Pro-Dosa BOOST is formulated to replace essential nutrients lost in training, competition, transport or stress, so many people use it to ensure their horses have the energy needed for competition, but did you know that Pro-Dosa BOOST contains nutrients that help manage your horse’s nervousness or excitability too?
There are several nutrients recognised to be important in the maintenance of normal nerve and muscle function when horses are under stress. Magnesium, Tryptophan, Tyrosine, and Thiamine (Vitamin B1) have all been used for nervous horses, and these nutrients can have a greater impact when used in optimal balance together than when fed separately.
Magnesium is the most commonly known nutrient for calming. It is an essential mineral involved in nerve transmission, cardiac rhythm, muscle function, and relaxation. Low magnesium can lead to nervousness, loss of appetite, and poor body condition in horses. This can be a vicious circle as nervous horses tend to use extra energy and sweat profusely, further depleting their magnesium stores.
Tryptophan is an essential amino acid required for the production of serotonin in the brain, and as serotonin functions to maintain mood balance, tryptophan has been associated with reducing distress and aggression. Essential amino acids are not produced in the body, so they must be provided in adequate quantities in the feed. Some standard hay and grain diets are deficient in tryptophan.
Tyrosine is another amino acid that is an essential component for the production of several brain chemicals called neurotransmitters. These help nerve cells communicate and influence mood.
Thiamine has a direct role in nerve impulse transmission, and scientific research has shown it to relax horses. It is also important in energy metabolism and helps to control hyperactivity. Thiamine works cooperatively with magnesium and other B vitamins and should be given with calcium, which potentiates effect. Thiamine is produced in the hindgut by microbes, providing the horse with sufficient amounts on a daily basis. Horses that are under stress or have impaired digestive functions, however, may not produce enough to meet requirements. They may benefit from supplementation.
Pro-Dosa BOOST contains all four of these vital nutrients in optimal balance with each other and with all of the other nutrients required for their absorption and function. It is important to remember that the body needs a full complement of nutrients in careful balance to achieve optimum health, performance, and recovery. Administration of individual nutrients may result in imbalances that actually impair availability and usefulness. By providing all of the nutrients required in greater doses when horses are under stress, energy levels and attitude can both be supported, while normal appetite, thirst, and metabolism are also maintained.
For the past decade, Pro-Dosa BOOST has been used in 35 countries, in endurance, show jumping, eventing, hunt, and dressage horses, whether travelling and competing at a novice or international level, for performance, recovery and health.
Did you know that you are probably the very best person to determine if your horse is a “bit-off-colour”? You know “normal” behaviour for your own horse and you know their habits. Just by observing their day to day routine, you can get a feel for your horse’s general well-being and identify any changes that may indicate potential health issues. If you do become concerned about something, you will be better equipped to give the veterinarian a detailed account of when the horse was last normal and what has changed since then, to help in their assessment.
So what should you keep your eye on and what regular checks should you make to establish what is normal for your horse and then to monitor their health?
Here is a list of health checks that you should include:
Demeanour: Has your horse changed the way it acts? Horses should be alert and inquisitive, watching any changes in their environment. If your horse looks a bit sad, is uninterested in what is happening around them, and its head is down (and it is not eating or sleeping), your horse is off-colour and some further investigation is required. Contact your veterinarian.
Eyes: Your horse’s eyes should be open, clear and bright with no discharge or swelling. If you notice excessive discharge or weeping, swelling around the eye or in the corner of the eye, a closed or partially closed eyelid, sensitivity to light, or cloudiness, contact your veterinarian immediately. Eye problems are always an emergency and must be tended to urgently.
Appetite: Most people monitor how their horse is eating concentrate feed, but it is equally important to watch how much time is spent grazing in the paddock. Did you know that when turned out on pasture, a horse will graze about 18 hours a day? Keep an eye on your horse to see if it is spending more time grazing or standing around. If your horse is standing around more than grazing or leaving feed in its bin, then this should be investigated. Take your horse’s temperature and call your veterinarian immediately. Check their water, and look around the paddock or stall to see if they have been passing manure. The veterinarian will ask you about these things, as well as when your horse last had dentistry, and they will certainly do a more complete exam.
Water Consumption: Your horse needs access to clean, fresh water 24/7. A resting horse on a mild day can consume between 20 and 40 litres of water (five litres of water/100 kg of body weight). This amount can increase dramatically (up to 100 litres) after exercise, on hot days, or if lactating (broodmare feeding her foal milk). Horses also don’t like to drink water that is too cold, so if you live in cooler climates, make sure ice and snow is removed from water troughs and buckets. Some horses won’t drink as much if they graze on green, lush pastures as these will have a high-water content.
If you have difficulty getting your horse to drink, make sure the water is not too cold, is clean, and is fresh. If they are still not drinking that well, you can try offering an additional bucket of water with molasses or other tasty flavourings added to it to encourage drinking. Sometimes horses don’t like the smell or taste of plain water they are not used to. When you travel with your horse, if they are fussy about water, try bringing some from home, or if your horse enjoys a drink of molasses flavoured water at home, you can just bring some molasses with you to add to camouflage the taste and smell.)
Urine: Normal urine should be a pale yellow colour, a little like apple juice. If it is darker and thicker in consistency, it may be an indication of dehydration, kidney issues, or tying up. Due to the calcium content of equine urine, cloudy or foamy urine is also normal. Have you watched your horse urinating? Your horse should pass about 8-10 litres of urine per day and should urinate about every five hours. If your horse is having difficulty stretching out to urinate or stands unevenly while doing so, this could be an indication of lameness, muscle soreness, or kidney issues.
Manure: Have you checked your horse’s manure? If not, it might be time to take a closer look. Horse manure should be a rich medium brown colour and should be a formation of small round balls that shatter when they hit the ground. Your horse should pass manure six to eight times per day. In the spring, when pasture is more lush, the manure can have a green tinge and be quite soft. It can also be a bit loose at times of stress, after excessive electrolyte administration, or if there has been a change in diet. If soft manure continues for more than a few days, you should consult your veterinarian. Manure that is actually runny or is soaking the underside of the tail may indicate an urgent problem, so your veterinarian should be called immediately. If your horse’s manure is comprised of dry round balls that stay formed when they hit the ground, this can be an indication that the horse is suffering from dehydration.
Temperature: The normal body temperature of a horse should be between 37.0 and 38.5 degrees Celsius (98.6 and 101.3 Fahrenheit). Body temperature can be elevated because of inflammation and infection, but don’t forget, that a horse’s temperature can also increase when exercising, when rugged, in hot weather, and when they are excited. Body temperature fluctuates during the day, and it is often slightly higher later in the day. In mares, temperature can be seen to fluctuates with their heat cycle.
Body temperature should be taken rectally, ideally with a digital thermometer. (You can purchase a digital thermometer from your local pharmacy). If you have never taken a horse’s temperature before, get your veterinarian/instructor etc. to show you how.
Heart Rate: (Pulse) The resting heart rate of a healthy horse should be between 32-40 beats per minute (bpm). Draft horses will have a slightly lower normal rate, and foals will have a much higher one, up to 60-100bpm. Newborns will be towards the upper end of the scale, while older foals will have lower heart rates under normal conditions. Again, heart rate is affected by excitement, exercise, heat, pain, inflammation, and stress.
