Tuesday, July 28, 2009

Poisoning in Horses: Common Toxic Substances

Thehorse.com - Full Article

by: Equine Disease Quarterly
October 01 2008, Article # 12815

Poisoning in horses is not a common occurrence, but when poisoning occurs, effects can be disastrous and far-reaching. Listing all toxic substances is impossible, as virtually everything on the planet can be toxic at sufficiently high dosages. What dose is safe and what dose is toxic varies with each toxin, each animal, and each situation. Factors that influence risk from a toxic substance include animal age, concurrent diseases, exposure to concurrent toxins or drugs, reproductive status, and route of exposure. This article will briefly summarize some of the more common toxic substances that can pose risks to horses in North America.

Herbal Supplements: The use of herbal supplements for horses has become common in recent years. Many people believe that if something is "natural," it must be safe and non-toxic. However, some of the most toxic substances on earth are completely natural (such as botulinum toxin, taxine in yew plants, and nicotine). Many herbal and natural supplements are inherently toxic, and many herbal products contain impurities and unknown amounts of "natural" ingredients. Herbal supplements are not well regulated, and studies investigating risks associated with use of these products in horses are lacking.

Plants, Feeds, and Feed Additives: Pastures can contain toxic plants and grasses that can pose risks at certain times during the year or under certain circumstances. Too many toxic plants exist to list here, and importance varies greatly with geographic location. However, all weeds should be viewed with suspicion and identified if possible. Additionally, grains can be contaminated with seeds from poisonous plants. Many shrubs, trees, and ornamental plants can be toxic to horses.

Hay and feed pellets can pose a toxic risk when unintended substances are incorporated into the feed. These substances include toxic weeds, toxic insects such as blister beetles, and dead animals that can serve as the origin of botulinum toxin production. Rotting, decomposing feeds or improperly stored haylage can also contain botulinum toxin. Pelleted or supplemental feeds can contain contaminants such as ionophores (such as momensin) or antibiotics due to mixing errors or contamination from transport vehicles. By-products from grain distillation can be present in supplemental feeds and can contain mycotoxins and antibiotic residues.


Monday, July 27, 2009

The Science of Wound Ointments for Horses

Equisearch.com - Full Article

A topical wound preparation can have a big impact--positive or negative--on the healing process. Here are tips from a wound-care expert for selecting the right product for your horse's injury.

By Christine Barakat

Your horse comes in from the pasture with a small cut on his chest. Maybe he hit the fence while playing or perhaps it was a tree.

In any case, the wound is fresh, clean and small. No need to call the veterinarian--you can handle this yourself. You reach for a tube of the thick wound ointment you've always used and smear a good-sized glob across the cut. That'll take care of it. Or will it?

Perhaps, says researcher Georgie Hollis, BSc, MVWHA, but it depends on what's in the tube.

The right preparation applied at the right time can protect a wound, support natural healing processes and minimize the risk of complications. But, warns Hollis, use the wrong type at the wrong time and you could actually slow down or even halt healing.

For the past three years, Hollis has been working to help make choosing the right ointment for each situation easier. A former podiatrist, she first observed the challenges of wound healing when she treated foot lesions in diabetic patients. In late 2006, Hollis, motivated by her personal interest in animals and horses in particular, began studying veterinary wound care. She now works with leading equine researchers, such as the University of Liverpool's Derek Knottenbelt, DVMS, MRCVS, in investigating and sharing information about how various treatment techniques affect healing.


Friday, July 24, 2009

Water and Dehydration Study Clarification

by: Multiple Authors

A 2008 Equine Veterinary Journal (EVJ) publication examining dehydration in working horses was summarized and printed onTheHorse.com on April 24, 2008, prior to its actual publication in EVJ. It was reviewed and approved by the researcher. The complete publication (in which Dr. Joy Pritchard was first author) was titled "Validity of indicators of dehydration in working horses: a longitudinal study of changes in skin tent duration, mucous membranes, and drinking behavior."

Recently, Dr. Olin Balch, a member of Veterinary Committee of the American Endurance Ride Conference (AERC) contacted Pritchard and TheHorse.com with committee concerns that the summary could be misinterpreted, especially where endurance horses are concerned.

