitamin E supplement for horses that do not have access to fresh forage. Water-soluble, natural-source vitamin offers the greatest antioxidant advantages for this nutrient.
Kathleen Crandell is an equine nutritionist for Kentucky Equine Research. Located in Versailles, Ky., the firm is an international research, consulting and product development firm working in the areas of equine nutrition and sports nutrition.
Hoof Nutrition Intelligence is brought to you by W.F. Young Co. (Absorbine).
Like many significant achievements, Absorbine® grew out of humble beginnings—and through the tenacity of someone willing to question the status quo. In this case, it was a young woman in late 19th-century Massachusetts: Mary Ida Young. Her husband, Wilbur Fenelon Young, was an enterprising piano deliveryman who relied on the couple’s team of horses to make deliveries throughout the Northeast. Inspired by Mary Ida and Wilbur’s vision, Absorbine® has continued to add innovative products throughout the years — products used every day by horse owners around the world. Which is why, since 1892, we’ve been The Horse World’s Most Trusted Name®.
Click here to read Part 1 of the November 15, 2016 installment: What diet changes do I need to make with a horse suffering from endocrine laminitis?