To take the heart rate, place a stethoscope on the chest just behind the elbow on the left side of the horse. Count the beats for a full minute, if you can, or for 30 seconds and then multiply by two to get the heart rate per minute. If you don’t have a stethoscope, don’t worry. You can take the pulse by putting your finger on the mandibular artery, found running your finger across the underside of the jaw, just where it joins the cheek or in the groove under the jaw inside the cheek, the radial artery on the inside of the knee, or the digital arteries at the back and bottom of the fetlock and along both sides of the pastern, at 4 and 8 0’clock. Be sure to use your fingers as you might feel the pulse in your own thumb.
Respiration Rate: (breathing) Watch your horse breathing over a full minute. When it inhales and then exhales, it has taken one breath. The normal respiratory rate for an adult horse at rest is 8 to 12 breaths per minute. In contrast, a new born foal will breathe 60-80 times a minute, and an older foal will take 20-40 breaths. As with a horse’s temperature, the respiratory rate will also increase with exercise, excitement, and in hot weather.
You can use a few different techniques to count the respiratory rate. The simplest way is to stand near your horse’s shoulder, facing towards its hindquarters, and watch its abdomen move in and out (one breath). As an alternative, you can feel for the air coming out of the nostril on your hand. If you have a stethoscope, the best way may be to listen to the breath sounds as air passes through the trachea (windpipe). This will enable you to hear the quality of the sounds your horse makes when breathing. You might notice deep or shallow breaths, and you might hear unusual crackling or whistling sounds that are an indication that you should consult your veterinarian.
Mucous Membranes: The mucous membrane are the tissues that line the gums, inside of the mouth, inside of the eyelid, inside of the nostrils, and the sac in the corner of the eye. They should be pink in colour and moist to touch. If the gums are dry or tacky, this can be an indication that the horse is dehydrated. Check the colour of your horse’s gums. If they are white, dark red, blue, or yellow-tinged, call your veterinarian immediately! These changes in colour indicate serious health issues.
Capillary Refill Time: This gives a good indication of how well the horse’s circulatory system is working. (A normal capillary refill time indicates that blood and oxygen is moving efficiently around the body). Push your finger on the gum for a few seconds until the gum in that area goes white, then release. The area should return to its original pink colour, within two seconds, as the blood returns to the area. If it takes longer than two seconds to return to normal, or if the gums are any colour but pink, call your veterinarian.
Skin Pinch Test (Skin Tent): This is another test to check your horse’s hydration status. On the neck, or on the upper eyelid if you are able, pinch a piece of skin between your thumb and forefinger for a second. When you release the skin, it should return to normal within one second. If it stays pinched for more than a second, there is the possibility of dehydration. The skin tent performed on the neck can be affected by age and body condition, with older animals and thin animals having a slower skin tent than younger and thinner animals. In horses, unlike in humans, the loose skin above the eye isn’t as affected by age, and fat doesn’t really accumulate under the eyelid.
Gut Sounds: You will generally need a stethoscope to listen to your horse’s gut sounds, though by simply pressing your ear to your horse’s flank in the right place, you will likely hear some. Place your stethoscope on the belly, just behind the ribs and in front of the stifle, on both sides. The second place to listen is a little further straight up from there, about the width of your hand in front of the whorl and about a hand’s width below it. Depending on the size of your horse, the specific location varies, so ask your veterinarian to help. You should be able to hear fluid rushing, tinkling, squeaking, gurlgling or rumbling in all four areas, but you will likely hear less in the top left area than in the others. You must be patient to hear gut sounds as they are not continuous. Listen for a full minute in all four places. Ideally, we expect to hear the sounds of gut contents moving a couple of times a minute. Researchers have found that eating or drinking results in more food particles and fluid passing through the digestive tract and an increase in gut sounds. If the rumbling continues at a much higher rate than normal, it may indicate some underlying issue and a veterinarian should be consulted. If gut sounds are very infrequent or not present at all, this can be cause for concern as there may be a blockage. Call your veterinarian immediately. In general, a slightly more active gut is not serious while a quiet gut will always require urgent veterinary care. Check your horse’s stall/paddock/stable for manure as this is a good indication of how long it has been since the gut was working normally.
Hoof Wall Temperature: An easy health check for your horse is to feel each hoof to see how hot it is. Hoof walls should generally be cool to touch, however each horse will be different. Get to know how warm your own horse’s hooves are in a variety of conditions. Exercise and warm weather can cause them to have an increase in temperature, so mildly warmer feet are not always a problem. It is especially useful to compare the temperature of the feet to each other. If one foot is warmer than the other, that is reasonably reliable indication of inflammation in the warm foot. It may indicate a bruise, the start of a hoof abscess, coffin joint synovitis, or a fracture. Tip: Watch to see if all four feet dry at a similar speed. Warmer feet will dry faster. If both feet are unusually hot for the conditions, it may be an indication of laminitis. A sudden flare up of laminitis is always an emergency, so call your veterinarian immediately!
Digital Pulse: Another indication of inflammation in the foot is a digital pulse. The digital pulse can be found on the back of the fetlock at the base of the sesamoids. By gently pressing and sliding your fingers side to side at the back and base of the fetlock, you can often feel the firm digital artery, which supplies blood to the extremities, roll under your finger. Once you locate it, lighten the pressure slightly to feel the pulse through it. You can also feel the digital arteries as they continue along the pastern at 4 and 8 o’clock, and only light pressure is required to feel the pulse here. If the pulsing or throbbing is quite strong and you can feel it easily, this may actually be an abnormal digital pulse and your veterinarian may need to do some further investigation. The normal digital pulse is a tricky one to locate, and this can be even more difficult on fit, healthy horses. If you get the opportunity, ask your veterinarian or instructor to show you how to locate it and try to get familiar with how mild that pulse is when it is normal.
My mentor in veterinary college, the great Dr. Otto Radostis, began all of our Large Animal Medicine lectures with a bit of his personal philosophy. This was one piece of wisdom he tried to impart on us that I will always remember. He said, “You miss more for not looking than for not knowing”. The best thing you can do is observe your horse in their environment, each and every day. Run your hands over them from top to toe, and get comfortable with doing the extra checks listed above. Keep a record of everything you see and of the daily health parameters you measure. Keep the information in your first aid kit (read our First Aid Kit blog article by clicking here) or stable so you have easy access to it. Remember, the sooner you notice that something is amiss and contract your veterinarian, the better the outcome is likely to be. Also, the more information you can give the veterinarian about normal and abnormal for your horse, the easier it will be for them to accurately assess your ailing equine friend.
“You miss more for not looking than for not knowing.” Dr. Otto Radostits
Below is a story from Michele of New Lives Animal Rescue based in the Waikato, NZ. This organization was established in 2014 and is a Registered Charity that specializes in the rescuing and re-homing of dogs, puppies, cats kittens, horses and can accommodate other species where possible. Pro-Dosa International Ltd. is proud to be able to provide support to New Lives Animal Rescue. To see how well these rehabilitation cases are progressing with the help of Pro-Dosa BOOST is really very cool!