Balch and Pritchard coauthored the following clarification.

Pritchard said, "My research studied changes in physiological parameters in 50 working horses pulling carts or carrying loads at moderate speeds in Lahore, Pakistan, over a period of 5 hours. While these results could be generalized to similar horses in developing countries, the conclusions are not directly transferable to any other horses, endurance or otherwise.

"The results illustrate that--in the sample population studied--neither a set of standardized skin tent tests, nor gingival mucous membrane dryness, nor other clinical parameters including heart rate, respiratory rate, and coat dryness/wetness were associated with hydration status," she continued. "Only volume of water drunk and drinking behavior were significantly associated with hydration status in these animals.

"The EVJ paper states clearly in the discussion and conclusion that working horses may not drink for internal and external reasons. Lack of drinking is not a conclusive sign of normal hydration status in the animals studied."

Balch said, "As a member of the Veterinary and Research Committees of the AERC, I believe that Dr. Pritchard has written a very important paper emphasizing that classic indicators of dehydration in horses (such as skin tent duration and mucous membrane dryness) may be quite misleading. The AERC sanctions approximately 23,000 horse starts in well-organized, veterinarian-supervised endurance rides in the U.S. and Canada annually.

"It is our collective experience, as experienced endurance veterinarians, that it is extremely common for horses in endurance rides to become dehydrated and yet refuse to drink water," continued Balch. "This is especially common early in rides where an excited horse may travel 25 miles without taking a drink. Additionally, we are convinced that exercising horses who refuse to drink water and become extremely dehydrated run the very real risk of suffering metabolic disorders. That is why riders must be attuned to their horses' water intake and take care to assure their horses are drinking adequately during endurance rides. The consequences of severe ileus or other forms of colic following dehydration and electrolyte depletion, although extremely rare at endurance rides, may lead to death.

... full article

AHC Seeks to Document Equestrian Access Issues on Public Land

The American Horse Council has launched a new effort to collect information on access issues equestrians are experiencing on federal lands. The center piece of this effort is an online form equestrians can use to report their personal experiences regarding trails and federal lands that have been closed to them or other access issues.

Americans who use horses and pack stock enjoy a unique experience when they ride on trails and public lands. It is an experience that ties them to the 'pioneer' era and provides not only a way to connect with America's vast and unique natural resources but a link with America's history and traditions. It is an experience that cannot be enjoyed without a trail system, trailhead access and areas for camping. It is an experience that Americans enjoyed even before there was a national park system and an experience they want to continue.

Unfortunately, equestrians are seeing an increasing loss of access through trail restrictions, trail closures, and use restrictions. Riders and stock users are being excluded from areas that they have historically traveled through and indeed first opened up. It is a loss of opportunities for riders, families, persons with disabilities, school groups and others. There seems to be a management environment less open to these traditional forms of use. Sometimes restrictions on equestrian use are done intentionally through management plans that reduce, restrict or eliminate horses, horse facilities, camping or grazing restrictions, cross-country travel restrictions or closures. Sometimes the restrictions are indirect though a lack of trail maintenance, or over regulation, or lack of services to the public like facilities that provide saddle and pack animals or parking for horse trailers.

In order to better combat this disturbing trend the AHC is asking equestrians to document examples of trails or entire areas that have been closed to equestrians on federal land (National Forest Service, National Parks Service, and Bureau of Land Management, etc). The AHC is seeking all relevant information concerning these closures such as the reason for the loss of access, details concerning any public process that was involved and the history of equestrian use on the closed trail or area.

The AHC is also interested in examples of attempts to bar equestrian access that have been defeated.

"The reduction of trails, trail heads and the closure of public lands to horses and pack animals is a continuing problem for equestrians. However, there is no centralized, comprehensive database that documents any loss of access and even fewer specific examples," said AHC President Jay Hickey. "We hope by giving equestrians a place to report their experiences we can get a better picture of the problem and use that information to fix it."

The AHC is asking all recreational riders to visit the AHC website and report any access issues they have had using this electronic form https://www.horsecouncil.org/survey.php. This will be a permanent feature of the AHC website.

