Despite its use by trainers looking for an edge since the 1980s, a new study has suggested that the process of “milkshaking” a horse may in fact do nothing to enhance performance. A study published in September in the Journal of Equine Science rounded up previous research trials looking at the use of sodium bicarbonate in Thoroughbred and Standardbred racehorses.
The research team looked at seven randomized and controlled trials that spanned 74 horses and had been published in peer-reviewed journals. Horses were given sodium bicarbonate between two and a half and five hours ahead of exercise and had their results compared to control horses who did not get sodium bicarbonate. Exercise took different forms in different trials; sometimes the two groups of horses were put on a treadmill while in others they worked over the track. Both the time to exhaustion and performance were measured, and researchers could not find that the administration of the “milkshake” improved either factor in a statistically significant way. In fact, for treadmill exercises where time to exhaustion was measured, milkshaked horses actually performed slightly worse than their controls.
Sodium bicarbonate, usually given in the form of baking soda mixed with some sort of liquid, is typically given through nasogastric tube within hours of race time. It has long been believed by horsemen that the baking soda acts as a neutralizer of lactic acid, which is responsible for the feeling of achey or tired muscles during exertion.
For lead author Dr. Joshua Denham, lecturer in exercise science at RMIT University, the findings were not a surprise.
“Some recent reviews on the influence of sodium bicarbonate on endurance performance in humans have emphasized equivocal findings,” said Denham. “Given we know humans are prone to placebos, I was always skeptical about its utility as an ergogenic aid.”
Milkshaking has been banned within 24 hours of a race by most racing authorities, but the study suggests it “remains an issue in modern horse racing.” TCO2 tests, designed to pick up on the administration of sodium bicarbonate, are part of the standard pre-race testing procedures in most states, though not all horses in all races are tested in some places.
Besides being an uncomfortable and apparently unnecessary procedure, milkshaking can be dangerous if it goes wrong. In addition to potential gastric upset and possible injury to the nose and throat that can happen during tubing, an inexperienced practitioner can also send the tube down the trachea rather than the esophagus, sending the sludgy solution into the horse's lungs instead of the stomach.
It's not totally clear why people first began milkshaking horses, except that sodium bicarbonate ingestion was at one time thought to improve human athletic performance. The study authors note however that previous research shows this improvement at exercise periods of around four minutes in people, while flat races are significantly shorter. Of course, it's also possible human test subjects may have been influenced by a placebo effect.
“Although it's certainly not my area of expertise, I'm tempted to speculate that early positive findings in humans prompted trials in racehorses,” said Denham. “Some positive results may have occurred by chance or because the trials were always going to show positive results – whether it was on purpose or not. It reminds me of the church bell fallacy: Although one church bell rings at noon and another a block over rings one minute later, the first bell ringing did not cause the second one to chime. Once someone believes in something, it can be easy for them to pass on that information – whether it is accurate or not.”
As many people continue to struggle with economic uncertain or job instability due to COVID-19, university experts say one of the best ways to cut costs of horsekeeping is probably right outside your window.
In the first session of this year's virtual Thoroughbred Aftercare Summit presented by the Retired Racehorse Project, Krista Lea, research analyst at the University of Kentucky Department of Plant and Soil Sciences, said good pasture management is key to trimming budgets. Pasture is a cheaper feed source than growing or purchasing hay when it's maintained properly. On one acre of pasture, every inch of grass growth is equivalent to roughly 200 pounds of dry matter, or four 50-pound bales of hay.
“That may not seem like a big deal, but if you look at it across the entire pasture and how many inches there are, it adds up pretty quickly,” said Lea, pointing out that six inches of growth adds up to 24 bales per acre of pasture.
One of the reasons pasture is a better option than hay is that a considerable amount – up to 60 percent – of hay can be lost in the storage and feeding process, which leads to a lot of wasted money, particularly if hay prices are high in your local area. Proper pasture maintenance can not just improve the quality of the grass grown, but extend the growing season. Dr. Jill Stowe, associate professor with the University of Kentucky Ag Equine Programs, found that even assuming a cheap hay price of $4 per 50-pound bale, extending the pasture grazing season by a week can save up to $28 per day per horse.
