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21 Sep

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It has been reported that about 90% of poor performance cases can be attributed to lameness, either clinical (obvious lameness) or sub-clinical (lameness not readily visible under normal exam conditions).  

It is logical that noticeable lameness causes horses to perform below their potential, but sub-clinical lameness can be an even greater problem.  Clinical lameness can be quickly recognized, investigated, and corrected.  In horses with sub-clinical lameness, however, the disease process remains undetected and untreated.  It is allowed to progress, resulting in irreversible damage to the structure of joints, secondary lameness, muscle pain, behaviour problems, impaired performance and economic losses.

Early diagnosis and intervention can stop minor problems from deteriorating, preserving long term soundness and maximizing performance.

Most of my clients present every horse in their stable, on a regular basis, for physical exams.  This enables the identification of subtle or sub-clinical problems.

Clinical Lameness

A horse is clinically lame if it has a visible limp or asymmetric gait.  It will try to lift its weight off the sore leg and place more weight on the sound legs.  A “head-nod” results.  (When the sore front leg hits the ground, the horse lifts its head up to shift weight to the back legs and off the sore front leg.  When the sound front leg hits the ground, the head nods down, loading that leg excessively.)  Sometimes, when a horse is very lame in a hind leg, the horse will nod its head down to shift weight onto the front legs and off of the hind legs. Sometimes, a horse with a sore hind leg will lift its pelvis higher on the lame side (called a hip-hike).

Lameness is only visible (clinical) when one leg is relatively more painful than the opposite leg.  Both legs can be sore, but as long as the pain is unequal, the horse will protect the more sore side and the head nod will be evident.  There are various degrees of clinical lameness ranging from an inconsistent or almost imperceptible limp to an inability to bear any weight at all on the affected leg.

Sub-Clinical Lameness

Sub-clinical lameness is lameness that you can not see under normal conditions.  Bilateral lameness, lameness in all four legs, and lameness that only manifests under extreme stress or speed is sub-clinical.

Bilateral lameness is often inapparent.  If a horse’s legs are equally sore, he will not favor one and will not limp.  Instead, he will shorten his stride, develop back or muscle pain, perform below expectations, make breaks, “stop” in the last part of a race, refuse jumps, make mistakes of stride in dressage tests, tie up, blow after working, have a longer than normal recovery, or develop behaviour problems such as pulling, bucking, and rearing. Many horses just develop a poor attitude to work. “Bleeding” or Exercise Induced Pulmonary Hemorrhage and dorsal displacement of the soft palate (“flipping the palate”) are common presenting complaints.

Some lameness only shows up at high speed or under extreme stress such as in the last part of a race.  Some will manifest only with a rider or doing particular movements like flying changes or lateral work.  Some will appear on a lunge line or on particularly hard, soft, or irregular or unstable footing.  Some only present in the cart and not in-hand. Once again, these lameness cases are often presented for performance and behavior problems, back, or other muscle pain.

Lameness In My Practice

In my practice, the majority of horses presented for lameness or performance problems have one or more of the following:  1) foot pain including sole bruises, abscesses and, corns; 2) arthritis (joint inflammation); 3) tendonitis (a bowed tendon) or; 4) suspensory desmitis.  Bowed tendons and suspensory desmitis present as clinical lameness and there is obvious pain, heat, and swelling.  By far, the most common sub-clinical lameness or performance problems involve joint and foot pain.  In many cases these conditions are both present.


Arthritis is a term that means “joint inflammation” (arth-joint, itis – inflammation).   Inflammation occurs in joints when they are placed under stress in excess of what they have adapted for.  This stress can be sudden and severe (stepping in a hole, taking a bad step on poor footing, or some other accident), or it can be repetitive and low grade (wear and tear).

Horses are designed for eating grass and running away from the occasional predator.  They are designed to land flat on their feet, load bones and joints evenly from side to side, and break over the middle of their toes. Unfortunately, not many horses have perfect conformation, perfect hoof balance, or work on perfect footing so stress is not distributed evenly.  They are not born readily adapted for repeatedly pulling a sulky or carrying a rider around a track at top speed or over jumps.  The idea behind training is to gradually increase the stress on a horse causing them to adapt to the work we expect them to do.  In short, training a young horse or training a more mature horse down to race after a spell is constantly placing their joints under stress they have not adapted to. Therefore, inflammation occurs on an ongoing basis in most horses in training.

Joints are made up of the ends of two or more bones which are covered with cartilage and joined together by the joint capsule.  The joint capsule is lined by the synovial membrane.  This membrane is very important as it produces the synovial fluid (joint fluid) that lubricates, protects and nourishes the joint cartilage.  In a healthy joint, synovial fluid is thick like syrup.  It is replaced every 24 hours or so on an ongoing basis.

Inflammation in joints begins with synovitis and capsulitis. In synovitis and capsulitis, enzymes are produced that breakdown joint fluid, making it thin and watery.  It no longer lubricates and protects the joint properly.  With a lack of nourishment and lubrication, the cartilage surface of the joint becomes abraded.  Over a more extended period of time, the sub-chondral bone (bone underneath the cartilage in the joint) begins to change.

Over time, then, synovitis and capsulitis will progress to sub-chondral bone disease and osteoarthritis.  This entire process is referred to as arthritis or degenerative joint disease (DJD).  X-rays only show bone, so relatively advanced DJD is the first stage that is reliably visible on radiographs.

It is much better to identify and treat joint problems before they are visible on radiograph. If inflammation is stopped, the synovial membrane will make new fluid that will remain thick and sticky.  If the breakdown of synovial fluid is the only damage that has occurred, a completely normal joint environment will be restored.  If the cartilage surface has been damaged, some treatments can provide repair, and a normal joint can be created.  Once bone has changed, however, it cannot be reversed.  Thick, healthy joint fluid will stop rough bones from rubbing together in the joint, and DJD will be arrested, but a truly normal joint cannot be restored.


Since the primary goal of therapy is to stop inflammation and to stop the progression of degenerative joint disease, the treatment of choice in most cases is intra-articular cortisone.  Cortisones are very effective anti-inflammatories, and remain the treatment of choice in human medicine for intra-articular therapy.

There are several different types of cortisone that can be used in joints.  Controlled studies have shown that all cortisones reduce inflammation and that most improve the health of joint cartilage. Triamcinolone (Vetalog, Kenalog, or Kenacort), Isoflupredone (Predef 2X), and Betamethasone (Celestone Soluspan) have all been shown to be safe or beneficial for joint cartilage. Methyl Prednisolone (Depo-Medrol or Vetacortyl) is likely safe in low doses, but can impair the healing of joint cartilage if given too frequently or in large amounts. Triamcinolone has been anecdotally linked to laminitis, but the relationship has not been confirmed.  It has never been caused in healthy horses at normal doses and has not been caused experimentally using doses up to six times those commonly used.

NSAIDS like Bute and Banamine tend to kill pain better than they reduce inflammation in joints, so they are not a sufficient treatment in most cases.

Once inflammation is resolved and DJD is arrested, the second goal of therapy is to restore a normal joint environment.  Hyaluronic acid (HA) is a building block for thick joint fluid, so supplementation may be useful.  HA can be administered directly into a joint, however, it does not work very well if there is a great deal of inflammation present and it is generally used in joints along with cortisone.    Studies have shown that IV HA (Hyonate or Legend) is as useful as intra-articular treatments, and recent research indicates that oral administration of HA may be helpful.

If cartilage damage has already occurred, then it can be beneficial to treat horses with a product that can stimulate joint repair or provide the building blocks for cartilage repair.  Adequan, Glucosamine Sulphate, and Pentosan may be used for this purpose.  Glucosamine Sulphate supplementation increases the body’s production of hyaluronic acid as well.

Additional medications are available to treat arthritis including some homeopathic treatments that reduce inflammation and stimulate joint healing.  The homeopathic medications I mainly use are Traumeel and Zeel.

Finally, the third goal of therapy is to prevent reoccurrence of lameness.  Adequan, Glucosamine, or Pentosan can be given regularly to reduce inflammation and repair cartilage.  They can keep inflammation at bay in sound horses in training, and they can increase the interval between joint injections in horses with lameness problems.  Optimal shoeing and good footing are of utmost importance, and adjustments to the training regimen may be helpful in some cases.