"The AHC is committed to preserving equine access to public lands. It is very important for these efforts that we have evidence that demonstrates the extent of the problem and the need for action on the part of Congress or the federal land agencies," said Hickey.

Contact: Bridget Harrison

Tuesday, July 21, 2009

Joint supplements - a vet's perspective

Question 1:"what are the best and least expensive joint supplements to use on my horse for healthy joints?"

Question 2: "what are the benefits of Adequan vs Legend?"

Answer by Susan Garlinghouse, DVM, MS:

Answer 1: Here’s my opinion about joint supplements, both oral and injectable.

There’s no data to support that providing any sort of supplement prior to actual clinical signs of degenerative joint disease actually delays its eventual onset. However---if we consider what we ask these horses to do, even the best conditioned, most intelligently managed horse is going to have *some* degree of inflammation in its joints after a ride, and even though that inflammation may be insufficient to appear on an x-ray or in a lameness exam, it makes sense to protect those joints as much as possible. As such, I give my horses joint supplements when they’re working hard; and the 17-year-old campaigner I’m currently riding is getting practically marinated in the stuff, even though he doesn’t have a whisper of lameness, just because he’s working hard and is seventeen years old.

Of the oral forms of supplements, the best data available is from NutraMax Labs, that developed and markets the original oral supplement, Cosequin. They do show a measurable benefit provided by regular dosing, BUT---even the most expensive, name brand stuff out there only has a bioavailability of about 3-4%---which means you have to feed boatloads of it to get a smidgen of it into the circulation where it can eventually be taken up by inflamed joint tissue. Pretty expensive stuff for most of it to end up in a poop pile (though I’m happy to report the flies on my property feeding on that poop have never looked so spry). The bioavailability goes down when you get into the generic versions---even though the ingredient label may still say “chondroitin sulfate”, the label doesn’t tell you the Daltons (size, more or less) of the molecule in question. The bigger (read “cheaper”) the molecule, the less likely it is to be absorbed in the GI tract and thus get used effectively. There’s a good bit of data that supports the notion that most of the generic joint supplements available at Costco don’t do a darn thing, just because the molecule is too big to be absorbed. And remember, the very BEST source out there is only 3-4% available when fed orally.

That being said, I hugely prefer going the injectable route, because then I’m bypassing the GI tract entirely and most of the injected dose is getting to inflamed tissue where it belongs. Yes, I know the injectables are more expensive per dose, but I’d rather pay more for a vial of liquid gold that’s almost entirely bioavailable, then paying a lot less for an oral supplement that’s mostly ending up in the manure dumpster. Even I can do that math. I’ve heard differing things about the oral hyaluronates, but still prefer going the direct injectable route with that as well, for basically the same reasons.

Because I own an animal hospital and mostly work on companion animals for a living, I use the injectables in a whole lot of different species and it helps a bunch, especially in creaky, arthritic old dogs. Sometimes it’s hard to see a tangible difference in horses that are still pretty much moving okay, but I know a dog is feeling better when he starts asking to go for walks again, jumping into the car without help, whatever. I always tell my owners not to expect a miraculous improvement overnight, because we’re not just masking symptoms with a painkiller, we’re approaching the source of the disease process directly, and that takes some time. I usually dispense enough for the initial loading period of six weeks or so and sometimes then I’ll ask the owners if they saw an improvement and would they like a refill. Sometimes they tell me they didn’t see much benefit, so nope, they’ll skip the refill. I can pretty much set my watch that a month later, they’ll be calling for that refill, because they didn’t realize how much better old Duffy was until they STOPPED giving him the Adequan. I’d guess I probably have about a hundred patients on it in my practice at any given time.

I couldn’t tell you the efficacy of the generic injectables. I know they’re out there, but I use the brand name Adequan and/or Legend in my practice, just because I’m positive those are effective, and I need to use that not only for my own animals, but also for my clients.