Lea is frequently called out to consult with horse farms on the best ways to improve their pasture quality and said she finds a few common, costly mistakes. Many people will skip fertilizing their pastures, which ends up costing more in the long-term than it saves in the short-term. Pastures need a replenishment of nutrients, particularly nitrogen, in both spring and fall. There are horse-safe pelleted fertilizer products that can be used on actively grazed pastures as long as they're well-distributed.
Reseeding is also an important aspect of improving pasture, and it can be one of the more costly tasks at up to $150 per acre. To maximize germination success, Lea suggests planning reseeding timing at least a month ahead of time to ensure you have the right mix of seed and have completed your preparation in plenty of time for the seeds to take. Complete reestablishment of a pasture that needs to start from scratch should be planned six months out.
Over-mowing can also be a common error.
“The ultimate goal when mowing pastures is you're mostly mowing off the weeds and seed heads and leaving as much grass as you can for the horses,” she said.
With winter coming, establishing a sacrifice area from a dry lot or area around a gate can be a good way to keep horses from beating up so much ground during wet winter conditions. Adding gravel to a flat space and feeding/watering in this area will keep horse traffic more focused and help combat mud.
Each state has a cooperative extension service, which can provide free educational resources for best pasture practices, and Lea said there are government programs that can help horse owners defray the costs of pasture maintenance, too. The County Agricultural Improvement Program is a cost share program that can provide reimbursements for new fencing and waterers. The Natural Resource Conservation Service also offers a similar program, since properly-maintained pasture is beneficial to the ecosystem.
The most important thing Lea recommended for managers and owners is an open mind.
“So many times I get on horse farms and we've found a problem and we're presenting solutions for it and they say, 'That's just not how we do things here, we can't do it that way,'” she said. “The truth is, that costs you a lot. I think one of the best ways we can improve the way we manage horses is being more open to new things, whether that's being open to new grasses that are out there or new ways of managing our horses.”
Lea suggested that cattle farmers are particularly attuned to pasture management since there is such a direct correlation between pasture quality, weight gain, and final price for their cows. While cows can and will eat some plants horses will not, the basics of the educational resources offered to cattle farms can still be helpful for horse owners.
Other ways to cut costs
As an economist, Stowe is a fan of budgeting as a way to restrict costs. Excel offers simple, free templates for personal budgets that can be easily modified for a hobby horse owner, while for-profit operations often need more complex software. She also recommends weighing options for mortality and other types of equine insurance or establishing an emergency savings account, along with a series of emergency action plans. Now is the time to decide what you'll do if your horse needs colic surgery and your finances are still tight.
Keeping a record of your expenses is an important way to help you decide where you can cut your budget – even if your horse isn't a for-profit entity.
As COVID-19 remains a threat, this is also the time to make a care plan for your horse should you or your family become ill and prevent your being able to provide feeding and turnout. Stowe suggest having feed requirements and pasture assignments written out in a clearly visible location and clearly labeling things in the barn in case a substitute carer needs to find supplements or medications.
If you're worried about budgeting, Stowe said it's best to prioritize your horse's needs, keeping in mind the requirements for forage, friends, and freedom. Those are likely the most important things to the horse himself. Besides water, good quality forage is the most important part of the diet, so Stowe doesn't recommend cutting back on hay or pasture. You may be able, with guidance from a cooperative extension agent or veterinarian, to trim costs when it comes to concentrate and supplements.
“We have so many feds and supplements to help our horses in every way possible,” she said. “I think when finances are tight, it's important to sit back and think about which of these are absolutely critical to the health of my horse. I've got my horse on one or two things that it makes me feel better that he's on them. I don't know if there's a benefit or not. I think it would be really wise to give as objective a look as possible at what your horse is eating and what he or she really needs.”
Watch the complete session below. Virtual Makeover Week webinars continue Tuesday at 7 p.m. Eastern, where a panel will field questions about Thoroughbred behavior.
