Ask the Vet: Nutrition

Answered by Lydia Gray, DVM, MA, SmartPak Equine
Courtesy of AAEP

Question: Can you advise me on hemp oil and hemp meal for my horses?

Answer: The good news is that hemp (Cannabis sativa) is a nutritious agricultural crop, providing a complete essential amino acid profile, healthy fats, and generous servings of many vitamins and minerals. It’s also popular as bedding for horses because it’s less dusty and more absorbent than some other options. Hemp is a sustainable plant that’s been cultivated for use for thousands of years around the world.

The bad news is that in the US, federal agencies and laws do not recognize the difference between hemp and its cousin, marijuana, which is the same genus and species but a different variety. So right now in this country, it’s not practical to rely on hemp-based products as a regular source of nutrition for horses since, at the federal level, large-scale hemp production is not permitted. Hemp import with permits is allowed – that’s why you see food, oil, and fiber products — but the laws are still being sorted out between state and federal governments regarding the raising, processing, and selling of hemp as a commercial crop.


Question: What is the right amount of hay to feed an adult horse per day? I have two Thoroughbreds that weight 1,000 and 1,200 lbs. Both are in their mid-teens in age. I typically put out a 40 lb bale of timothy/alfalfa in the morning and the same at night. Is that about right or is it too much?

Answer: Let’s take a look at the math first, then address other aspects of feeding horses since equine nutrition is both a science and an art. The rule of thumb is that horses should have at least 1% but preferably 2% of their body weight each day in forage (hay or pasture). That means:

–Your 1000 lb horse needs between 10 and 20 lbs of hay each day
–Your 1200 lb horse needs between 12 and 24 lbs of hay each day

Together, the horses need between 22 and 44 lbs of hay each day. If you’re putting out a 40 lb bale twice a day, on the surface, this sounds like twice as much as your horses need (i.e. 80 lbs of hay a day). HOWEVER, there are several factors that can change the basic math or contribute to more hay being required to maintain a healthy weight:

1. Thoroughbreds are known to be “hard keepers” with a metabolism that can burn up calories quickly, so it doesn’t surprise me that two Thoroughbreds can put away this much hay

2. As horses age (and yours are in their mid-teens), some begin to lose their digestive efficiency, requiring more calories and other nutrients just to stay at the same weight and energy level.

3. Extra hay is exactly the right thing to give to help horses stay warm in the winter, so during the cold months, additional flakes are an excellent idea.

4. Horses in work require additional calories and reaching for hay to provide these is another great strategy.

Now, 80 lbs of hay/day between two horses still seems a little on the high side to me, especially as part of the hay is alfalfa (what we call “ice cream” for horses in the Midwest!) and is not to be fed free-choice. Only grass hay should be available ad lib or 24/7. Are the horses wasting a lot of it? If so, then you may want to invest in an all-day hay bag or some kind of hay feeder that both protects the hay from being stepped on/laid on/defecated or urinated on AND slows down the rate of eating. There are more and more small hole hay nets and other devices to choose from every day. Just be sure to select one that is safe for unsupervised horses turned out in a group situation, like it sounds yours are.

My final word on the subject is: don’t be pigeon-holed by the numbers. If your horses look great and feel great on the amount of hay you’re giving them, then ignore what the textbooks say as long as their body condition score is close to the ideal of 5, you’re confident their diet is otherwise complete and balanced, and their annual veterinary exam pronounces them in great health!