“Thank you so much Pro-Dosa for your wonderful ongoing support of New Lives Rescue horses. We just love your BOOST paste!
All our rescue horses are given your paste on arrival, we find it is a great pick me up tonic and shows an immediate difference.
We thought it might be an appropriate time to tell you about how incorporating Pro-Dosa BOOST into your final stages of preparation could benefit your horse when training, travelling and racing. Pro-Dosa BOOST contains vitamins, minerals and amino acids in balanced proportions to replace those essential nutrients loss during exercise and when under stress.
Horses under stress (through hard work, travel and racing etc.) have increased requirements for a broad complex of nutrients necessary to support metabolism, health, performance, and recovery. Unfortunately, when horses are under stress, they tend to go off their feed, resulting in reduced intake of essential nutrients just at the time they need more.
Horses have significantly increased requirements for B-vitamins at these times, and Pro-Dosa BOOST contains all of them in doses that are properly balanced with each other and with all of the other nutrients required for their absorption and function. B group vitamins play an important role in coat and skin condition, energy production (so tired or lethargic horses may get a lift), nerve cell function (so nervous horses may be better able to relax and focus), and red blood cell production. Most importantly, when horses are transported and then tabled in a new environment, they help to maintain normal appetite!
Pro-Dosa BOOST contains a sizable dose of Vitamin C which supports immune function and helps to protect muscle cells from oxidative damage that occurs in transport and training. (Did you know that oxidative muscle cell damage can occur in as little as one hour, as the horse works to keep itself balanced during transportation)? Horses will arrive at their destination in the best possible condition if given one full tube of Pro-Dosa BOOST a couple of hours prior to loading them on the float each day. If you are leaving early in the morning, it can be given the night before instead.
If you have a nervous horse that does not settle into its new environment, try giving it half to one full tube of Pro-Dosa BOOST each day. It contains as much Magnesium and Thiamine as many calming products, and these nutrients actually work better when given in combination with each other and with the amino acids, Tryptophan and Tyrosine, than when administered separately.
Pro-Dosa BOOST contains a broad range of electrolytes including calcium, magnesium, and phosphorus, as well as sodium, potassium, and chloride. These will help maintain normal hydration and the electrolyte balance necessary for muscle cell, cardiac, and nerve function. Once horses are dehydrated, however, electrolytes will fail to stimulate thirst. When that occurs, unassembled amino acids stimulate thirst more effectively.
Pro-Dosa BOOST contains 22 unassembled, rapidly-absorbable amino acids in the optimal ratios required for protein synthesis and muscle development. Muscle cells take up amino acids most efficiently for about an hour following hard work. Providing a full tube of Pro-Dosa BOOST as quickly as possible after the last hit out prior to racing will aid muscle cell repair and recovery, ensuring horses will be in top condition on race day. A full or a half tube fed regularly after each fast work can help your horse to recover well, maintain normal body condition, and perform consistently over the long racing season ahead.
When race day comes around, give one full tube of Pro-Dosa BOOST on the tongue the night before or mix it in with feed.
We wish you the very best of luck over this fantastic racing carnival. if you require any further information. Contact the team at Pro-Dosa International.
Equine Gastric Ulcer Syndrome (EGUS) is a term that covers the damage and ulceration of the stomach lining in the horse. EGUS is a very prevalent disease affecting horses. EGUS is found in up to 90% of all race horses and endurance horses. The incidence of EGUS in sporthorses can also be as high as 60%.
The Stomach and Digestion Process.
The stomach is small relative to the size of the digestive tract of the horse and has a small role in the digestion process to help further liquefy food particles as they pass through to the small intestine.
The stomach has two distinct areas the non-glandular section which is located the top one third of the stomach and has the same thin, smooth wall lining as the oesophagus. The glandular section of the stomach is the remaining two thirds of the stomach its wall lining is made up of glands which secrete hydrochloric acid, pepsin, bicarbonate and mucous.
The Equine Stomach showing the Glandular & Nonglandular Sections
Richards, Elenor – Equine Stomach, Nutrition for Maximum Performance
The horse is unique in that it continuously secretes hydrochloric acid to break down food particles. It also produces the enzyme pepsin that helps break down proteins. It is these gastric acids that ultimately damage the non-glandular region of the stomach as this area has thin, smooth walls which are not protected by glands as found in the glandular region of the stomach.
The time it takes for feeds to be digested in the stomach varies with the type of feed, forage or grain and the size of the meal. Grain can take as little as ten minutes to pass through the stomach and forage can take up to 24 hours so the stomach has little time to empty and hydrochloric acid is being used to break down food particles.
To address EGUS, our aim is to neutralise the stomach acid and the horse has its own neutralising agent bicarbonate which is produced in its saliva. As a horse chews it produces saliva the more time it chews the greater the amount of saliva thus bicarbonate produced. The bicarbonate then reacts with to neutralize the gastric acids.
It is important that all stable staff know the horses that are in their care so they are able to determine when there has been a change in their behaviour, eating habits, weight loss etc which could well mean the early detection of EGUS.
Clinical Signs of EGUS
The following are clinical signs that different studies have found can indicate EGUS.
- Horse cast or lying on its back
- Grinding its Teeth
- Poor Performance
- Weight Loss and Poor Body Condition
- Dull or poor coat
- Colic (Abdominal Pain)
- Changes in attitude and behaviour
- Poor Appetite
The only way to absolutely diagnose EGUS is by gastroscopy which is a long endoscope with a light and camera that is passed into the stomach via nostril and eosphogus to identify any ulcerations or damage to the stomach lining.
Management & Nutrition
- Provide high quality forage ad-lib, 1 kg of forage requires the horse to chew approximately 3000 times producing high quantities of saliva and bicarbonate to help neutralise gastric acid. Alfalfa high in protein 21% and calcium is ideal as there are buffering qualities provided by the calcium.
- Provide Water ad-lib at all times – water is required to produce saliva and studies show horses who are intermittently without water are more susceptible to ulcers.
- Keep horses on pasture 24/7 if at all feasible, as they are grazers and can do so for up to 18 hours per day and this will help keep feed passing through the stomach working to neutralize gastric acids.
- If horses are stall confined, make sure they can see other horses and can socialise to reduce stress. Give them a ball or something else to keep them amused and free from boredom.
- Feed smaller feeds more often, due to labour and time constraints many stables make the mistake of only feeding horses twice a day, which means the horse can go without feed for a period greater than six hours which studies suggest increases the likelihood of EGUS. Horses were designed to graze throughout the day not eat once or twice.
- Start with forage and build the diet from there adding a vitamin and mineral balancer then adding energy sources to meet requirements of the horse. Remember you can add fats such as oils to replace grain.
- If the horse bolts its feed place rocks in its feeder to try and slow its feeding rate down making it chew the feed, which means it takes more time for the feed to pass through the stomach.
- Transportation is a cause of EGUS – to help eliminate this break up longer travel periods to allow for rest, feed and water. Provide a travel companion to help alleviate stress.
- Performance horses are more susceptible to EGUS as they are often fasted prior to racing or competing, this needs to be addressed by the stable so the stomach does not completely empty out.