After the announcement that top 3-year-old Honor A.P. was retired a few weeks ago due to a tendon injury, many readers had questions. How serious are tendon injuries, anyway? Don't horses come back from them all the time? And what about breeding a horse with a tendon – does it place subsequent generations at risk for the same problem?
As with most injuries, the seriousness of a tendon problem depends largely on the severity and location.
“Tendon will generally swell before it tears,” said Dr. Ryan Carpenter, surgeon at Equine Medical Center in Cypress, Calif. “if you can catch a swollen tendon before it tears, then those horses do very well with time off. your typical juvenile tendonitis, you're going to give them 60 days off, let that tendon “set up” basically the inflammation will go down, and then those horses go on and have very long and successful careers with low rate of recurrence.
The problem comes when it tears.”
Carpenter also added that a tendon has to swell by about 20 percent before it could be perceptible to the naked eye. Fortunately, he said the attention paid to racehorses' legs means they're more likely than many other equine athletes to have a groom notice a change quickly.
It's also possible for tendon injuries to take several days after a race to become fully apparent. When Carpenter gets a call about a condylar fracture, it's usually because someone has noticed a horse looks uncomfortable after walking back to the barn and standing for a bath. Tendons don't tend to spark a lameness as quickly unless there's a major tear present. It's typical for ice boots or wraps to go on after cooling out, and if someone noticed a minor swelling with no lameness the next day, they may try icing it for a day to see if it was normal post-exercise edema before getting really concerned. Horses with tendon injuries may even jog sound initially. Generally, it's when a minor change seems to be stubbornly sticking around that Carpenter gets a call and comes out with his ultrasound machine to find the problem.
If a tear does occur, the location of the tear along the length of the tendon and within the tendon's width makes a difference in the level of severity, as does the size of the tear and whether or not there's fluid built up around the injury.
Tendons connect muscle to bone, while ligaments connect bone to bone. Both are made of stretchy fibers, and their stretchiness is especially important for front legs, which bear 60 percent of a horse's weight. During a gallop stride, a horse's front fetlocks flex and descend nearly to the ground, absorbing the shock of the footfall. That motion is possible because the tendons and ligaments have so much elasticity to them. That stretchiness also stores energy to propel the foot back up and the leg forward for the next stride. The suspensory ligament and the superficial digital flexor tendon are the most important to that process, which is why an injury to these structures is especially problematic.
When a significant tendon heals in a mature horse it must do so with scar tissue which is relatively inelastic because mature animals can no longer create tendon fibers. The scar tissue cells may adapt somewhat over time and become a little more stretchy, but they'll never be as good as the original tendon cells.
“You take what amounts to a rubber band and make part of it a piece of string that won't stretch,” explained Dr. Larry Bramlage, equine surgeon at Rood and Riddle Equine Hospital. “When you do that, the load stays the same, so the remaining tendon has to stretch even farther than it did before because it has to make up for the loss of elasticity in the segment that has the injury. So that means the probability of tearing the tendon again is very high, even higher than it was before it occurred the first time.
“All “bowed tendons” are not equal.”
In Bramlage's experience, tendon injuries in front legs are more difficult to rehabilitate than hind legs – particularly the superficial digital flexor, which he says is the worst soft tissue structure in the leg in which to have an injury. Tendons also don't do as well as suspensory ligament injuries in that they don't respond as well to treatment aimed at reducing the formation of scar tissue.
There are a few treatment options that may be used singularly or in combination, depending upon the injury. Stem cells or platelet-rich plasma may be injected at the injury site with the hope the cells can engineer a better healing process. Stem cells are immature cells which read the local environment and direct the repair. The goal is for them to order the formation of new, healthy tendon cells rather than scar tissue. Bramlage has found that this works better for ligament injuries than tendon injuries; the stem cells can make some improvement, but don't seem to consistently be as good at producing new, flexible tendon cells as they are at directing the formation of new ligament cells. The reason why still evades veterinarians. Some people use platelet-rich plasma, but it tends to promote filling the defect with more scar tissue, something Bramlage likes to avoid.
