VITAMIN C for your OLDER HORSE (and maybe your dog/horse with bladder issues…)!

I will start by saying that I am not a vet… so what I’m writing here is my experience and I’m not suggesting you do anything before consulting your vet.


Scouty is our female mastiff.  Right now, she is 5 years old.  Approximately 2 years ago, she became lethargic – and was licking her private parts constantly.

I took her to the vet.  They said that she checked out fine.


Scouty continued to lick her girl parts, too often.

Well, I’m a girl who suffers from bladder issues.  Most of us know how awful a marginal bladder infection can be… not to mention one in full force… So, I got the hit that maybe Scouty had an undetectable bladder infection.

On a hunch, I crushed up a few large dose (1000 mg) chewable vitamin C pills and put them on her food, twice a day for 3 days and then I lessened the dose for the next several days.

Voila.  No more licking.  None.  And, she perked up!!

Since that day, I’ve been giving her a 500mg chewable Vitamin C pill every morning.  She has never licked herself  since.  And, she is a MUCH happier dog.

As an aside, I sometimes will use EmergenC as well.  I cut open a packet and put it on her food with water.

Scouty and her brother when they were puppies.

HOW ABOUT NORMA JEAN?… She has bladder issues, too.

So a while back, Norma Jean (my 25 year-old donkey) had remnants around her girl parts that had crusted.  I noted that I was washing off this ‘crust’ for a few days in a row.  Not good.  Also, she was tender on her kidneys.

The vet came out.  He said that she had a urinary tract issue and gave us antibiotics.


Well, when I saw the crusts again, I looked up ‘Vitamin C in older equines’.  The literature says that young horses manufacture Vitamin C from their food.  But older horses lose that ability.


And it said that Vitamin C is water soluble so excess is flushed out.

Hmmmmm again.

I decided to give Norma Jean some crushed up Vitamin C to see if it helped her.

After 2 days, the crust was gone.

So, now I give her crushed, large dose Vitamin C in her bucket.  (Dodger, too.  He is 36.)

Norma Jean.


Below, I have several articles written about Vitamin C in equines.

–The first states that horses make their own so you don’t have to supplement.

–The second speaks to equine bladders… and Vitamin C

–The third article speaks to the need for Vitamin C in older horses.


CLICK IMAGE to go to the original article

Information on Vitamin C

The main function of Vitamin C is as an anti-oxidant. This means that it works to prevent oxidation, or free-radicals destroying cells.

Research is lacking when it comes to determining how much C is found in common feedstuffs. In fact, C concentrations in typical horse feeds is unknown.

What is known is that the horse is able to synthesize C from glucose. Based on a number of studies, it is currently assumed that the horse meets his entire C need by manufacturing it in his own body, meaning he does not need an outside vitamin C source.

It also appears that C deficiency and toxicity are of very little concern in horses…which is good news for us owners!

Vitamin C Deficiency

Scurvy, which is characterized by tiredness, rash on the legs, and bleeding gums, is the classic sign of vitamin C deficiency. However, scurvy has never been reported in horses.

Even though scurvy has never been reported in horses, a few studies have linked low ascorbic acid blood levels with other diseases.

It is important to realize that these studies have simply linked the two…as of yet, there has been no determination as to whether or not it is a cause and effect relationship.

For example, it could be something completely different that is causing both the low ascorbic acid blood level AND the disease — in which case supplementing to increase the ascorbic acid blood level would not get rid of or prevent the disease.

These diseases include strangles, acute rhinopneumonia, increased wound infections after operations, and decreased performance levels.

Vitamin C Toxicity

Even more good news about C…vitamin C toxicity has never been reported in horses!

In fact, a toxic level hasn’t even been established in most domestic animals. Since C is one of the water-soluble vitamins, this is not really surprising, as excess is simply flushed out of the body.


Click image to go to the original article.

Balance is relevant to many aspects of horse care and management—for their feet, effective riding, nutrition and body condition, and of course for pH (a measure of acidity or alkalinity), electrolyte, and fluid levels. Of those, the pH or degree of acidity of specific environments and fluids within the body and electrolytes must be maintained within very narrow parameters to keep your horse healthy.  A pH measure of 7 indicates a neutral solution such as distilled water whereas values below 7 are considered acidic and those above 7 are referred to as basic or alkaline.

One place where pH is particularly important is the urinary tract. Because equine urine normally has a basic pH (more alkaline than acidic with pH greater than 7) and is high in minerals, some horses are at risk of developing stones in their bladders, called uroliths, especially if their diet is high in minerals.

One way to prevent uroliths is to acidify the urine (i.e., decrease urine pH). As easy as it sounds, it’s actually quite tricky. According to a group of German researchers*, hay and feeds containing hay (green fodder) are known to stabilize urine pH, making it difficult to acidify the urine when desired. What isn’t known, however, is what exactly makes hay such a poor urinary acidifier.

The researchers fed four ponies six different diets, either with or without additional urinary acidifiers to better establish how those diets impact urine pH. They found that a variety of diets were capable of acidifying the urine. The most impressive decrease in pH, from 7.8 to 5.2, occurred when the ponies were fed straw or extruded straw with a urinary acidifier (ammonium chloride, methionine, monocalcium phosphate). In contrast, any diet—even those containing urinary acidifiers—that included fresh or preserved green fodder could not be acidified. Urine pH remained above 7.