- Grains and or concentrates should never make up more than 1 – 2 kg of any meal given to the horse. Especially if it contains Sweetfeeds as these contain VFAs (volatile fatty acids) which can cause damage to the non-glandular stomach lining.
- Turning the horse out on pasture with access to quality forage for a period of a month will most likely allow the healing of any stomach ulcers, however this may not be practical for performance horses.
- The only registered treatment for the treatment of ulcers is Omeprozole (Gatroguard or Ulcerguard).
- There are other solutions available that line the stomach to help reduce the pain associated from ulcers.
If you require a PDF version of this fact sheet please click here and we will send one to you.
For more information read Dr Jenny Stewart “Update on Ulcers“
References
- Cubitt, Tanya. PhD,The Horse’s Digestive System,Hygain Health & Nutrition Articles
- Sykes, B.W., Hewetson, M., Hepburn, R.J., Luthersson, N. and Tamzali, Y. (2015), European College of Equine Internal Medicine Consensus Statement—Equine Gastric Ulcer Syndrome in Adult Horses. Journal of Veterinary Internal Medicine, 29: 1288–1299. doi: 10.1111/jvim.13578
- Andrews, Frank. M. DVM, MS, DACVIM,American Association of Equine Practitioners,Equine Gastric Ulcer Syndrome (16 June 20216),Website – Horse Health Publication 816
- Lesté-Lasserre, Christa. MA,TheHorse.com,Got Ulcers? (1 February 2014),Website – Article 33283
- Merck Veterinary Manual,Gastric Ulcers in Horses: Gastrointestinal Ulcers in Large Animals
- McClure, Scott. R, DVM, PhD, Diplomate ACVS, Diplomate ACVSMR, American Association of Equine Practitioners,Equine Gastric Ulcers: Special Care and Nutrition,Website – Horse Health Publication 817 (January, 2016)
- Geor, Ray. J. DVM, PhD.,American Association of Equine Practitioners,How Horses Digest Feed,Website – Horse Health Publication 861 (February, 2016)
- Liburt, Nettie. PhD, MS,TheHorse.com,Tips for Managing Gastric Ulcers in Performance Horses,Website – Articles 37542 (9 May 2016)
- Drs. Foster & Smith,Gastric Ulcers in Horses: Causes, Signs, and Treatments,Website – Article 1587
- Niteo, Jorge. DVM, PhD, DACVS,Centre for Equine Health, School of Veterinary Medicine, University of California, Davis,Diagnosing and Treating Gastric Ulcers in Horses,CEH Horse Report (October 2012)
- Kentucky Equine Research,Gastric Ulcers in Horses – A widespread but Manageable Disease,Vetzone,Article (June 2012)
Upper respiratory infections are a significant problem across all equine industries and in the racing industry, in particular. Studies have demonstrated considerable economic losses resulting from subclinical disease (when horses don’t look obviously sick but are performing below expectations), from acute infection (when horses have nasal discharge, a cough, and obviously need rest or a reduction in training), and from the hypersensitivity and chronic inflammatory airway disease that develops in the lungs as a result.1, 2 As there has been a sudden increase in the number of upper respiratory infections in racing stables in New Zealand over recent months, I thought now might be a good time to write something about Equine Herpes Virus.
Most frequently, outbreaks coincide with yearling sales or a change in season, as this is the time of year in which racing stables introduce new horses to their yards, many of whom will bring “colds” or upper respiratory infections with them. Horses get “colds” just like people. They will have a fever, runny nose, sore throat, and occasionally a cough. Many will also appear depressed and lose their appetite.
There are a number of pathogens that cause upper respiratory infections in horses including Equine Herpes Virus, adenoviruses, rhinovirus, Equine Viral Arteritis (EVA), Streptococcus Equi Equi (Strangles), Streptococcus Equi Zooepidemicus, and Equine Influenza (EI). (In New Zealand, so far, we haven’t had EI…touch wood…) Equine Herpes Virus (EHV), identified over 60 years ago, remains the most common and economically significant cause of upper respiratory infections, world wide. 3,4, 5, 6, 7
There are actually nine different strains of Equine Herpes Virus, but only a few of them are clinically significant. The most important are EHV type 1 and EHV type 4 as they produce the most virulent, easily communicable, and most costly outbreaks across equine industries, all over the world. While EHV types 2 and 5 are ubiquitous (everywhere) and commonly cultured, the respiratory signs produced are generally mild, and they have not been demonstrated to produce serious outbreaks and economic loss. A recent study done in New Zealand determined that 44% of individuals from a small group with nasal discharge had positive cultures for EHV type 2 and type 5 was identified in 50%. EHV types 1 and 4 were only identified in 6% and 27%, respectively, though the small sample size and specific population tested were cited as limiting factors. Some heathy horses also cultured positive for EHV type 2 in the study, and the author explained that there were difficulties in positively identifying EHV type 4.8 All in all, the researcher found that EHV was strongly associated with respiratory disease. Previous studies done in New Zealand demonstrated evidence of recent EHV Types 1 or 4 infections in 72- 100% of horses and foals.9, 10
Equine Herpes Virus can be transmitted directly from horse to horse, but it can also be transmitted by droplets in the air (which can travel the length of a football field when a horse coughs). Exposure to virus particles in the environment on fences, gear, water troughs, clothing, shoes, etc. can also produce infection.
Horses of all ages are susceptible, but animals under three years of age and those under stress are most frequently affected. This would include most weanlings, yearlings, racehorses, and horses in training of any sort. 6
Immunity from natural infection lasts for only 2 to 6 months, so the same individual can become infected more than once in a year or their lifetime. While horses older than 5 years of age seldom show signs of illness, they often harbour the virus and provide a source of infection for the younger, more susceptible horses in the population. Young horses, with little immunity, will almost certainly become clinically ill when exposed. As they recover, over about 4-28 days, the virus, rather than being eradicated, enters the latent (silent) stage, sheltering in lymph nodes.6 Once the horse is under stress due to travel, training, or co-mingling at sales, the virus becomes reactivated and is shed into the environment, infecting other susceptible individuals. Studies have shown that between 60 and 88 percent of horses may be silent carriers.6
Other Clinical Syndromes Including Abortion and Neurological Disease
Equine Herpes Virus can cause a few different types of disease syndromes including respiratory disease, abortions, and neurological problems. EHV type 4 is believed to cause the vast majority (up to 90%) of significant upper respiratory infections11 and has been identified in some abortion cases, while EHV type 1 causes the majority of abortion cases, some respiratory infections, and most of the neurological cases.6
The evidence, so far, suggests that EHV infection begins in the respiratory tract, and once the virus multiplies enough in susceptible horses, it gets into their blood stream where it produces a “viremia”. (This just means virus in the blood.) If there is a large enough amount of virus in the blood, it gets into the central nervous system where it can damage the brain and spinal cord. It appears that EHV-1 is the only type, or at least, the type most likely to produce neurological symptoms as it appears to be the only one that settles in central nervous tissue.12
The neurological form of EHV (Equine Herpes Myeloencephalopahy or EHM) is fairly rare, especially in Australia and New Zealand, though there is some evidence that the incidence is increasing. 13
Clinical signs often develop 8 to 12 days after a respiratory infection and begin with weakness in the hind legs and incoordination. It can quickly progress, and within a day or two, horses will go down and be unable to get up. In some cases, no signs of respiratory infection are obvious, and the only early indication of a problem is a fever. Sudden weakness and death may be the first noticeable sign.