  • The products of inflammation are enzymes that damage the joint.
  • Early diagnosis and treatment will preserve normal joint structure and function maximizing long term soundness and performance.
  • The first goal of therapy is to stop inflammation and, therefore, to stop the progression of degenerative joint disease.
  • The second goal of therapy is to restore the most normal joint environment possible.
  • The third goal of therapy is to prevent reoccurrence of the problem.3

Dr Corinne Hills, Pro-Dosa International Ltd., 34 Ryan Road, RD 4, Pukekohe, New Zealand.

Phone: +64 27 238 8482 Email: Website: FB: ProDosaBoost

18 Sep


Now that you have supplements sorted out, what about feeds? Comparing prepared feeds is just about as confusing as comparing supplements, but with less math, you’ll be pleased to know.

Somehow, until the mid-2000’s, I managed to go through life blissfully unaware of the complexities of choosing prepared feeds. I worked in racing stables, and all my clients fed a prepared racing formulation to their racehorses. Though some added bits and bobs, such as barley, supplements, and oils, they didn’t really ask me that many questions about their basic feeding regimens. Then, I set up a mobile equine veterinary practice in Al Wathba, Abu Dhabi, UAE. It was a pretty interesting place where I met a broad range of people, from nearly every background and nationality, with a wide range of horses, in a whole array of different management situations, doing every possible activity. To add to the rich tapestry of experiences, I’d often find the entire equine and human smorgasbord at a single stable.

This complex set-up, the need for refrigerated feed rooms (Outside temperatures soar to 45-50 degrees Celsius, and inside it would be even hotter. Nutrients aren’t very stable when they are heated excessively, and moulds etc. do really well.), and the ordering systems for some feeds meant that many of these stables had an entire pallet of feed, for each type of horse, in each activity. This, of course, cost a fortune and took up way more space than anyone really had in their refrigerated feed rooms. To top it all off, the forages available (…and there is no grass…ever), are variable in quality throughout the year. Some had imported hays that were expensive but quite nice for at least part of the year, and some had the highly variable and often not very nutritious local hay. This meant that feed costs and logistics were of major concern to virtually all of my clients. They pretty much all asked me about the prepared feeds they were feeding and asked about simplifying the whole ordeal. (They also asked me about the value of dates and camel’s milk in the equine diet which I looked into, being open minded and all. I was a bit impressed with camel’s milk in particular and would quite like a dairy camel at home in NZ… I’ll tell you about what I found out sometime…but I digress…)

In order to answer all the questions about feeds I was getting, I took myself off to the camel souk (a market at the camel racetrack where, ironically, most horse products can be found) and had a look at the myriad feed stores. There were feeds from every company I could think of, from every country in the world. It would take a lifetime to sort through the entire selection, so I started by looking at the ranges of feeds from each of the brands that my clients were feeding.

I found an enormous number of feeds that looked pretty similar. I had a hard time telling apart…
1. the different formulations from the same company as well as
2. the formulations from different companies, all of whom had similar feeds and ranges as the others.

The bags were different, but what was in them was pretty much the same. They all had very similar ingredients, in very similar, but not quite identical, proportions. I couldn’t really tell them apart, and I’m guessing, without referring to the names on the bag, like Racehorse Mix or Cool Feed, you would struggle to tell the difference too.

Before we begin sorting out how to compare different feeds, you should know some feed basics.

It is important to know something about the volume a horse will eat in a day. Most horses will eat between 2-3% of their body weight per day in feed, including hay, grass, and concentrate feed. When horses are working very hard, their feed consumption is generally at the bottom of the range, and for that reason, they can’t normally meet their protein and energy requirements by eating grass or hay. A concentrated form of those nutrients must be fed.

Since a 500kg horse in hard work will only eat about 10 kg per day, all of the nutrients required must be fed in that volume of feed. It is also important to keep in mind that the larger part of the ration should be provided in the form of roughage as that is what keeps the gut moving properly and the flora healthy. For this reason, you really can’t just feed a horse 10kg of a concentrated feed and nothing else.

So, before we begin to talk about feed, then, we have to talk a bit about hay and grass. It is important to know something about the quality of your forage. You can use average values for the nutrient content for each plant species to get a rough idea of what your hay or grass is contributing to your horses’ daily rations, but an analysis provides more accurate information. You may be able to ask your feed supplier for an analysis of the hay they sell, or you may send samples of your pasture grass and hay to a laboratory yourself. There are also packaged hay products available in most parts of the world. These are labelled with nutritional information, just as concentrate feeds are, but there is one catch you may not be aware of. Nutritional information can be listed on a “Dry Matter Basis” or on an “As Fed” Basis. “As Fed” is pretty self-explanatory. Nutrient content is measured in a kg of the forage in the form that you’d feed it. When you feed 1 kg of it, you will be feeding the feed, moisture and all. “Dry Matter Basis” means that the nutrients are listed as a percentage of just the dry component of feed that is left when the moisture is removed. When you compare feeds, you will need to calculate the amount of nutrients on an “As Fed Basis”, as when you actually feed your horse, you will be feeding the feed, moisture and all. For example, if a packaged forage lists their nutrient content on a Dry Matter Basis, but the moisture content is listed 50%, 1kg of that forage contains only 500g of dry matter and 500g water. If the label says there is 20% protein on a dry matter basis that is the same as saying there is 200g of protein per kg of dry forage. When you actually feed it to your horse, however, you will be feeding the forage along with an equal amount of moisture (water). To get 1 kg of dry matter from that feed, therefore, you have to feed 2 kg. If 1kg of the feed, on a dry matter basis has 200g of protein, when the 1kg of moisture is added back into the calculation, there is only 200g of protein in 2 kg of the feed as fed. On an as fed basis therefore, the feed is only 10% protein or 100g of protein per kg of feed. In this example, content “as fed” = 20% protein on a DM Basis x 50% moisture/100%

To convert from dry matter basis to as fed basis, multiply by the percentage moisture and divide by 100.

With dry hays, the moisture content is less than 10%, so the “as fed” content is almost the same as the content on a dry matter basis. Grass, in contrast, in about 90% water, so the as fed content is very different than the content on a dry matter basis.

Depending on the maturity and conditions at harvest as well as the type of hay, protein content can vary from well under 10% for poor grass hay up to 18-20% or so for nice Lucerne (alfalfa) hay, chaff, or cubes. The poorer the hay being fed; the greater the importance of the hard feed.

Horses need energy, protein, calcium balanced with phosphorus, vitamins, and minerals including salt. All horses need these same nutrients, but those working hard, growing, in foal, and lactating, need more of them. You can find nutrient requirements for your specific horse by looking up NRC or by asking your feed supplier, nutritionist, or veterinarian. I talk about some of the requirements later in this post.

When nutritionists balance rations, they start by looking at the protein and energy content (and costs) of the feed ingredients available. Then, once they have decided on the main components, they look at vitamins and minerals etc. which can be added and adjusted to achieve optimal balance while considering the contribution of the main components of the feed. So, just as if we were formulating a new feed or ration, we will start with energy and protein.

The main differences between the varieties of commercial preparations include…

1. The concentration of nutrients, especially energy and protein, and
2. The specific form of energy and protein provided.

For example, spelling mixes have lower concentrations of energy and protein than racehorse mixes. This is generally because most feeds are designed to be fed at a rate of 4-6 kg per day. A spelling horse will need to eat 5kg of a spelling mix to meet its lower requirements for energy and protein, and a racehorse needs to eat 5kg of a racing mix to meet its needs. In fact, if the spelling horse ate the racehorse mix, it could just eat less of it to get the required amount of nutrients.

Protein Quantity

For this section, remember that there are 1000 grams (g) in 1 kilogram (kg). I’m sorry, but I didn’t promise there wouldn’t be ANY math; just less of it.

Protein is often expressed as a percentage on feed bags, and horsemen tend to think of protein requirements in terms of those percentages. (ie. Racehorses need 16% protein and spelling horses need 10%.) In fact, protein requirements are in grams per day and not in percentage at all. 100g of protein could be found in 100g of a 100% protein feed; 1kg of a 10% protein feed; or 10 kg of a 1% protein feed. So, the percentage of protein in a feed is only important when you consider how much of that feed your horse will eat.