Some veterinarians may also suggest an operation to cut the superior check ligament (referred to as a ligament desmotomy), which is part of the superficial digital flexor tendon unit. In other species, the superior check ligament is muscle, attaching to the radius and is called the radial head of the superficial digital flexor. But in the horse, all of the muscle in this portion of the superficial flexor has disappeared, replaced with inelastic ligamentous tissue. The superior check ligament is one of the evolutionary wonders that makes the mechanics of the fetlock possible and makes a horse function the way it does. Mechanically, muscle tissue the size of the superficial digital flexor could never withstand the load of a 1,100-pound horse going 40 miles an hour on a lead limb. “Pulled muscles” would be the rule. But the superior check ligament absorbs the load, protecting the muscle above it. This protection comes at a cost, however.
The presence of the superior check ligament creates a tendon of finite length, where the load progresses up the limb from the bone insertion of the tendon, up the back of the cannon bone via the tendon and then is transferred to the check ligament and into the radius in turn. This “unit” is what is able to withstand the stress generated by the size and speed of the horse. But the “unit” has a finite length and therefore a finite amount of elasticity within the tendon which makes the unit function. That elasticity is fine tuned to allow the fetlock to flex enough to absorb the weight bearing stress, but not stretch so much as to injure the fetlock joint during flexion. When the allowable stretch is exceeded and injury occurs.
Hind limbs have no comparable check ligament. Mechanically, they don't need one. That is why it is much easier to treat a hind limb tendon injury than a front limb.
One of the treatment options with a bowed tendon is to cut the check ligament after the bowed tendon occurs, adding some length to the check ligament, which lengthens the “tendon unit” trying to protect the tendon. The idea is that the approximately one centimeter of extra length provided to the wounded tendon will help prevent “over stretch” again. It will also remove some tension from it during healing optimizing healing.
If fluid is present within the tendon at injury, it is best drained to prevent the pocket of fluid from turning to added scar tissue. This procedure is called “tendon splitting” although it doesn't actually involve cutting the tendon fibers. Rather, it refers to the surgeon cutting the thin protective layer of cells around the tendon to let the fluid out. That layer will heal itself.
Regardless of the treatment, the key component of recovery is patience.
“No matter what you do, nothing is going to take the place of time,” said Carpenter. “Time is what you need to get these things to heal. 'Time' on a decent sized lesion is going to be six, eight, months at minimum. That's the frustrating part from an owner's standpoint is you've got a horse that's injured and now he needs a year before he can run again. And when they do run again, a lot of these horses run a race or two and then they reinjure themselves and are back on the shelf again.”
Bramlage echoed those sentiments, referring to a published study finding that of 332 horses that had bowed tendons and underwent superior check ligament desmotomy, roughly two-thirds came back to the races, but only 48 percent made five starts or more. Of black type horses he looked at in unpublished data, only 20 percent ever ran in a black type race again, suggesting it can be very difficult for a horse to maintain class after a lay-off for a tendon injury. The average time from injury to first start was 10.5 months. Veterinarians have since learned to shorten this some since the study, but the degree of injury plays a role.
Carpenter points out that rehabilitation time is the most expensive of all the potential treatments, and it's the one a horse must undergo. In Southern California, he estimates a horse who gets “the works” in terms of treatment may rack up $2,000 for stem cell therapy, another $3,000 for surgery, $10,000 to $15,000 at the farm for lay-up and another $10,000 for training to get back to the races. Those prices make it unlikely a cheap claimer will be brought back. For a top stakes horse, the question is more about opportunity cost than bills.
“I don't know anything about Honor A.P., but in general on a horse of his caliber you ask yourself, is it financially worth him to rehab for a full year to come back?” said Carpenter. “He'd have to run at Grade 1 level, because if he runs at the lower level you haven't accomplished much for him and his value. If we do that now, we've missed our breeding season that's coming, hoping he can do something great that will make him more valuable in the future. The chances of that happening are very low.”