Alternatively, the viremia can allow the virus to get into the uterus. Once there, it causes the placenta to detach and the foal to be aborted. EHV-1 abortion was, up until the mid-80’s the most costly equine disease in North America, resulting in abortion storms that affected large percentages of mares on stud farms. From the mid-80’s, a widespread, aggressive vaccination program was instituted, and the incidence of EHV-1 abortion was reduced by 75%. Fortunately, in New Zealand, the incidence of abortion has been lower than in other countries.
Vaccinations
Treatment of viral infections is difficult. There are no really effective, economical anti-viral drugs available. Antibiotics do not kill viruses, and can only be used to treat animals with bacterial infections.
The best way to deal with EHV infection is to prevent it. Prevention requires a multi-faceted approach including quarantine, hygiene, and vaccination programs. Isolation of sick horses and quarantine of exposed animals and premises are useful measures, but they are not always practical at racing stables and farms. When horses attend sales or races, they are almost certain to be exposed to individuals who may not have been adequately isolated at their home stables and who may be shedding virus. Vaccination is the most practical way to reduce the rate and severity of infections in a racing stable environment where the horse population travels and changes regularly and in the racing industry as a whole.
Vaccinating a single horse will not reliably prevent that horse from getting sick if it is exposed to an overwhelming dose of virus.14 Instead, to protect individual horses from viral infection, it is necessary to produce “herd immunity”. The epidemiological term, herd immunity, can be explained like this. If 100 percent of the horses on a farm are vaccinated, it is expected that 70 percent of those horses will become immune. If 70 percent of the individuals in a population have immunity, then virus will not have enough susceptible hosts in which to multiply. This will reduce the overall viral load in the environment and reduce the viral challenge to each individual. This will stop the transmission of virus in the herd.14
That is the long way of saying that ALL of the horses on a farm or in a population must be vaccinated to prevent respiratory infection from being transmitted from horse to horse and therefore to protect individual horses.
A vaccinated horse may still get sick if it is exposed to an overwhelming viral challenge at the races or during shipping. They may be exposed to a sick horse or placed in a stall where a sick horse has been. Vaccination, however, will ensure that the horse will not get as sick and will recover faster than if not vaccinated. 15
Vaccinate all young horses frequently and older horses regularly, particularly if there is an outbreak. Use a modified live vaccine containing EHV 1 and 4, if possible. If horses have never been vaccinated for EHV before, 1 to 2 booster shots are recommended at 4-6 week intervals after the first dose. Foals should have their first dose at 4 months of age. Since immunity only lasts 12 weeks, one EHV 1+4 vaccine should be given every 3 months for optimal protection and for young horses in higher risk environments (racehorses in training would fall into this group), though the minimum recommendation is every 6 months.11,16,17
Vaccinate pregnant brood mares at 5, 7, and 9 months of gestation with an inactivated vaccine that contains only EHV-1, preferably at high antigenic levels. Pneumabort K, which is available in New Zealand, and Prodigy are two brands to consider.
There is very little evidence that vaccination can specifically prevent the neurological form of the disease, but recent studies have found that modified live vaccines can reduce the “viremia” and this may reduce the likelihood that the central nervous system of the horse will be affected.18
It has been noted that EHV types 1 and 4 are fairly consistent and antigenically stable,19 so unlike influenza viruses that mutate regularly, the same strains of EHV 1 and 4 remain basically unchanged over many years. The implication of this is that vaccines need not be adjusted annually or for each outbreak to be effective.
It is important to understand that once horses are affected with Equine Herpes Virus, they can continue to be carriers for life. At times of stress, they may begin to spread the virus around in their environment and infect susceptible horses around them. As a result, it is worthwhile to vaccinate young horses regularly to reduce the likelihood that they will become infected and then become silent carriers, even if there are no reports of a serious outbreak.
References
1. Viel, 2009. A New Understanding of Equine Inflammatory Airway Disease, OVMA Conference Proceedings, 2009.
2. Bailey, 1988. Wastage in the Australian Thoroughbred Industry)
3. Allen, GP, 2002. Epidemic Disease Caused by Equine Herpesvirus-1: Recommendations for Prevention and Control, Equine Veterinary Education, 2002.
4. Bryans, JT & Allen, GP. 1989. Herpes Viral Diseases of the Horse, Herpesvirus Diseases of Cattle, Horses and Pigs, edited by Wittman, G.
5. Crabb, BS. & Studdert, MJ, 1995. Equine 86 Herpesviruses 4 (Equine Rhinopneumonitis Virus and 1 Equine Abortion Virus, Advances in Virus Research, 45, 153–190.
6. Allen GP, JH Kydd, JD Slater and KC Smith. Equid Herpesvirus 1 and Equid herpesvirus 4 infections. Infectious Diseases of Livestock, (Ed.) JAW Coetzer and RC Tustin. Oxford Press (Cape Town), Chapter 76, pp 829-859, 2004.
7. Ostlund, EN, 1993. The Equine hHerpesviruses. Veterinary Clinics of North America, Equine Practice, 9, 283–294.
8. McBrearty, Thesis, 2011.
9. Dunowska, M, Wilks, R, Studdert, MJ, and Meers J, 2002. Equine Respiratory Viruses in Foals in New Zealand, NZVJ, 50, 140-147.
10. Dunowska, M, Wilks, R, Studdert, MJ, and Meers J, 2002. Viruses associated with outbreaks of equine respiratory disease in NZ, NZVJ, 50, 132-139.
11. Townsend, H and Morley, P, 1992. Western College of Veterinary Medicine, Department of Large Animal Internal Medicine, lecture notes.
12. Allen GP, JH Kydd, JD Slater and KC Smith. Equid Herpesvirus 1 and Equid herpesvirus 4 infections. Infectious Diseases of Livestock, (Ed.) JAW Coetzer and RC Tustin. Oxford Press (Cape Town), Chapter 76, pp 829-859, 2004. 13.
13. D.P. Lunn et al – EHV-1 Consensus Statement J Vet Intern Med 2009;23:450–461
14. Iverson, J, 1992. Western College of Veterinary Medicine, Department of Veterinary Epidemiology, Lecture Notes.
15. Patel, JR, Foldi J, Bateman H, Williams J, Didlick, S, Stark R. Equid Herpesvirus (EHV1) Live Vaccine Strain C147: Efficacy Against Respiratory Diseases Following EHV Types 1 and 4 Challenges. Veterinary Microbiology vol 92, Issues 1-2, 20 March 2003, pg 1-17.
16. Hines, M. Department of Veterinary Clinical Services, Washington State University, Recommended Vaccinations for Washington Horses, 2001.
17. AAEP website, 2001.
18. University of California Davis School of Veterinary Medicine, EHV-1 Vaccination Fact Sheet.
19. Allen, GP & Bryans, JT, 1986. Molecular Epizootiology, Pathogenesis, and Prophylaxis of Equine Herpesvirus-1 Infections. Progress in Veterinary Microbiology and Immunology, 2, 78–144.