Horses in hard work need about 1000-1500g, particularly if they are also growing.
Spelling horses need about 750g
Ponies (adult weight 200kg) in hard work need 350-450g

The average 2-3 year-old racehorse in intense work needs 1000-1500g of quality protein per day. As I already said, a horse in hard work will eat 2% of their body weight per day. As a result, a racehorse could be expected to eat only about 5kg of concentrate feed and 5kg of roughage. If the average protein content of hay is 13%, then about 650g of protein can be derived from hay. The rest has to come from the concentrate feed.

A concentrate feed of at least 13% protein fed at a rate of 5 kg per day might be enough for the average horse, but some will need more like 850g of protein from their concentrate feed, and since that must be provided in 5kg or less feed, then the feed would have to be 17% protein to meet requirements. If it was 20% protein, the 850g could be fed in 4kg of feed, and the 650 would be provided in 3kg. That would allow that horse to eat a bit more hay, which has some benefits for the health of the gut.

Remember, don’t worry about the percentage of protein in the feed being high. If the percentage of protein in the feed is high, you will simply be able to feed less of it to meet your horse’s protein requirements.

Protein Quality

In order for horses to make proteins (which are the building blocks of muscle cells), 10 essential amino acids must be provided in particular ratios. (Essential amino acids are those that horses cannot synthesise and, therefore, must consume.) If even one of these essential amino acids is in short supply, protein production will stop. The amino acid, available in the lowest relative amount, is said to be the limiting amino acid. The excess amino acids (the ones in higher amounts than the limiting amino acids, that now can’t be used for protein and muscle cell synthesis in the horse) become waste products, resulting in increases in heart rate and load on the kidneys. For this reason, the best protein sources have the best essential amino acid balance, and as many of the amino acids provided as possible can be used for protein synthesis and muscle development in the horse.

Grains, like barley and oats, have some imbalances in the amino acid ratios, and as a result, only about 40% of the protein in an oat or barley-based feed will actually be useable by the horse to make muscle. In comparison, the ratio of essential amino acids in peas, lucerne (alfalfa), lupins, or soy allows for about 80-90% of the protein to be used. Make sure you consider, therefore, the type of protein provided in a feed.


Horses in hard work need about 26-35 Mcal of DE (Digestible Energy)
Spelling horses need about 15-18 Mcal of DE
Ponies (200kg mature weight) in hard work need 11-14 Mcal of DE

Energy requirements can often be met by pasture or hay in spelling horses, but for horses in hard work, it is necessary to feed a concentrated feed in addition to forage. Energy is provided in equine feeds in the form of carbohydrate (grains, corn, etc.) and as fat. Traditionally, oats and barley were fed as the primary energy source. They are a cost-effective way to provide energy, and some horses do very well on them. Some individuals, however, do not. Horses that suffer from a tendency to tie-up, those that have a tendency to founder, and those that colic are generally better avoiding grains.

Normal carbohydrate digestion starts in the small intestine. Starch is broken down to complex sugars, and the complex sugars are, in turn, broken down to glucose. Glucose is absorbed through the small intestine. Any starch or sugars that aren’t digested and absorbed by the time the digesta leaves the small intestine are dumped into the cecum and large intestine. That part of the gut, known as the hindgut, is a big fermentation vat. Bacteria in the hindgut work slowly on the digesta, breaking down roughage to molecules called volatile fatty acids that can be used by the horse for energy.

Horses’ guts, however, were never designed to process large amounts of starch, so the enzymes required for its digestion are produced in limited supply. Grains are very high in starch and sugar and can, therefore, pose problems for digestion. If large amounts are fed at one time, some starch and sugar pass undigested into the hindgut, making it’s environment more acidic. The beneficial population of bacteria can’t survive in an acidic environment, and when they die, they release endotoxins. Those endotoxins are responsible for problems such as colic, laminitis, and diarrhoea. In addition, undesirable bacteria are able to thrive, further disrupting the cecal pH and worsening the environment for beneficial bacteria and so on.

While the rule of thumb is to limit grain feeding to 2kg at a single meal, some susceptible individuals will not even tolerate that quantity at once.

In comparison, fat is a reasonably safe source of energy. While horses were not really designed to eat fat either, they do not seem to have problems with it. Researchers have found that horses tolerate as much as 10% of their diet as fat. For horses in hard work who may require quite a bit of extra energy in their concentrate feed, or for individuals prone to laminitis etc, look for a feed that has less grain and more fat. It can take muscles cells 2-4 weeks to adapt to fat as an energy source, so if you are switching a racehorse to a high fat, low soluble carbohydrate diet (low grain), try to do it when they are not racing in a week. Once metabolism adapts to fat, there is evidence of improved endurance, lower body temperatures, and a reduced incidence of tying-up, laminitis, and colic.

Vitamins, Trace Minerals, and Extras

Pasture and hay may not meet all of the vitamin and trace mineral requirements, even in spelling horses. These nutrients, in most cases, will need to be supplemented, either on top of a plain feed, or in the form of a prepared feed. I wrote about vitamin and mineral requirements as well as the need for balance between each of these elements in the first parts of this reading labels series, so I’ll just mention a few things here.

I generally prefer people to provide a prepared feed rather than mixing their own, unless they know a bit about nutrition or have had advice from a nutritionist. It is easy to get the balance wrong and cause more problems than you fix. Companies making feeds employ nutritionists and provide reasonably balanced preparations for you. I would go so far as to say that all feed companies refer to nutrient requirement standards when formulating their products. In reviewing the huge range of feeds available in the UAE and New Zealand, all I looked at appeared to meet the basic, daily requirements for fat soluble vitamins and trace elements when fed according to package directions. Some provided those nutrients in more bioavailable forms than others (see part 2 of our reading labels post), and I would certainly choose the feeds that include more bioavailable forms of nutrients, but most would be pretty acceptable.

Calcium and Phosphorus must be provided in the diet of horses in a 1.5-2:1 ratio. Commercially prepared feeds will all be pretty well balanced in this department, so you won’t have to worry about this much. In general, grains are high in phosphorus, while lucerne (alfalfa) is high in calcium. Be careful to get this right if you are mixing your own feeds or adding additional grains to prepared feeds.

I talked about most of the trace minerals in previous sections of this marathon post about reading labels, but I didn’t say much about selenium. NRC says that horses in hard work require 1 mg per day, and most nutritionists would probably agree that 3mg is a better dosage to aim for in the diet. The interesting thing about the requirements, is that horses really don’t have a requirement for elemental selenium (just plain, selenium). Their requirement is actually for the selenium containing amino acids, seleno-methionine and seleno-cysteine. This is important.

Selenium is described as having a “narrow therapeutic range”. What that means is that the amount that is toxic for horses is not that much more than the amount they require for normal health. This is also important to know.

Selenium can be provided in several forms. It is provided in feeds as sodium selenite, sodium selenate, selenium yeast, seleno-methionine, and seleno-cysteine. These forms have some fundamental differences. They are not all absorbed, used, and excreted by animals to the same extent. Selenium yeast is a form of selenium that is created when yeasts are grown in an environment with lots of selenium. The yeasts incorporate the selenium into their own amino acids, so the selenium in selenium yeast is actually provided as seleno-methionine and seleno-cysteine for the most part. So, you can consider the last three forms as essentially equal. They are organic molecules that the body is good at absorbing and using.

The sodium selenite/selenate molecules, on the other hand, are inorganic salts that are unpredictably absorbed and used by animals. Studies done about 20 years ago in dairy cows demonstrated that cows supplemented with the same, standard amounts of those forms of selenium in the same diets, ended up with very different levels of selenium in their blood. Some were in the normal range, and some were deficient. When the level of supplementation was increased to correct the deficiencies seen in part of the herd, others started to show signs of toxicity. The conclusion was that the ability to absorb and use sodium selenate and sodium selenite was very individual and quite unpredictable. It was recommended to measure blood selenium in each animal before deciding on the appropriate dietary amount of selenium to feed. When the herd was placed on organic forms of selenium instead, the absorption and use was much more uniform across all individuals in the population. I haven’t found a link to this study to post, but Alltech, a supplier of vitamin and mineral supplements, used this study in their promotional info in Canada probably 20 years ago, so you might have a look at their website for more details about selenium yeasts. Dr. Pagan from KER did a study that demonstrated much higher bioavailability of yeast-based selenium compared to inorganic forms, (link below) and many other researchers have demonstrated similar results with all the organic forms.