So, I know you’re looking for something inexpensive to feed, but I’m going to go out on a limb and also assume you want the most bang for your buck. My advice would be to skip all the oral supplements entirely, with the possible exception of some source of omega-3 fatty acids, which have a different mode of action but are still pretty good for assorted inflammatory conditions, including those affecting the joints. The most cost-effective source of the O-3s is maybe a cup or two of freshly ground whole flax seed---grind it up yourself in an electric coffee grinder, stick it in baggies into the freezer and give your horse a baggie once a day.

Take whatever your annual budget is that you were planning on spending on oral joint supplements and figure out how much Adequan, or Legend, or both, that you can afford. Do that. Resis the urge to feed something other than the aforementioned flax seed. You’ll get more benefit from an Adequan or Legend injection once a month, or twice a year, or whatever suits your budget, than you will by feeding the oral supplements on a daily basis---especially if the oral supplement is one of the cheap ones that oh-by-the-way, has such low bioavailability that 99% of it is going into the dumpster.

Hope this helps. BTW, all the above comments also apply to arthritic dogs, kitties, bunnies and darn near every other species out there. I won’t comment publicly on its applicability to humans, because I’m not licensed for that species and the DEA would be sending me nastygrams as soon as they finished tracking down whoever it was that sold propofol to Michael Jackson.

Susan Garlinghouse, DVM

Answer 2:
That’s a really good question, and I’m going to go out on a limb here and assume you’re interested more in a practical answer than debating the p-values and historical influence of the senate subcommittees on its use, so forgive me if I gloss over some of the finer biochemical details. Both Adequan and Legend tend to achieve the same end goal of by slightly different pathways. Both have the end effect of increasing the concentration of hyaluronic acid in joint capsules and tendon sheath (and a few other assorted locations). Hyaluronic acid is a nifty little ‘backbone’ molecule that binds water within the joint fluid---the best analogy I can think of is one of those coat hangers with all the clips on it for hanging pants and skirts and things. The more coat hangers you have, the more things you can grab onto. So, the more hyaluronic acid, the more water molecules you can grab. That’s handy, because water is about the only substance on earth that doesn’t compress under pressure and so is a really great shock absorber within the joints. That helps prevent rubbing and friction within the joint during high-concussion which is likely to result in inflammation and, over time, arthritis.

So Adequan acts by stimulating the cells that line the cartilage (that’s the layer inside the joint capsule that covers the ends of the bones) to naturally produce more hyaluronic acid. Legend is actual hyaluronate itself, which after injection, is preferentially taken up by inflamed tissues throughout the body, including within joints. Dunno how the body ‘knows’ but that applies to lots of different processes in the body we still haven’t figured out but are happy to take advantage of, anyway. Hyaluronate is also commonly one of the substances injected directly into a joint, usually along with a small amount of a long-acting steroid, but that will only directly affect one joint; whereas systemic administration will affect pretty much all the joints within the body, though to a lesser overall extent. If you’ve ever heard of a horse getting his hocks injected (or knee, or fetlock or coffin joint), that’s what they’re talking about. Not something you do lightly, though, because directly injecting a joint is definitely a veterinary procedure that has to be done exactly right.

If you absolutely had to choose between Adequan or Legend, then the general concensus in the online vet community (we have our own discussion groups where we chat about this kind of thing and no, they’re not open to non-vets) is that Adequan is preferred if you have soft tissue involvement (like tendons and ligaments), and Legend is a bit preferred for straight arthritic conditions. Adequan, of course, also benefits arthritic conditions as well, but seems a bit better for general wear-and-tear. If you want the absolute best of both worlds, then do both, and that’s what I do for my horses that are working hard or have some issues they’re dealing with.

If I had to choose between one or the other for preventative maintenance, then I would probably go with Adequan, because I think it benefits tendon and ligaments as well as strictly joints a little better, and I want to cover as many bases as possible. For an older horse with DJD, then I think you’ll get more benefit with Legend. As I said, though, the gold standard would be both but hey, we can’t all wake up with Oprah Winfrey’s budget every morning.

Someone else asked me if they could only afford a few injections a year if there would be any ‘spiking’ effects and no, there’s no downside to less frequent dosing except that you’re just not getting as much benefit as you would with frequent administration. If I had to time it around a riding season, I would probably use up my budget starting a month or so before the first ride, when presumably, you’re starting to ramp up workouts. If you can give the horse some additional during the season, better. If you can give them some more right at the end of the season when they’re about ready for a rest and probably have some active inflammation to one extent or another, that would be great.