20. Perkins, NR, Reid, SW, And Morris, RS, 2004. Profiling The New Zealand Thoroughbred Racing Industry, NZ Veterinary Journal 53, 69-76.
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.
Completeness
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.
Balance
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
| NUTRIENTS | RATIO |
|---|---|
| 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
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.
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, Vitamin
B12 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 |
|---|
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 |
|---|
| Conversion Factor for Milligrams per Pound to mg/g
mg/lb X 2.2 and divide by 1000 = 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.
| NUTRIENT | AMOUNT IN 1 IU | AMOUNT IN 1000 IU (IU OR KIU) |
|---|---|---|
| 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.
To get the most out of this article, you really need the pictures that go along with it. Please download the PDF version here. EQUINE CONFORMATION – WHAT IS CORRECT?
Definition: Conformation refers to the shape, dimensions, and proportions of a horse, created by its musculoskeletal structure.
Wider Definition: A more holistic definition considers the implications of form for dynamic function as well.
Beauty is in the eye of the beholder. The assessment of conformation is subjective, and different people will have different preferences, tolerances, and intolerances. In addition, different breeds and horses with different jobs to do may be compared to slightly different ideal conformation standards. For our purposes today, we will mostly talk about racehorses, and Standardbreds in particular. We will talk about the most common conformation flaws and why some might be quite tolerable in the Standardbred racehorse and why others aren’t. As many racehorses will be evaluated and selected as foals or yearlings, I will also try to touch on a few developmental features of conformation.
When selecting yearlings at a sale, what we would really like to know is which individuals have the X-factor that will make them great racehorses. That, unfortunately, is an intangible factor that we have no measure for. Instead, we try to choose individuals that are likely to stand up to the physical stress of training. At least, we try to reduce the list of yearlings with bloodlines we are keen on, by eliminating the horses with significant conformational flaws that will predispose them to injury and reduce the likelihood they will ever make it to the races.
Overall and the Body Proportions:
When you look through references on judging conformation, you will find a variety of “standard” measurements recommended for evaluating the overall shape of horses. Some suggest that the length of the head, neck, shoulder, back, and hip should be equal; others say that the height of the horse at the wither and the length, from point of shoulder to point of buttock, should be equal; and still others say that the shoulder, body, and hip should be of equal lengths. In general, these are reasonable rules of thumb to follow as they are all about overall good balance, and horses that depart significantly from these proportions are unattractive and may have difficulties with some types of work.
There are recommended proportions for heads and for the relationship between the size of the head and the length of the neck, but I’m sure we have all known pretty decent Standardbreds with roman noses or relatively long heads that would be considered poor specimens by these measurements. On the whole, if the horse has to be a riding horse that must engage the hind quarters and lighten the front end for jumping or dressage, a big head makes that more difficult and it could be considered a flaw. For Standardbreds, it probably doesn’t affect balance and performance to the same extent, and whether these proportions are considered a flaw or not largely comes down to personal preference. In fact, the only conformational flaws of the head I worry about involve the eyes and mouth. Horses with narrow foreheads and small eyes can have some difficulty seeing, and parrot mouthed horses (where the upper jaw protrudes beyond the lower jaw) or monkey mouthed horses (where the lower jaw is longer) will have more dental issues than average that must be looked after regularly. The neck shouldn’t be too short as it is important for balance, but a slightly longer neck isn’t a disaster, so long as it is not set on too low, shifting weight bearing towards the front and loading joints in front legs. In running quarter horses, researchers found correlation between longer necks and an increased incidence of knee chips. Jumpers, on the other hand, need a relatively long neck for balance over jumps.
The shoulder should be relatively sloping, forming an angle of 45 degrees or so with the ground. A more vertical shoulder often goes hand in hand with a shorter humerus and a lower neck set. The upshot of all of this is a shorter stride.
It is also worth noting that the pastern angle, when viewed from the side, is generally the same as the slope of the shoulder. An overly sloping shoulder, therefore, often comes along with a long, sloping pastern, low heels, and a whole host of problems associated with that. This reminds me of the song…the hip bones connected to the thigh bone, the thigh bones connected to the leg bones…and so on.
For most breeds, a short back is considered ideal, and one standard suggests that the shoulder, back, and hip should all be of equal length. In the picture with the grey horse above, the three sections, while similar, are not quite the same. If the back was really the same length as the shoulder, it would really be too short, in fact. Horses with very short backs may be predisposed to interference problems. Horses with long backs, in contrast, are susceptible to injury due to weakness.
The croup in some breeds should be relatively flat, and in others, a moderately sloping croup is ideal as it allows for easier engagement of the hindquarters. A very sloping croup or a very flat croup are not ideal in Standardbreds, as both conformations limit the power generated by the hindquarters. Arabians shown at halter have quite flat croups, while Arabian flat race horses look like slightly smaller thoroughbreds with moderately sloping croups and well developed hind quarters.
Feet and Legs:
While “ideal” body conformation varies quite significantly for horses of different breeds and purposes, standards for legs and feet apply quite uniformly across breeds. While not many horses are perfect specimens, those that come closer to the ideal, generally have the right biomechanics for correct and athletic movement. They will suffer the least abnormal forces on feet, legs, and body; hopefully preserving soundness and health during training and racing. In this section, I’m going to address the significance of conformation flaws while discussing normal conformation to help you to decide which flaws you might tolerate and which you really shouldn’t.
Front legs:
When a horse, standing square, is viewed from the side, a plumb line, dropped from the top of the leg along the middle of the forearm (elbow joint), should fall straight through the middle of the knee (carpus), down the back of the cannon bone, pass through the middle of the fetlock, through the back of the heel bulbs, and end up on the ground just behind the heels. If the knee falls to the front of middle, the conformation is referred to as buck-kneed or over-at-the-knee, and if the knee falls more to the back of the midline, then the conformation is referred to as back-at-the-knee.
The back-at-the-knee conformation is an interesting one. Depending on the breed and work a horse does, it may or may not be significant. You could well imagine that horses with a back-at-the-knee conformation would be a greater risk for fracture, or at least lameness, as the joint appears to be partially hyperextended, even when at rest. Interestingly enough, research says that for most breeds, unless the flaw is severe, there is little impact on the incidence of chip fractures or lameness. This may be because the back-at the knee conformation is created when the top row of bones in the knee is set slightly back of the bottom row. In the normal horse, these rows of bones are arranged so that the front faces are lined up with each other. Some evidence does exist of increased incidence of lameness in racehorses, but it isn’t the same for all types. Thoroughbreds and trotters appear to have a bigger problem with slight back-at-the-knee conformation than pacers do. A slightly back-at-the-knee conformation is pretty common in Standardbreds, and if the shoeing is right, pacers, at least, can generally be managed. (Research has demonstrated an increase in carpal chips and synovitis in horses with long toes in combinations with a slight back-at-the-knee conformation.) In more significant cases though, it should be avoided for any racehorse.
The over-at-the-knee conformation in young racehorses is associated with a reduction in risk for carpal chips, but the incidence of tendonitis is clearly increased. Bowed tendons are best avoided, and any conformation that predisposes a horse to this injury is best avoided. In older jumping horses (steeplechasers, show jumpers, and eventers), the over-at-the-knee conformation can be acquired and this acquired form does not appear to be correlated with lameness or instability, despite all appearances.