The other thing that is worthwhile noting is that inorganic selenium is not excreted very easily. If you end up with a low-grade toxicity, it can take months for the levels to drop back down to normal. If you feed a feed that has selenium in one of those forms, it’s fine, but make sure you have your veterinarian check blood selenium levels from time to time and follow their recommendations for supplementation. Please don’t sprinkle inorganic selenium on your feeds willy-nilly! More is NOT better in this case!

The moral of that story is… when you are comparing different feeds, try to choose one that includes selenium in an organic form. The chances of having normal blood selenium levels will be improved.

Finally, the end is near!

To summarize, evaluate your forage and determine how much additional protein and energy will be required from the concentrate portion of the ration.  Then, you can probably just pick a company that you like to deal with, as most have similar ranges.   Pick a feed from their range that has nutrients in a high enough concentration that your horses in intense work can meet their protein and energy requirements by eating no more than 5kg of hard feed so they can eat 5 kg of hay (or other forage) to meet fibre requirements and to maintain healthy gut motility etc.  Try to pick a feed that has a good quality protein, so pick one with a bit more soy, peas, lupins, or alfalfa, rather than just oats and barley.  If you want to avoid problems related to high carbohydrate diets, then look for higher fat diets with little or no oats and barley.   Finally, have a look at the trace minerals provided in the daily ration.  Pick a feed that has bioavailable forms of trace minerals in proper balance with each other.

Once you have selected a good quality, safe, and healthy feed, then you can probably feed it to most of the horses at your stable.  Spelling horses and smaller horses will need to eat less of it with more hay or grass.  Racehorses or broodmares etc will need to eat more of it.

Best of luck with choosing feeds. Remember… we are happy to help you read feed and supplement labels, and we are happy to do comparisons for you. Contact us via the website.


I thought I was finished. I celebrated being finished, in fact… and then I thought about product quality and

How do you know if the product you are looking at contains what is says it does; only a fraction of what it
says it has; or way more than it is supposed to have? And even more alarmingly, how do you know it
doesn’t contain contaminants that aren’t supposed to be there?

There was an interesting study presented at the AAEP (American Associate of Equine Practitioners), several
years ago, in which a number of nutraceuticals were analysed and their results compared with label claims.
Those products were found to contain anywhere from 10-200% of the active ingredients that they were
supposed to have. Apparently, this is a more wide-spread problem then you would think or hope.

To bring that home for you, many people will have heard of the tragic, fatal cases of selenium toxicity that
occurred a few years ago in a group of polo ponies fed a feed that was made with far too much selenium.
The manufacturer had simply made an error in calculations and had put a decimal in the wrong place,
resulting in 10 or 100 times the selenium being added to a batch of feed.

A few years ago, the trace-element, cobalt, made the news. Required for normal health in trace amounts,
excessive levels constitute a positive test. Several cobalt positives were investigated by racing authorities.
In some of the cases, injectable products were found to be at fault, but in one, a powdered feed
supplement, that contained cobalt levels far in excess of label claims, was implicated.

As racing authorities did not know how much cobalt could be fed before a positive test was produced, ProDosa International Ltd conducted a cobalt clearance study using commonly used feedstuffs. The results
were interesting, and you may wish to read them here. Following that study in 2016, cobalt was eliminated
from the Pro-Dosa BOOST formulation. Despite that, we still test our raw ingredients and finished product
for cobalt, to reassure horsemen and racing authorities that Pro-Dosa BOOST will never produce a positive

Almost everyone in racing will know of someone who has ended up with a caffeine positive as a result of
feed contamination, and I believe there was a recent case in European equestrian circles in which a feed,
contaminated with poppy seeds, resulted in a positive test and the disqualification of a prominent horse
and competitor.

So, how do you know if a product is manufactured safely and meets label claims?

This information frequently isn’t on the label, but it’s just as important as the ingredients list, so it’s well
worthwhile to make the effort to source the information. You could look for a statement on the website
about quality management, or you might have to ask the manufacturer some questions. Does the
manufacturer have a quality management program? GMP or ISO certification provides hard evidence of

Tip:  Be sure to ask every rep that visits your stable about quality management as they will almost certainly be the most readily available source for this information.  That will also be a simple way to separate the wheat from the chaff. Any rep that can’t talk competently about their company’s quality management program probably represents a company that doesn’t have one.

GMP stands for Good Manufacturing Practice, and this is a specific standard required for pharmaceutical
producers. It is, however, voluntary for feed supplement manufacturers. A generic version of good
manufacturing practice, abbreviated with small “gmp”, is a reference to a quality management system that
is not name-brand, government specified and inspected, GMP. It could be the same as GMP or it could be
applied to a non-standardised or less complete quality system.

Compliance with a name-brand GMP program ensures that quality is built into the product at the time of
manufacture and provides assurance that products are consistently manufactured from quality inputs; in a
safe and clean environment; by trained and diligent staff; using carefully defined procedures. It is a means
of giving consumers confidence that products meet the required quality standards, are safe, and are
reliable. A documentation trail that links starting materials, through the various manufacturing processes,
to the finished product confirms that dispatched product has been approved through quality control
measures. It also ensures that product can be tracked and recalled if any issues arise.

ISO9001/22000 refer to slightly different quality management standards that do not relate directly to
pharmaceutical production but that cover many of the same principles. They demonstrate a commitment
by management to food safety, and they ensure that consideration of potential hazards and critical
processes have been considered in the development of the product and production procedures.

If a company has either ISO or GMP certification, you can be sure that the supplements they produce will
be safe, secure, and generally meet label claims.

If a manufacturer lacks certification, it doesn’t mean they aren’t doing a fabulous job of quality
management. They might have a written statement about their commitment to quality management or
you might have to ask some questions to be sure. If at least some proportion of finished product
undergoes analysis for common contaminants, the concentration of active ingredients, and microbial
testing, it will likely be safe. If no testing is done, and the company doesn’t talk about product quality,
safety, and security, I’d worry.

FYI, Pro-Dosa International Ltd. is GMP certified by the Government of New Zealand, Ministry for Primary
Industries, Agricultural Compounds and Veterinary Medicines group. Our quality management system has
been in place since 2005, and it was originally developed along GMP, ISO22000, and ISO9001 standards.
The whole team is very proud of our standards, and we would be happy to tell you all about what we do, if
you really want to know.  Part 4 – Feed.

15 May

Download the PDF Article Here Think Again

The composition and balance of nutrients included as well as the safety and quality of each product is different, so buyer beware!

Recently, we have noticed a number of copy-cat “boost” products appearing in the marketplace. Some have chosen the same colours and package appearance or promotional text, and all have chosen a similar name and appear to have copied part of our formulation (the less expensive parts, anyway). None of these products have included the complete formulation contained in a Pro-Dosa BOOST, but they think you will be fooled by an only partially complete product that looks and sounds similar and sells at a lower price. I think, horsemen should think about why someone would do that.

It is said that the sincerest form of flattery is imitation. It does appear that some of our new competitors have recognised Pro-Dosa BOOST is of exceptional quality and composition, and they can’t compete with that. Instead, they hope to be mistaken for the same thing at a lower price. Since I didn’t make Pro-Dosa BOOST to be a cheap product with a large profit margin, I know they can’t make a similar quality product, any less expensive. They have to make a less-complete, poorer-quality supplement instead. While I suppose I should be flattered, instead, I am concerned about how many horsemen will think they are feeding my product, when they’ve bought a “copy-cat” by mistake. How many horses will be fed supplements that aren’t complete, balanced, or safe enough? How many people, feeding a copy-cat they think is ours, will think our product isn’t as good as it used to be when they don’t get the observable effects they have been accustomed to when feeding the original, tried and tested, Pro-Dosa BOOST, established in 2001?


In order to achieve optimal metabolism, performance, recovery, and health, it is necessary to provide a broad spectrum of nutrients, in bioavailable forms, in ideal balance with each other and with the cofactors necessary for their absorption and function. The doses provided must reflect the requirements of horses under stress due to travel, hard work, racing, competition, and illness, as the administration of only some of the nutrients required or feeding quantities below or above requirements may result in imbalances that actually impair absorption and function. With this in mind, I developed Pro-Dosa BOOST to provide complete, balanced, and bioavailable nutritional support.

