Vitamin A Deficiency in Horses

Seasonal changes and how they can increase Vitamin A deficiencies

As horse owners, we strive to provide our companions with the best care possible. Every decision we make from the veterinarian and farrier to feed and hay reflects our care and concern for our horse’s health. Even with the best care, nutritional deficiencies can appear.  Vitamin A deficiency in horses is reportedly on the rise in the US, so I wanted to write about what it is, what might be causing it, and how our product can support healthy Vitamin A levels.

For many owners, it’s a challenge to spot even the most common nutrient deficiencies in horses. Most deficiencies are sub-clinical, which means there are no visual signs or symptoms that tell us that something is amiss, like lameness, an abscess, or an episode of colic does.    

Old and very young horses are at the greatest risk for nutritional deficiencies.  Old horses may have difficulty chewing coarse hay, and young horses are born deficient and rely on their mother’s milk for nutrition.  If the mare is deficient, the foal will also be deficient.

Other factors that increase your horse’s risk include:

• All-hay diet
• Nutrient-deficient soil
• Limited pasture access
• Around-the-clock stall confinement

I have never met a horse owner who is not aware that the quality of hay they feed to their horse is important.  Likewise, I think we would all love to provide our horses with access to a lovely mixed-grass pasture year round.  Unfortunately, what we want is not always affordable let alone available, and even when it is, a horse may still be lacking in important vitamins and minerals due to deficiencies in the soil.  There are several variables that affect the quality and nutrient content of your pasture and hay, many of which are beyond our control.  These include:

• Climate
• Available water and the source of that water
• Soil fertility due to land use and ineffective management practices
• Soil content
• Growth stage of pasture

So, what is Vitamin A and why do horses need it?  It is important to note that Vitamin A is not directly found in plant sources; instead, the horse converts beta carotene from fresh and green grass to Vitamin A.  Vitamin A is fat-soluble, which means it requires a source of fat to be absorbed.  This fat is available in fresh grasses. Once in the horse’s bloodstream, “A” travels to where the body needs it.  If there is no need for it, the horse’s body stores it for future use.  

Vitamin A supports:

• Vision
• Reproduction
• Immune function
• Synthesis of protein to keratin (hoof/hair health)
• Bone growth
• Mucous production

What are some signs of a Vitamin A deficiency in horses?

• Infertility
• Impaired immune function
• Chronic lameness
• Impaired red cell function
• Joint pain
• Night blindness
• Dull hair coat
• Weight loss
• Decreased appetite
• Brittle hooves
• Tearing eyes  

How much beta carotene does a horse need? 

The NRC (National Research Council) has determined that a 1,000 lb. horse in light or no work needs approximately 14,000 IU of beta carotene each day.  Exercise level, age, growth, and pregnancy all increase the requirement, sometimes dramatically. I have specified beta carotene very deliberately because it is possible to cause toxicity by giving your horse too much Vitamin A, which is not the case with beta carotene.  

Most commercial feeds add Vitamin A instead of beta carotene.  Look at your feed bag to determine how much your horse is receiving and in what form. If the feed manufacturer uses a synthetic form of A, your horse is likely only absorbing approximately 10% of that nutrient. You can add foods rich in beta carotene to increase your horse’s Vitamin A intake without concern because your horse will eliminate any excess in their urine, but it is always wise to consult with a veterinarian or equine nutritionist prior to making significant dietary changes so that you do not inadvertently create another problem in another body system.

Our carrot chia products

Our Carrot Chia products are not meant to treat or cure vitamin A deficiency in horses.  They do, however, provide 2,100 IU of bioavailable beta-carotene and the fat necessary for your horse to properly utilize that nutrition, all in an easy-to-feed format of your choice.   

If your horse is on a restricted diet with little or no access to fresh grass, we recommend that you consult with your veterinarian or an equine nutritionist to determine if Vitamin A supplementation would be good for your horse. Making dietary changes for your horse should always be done in consultation with an equine health care professional to avoid having our good intentions go awry.