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What's a bisphosphonate?
Recently, two new products hit the market for the treatment of navicular disease. They are Tildren and OsPhos, which are both in a class of drugs known as bisphosphonates. These types of  drugs decrease bone loss by stopping the action of cells called "osteoclasts". In normal bony remodeling, osteoclasts work by breaking down bone to release calcium, while osteoblasts rebuild bone. It's not that osteoclasts are bad, they are just a portion of the balance of bone maintenance. Disease processes disrupt this balance and can lead to more bone loss than bone growth.
Bisphosphonates bind to the calcium in the bone and inhibit the osteoclasts. Since the drug is stored in the bone, it generally gets released into the system slowly as the bone is remodeled. Pretty neat, huh? There's a catch, however (isn't there always?) - while we know that's what they're supposed to do,  we do not know exactly what they are doing in the horse.
So what's the difference between the two new drugs? Tildren is tiludronic acid and is administered via an intravenous infusion. This involves sedation, a catheter and running fluids over about an hour. OsPhos is clodronate, which is given via an intramuscular injection divided over 3 sites. Doses can be repeated in about 3-4 months, however improvement does take several months to manifest.
Both come with potential side effects, the most common of which are colic signs. These are generally transient signs and resolve fairly quickly. It's important to keep in mind that bisphosphonates do affect the kidneys, so the administration of an NSAID (like banamine or bute) is actually contra-indicated.
While anecdotal results seem positive, these products should not be considered a magic bullet. In the research to approve tildren, it was shown that over a 2 month period, 64% of horses treated improved by at least 1 lameness score. That's compared to 48% of horses improving with just a placebo (both groups also received therapeutic shoeing and rest). A majority of these study horses also had a lameness of less than 6 months duration. So while these drugs may help in some instances, we don't expect them to be a cure-all.
If you would like more information on these drugs, feel free to discuss them with us at your next farm call or read the FDA's guidelines on the drugs.
For another objective (and somewhat colorful) look at these drugs, take a read of Dr. Ramey's blog.
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Back Dimensions & Excercise
 Dr. Sue Dyson, one of the leading lameness diagnosticians in the world, recently looked at the changes in back dimensions after exercise. Normally, when a horse is exercised, the back musculature increases in size. She noted that "The mean back-shape ratio immediately after ridden exercise was greater compared with before work at all [measured] sites."
She also noted that this only occurred in horses that were working correctly, meaning the saddle fit correctly, the rider was balanced and the work was performed appropriately. Lameness was also a significant factor.
Of these, one of the biggest factors was the saddle fit. The increase in back dimension does not occur with an improper fitting saddle. This indicates that the back musculature is not being used appropriately and your horse may not be performing up to intended standards. Having your horse's saddle fitted before and after exercise is important to ensuring appropriate movement and exercise.
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Henderson Castration
Beginning this year, we will be introducing a new castration technique. This is referred to as the Henderson Castration and utilizes the picture tool along with a cordless drill. This effectively removes the testicle and seals the cord in one step. Previously, it required us to suture the spermatic cord prior to removing the testicle. Research has shown that the complication rate is similar to that of regular castrations, however bleeding and infections were effectively reduced to zero. Using this tool should help us to reduce surgery time and decrease the average amount of drugs needed for a routine castration.
Please note that while we take as many precautions as possible, there can still be complications with any surgical procedure.
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Sleep Induced Somnolence
There is some really cool research going on regarding "sleep induced somnolence" and dummy foals. Sleep induced  somnolence (SIS) is more easily described by saying when you squeeze a foal, it falls asleep. It is believed that this squeezing mimics the compression the foal feels as it exits the birth canal. This is important in a couple of ways.
First, it gives us a way of restraining foals without having to sedate them. This has been known for a long time, however having research to back it is always helpful!
The second reason this is important is because it may be beneficially in treatment of dummy foals. A dummy foal is a one that has neurologic deficits upon birth, most likely due to some form of hypoxia (lack of oxygen). In some instances, it has been shown that with prolonged "squeeze induced somnolence", the dummy foal can be reset. It is almost as if it can become reborn and get a fresh start. After the SIS period, these foals will get up and begin nursing and acting like normal foals. Horses aren't the only species this has shown promise in.
This all has to do with neurosteroids, which in a normal foal drop off rapidly after birth. In dummy foals, these hormones remain at  high levels, causing the mind to think that it is still in the uterus. If these neurosteroids are isolated and injected into a normal foal, the normal foal will instantly begin showing signs of being a "dummy".
There's still a lot we don't know about these compounds, and research is ongoing to help us continue to learn more.
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| Wellness 2015
Our Wellness Program is available once again for 2015. We've made a couple of changes and added a Senior Plan, which includes everything in the basic but adds testing for metabolic diseases.
Enrollment is now open and runs through March 31, 2015. If you have any questions about any of our plans, please feel free to contact us.
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