Because I made Pro-Dosa BOOST for the stables I had worked for in my veterinary practice, for years, I didn’t make it with profit margins or easy marketing in mind. I made it to make a difference to my patients and to make things easier and less expensive for my clients, who were my friends and not just face-less consumers, I didn’t know. I looked up the nutrient requirements published by NRC, and then I looked up other nutrition research and texts to fill in requirements not available through NRC. I compared those to what I had been providing for my patients in injectable form, and I referred to veterinary pharmacology texts and talked to exercise physiologists. I came up with a profile and doses of nutrients that, I believed, would be the most scientific and practical for competitive horses in my veterinary practice. I didn’t worry about whether or not horsemen would immediately understand the formulation or recognise the importance of some of the less familiar sounding nutrients. I focused on making a difference to equine health and welfare.

As a veterinarian, my clients trust me to provide safe, secure, efficacious, and ethical treatments for my patients. Product quality, therefore, had to be of paramount importance. I decided to make Pro-Dosa BOOST out of human food or pharmaceutical grade nutrients that would meet much higher purity standards than animal feed grade nutrients.

I thought it was important to measure the concentration of nutrients in the final product, because I wanted to be confident that I would be providing my patients the correct doses of each nutrient, not more or less, for best effect, and for their health and safety. If insufficient doses are given, then no impact or a negative impact on the overall health of horses may result. If you are buying a supplement that doesn’t contain what the label says, then at best, it’s a waste of money. At worst, it could be detrimental to your horses’ health. At the same time, giving too much of some nutrients is dangerous. Many horsemen will recall the tragic story from a few years ago about the group of polo ponies who died as a result of eating a feed supplement that contained ten times the amount of selenium that it was meant to, when an error was made in production of the product. I wanted to make sure that would never happen to a horse fed Pro-Dosa BOOST.

Finally, I wanted to be certain that I would not inadvertently cause harm though contaminants. I made my production and product tracking procedures as safe as possible by registering my facility in the NZ government inspected and certified GMP program. I used hazard analysis principles (HACCP) in developing methods of raw materials procurement, manufacturing, and finished product quality and safety assurance. I decided to submit all finished product for analysis for naturally occurring prohibited substances that may contaminate feed grade nutritional products and cause positive drug tests, and I submit all finished product for microbial culture to ensure it is sterile. Finally, I validated (proved) that my processes were consistently effective in producing a quality, sterile, and safe product that horsemen could feel confident and secure feeding to their horses. I wanted them to know that they could trust Pro-Dosa BOOST to be providing exactly what they were paying for and what their horses actually need to perform and recover at their best.

Think about what you are spending your money on and learn to read labels critically. Read my series of blog articles on “Reading Labels”, and please do contact me if you’d like help with general nutrition or comparing supplements and feeds.

05 Nov



Could Pro-Dosa BOOST produce a positive test? This question was asked of us frequently by trainers and horse owners, a few years ago. At the time, Pro-Dosa BOOST only had 1 mg of cobalt per tube, so the short answer was, “no, it wouldn’t produce a positive test”.  We were asked the question many times though, and we felt there were likely many, many more horsemen who had the same concerns but who did not contact us to ask. We decided we had better take action to try to get some information out there for the wider horse community to see.

Cobalt has become a very significant issue in racing and other sports over the past few years.  Following positive tests in Australia, racing authorities have made cautionary statements about the administration of cobalt to horses, and it has been reasonably well publicised that administering it at levels that result in the excretion of more than 100-200 micrograms of cobalt per litre of urine (depending on the racing jurisdiction) will result in a positive test. What hasn’t been explained is how much cobalt you can safely feed before those levels are reached. Racing jurisdictions have been working towards finding that threshold but have not yet released any information.

On a more basic level, horsemen and veterinarians have been provided with very limited information about the impact of “normal” levels of cobalt in the feed on the cobalt levels in urine. “Normal” levels may be significantly less than the threshold doses that will eventually be established. Instead, regulatory authorities have said that cobalt deficiencies are not common in horses, and they have recommended that it should be eliminated, as much as possible, from the equine diet until data is published indicating the maximum amount that can be fed.

What is cobalt and how much do horses require?  Cobalt is a trace element needed by horses in very small amounts to facilitate normal physiology and metabolism.  It is naturally present in feed stuffs, but as levels may be quite low, it is generally included in the formulation of prepared feeds and supplements.

The National Research Council (NRC) pre-2011, recommended daily dietary requirement is at least 0.1mg of cobalt per kilogram of dry matter intake per day. Your average 500kg racehorse can be expected to eat 2% of their body weight per day, which would be 10kg of feed on a dry matter basis. 10kg dry matter intake X 0.1mg cobalt required per kg dry matter = 1mg of cobalt required per day for normal health. According to NRC, resting horses require about half of that. NRC 2011 standards list reduced minimum requirements, ranging from 0.5mg to 0.6mg, depending on age and level of work.

In virtually all cases, feed companies use NRC guidelines when developing formulations, so most complete feeds will contain at least 1mg of cobalt per day, when fed as directed. A horse’s cobalt needs, therefore,  should be readily met by its basic feed intake, as long as the cofactors needed for absorption and function are present in the diet.  As horses in training for competition and racing are generally fed a well-balanced diet, most will be receiving the cobalt needed for normal health.

After completing a cobalt clearance study in Standardbred horses in training, in New Zealand, we concluded that we could remove cobalt from our formulation while feeling confident that Pro-Dosa BOOST would still provide complete and balanced nutritional support for optimal performance, recovery, and health.  We wanted to ensure that trainers and horse owners, from all disciplines, could incorporate Pro-Dosa BOOST in their training regime, without any concern about producing a positive test for cobalt.

If you would like to read more about our findings, please follow the link to our cobalt clearance study.


08 May


Does It Have the Right Stuff and Is the Balance Right?

When reading labels, it is important to consider all aspects of the nutrient composition, including, completeness, balance, form, and dose.  Then you can compare the composition to the nutrient requirements of your horse.


Metabolism is quite complex, requiring a broad range of essential nutrients to function optimally.  You can’t just feed two or three nutrients and hope to support performance, recovery, health, and metabolism.  A lot of one nutrient doesn’t make up for deficiencies in another.  If you ran out of food in your house and tried to just live on a big bag of salt, you wouldn’t last long.


The balance between nutrients is equally important.  Some nutrients are required for the uptake and function of other nutrients. (These supportive and cooperative nutrients are called co-factors.) Too much or too little of one nutrient may result in deficiencies or toxicities of other nutrients.  Imbalances, therefore, can adversely affect health, performance, and recovery. At a minimum, imbalances in a feed or supplement can render a product ineffective.

For instance, vitamin C is required for the absorption of iron from the gut.  Without vitamin C, iron passes straight through the gut and out in the faeces.  Vitamin E, on the other hand, has a negative interaction with iron.  It binds with iron and reduces its absorption, causing much of it to be wasted. So, in order for horses to use dietary iron effectively, it must be administered with vitamin C and without vitamin E.  Iron balance is also closely related to Zinc, Manganese, Cobalt, and Copper.

Common Feed Ratios

Ca:P 1-2:1
Zn:Mn 0.7-1.1
Zn:Cu 3-4:1
Fe:Cu 4:1

B vitamins are known to work better when administered in optimal balance with each other.  They act in concert in many metabolic pathways important in energy production, red blood cell production, coat and skin condition, nerve cell function, and appetite.  Giving a bigger dose of one B vitamin may not produce improvements in health or performance if the entire range of B vitamins is not supplied in optimal balance.

Amino acids are another good example of how nutrient balance is important.  That is a topic I will discuss further in READING LABELS PART 4 – about evaluating feeds, but in the meanwhile, read the article written by Dr. J. Stewart that we posted on our blog about top-line.  In that article, Jenny explains how the balance of amino acids in a feed is as important as the amount of protein.  Imbalances in amino acids limit the amount of protein in a feed that is usable in the horse to produce proteins and muscle cells, and the wasted amino acids, that can’t be used for protein synthesis, create a load on kidneys, elevate body temperature, and elevate heart rates.