The other question someone asked me was whether this was something an owner could do, versus having to call out the vet. Adequan is an intramuscular injection, so most owners can do that. Some drugs (like procaine penicillin) you have to be careful to keep out of veins and such, but Adequan isn’t a problem if you happen to hit a vein. Some of the racetrack people prefer Adequan IV, though I go IM myself. Legend might be bioavailable if you injected it IM, but is best IV---so if an owner were comfortable doing an IV injection themselves, fine. It’s legal for an owner to administer meds to their own horse by any route, but starts getting into gray areas doing it to anyone else’s horse, aside from potential liability problems if you do it wrong. So if your vet is willing to supply you with either Adequan and/or Legend, and/or you’re otherwise able to obtain it somewhere (I don’t know if you can buy it online without a prescription, you probably can), and you’re comfortable injecting your own horse, go for it.

Hope this helps.

Susan Garlinghouse, DVM, MS

Friday, July 17, 2009

Why Horses Stumble

Heather Smith Thomas

Some horses stumble or stub their front toes frequently, with the toe hitting the ground while the knee is still bent and the leg collapses instead of taking weight. The horse's head and neck drop down, but he usually catches himself by rapidly extending the other leg. Most of these horses are not lame, yet might occasionally fall to their knees or go down with a rider. The habitual stumbler might manage fine when running free, but tends to trip and stumble when being ridden or led. The stumbling horse is frustrating to ride, and he can be dangerous.

Stumbling can be caused by a number of things, including long toes, long feet, hoof imbalance, laziness or boredom, and in some instances devious behavior--a few horses learn they can get out of work if they stumble because a concerned rider thinks there is something wrong and ends the ride. Stumbling can also be due to inadequate conditioning (such as a young horse unaccustomed to carrying a rider, or a horse whose muscles are out of shape), poor conformation, incoordination, joint problems, chronic foot pain, damage to the central nervous system (brain and spinal cord), brain disorders such as narcolepsy (sudden attacks of sleep), or weakness due to fatigue or illness.


Thursday, July 09, 2009

Suspensory treatment: Mending With Marrow

by: Heather Smith Thomas

Suspensory ligament injury is a common problem in athletic horses, and it is often slow to heal, with a high recurrence rate when a horse returns to work. Douglas Herthel, DVM, of Alamo Pintado Equine Clinic in Los Olivos, Calif., has been using bone marrow in a new technique for treating these injuries. He began his study in 1995, looking at bone marrow, which contains stem cells, monocytes, platelets, and fat.

"A recent unpublished survey that was done at UC Davis indicates this is the single most common cause of lameness in the show horse," says Herthel of suspensory ligament injury. "It can affect almost any horse that is in athletic performance.

"The experience we had in treating these during the past 25 years--prior to stem cell therapy--was fairly dismal," he continues. "Ours is a referral practice, and we usually got the cases after they'd been looked at and treated numerous times. We were averaging only 20% success in return to full work."


Monday, July 06, 2009

Study: Offering Water an Accurate Gauge of Dehydration

Thehorse.com - Full Article

by: Christa Lesté-Lasserre
April 24 2008

If you lead a horse to water, you might not be able to make him drink, but it's still a great way to gauge whether he needs that water or not, according to recent British research examining working horses and dehydration levels.

The researchers found that the commonly used "skin tent test" (pinching up a section of skin to note the time it takes to return to its normal position) varies greatly according to the horse's age, the humidity of the coat, and the site of the skin tested. Furthermore, it has no significant connection with the actual state of hydration in the horse, according to the study.

Because of this, the skin tent test is not a valid method for evaluating dehydration in horses, said Joy Pritchard, PhD, DVM, co-author of the study and a researcher at Bristol University. Pritchard is also head of animal welfare at Brooke Hospital for Animals, a U.K.-based charity that focuses on equids in developing countries.