The take-home message of these findings is not to recommend a diet of straw and urinary acidifiers for horses at risk of uroliths, but simply to bring attention to the fact that adding a urinary acidifier to a horse’s normal diet might not produce the desired result. In addition, many common urinary acidifiers are unpalatable (such as ammonium chloride) or ineffective unless very large doses are administered. For example, 1-2 grams of vitamin C per kilogram of body weight is equivalent to 500-1000 grams of vitamin C daily–that’s a lot of 1-gram tablets! Vinegar is not widely deemed an effective urinary acidifier, either. More research in this area is needed to find effective and palatable solutions to this clinical issue.

*Foren, G., J. Fritz, N. Dillitzer, B. Hipp, and E. Kienzle. 2014. Fresh and preserved green fodder modify effects of urinary acidifiers on urine pH of horses. Journal of Animal Physiology and Animal Nutrition 98:239-45.


CLICK IMAGE to go to the original article.

As if aging isn’t hard enough! Creaky joints, sagging backs, loose teeth, increased infections, poor digestion, and embarrassing gassiness — just a few of the problems associated with getting older (for your horse, not you!). But what was once a given in youth, now turns into a deficiency – vitamin C must now be added to the diet. You see, young horses are able to produce all the vitamin C they need for every-day health. This is why you typically do not see it added to commercially fortified horse feeds. But as horses get up in years, they are less able to manufacture vitamin C. Decreased liver function is the main reason, but it can also be due to a decline in hindgut microflora and an increased propensity for pituitary dysfunction.

Why is vitamin C so important?

 It prevents oxidative damage to your horse’s tissues and organs. In other words, it is an antioxidant. Antioxidants donate electrons to highly volatile, damaging molecules known as free radicals. Free radical production is accelerated during any type of physical or mental stress, muscle and joint inflammation, allergies, illness/injury, or exposure to toxins and pollutants. But once free radicals receive their missing electron from vitamin C, they are neutralized – calmed down – and are no longer harmful.

Vitamin C has two other major roles

 While its antioxidant capability is paramount to your horse’s overall health, vitamin C protects your horse in two other significant ways:

  • Collagen synthesis. Collagen is a protein that creates a matrix within bones and joints to which minerals and other substances can attach. It is also part of connective tissue and maintains blood vessel integrity. Therefore enough vitamin C is important for keeping bones and joints healthy, reducing tooth loss, as well as preventing ruptured capillaries than can lead to abscesses.
  • Natural antihistamine. Horses that suffer from respiratory or skin allergies will benefit from additional vitamin C. As an antihistamine, it reduces the histamine response, making your horse more tolerant to allergens and hence, more comfortable.

Finding the right supplement

 Vitamin C is known as ascorbic acid. It can be derived from food or flowers (e.g., rose hips) or can be made in a laboratory. Regardless of the source, they are chemically identical, so there is no need to spend more on natural vitamin C. Ascorbic acid comes in several different forms, all similar in absorption and efficacy:

  • Buffered mineral acorbates. These are less acidic. Horse preparations typically mix vitamin C with calcium or magnesium to ease digestive upset. These forms may be beneficial for horses with digestive ulcerations or chronic diarrhea.
  • Ester-C. Ascorbic acid is chemically esterified (attached) to calcium. It also contains vitamin C metabolites that may be better absorbed, and easier on the digestive tract lining. There is little scientific basis for this but in cases where a horse is suffering from gastric ulcers, it may be helpful.
  • Ascorbic acid with bioflavonoids (such as quercetin, ruin, and hesperidins). This complex may allow for better vitamin C absorption. Bioflavonoids are also beneficial for respiratory allergies.
  • Ethyl cellulose coated ascorbic acid. This coating helps improve shelf life, especially when mixed with minerals that can promote oxidation.


Since vitamin C is water soluble, excess amounts are easily excreted in urine. Therefore, it is best to divide dosages between meals to avoid urinary losses. It also tends to be bitter-tasting, so less at one time will be better received.

I routinely recommend vitamin C supplementation for all horses in their late teens (unless they are grazing on healthy pasture for at least 8 hours each day). Start by adding 3 to 5 mg per pound of body weight per day. Once your horse is over 20, give him 10 mg for every pound of body weight. For more intense needs, the National Research Council (NRC) suggests an upper safe limit of 44 mg of vitamin C per kg of body weight. For an 1100 lb (500 kg) horse, this can be as high as 22,000 mg per day.

Protect your supplement

 If you have a container of vitamin C sitting in your hot barn, protect it from a cruel fate — keep it in a cool, dry place where the container is sealed shut. Refrigeration is fine. Purchase small sizes unless you are feeding it to several horses. Your supply should be finished within six months.

Remember, your older horse needs vitamin C to replace what he no longer produces on his own. Therefore, he should be supplemented indefinitely, for the remainder of his life.

Helpful supplements

If your horse needs vitamin C, consider the following:

  • Pure C (Vita-Flex) is pure ascorbic acid.
  • C-442 (Horsetech) is buffer, coated vitamin C for longer shelf life.
  • Ester-C (Med-Vet Pharmaceuticals) offer esterified vitamin C to help horses with ulcers.



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