Bioavailability refers to how absorbable and usable nutrients are.  While this is partly related to the composition and balance of nutrients in a product, the term is most frequently applied to the form each nutrient is provided in.

Some forms are more easily absorbed and used than others.  The trace element Chromium, for example, exists in several different forms.  The form of chromium found in a chrome bumper on a car is not very digestible at all, but the form incorporated into yeasts is very easily absorbed and then used by cells.  Minerals including Calcium, Magnesium, Iron, Cobalt, Copper, Zinc, Selenium, and Manganese can all be provided in a variety of forms, each of which have differences in their bioavailability.  In general, inorganic forms of nutrients are less well used than organic forms, though that is not always a reliable rule.  Zinc Oxide is one of the most bioavailable forms of Zinc, whereas Zinc Chelate forms a big molecule that remains quite inert.  In most cases, though, minerals provided as gluconates, lactates, and amino acid or protein complexes are well used.

When reading labels, you should note whether the amount of the ingredient or the amount of the active molecule is listed.  For instance, Iron Bioplex (iron is bound to amino acids or protein) contains only about 10% iron.   If a label says a product contains 400mg of iron per dose, that would mean that a dose contains about 4000mg of Iron Bioplex yielding 400mg of very well absorbed and used iron.  If the label says a product contains 400mg of Iron Bioplex per dose, then it really only has 40mg of iron.  Make sure that you read those details carefully when reading labels and comparing products.

So that’s part 2 done!

To recap Reading Labels – Parts 1 and 2 on Supplements

From Part 1:  If labels are easy to understand so that you can tell, at a glance, what you are giving your horse, then the manufacturer is probably proud of their formulation and believe it will stand up to scrutiny. If you have to perform too many calculations to figure out what you are giving, there is a fair chance that the formulation isn’t great. In any case, take the time to do the math and make sure you are comparing apples before picking the cheapest or prettiest product on the shelf.

From Part 2:  When reading labels, it is important to consider all aspects of the nutrient composition, including balance, form, and dose, in relation to the nutrient requirements of your horse.

Make sure you read the third instalment of this Reading Labels Blog Reading Labels Part 3 – Product Quality Management. This looks at the quality of ingredients and manufacture.

08 May


Are You Comparing Apples with Apples?

(After working on this for more than an hour and barely scratching the surface, I suddenly realized that this will end up a very long (and boring) blog entry, indeed, so maybe I’ll try to do this in a series of smaller bite-sized chunks.  For now, I’m going to start with supplements. I think they will be easier to sort out.  If you want to know more about feeds, keep checking back.  I’ll eventually finish this…I hope.)

With the tremendous range of feeds and supplements available, how do you even begin to select the right ones for the horses in your stable?

Do you mostly rely on testimonials from friends, feed merchants, or sales reps from the feed/supplement companies themselves?  If so, you are not alone. The most common questions I am asked, by the horsemen I meet, from all around the world, relate to comparing feeds or feed supplements.  I get a lot of,  “hey doc, a rep from a supplement/feed company came the other day and told me about one of their products.  They said it was the best ever… but they all say that.  What do you think of it?  Should I feed it to my horses?”

If you have ever wanted to ask those questions, read on.  I’ll try to give you some tools to sort out the wheat from the chaff.  Just like the horsemen who ask me about new products they have come across, I can’t always answer those questions immediately.  I have to follow a process to objectively evaluate them.  I’ll get to that next.

To begin with, so you feel better about your state of confusion when looking at supplements, here is my experience with the same thing.  (…and keep in mind, I am a veterinarian, and I studied nutrition in university before starting veterinary school.)

Back in 1999-2000 or so, I started looking at oral pastes and powders as a practical, economical alternative to the more invasive and expensive pre-race treatments I used to give my patients.

(My “loaded amino acid jug” was a Duphalyte or Amino Plus with 30cc’s CaCo Copper, 10cc’s Hemo 15, and 10cc Hippiron, with or without vitamin B12 and vitamin C, given iv along with folic acid given im.  Some of my clients liked to have their horses tubed with electrolytes and given Co-Forta injections instead).

In order to find one, or a couple of pastes in combination, that I could recommend to my clients, I looked at lots of supplements…practically all that were available in 2000, in fact.  I found a huge number of products listing different combinations of nutrients that were:

  • included in different forms (For example, Calcium could be provided as Calcium carbonate, Tri-calcium phosphate, or Calcium gluconate), and
  • quantified with different units of measure (mg/kg, %, ppm, to name only a few).
  • Then, they were to be given in different doses.

The most confusing paste I found listed contents in terms of parts per million (ppm), percentages, and mg/kg.  Then, the syringe was in pounds and the recommended dose in ounces. OMG!!!  Clear as mud!!!  What I was beginning to wonder, was that if some companies don’t actually want you to know how much or little of each nutrient is in their product.  Standing in the feed store, it was nearly impossible to do all of the mental gymnastics required to evaluate and compare the products available. So, I did what you must do if you want to fairly compare apples to apples rather than apples to oranges.

  •  I made a list of label information and recommended feeding rates.

Then, before I could really compare supplements, I had to go home with my lists of label information, sit down with a calculator or spreadsheet (…and a wine…or a latte…), look up conversion factors, and look up nutrient requirements.

Here is a link to my basic spread sheet that you are welcome to copy rather than typing all the nutrients into your own.


(If you just fill in the quantities and units as well as the dosage found on the label, the spread sheet should calculate the contents per dose for you.  If you come across units not covered in my spread sheet, please read on and try and understand how to convert units yourself.  If the math is just too off-putting for you, contact us at Pro-Dosa, and we will be happy to do the conversions for you and add them to my spread sheet for everyone else’s benefit.)

  • Enter or write down the contents as listed on the label, including the units.

Are the quantities listed in micrograms (mcg or ug), milligrams (mg), grams (g), kilograms (kg), parts per million (ppm), percentages (%), international units (iu), or 1000-international units (kiu or IU)?  Are those quantities listed per kg, pound,or dose of the product in question?

Here’s an example.

In this example, Arginine is listed as                                                                                                                                  0.31%, Iron is 3500 ppm, VitaminB12 is 1013mcg/lb, and Thiamine is 992mg/lb.  (…No, it doesn’t make much sense to me either…Yes, stop now and go get that glass of wine!)  Here’s where we will start to make some sense of this stuff.

You will need to convert all the units to milligrams per gram (mg/g) or whatever units you understand.  (In NZ, we use the metric system.)  I generally convert everything to mg/g, as I have entered the nutrient requirements into my spread sheet in milligrams (mg) (more on that later), and the dose of product you will give your horse will mostly be measured in grams (g).  You can use the conversion factors here or google each nutrient.

A percentage, as you know, is a number out of 100, so a percentage is the same as an amount in milligrams per 100 milligrams or the amount in grams per 100 grams or the amount in peaches per 100 peaches.  Make sense?  Then, there are 1000 milligrams (mg) per gram (g), so we have to multiply the amount per 100 mg by 10 to get the amount per gram.

Conversion Factor For Percentages to mg/g

% X 10 = mg/g

OK, in this example, Arginine is listed as 0.31% so that means there is 0.31mg per 100 mg.  We multiply this by 10 to get 3.1mg of Arginine per gram of paste.

Parts per million (ppm), using the peach analogy, is the amount in peaches per 1 million peaches.  So that is the same as the amount in micrograms per gram.  There are 1000 micrograms (mcg) per 1 milligram, and there are 1000 milligrams in a gram, so there are 1 million micrograms in a gram.  Anything listed in ppm, therefore, can automatically written instead as mcg/g.  We, of course, are working towards having everything in mg/g, so divide the amount in ppm by 1000 to get the amount in mg/g.

In this example, the Iron is listed as 3500ppm.  That’s the same as 3500 mcg/g.  If we divide by 1000 to get mg/g, there is suddenly only 3.5mg/g.  That doesn’t sound like nearly as much.

Conversion Factor for Parts Per Million (ppm) to mg/g

ppm divided by 1000 = mg/g

Now, on to the vitamins in this example…

As we learned before, there are 1000 micrograms (mcg) per 1 milligram.  Divide the amount in micrograms by 1000 to convert to mg.  In this example, Vitamin B12 is actually 1.013mg/lb.  Easy!