Sunday, July 05, 2009

House Funding Bill Excludes Animal Identification System

Thehorse.com - Full Article

by: Pat Raia
June 16 2009

The National Animal Identification System (NAIS) will receive no new funding under a 2010 spending bill proposed by the U.S. House of Representatives Agriculture, Rural Development, and FDA appropriations subcommittee. Chairwoman Rosa L. DeLauro (D-Ct.) announced bill details on June 11.

The NAIS is a nationwide livestock database designed to help federal and state agencies locate and track the movement of animals in the event of disease outbreaks or natural disasters.

The program uses data provided by livestock producers and property owners to assign identification numbers to individual animals and to properties where animals are born or reside. Registry participation is voluntary. But the program has failed to attract substantial support among livestock producers.

"There is overwhelming concern about NAIS registration becoming mandatory. There is also opposition to the whole concept by some (who fear) that they will have to ID their animals to move them through commerce," said Nancy Robinson, vice president of government and industry affairs for the Livestock Marketing Association.


Thursday, July 02, 2009

Horses React to Human Heart Rates, Study Finds

Thehorse.com - Full Article

by: Nancy Zacks
July 01 2009

An increase in a human's heart rate affects the heart rate of the horse they are leading or riding, researchers at the Swedish University of Agricultural Sciences recently reported.

Linda Keeling, PhD, and colleagues tested horses and riders to see if humans inadvertently communicate fear and anxiety to horses. Using heart rate as a fear indicator, the researchers asked 20 people with varying levels of horse experience to walk and ride 10 horses from Point A to Point B four times. The researchers told participants an umbrella would open as they rode or led the horse on the fourth pass. The umbrella never opened, but heart rates in both horses and humans increased during the fourth trip between the points, when the human expected the umbrella to open.

"The increase in the horses' heart rates probably means that they are more alert and prepared to react to any potential danger," Keeling said. "In the wild, horses are adapted to respond to other animals in their group. A startle reaction is more likely when the horse is very alert."


Wednesday, July 01, 2009

So what happens to the Mongolian horses after the event?

July 1 2009 - Karen Chaton Enduranceridestuff.com

I wrote and asked the Aventurists that question a couple of days ago, and still have not gotten a response. However, I did get a couple of answers from Long Rider’s who have ridden in Mongolia.

I was wondering what might happen to the horses after they do their 25 mile (40 km) section of the Mongol Derby. Somehow, they need to get back home! Obviously the (possibly up to 26 used on each leg) horses won’t be hauled back home in a trailer. The consensus is that most likely the animals will be turned loose to find their way back home. It sounds like these are pretty smart horses.

Yet, that effectively doubles the distance that they must go. Granted, without the rider on their return trip. I know the website states that this race is not a test of endurance for the horse. I would consider it a test of endurance for my own endurance horse to be ridden 25 miles one day and then be turned around and set loose to find their way home in the next few days. Hopefully these guys will let the horses stay a day or two and rest and rehydrate and eat well before sending them on their way.

I have a quote from Bonnie Harpp who has ridden in Mongolia: “No Mongolian is going to give up his best horse for such a race. Horses are a spiritual symbol to Mongolians. They will pull out a few old nags or, I believe, go out and pull some of the more acceptable looking horses off the steppe. There are no barns there or corals. It is entirely different. People here would never believe it.”

I did the math to figure out how many 25 mile legs each rider will have to do per day in order to finish the entire race within a week. Since this is an event challenging the endurance of the rider rather than the horse I would think that each rider would be riding at least 50, 75 or 100 miles per 24 hour period. You couldn’t finish in three weeks if you only rode 25 miles per day. If you rode 50 miles per day, which would take two Mongolian horses each going 25 miles every single day - and you didn’t take any days off you would be riding for 12 days.

Most very fit endurance riders I know would be knocked on their butt riding 24 different horses 25 miles each for 12 days straight. I think they would find it very difficult riding their own same horses that distance in that same time period. Especially given the more extreme and rough conditions that these participants are sure to encounter. Endurance riders in the US are pretty spoiled and used to lots of creature comforts. These guys aren’t going to finish every night to a nice meal (after having lunch possibly provided, or at least easily made themselves) with a shower and a nice already made bed waiting for them. They are going to have a rough time.