That mostly leaves mid-level stakes geldings or hard-knocking mares available to try laying off and then coming back. It's hard for a horse to return to top form after a lot of time away – age factors into their ability to regain their previous athletic level, but it also may be an indication of how much the healed tendon struggles to keep up, allowing the same level of performance.
So, should those Grade 1 types enter the gene pool? Aren't they just passing along predispositions for the same injury to future generations?
In the case of tendon injuries, there's no evidence of that, according to Carpenter and Bramlage. Uneven or excessive loading of a tendon due to other soundness issues or unexpected abnormally high loads is most likely to contribute to a tendon injury, not genetics. However some conformational issues can make the horse more vulnerable (upright pasterns are one the upright angle comes from the fact the tendon is shorter in those horses). That doesn't mean there is an actual defect of the tendon itself. Injury can also come as a result of uneven footing, especially if it's soft. Bramlage has found though that oftentimes, a bowed tendon occurs secondary to another problem. “Horses with chronic low-grade lamenesses will preferentially load the sound leg and it's normally the sound leg that gets the bowed tendon,” he said.
The good news for a retiring horse with a tendon injury is that they're usually sound for other purposes. Some more severe cases may be restricted in how much they can jump, but others are able to move on to new jobs with no restrictions if they don't head to the breeding shed.
Veterinarians at Rood and Riddle Equine Hospital answer your questions about sales and healthcare of Thoroughbred auction yearlings, weanlings, 2-year-olds and breeding stock. If you have a question for a veterinarian, email us info at paulickreport.com
DR. BART BARBER: From this veterinarian's perspective, the changes that the sales companies have made are positive. The limitations that have been imposed add a degree of confidence to buyers while still allowing sellers and veterinarians to fully treat horses as needed with only a few exceptions.
Dr. Bart Barber
There are some subtle differences but the changes for both sales companies are very similar. One of the new rules that each have applied is that only one non-steroidal anti-inflammatory drug (NSAID) and one corticosteroid may be used. There can be no stacking of drugs within the classes. There are lots of drugs in each of these categories and they have similar actions and effects within each class. That said, there are differences that make drugs in each of those classes superior for treating specific conditions. For instance, one NSAID is preferred to treat pain associated with colic while another is preferred for musculoskeletal pain. Certain steroids are better suited for treating allergic reactions while others are best at treating head trauma. The point is that there are reasons why one NSAID or corticosteroid is chosen over another and why there are several different choices.
In the rare case that a horse has already been treated with one of these medications for a specific condition and another condition arises for which another medication in the same class is needed, decisions will need to be made. First and foremost the horse will be taken care of. It is important to point out that this situation would not automatically disqualify the horse from being sold. A positive test for multiple NSAIDs or corticosteroids merely gives the buyer the right to rescind the sale. The goal of the new regulations is not to limit treating horses appropriately but to limit indiscriminate stacking of NSAIDs and corticosteroids, which is in the best interest of the buyers, the sales process, the industry and, ultimately, the horse. It's a good change. When the situation described above arises, it will be in the best interest of all parties to come together, use good judgment and horsemanship to determine intent, the best interests of the horse, and whether or not the process was compromised. These occasions will likely be rare and I believe that even in these instances we will be able to care for the horses without compromising the intent of the rules.
Bronchodilators, including clenbuterol, have been limited in that they have been completely banned for a time period prior to the sale. There is a potential for abuse of these medications and again this is a positive change to protect the horse. When this change was announced some chose to not use this class of medications in horses at any age, for any condition and I believe that is a mistake. Taking this out of a veterinarian's toolbox for use in foals could have fatal consequences. There are legitimate uses for these medications and they should be used when they are warranted. The sales companies have not limited their use when appropriate for age and condition, they have merely asked for disclosure.
The balancing of allowing for appropriate use and imposing rules to curtail abuse is difficult. In this case it has been well thought out and will benefit all involved.
Dr. Bart Barber, DVM, is a shareholder in Rood and Riddle's veterinary practice and specializes in reproduction, primary and preventative ambulatory care, as well as operations at Rood and Riddle Veterinary Pharmacy.