Conversion Factor for micrograms (mcg) to mg

1000 mcg per mg
amount in mcg divided by 1000 = amount per mg

Whoa!  Not so fast.  That’s 1.013 milligrams per pound.  Now I didn’t grow up with the imperial system, so I had to think about that one.  There are 2.2 pounds per kilogram, and there are 1000 grams in each kilogram.  First multiply by 2.2 to find out how many milligrams are in a kilogram (1.013 x 2.2 = 2.23mg per kilogram) and then divide by 1000 to find out how many mg are in a gram.  It turns out, there are 0.00223 mg/g.

Conversion Factor for Kilograms (kg) to Grams (g)

1000 grams per kg
Amount in a kg divided by 1000 = amount per g


Conversion Factor for Milligrams per Pound to mg/g

mg/lb X 2.2 and divide by 1000 = mg/g
or……. mg/lb X 0.0022 = mg/g

Thiamine (Vitamin B1) is already in mg…thank you very much!! However, it is also listed per pound, so as we learned above, multiply by 2.2 and divide by 1000.  You can fill in Thiamine on your spreadsheet as 2.18mg/g.

You can then just repeat this process for everything listed on the label.

There are a few conversions that I haven’t included here.  International Units (iu) are frequently used as a unit of measure for vitamins, medications, hormones, and other biologically active substances.  These are different for every form of vitamin as they include a measurement of effectiveness or biological activity.   I have to look the conversion factors up every time I have to use them, and the best place to find them is on Google.   So you don’t have to, here are a few of the main ones.

Vitamin A (as Retinol) 0.3 mcg 300mg
Vitamin A (as Beta-carotene) 3.6 mcg 3600mg
Vitamin C 50 mcg 5000mg
Vitamin D 0.025 mcg 25mg
Vitamin E 0.67 mcg 670mg
  • Convert the contents per kg, L, g, oz, or pound to the content per dose.

If you have converted the contents to mg/g and the dose is in grams, just multiply your quantity in mg/g by the dose.  If you have converted to mg/kg, then multiply your quantity by the dose and divide by 1000.  (There are 1000 grams per kg).

We have already calculated the contents in mg per g, so we just have to work out how many grams are in our dose and multiply by that number.  In this example, there are 68 grams (1 full syringe) per dose.

Arginine = 3.1mg/g x 68 g = 210.8mg per dose syringe
Iron = 3.5mg/g x 68 g = 238 mg per dose syringe
Vitamin B12 = 0.00223mg/g x 68g = 0.152 mg per dose syringe
Vitamin B1 (Thiamine) = 2.18mg/g x 68g = 148.24mg per dose syringe

Conversion for mg/g to Contents of a Dose

amount in mg/g X grams in a dose

  • Write down the nutrient requirements for your particular horse, at the specific level of work and stress they are under. In my spread sheet, I have included the requirements for a 450 kg horse in intense work.  Those requirements will work fine for a Standardbred at 400-450 kg, a flat racehorse at 500-550 kg, or a sport horse at 550-600kg, but you can look up the precise requirements that pertain to your horse.  National Research Council (NRC) is the best resource, but you can check out our Blog, Google, nutrition books, or ask an expert (nutritionist, veterinarian, etc).
  • Compare the contents per dose that you calculated to the nutrient requirements you looked up just now.

Your average horse needs about 400mg Iron per day and there is 238mg in this dose.  That’s not bad.

Doses of thiamine required to support nerve cell function are 1000mg upwards, so the 148mg in this fall a bit short.


While that seems complicated, it is really the only way to do it.  If you do it a few times and get comfortable with converting units and doing the basic mathematics, and if you have some of the basic nutrient requirements committed to memory, then you can do a rough comparison in a feed store.

Quick and Dirty Method

Most commonly, companies based in countries that use the metric system list their contents in mg/kg.  Divide the contents by 1000 to get to mg/g and multiply by the dose.

For example, we will use a dose of 50g, As there are 1000 grams in a kilogram, then your 50mL dose has about 1/20th of the contents on the label (50/1000 is about 1/20th).  You can just divide the quantity on the label by 20 to get a rough idea of what is in a dose and then compare that to what you remember of the requirements.

If the label is more complicated, then I do the calculations for one nutrient and then figure out what to multiply or divide the label quantities by to get what is in a dose.  Then I apply that factor to all of the nutrients.  Easy!

In our example, nutrients listed as percentages can be multiplied by 680.  In your spread sheet, you can multiply the column of percentages by 680 and the results are half done.

In general, divide nutrients listed in ppm by 1000 and then multiply by the dose in grams.

In our example, the nutrients listed as ppm can be divided by 1000 and multiplied by 68…or just multiply by .068.  (68 divided by 1000).

The nutrients listed as mg/lb can be multiplied by the dose and 2.2 and then divided by 1000 or just multiplied by 0.15.

The hard part is done.  You can now easily compare the quantities in any product with nutrient requirements and see for yourself if each product in questions measures up and which ones looks to be the best.  To really make a fair comparison, though, you will still have to learn something about what nutrients to look for and why they must be in optimal doses; neither too much nor too little.

Next, you must consider the composition and balance of nutrients in the product, so once you have recovered from the mathematical ordeal, make sure you read Part 2 of our Reading Labels series.

08 May


Urinary Cobalt Excretion in Horses Supplemented with 1 mg Cobalt in Addition to Normal Dietary Levels


Cobalt is a trace element, required by horses in tiny amounts. It is necessary for vitamin B12 synthesis, and as a result, is a key nutrient affecting several aspects of energy production, metabolism, appetite, and health.  Along with copper, iron, B-vitamins, and other cofactors, it is involved in red blood cell production.   Cobalt is naturally occurring in feeds, in quantities reflective of the soils in which they are grown.  NRC 2011 lists several regions with soils known to be deficient in cobalt, including New Zealand and Australia.

National Research Council (NRC) is an organization that compiles and publishes the internationally recognized standards for nutritional requirements for most species, in various stages of life, environmental conditions, and levels of work. NRC 2007 standards indicate that horses in hard work or under stress require at least 0.1mg of cobalt per kilogram of dry matter intake. Your average 500kg racehorse can be expected to eat 2% of their body weight per day, which would be 10kg of feed on a dry matter basis. 10kg dry matter intake X 0.1mg cobalt required per kg dry matter = 1mg of cobalt required per day for normal health. According to NRC, resting horses require about half of that.  NRC 2011 standards list reduced minimum requirements, ranging from 0.5mg to 0.6mg, depending on age and level of work.

Cobalt has become a very significant issue in racing over the past year or so. Following positive tests in Australia, racing authorities have made cautionary statements about the administration of cobalt to horses, and it has been reasonably well publicized that administering it at levels that result in the excretion of more than 100-200 micrograms of cobalt per litre of urine (depending on the racing jurisdiction) will result in a positive test. What hasn’t been explained is how much cobalt you can safely feed before those levels are reached. Racing jurisdictions have been working towards finding that threshold but have not yet released any information.

On a more basic level, horsemen and veterinarians have been provided with very limited information about the impact of “normal” levels of cobalt in the feed on the cobalt levels in urine. “Normal” levels may be significantly less than the threshold doses that will eventually be established. Instead, regulatory authorities have said that cobalt deficiencies are not common in horses, and they have recommended that it should be eliminated, as much as possible, from the equine diet until data is published indicating the maximum amount that can be fed.

In general, feed companies use NRC guidelines when developing formulations, so most complete feeds will contain at least 1mg of cobalt per day, when fed as directed. Many racing stables, however, feed simple diets, comprised of unimproved pasture, home-grown hay, haylage, and chaff, supplemented with oats or barley. It is often necessary to top-dress these rations with broad-spectrum vitamin and mineral supplements to ensure that all nutrient requirements are met.  Based on the cautionary statements issued by some racing authorities about feeding cobalt, horsemen are now unsure if it is safe to continue feeding their usual preparations. Withholding all nutritional supplements, however, may not be the best approach, as far as equine health and welfare are concerned.  Some diets will almost certainly be left deficient in at least some vitamins and minerals.