A narrowing of the leg, just below the knee, is the feature of the tied-in-below-the-knee conformation. For some reason that is not obvious to me, researchers have found this problem to be of bigger concern in pacers than trotters. Again, there appears to be some correlation with increased incidence of tendonitis, so I think it is best avoided in racehorses of any type.
When viewed from the front, a plumb line dropped from the point of the shoulder should bisect the forearm, knee, cannon, fetlock, and foot. Deviations indicate a conformation flaw.
Toe in and toe out conformations both place extra stress on the fetlocks and coffin joints. The toe in conformation places the stress on the outside of the joints, and the toe out conformation places extra stress on the inside.
The toed in conformation results in a paddling gait in which the foot swings outward while the toed out conformation results in winging-in, with the toe at risk of contacting the other front leg. The toed out conformation, therefore, is a very undesirable one in Standardbreds as they will be at greater risk for hitting a knee or splint.
Normal – moves in a straight line
Base Wide – feet move forward in inward arcs
Splayed Foot – “toed out” feet move forward in larger inward arcs
Base Narrow – feet move forward in outward arcs
Pigeon Toed – feet move forward in larger outward arcs
The toed in conformation often goes hand in hand with offset knees. This conformation is associated with increased incidence of synovitis and capsulitis in the fetlocks and coffin joints, and the greater the offset, the greater the incidence of problems in the lower joints.
When the lower limb deviates outwards from the midline, the conformation is sometimes referred to as knock-kneed. It is actually an angular limb deformity called a Valgus deviation. The opposite condition in which the lower limb deviates inwards, is correctly termed a Varus deviation.
The valgus deformity is common at birth, but most foals straighten up within a few days. Those that don’t can be corrected with a surgery that slows the rate of growth on the inside of the leg and increases it at the outside.
You would guess, by looking at the valgus deformity, that additional stress would be put on the inside of the lower limb, and you would also probably expect some knee problems to go along with this. Oddly enough, research has demonstrated the opposite. The incidence of carpitis and fractures actually decreases in Thoroughbreds with a valgus deformity.
Pastern angle and foot conformation are closely related to one another, so we will discuss these together. The angle of the foot should be the same as the angle of the pastern. Both will be fairly similar to the angle of the shoulder, though not necessarily exactly the same.
Generally, a foot angle of 50 degrees or so would be considered ideal for front feet. With a foot and pastern angle of 50ish, the pastern will be neither too short and upright, which would place extra stress on the fetlock, pastern, and coffin joints, nor too long and sloping, which will place extra stress on the coffin joint, pastern, fetlock, knee, and the flexor tendons. From a soundness perspective, I would rather a horse be slightly more upright than have long, sloping pasterns that place the foot way in front of the leg. This conformation frequently results in crushed and underrun heels, and maintaining a healthy foot will be an ongoing battle. The long pastern/long toe/low heel conformation has been associated with an increased incidence of front leg fractures in general, and carpal chips in particular. While more upright pasterns are associated with an increased incidence of fetlock chips, it is a very slight increase that I think is a better risk to take.
Hind Legs:
To evaluate conformation of the hind legs when viewed from behind, imagine a plumb line dropped from the point of the rump. It should run down the middle of the hock and bisect the canon and foot. If the hocks deviate to the outside of the line, the horse is considered to be bow-legged, and if the hocks deviate to the inside, they are called cow-hocked. In fact, few horses are dead straight behind. The majority have a very slightly cow-hocked conformation. If either deviation is significant, it should be avoided.
The hind legs should also be viewed from the side, and you must take care to ensure that they are standing up square, with either the canon bone vertical or the point of the hock lined up under the point of the rump. A plumb line dropped from the point of the rump should run just behind the point of the hock and run straight down the back of the flexor tendons. Horses that stand too straight behind, post-legged, will have the plumb-line fall behind the leg, and a sickle-hocked horse, with too much angulation through their hind joints, will stand out behind the plumb line.
Some diagrams will show two additional conformations; camped under and camped out. These are not really different conformations but are, instead, positions. If a sickle-hocked horse stands with the point of the hock under the point of the rump, then the cannon bone will slope forwards. This is the usual depiction of the “sickle-hock” conformation. If that same horse stands up with the canon bone vertical, then they stand camped-out behind. The post-legged horse, in contrast, generally stands camped-under.
Post legged horses do not have enough angulation through their joints. These horses are predisposed to stifle and hock problems, and they are generally weak behind. They are unable to engage their hind ends sufficiently, and they should be avoided for jumping.
The sickle-hocked conformation is reasonably common in Standardbreds, and it has been associated with speed in some families. Sickle-hocked horses are predisposed to hock joint problems and curbs. From a soundness perspective, significantly sickle-hocked individuals should be avoided.
Dr. James R. Rooney wrote some very interesting text books about the biomechanics of lameness that are worth reading if you would like to know more about how form affects function and dysfunction. He explained that the sickle-hock conformation allowes horses to get underneath themselves and use their hind quarters for more power. As a result, draft horses should be slightly sickle-hocked, and so should be old-time Standardbreds who pulled heavier carts and drivers and who were required to race multiple heats in a single day, but were not required to pace or trot as fast as horses must now. As Standardbreds have had to go faster and faster, a straighter hind leg conformation has been selected for. I’m not convinced the straighter hind leg conformation is necessarily related to more speed, but it certainly helps horse stay sound enough to race successfully for a longer term. If sickle-hocks allow a horse to generate more power behind, then they should also provide for more speed. Soundness would certainly suffer, though, and lameness will almost always reduce speed in the end.
Conformation Changes from Birth:
Researchers have found that only 13% of foals can be considered to have straight legs during their first 10 days of life, however, only a few require any sort of intervention to help them to straighten up. The deviations notable at this early stage in life include angular limb deformities and rotation of limbs, mostly to the outside. After the first few days, weaknesses begin to correct, and many of these legs begin to straighten up. Rotational abnormalities of from the elbows start to straighten as pectoral muscles develop.
Between two weeks and 6 months of age, valgus deformities are improved as is a toed-out conformation. The base wide stance also corrects. Varus deviations, toed-in conformations, and offset knees can worsen, however.
By the yearling sales, leg conformation is permanent. The stage of growth, however, can mean the the croup is higher and yearlings can look poorly balanced. I would generally expect that Standardbred yearlings who have narrow chests and who toe out will have major interference problems, but many Thoroughbred trainers will overlook these flaws, believing that yearlings will straighten out as the pectoral muscles continue to develop with training and growth.
Conclusion:
While there will always been exceptional creatures who become champions despite dreadful legs, most will break down before they can distinguish themselves on the racetrack. It is an integral part of a horse trainer’s job, therefore, to select horses for purchase that will stand up to training and racing. To do this successfully, they must become students of conformation; learning how to evaluate it, how it affects function, and how it might lead to dysfunction.