Pro-Dosa BOOST is a complete, balanced, bioavailable multi-nutrient paste, developed to replace nutrients lost in hard work or required in greater doses when horses are under stress as a result of travel, racing, competition, or illness. Nutrients are provided in doses that directly reflect NRC requirements, so Pro-Dosa BOOST contains 1mg of cobalt. It is generally only used once or twice a week, on days in which horses are under greater stress, and is not a daily supplement. It has been widely used in racehorses and competitive horses of all types in 35 countries for the past 14 years. It has undergone in vivo clearance testing numerous times across Australasia and has previously been fed extensively in those markets, right up until race day, without incident. Currently, Pro-Dosa International Ltd fields weekly enquiries about the safety of feeding Pro-Dosa BOOST and/or normal rations to racehorses.


While the industry awaits peer-reviewed research to be published by regulatory agencies regarding maximum amounts of cobalt that can be fed on a daily or weekly basis without producing a positive test, we wanted to be able to answer questions about the cobalt levels in urine after feeding small amounts of cobalt, that are simply reflective of accepted requirements.

The purpose of our study was to measure the amount of cobalt excreted in the urine of horses in race training, fed a combination of typical, prepared feeds and home-grown forages, and then to quantify the increase in the amount of cobalt excreted in urine following the administration of an additional 1mg cobalt (provided as cobalt sulphate in Pro-Dosa BOOST) a very bioavailable form of the trace mineral.

Project and Study Design

We have conducted a fairly short, practical study of urine cobalt levels in horses given a small quantity (1mg) of cobalt sulphate, a dose that reflects the nutrient requirements of a horse in hard work as published by NRC (National Research Council) in 2007.

Specifically, the following are the steps we followed:

On day 1, we fed a group of horses a standardized diet in which cobalt content was measured, and then we collected a baseline sample of urine in which cobalt was also measured. (Sample 1)

A single syringe of Pro-Dosa BOOST, made without any cobalt, was administered to each horse (2), and urine samples were collected over 36 hours, at intervals reflecting label directions and typical race day schedules.  These were again analyzed for cobalt. This first treatment represented the negative control treatment. (Samples 3-7)

On day 3, a single syringe of Pro-Dosa BOOST containing 1mg of cobalt (as it normally does) was fed to each horse (8). Urine samples were collected at the same intervals for a further 36 hours, and these were also analyzed for cobalt. (Samples 9-13)


An “hypothesis” is what is expected to occur.  Since NRC recommends the daily administration of 1mg cobalt, we expected that 1mg of cobalt would be cleared within 24 hours, and since NRC suggests that horses actually require that much cobalt, we might have expected that no waste cobalt would be excreted at all when 1mg was fed. As the standardized diet, however, was understood to contain some cobalt, we actually expected (or hypothesized) that the administration of an additional 1mg, might produce a small increase in the amount of cobalt excreted.


Feed analysis was conducted at Hill Laboratories, an accredited feed testing facility.  Results indicated that the basic feed items including chaff, haylage, and barley did not, on their own, contain enough cobalt to meet requirements as set out by NRC.  Two of the prepared feeds appeared to.   Cobalt content in each feed constituent ranged from 0.009 mg/kg to 1.667 mg/kg on an as fed basis.  (See Figure 2) A complete feed analysis is available if requested.

Treatments were given and samples were collected close to the planned schedule.  Urine cobalt analyses were performed by Eurofins, Wellington, a laboratory accredited for that test.  They are not a racing laboratory, however.

While the trends appeared to be quite consistent, there was some individual variation between horses, with one horse excreting double the cobalt compared to the other two at baseline.  (See Figures 3 & 4)  The horses were all of similar size, ranging from 425-450kg, and one of the two larger horses had the higher cobalt excretion values.

Results indicated a slight reduction in urinary cobalt following the administration of the portion of Pro-Dosa BOOST containing no cobalt (the negative control), and in two of the horses, that reduction was to a level below detectable limits.  The reduction in cobalt concentration in urine occurred between 4 hours and 12 hours, with levels staying low until some time after 20 hours.  By 28 hours after feeding Pro-Dosa BOOST without cobalt, cobalt excretion had returned to levels close to baseline.

After feeding the portion of Pro-Dosa BOOST with 1mg of cobalt, urinary excretion of cobalt remained essentially unchanged from baseline.  Statistical analyses performed by the University of Auckland, Department of Statistics, demonstrated no statistical significance of the very slight increases in two horses or the slight decrease the other.

To get a perspective on the amount of cobalt excreted after feeding a basic, un-supplemented ration and the additional effect of feeding 1mg of cobalt in comparison to threshold levels that would produce a positive drug test, see Figure 5.

Figure 5:  Urinary Cobalt Excretion in this Study Compared with Industry Thresholds 

Discussion and Conclusion

It is important to understand that the number of horses used in this study was very small.  A larger number of horses and a larger number of samples would be needed to draw statistically significant conclusions.  Until this study was completed, we did not know what sort of data we might get, if any at all, and the cost was quite high. We had intended to repeat the study in a second and third stable, but only after looking at preliminary data.  Unfortunately, it was more difficult to collect the samples than expected.  After the first day or two of urinating in pots, the horses stopped cooperating, and the final sample could only be collected from one horse.  With no additional data to compare it to, that data was discarded.  Had the urine collection been easier, a second, larger group of horses could have been used to obtain more results.  As it stands, few stables would be likely to volunteer to participate in a follow up study, especially if they talked to the trainer and staff who were involved in this one.

It was originally planned that blood samples would be taken in addition to urine, but that had to be abandoned as no laboratory that was accredited to do cobalt analysis in blood or serum was willing to participate. If a suitable laboratory can be identified, serum cobalt may be measured in a second study.  That would be easier, and I’m sure racing stables would happily participate.

Despite the limitations in our data set, the results were interesting, and we have achieved some of our goals.  We are now able to answer questions regarding the amount of cobalt excreted in urine compared to threshold levels, in a small group of horses in training, fed a diet, fairly typical of racing stables in the Auckland, New Zealand region.

In general, urinary cobalt was quite low compared to threshold levels, with our group averaging a baseline excretion of only 2.97 mcg/L while the threshold for drug testing has been set 67 times higher at 200 mcg/L in New Zealand and Australia. The study group of horses was eating 4.64mg of cobalt per day; with 3mg coming from one feed source, and only very small amounts coming from the forage and plain barley.  While this cannot be considered an indication of all basic feed stuffs, it is reasonable to assume that at least some un-supplemented rations, comprised of basic feed constituents, with no pre-mixed feeds included may be quite low in dietary cobalt.

Additionally, we established that feeding 1mg extra cobalt, provided as cobalt sulphate, did not significantly increase cobalt levels in urine.  Our group demonstrated a very slight reduction over 12 hours with a return to baseline levels or just slightly above by 20-28 hours.  This change was not statistically different from baseline, though.

Finally, the negative control samples showed some interesting trends.  The reduction in cobalt clearance was small, but very consistent.  It occurred between 4 and 12 hours and lasted for 20 hours.  This reduction could have resulted from increased water consumption and increased urine output, thereby reducing the concentration of cobalt. Urine output was not measured in this study, however, and nor was water consumption.  Both would be useful and may be examined in subsequent studies.

The second possible explanation is that, by feeding Pro-Dosa BOOST, which provides a broad range of elements required for metabolism, energy, and red blood cell production, the utilization of existing dietary cobalt was improved, leaving less to be excreted as waste.  In either case, the implications for health, performance, and recovery are positive.


We are now confident that feeding Pro-Dosa BOOST according to directions will not contribute to increased levels of urinary cobalt excretion.

We are comfortable that the levels of urinary cobalt excretion found in our study are much less than that which would place horses at risk for a positive drug test.

Our negative control part of the study demonstrated that Pro-Dosa BOOST reduced cobalt concentrations in urine, and that was likely due to one of the two following effects:

  1. Pro-Dosa BOOST increased water consumption, improved hydration, and increased urine output.
  2. Pro-Dosa BOOST improved cobalt utilization from the diet, reducing the amount that was excreted, unused, as waste.

If a racing laboratory can be found who is willing to do analyses on blood or who might do urine assays at a more competitive price, and if horsemen volunteer to participate, additional studies could be completed.  These would provide more confidence in the results and give trainers reassurance that feeding rations and supplements that are adequate to meet nutritional requirements will be safe when presenting horses at the races.

Pro-Dosa Int’l would like to acknowledge Derek Balle Racing Stables, Pukekohe, New Zealand for participating in the study and for collecting all the samples. We really can’t thank you enough!