For more information, I would recommend reading Dr James R Rooney’s books, “The Lame Horse” and “The Biomechanics of Lameness”. It can be hard going if you aren’t fond of physics, but I think his books are fascinating. Dr W. McIlwraith wrote an article, “Conformation and Musculoskeletal Problems in the Racehorse” that is also worth a read as it talks about development of foals and the incidence of injury relating to conformation. Kobluk, C. N.; Robinson, R. A.; Gordon, B. J.; Clanton, C. J.; Trent, A. M.; Ames, T. R. have written “The Effect of Conformation and Shoeing: a Cohort Study of 95 Thoroughbred Racehorses”. This is about feet and their affect on lameness
Twenty years ago, stomach ulcers in horses were not a commonly reported problem and veterinary texts listed them only as an infrequent finding in sick foals. Today, they are reported to occur in anywhere between 60 and 90% of standardbred racehorses and 50 to 60% of show ponies, stabled yearlings, eventing and dressage horses. The only group of adult horses free of ulcers are those on pasture 24 hours a day.
Pastured horses have a very different diet to stabled horses – and diet has been shown to contribute to ulcers. Under natural conditions, horses graze for around 16 hours per day. The stomach has adapted to a constant intake of grass by constantly secreting acid (for around 45 minutes per hour). The acid is buffered by saliva, which is produced during chewing and has a very high content of bicarbonate and mucus. The number of chewing movements and the amount of saliva produced varies with the type of feed. One kilogram of hay requires over 3000 chewing movements and results in the production of over four litres of saliva. One kilogram of grain requires only one third as much chewing and yields only two litres of saliva. The sign of an acid stomach is chewing of bedding, wood etc – the chewing process stimulates the flow of saliva, which in turn lowers stomach acid levels and the horse feels more comfortable – a bit like chewing an antacid tablet.
Stabled horses spend an average of four hours a day eating – compared to 16 hours for pastured horses. When chewing time and hence saliva production are reduced, stomach acid levels rise, increasing the risk of ulcers. High acid levels are a result of modern feeding practices: the amount of roughage, feeding frequency and type of feed have profound effects on stomach acidity. If the stomach sits empty for a prolonged period, the acid is not buffered by the food and saliva and the stomach will empty less frequently, allowing the acid fluid to remain in contact with the lining.
When feed is eaten rapidly, less saliva is produced and the sudden flow of a large volume of feed into the stomach causes a rapid increase in acid secretion. Both grains and pelleted feeds have been associated with increased risk. High grain diets favour bacterial growth and fermentation in the stomach. There is an increase in the number of bacteria that produce lactic acid and gas. Acid secretion increases in response to pelleted feed because pellets are eaten rapidly. Both weanling and adult horses consume pellets faster than they eat traditional grain diets.
Simply changing from pasture to hay and confining a horse to a stall can cause ulcers. Because hay is drier and coarser than grass, it can damage the lining of the stomach. Soaking hay for 6 hours will soften it and also reduce dust and airborne particles that irritate the respiratory system. In addition, any alterations in intestinal function may also be associated with stomach ulcers. Insufficient blood flow due to worms can cause death of gut lining cells, resulting in slowing ulcer healing.
The most reliable way to produce ulcers in a horse is to provide insufficient roughage or to fast them. Multiple studies have demonstrated that periods as short as 12 hours without feed can result in low grade stomach irritation. Even beginning an exercise program results in more acid secretion by the stomach – making the provision of adequate roughage even more critical for the standardbred entering training.
Phenylbutazone or other anti-inflammatory drugs can also cause ulcers. The risk increases with long term use but can occur even after a single high dose. Phenylbutazone (bute) especially has an extremely low margin of safety and should only be used under veterinary supervision. A high salt intake can irritate or worsen pre-existing ulcers. To avoid excessive irritation, ensure that electrolyte intake matches need and give the daily dose with food.
Signs of stomach ulcers include poor performance, loss of appetite, poor condition and mild colic. With the exception of mild colic, these symptoms can also be found in horses with a developing lameness, subclinical tying-up, a gut upset, electrolyte imbalances, sand ingestion and enteroliths. However, loss of appetite for grain, signs of mild pain after eating, teeth grinding, salivation and belching are characteristic signs of stomach ulcers. While horses with a nervous temperament are thought to be more prone to ulcers, it is more likely that discomfort from stomach ulcers makes horses agitated and restless.
Horses with severe ulcerations and clinical symptom require treatment for at least 3 weeks. Around 20% of horses do not respond in that time and may need a different pharmaceutical or a spell. Horses with ulcers have notoriously poor appetites and may not have been eating all their medication if it was in the feed. If dosed with it, poor technique could also lead to loss of some medication. There is also a widespread problem with horses being given inadequate doses or not being dosed frequently enough, in attempts to save on the cost.
As few as 3% of moderate to severe ulcers heal without treatment in horses kept under conditions that predispose to ulcers. The only treatment that is 100% effective is to turn the horse out on pasture. Bear in mind also that the combination of poor appetite and alterations in gut pH, have negative effects that drugs cannot correct and supportive therapies, such as probiotics, should be considered. Even with improved appetite and weight gain, there can be a persistent mild dehydration, which can respond to combined probiotic/amino acid/electrolyte. Gamma oryzanol has been shown experimentally to have a protective effect on ulcer formation in several species, particularly ulcers induced by stress or fasting.
For less severe symptoms, and after the initial drug treatment, there are far less expensive therapies for continued treatment and prevention. Good results have been obtained with probiotics, gamma oryzanol, fermentation products, yeasts and digestive enzymes. These actives can be very effective in improving appetite, correcting diarrhoea and promoting weight gain. Some horses with ulcer-like symptoms that do not respond to anti-ulcer supplements respond extremely well to probiotics. In addition, under the guidance of your veterinarian, consider a special worming program for immature worm stages and for tapeworms.
In addition, not all gut symptoms are caused by ulcers and it is essential to have a veterinary assessment to rule out other causes of reduced appetite, weight loss and discomfort. Following a clinical and/or endoscopic examination, the various ulcer treatment options can be assessed. Because of the major drawbacks of treatment – cost, contravention of the Rules of Racing and recurrence of ulcers once treatment stops – long-term prevention with gamma oryzanol or another protectant, is advisable. Preventatives and treatments include good quality aloe vera juice, chlorophyll, gelatin kaolin, apple pectin, aluminum and calcium-based antacids, however, long-term use of compounds containing aluminium has been associated with toxicity.
The following feeding management practices can reduce the risk of ulcer formation:
- Avoid prolonged periods of fasting – ulcers have been shown to develop within 10-12 hours when horses have no access to feed – ensure roughage available at all times
- Feed on the ground – horses chew and swallow more efficiently when their heads are down and the throat extended. Feeding above the ground also results in abnormal movement of the lower jaw and unnatural patterns of chewing and teeth wear.
- Feed frequent small meals – optimum is 4 times a day and not more than 2 kg of grain per feed.
- Use steam-extruded grains and feeds which have been processed in such a way that eating is slower, resulting in more chewing, increased saliva production and higher saliva bicarbonate levels.
- Deworm regularly with the correct compound.
- Include probiotics and protectants such as gamma oryzanol in the daily diet.
By Dr. Jenny Stewart BVSc BSc PhD MRCVS
Equine veterinarian and Consultant Nutritionist