COW: Routine Castration(s)

Gelding horses is the most routine surgery done in equine practice. I thought you might enjoy seeing how this surgery is done in the field. What follows are pictures from a couple of castrations that I performed recently. The first victim was a Minature Donkey. The second is a 2yr. Fresian. Anesthesia, is of course an essential component, since most horses (or donkeys) are not necessarily fond of having their testicles cut off.

A word of caution: The pictures below are of the real word and involve real tissues. If you have a weak stomach and/or are in the midst of eating something, you may not want to scroll down.

We will start with the Donkey.

We use injectable anesthetic agents to anesthetize the patient.

Once the patient is out cold, the hind legs are restrained by tying them up with ropes.

After the area of interest is thoroughly scrubbed an incision is made over each testicle. The testicle is then identified and lifted from the incision.

Donkeys tend not to clot as well as horses do, so it is important when gelding donkeys to be sure the blood supply to the testicle is tied off well. We do this by ligating (tying an absorbable suture) tightly around the vasculature.

The testicle and epididymis are now ready to be transected from the patient. I like to place a clamp across the cord before cutting the cord.

It is essential to closely inspect the removed tissue to ensure that the testicle and epididymis have been removed in their entirety.

This is what it looks like once both testicle has been removed, but the cords are still being held in clamps.

Done. The incisions are not closed up, but rather are left open to heal by second intention. Significantly more complications are encountered if the incisions are sutured closed.

Now all that is left is to wait for the little guy to recover from anesthesia.

That is how it is done on a little one. Most of the time our patients are a bit larger. Here are some pictures of the same surgery, but on a much bigger horse.

General anesthesia is induced with an intravenous injection. This protocol usually gives us about 20 minutes of anesthesia.

Timber!

Once the horse is down, we tie the hind leg forward, providing a nice space in which to work.

With the surgical site thoroughly scrubbed, an incision is made over each testicle. Often in these large, more ‘well developed’ horses, we will remove a portion of the scrotum. The testicle is then identified and easily extracted.

After the testicle has been exposed we ‘strip’ the cord by removing any overlying connective tissue, so that we are left with the testicle fully dissected from the adjoining tissues.

I like to ligate the blood supply to the testicle in these big horses, like we do with the donkeys.

With the cord tied and clamped, the testicle is cut off with a surgical tool known as an emasculator. This instrument is specifically designed for this procedure. It not only cuts off the testicle and epididymis while simultaneously crushing the blood supply.

The second testicle is removed in like fashion. Here are the fruits of our harvest.

That is pretty much how it is done.

USEF Drugs and Medication Rule Changes

The recent changes demolition Google made to their Google Reader has made it much more difficult for me to post links in the 'Current News' section of this blog. So, for now, I am stuck posting links that I find of particular interest in its own blog posting, such as this.

This week the USEF made known some impending drug and medication rule changes. If you exhibit your horse in an event that uses USEF drug rules, it is well worth your time to review this information. Click here to get the details. This article also has links to some USEF literature that is worth reviewing.

Did You Know?

Did you know that WMVS has a clinic facebook page? Join in the fun by clicking here.

Also, did you know that we have an online pharmacy? Both prescription and non-prescription products are available through our online pharmacy. Prescriptions are processed automatically through our office for approval, so you do not need to do anything to send or fax any prescriptions in. Orders over $39 receive free shipping. So save your gas and order your Bute, Banamine, Adequan and all your other meds and supplies online.

We are also very close to completing a major update to our clinic website. Our new site will include a page with links to our clients web page. If you would like to have your website listed on the 'Our Clients' page, please call our office at 616-837-8151, ext. 5 to find out how to have your website included.

Fall Reminders

Right now is a great time to get on board with the 'new' deworming program since sometime over the next couple of weeks is the time to submit fall fecal samples. The details of our 'new' deworming recommendations have been discussed previously on this blog and have been posted here on our clinic website.

Now is also the time for fall checkups and vaccines. Typically in the fall we recommend boostering the Flu and Rhino vaccines your horse recieved this spring. The immunity from these vaccines is fairly short lived, thus semi-annual boosters are required. We also usually incorporate Rabies vaccines into the fall visit. The Rabies vaccine in horses requires annual boosters. Rabies is one of those diseases that has since an increased incidence in horses in Michigan over the past couple of years. The disease is always fatal and always poses a significant human health risk to those who come in contact with an infected horse. The vaccines is safe, effective and cheap. There really is no excuse not to vaccinate.

This is also the perfect time of year to schedule the routine dental care for your horses. Fall is the ideal time to provide for your horses dental health as we seek to maximize their feed efficiency through the quickly approaching winter months. The field of equine dentistry has seen significant advances in recent years. We are now better equipped than ever to address oral health issues including bite realignments and treatment of peridontal disease. Dental radiographs can be an invaluable tool in assessing diseased teeth. We believe strongly that your regular veterinarian is your best resource for equine dental care.

See you soon.

Welfare Reform

The ongoing discussions in the both the horse community and legislature about the social consciousness of horse slaughter continues. In 2006, Congress defunded inspection of horse slaughter plants. This act functionally shut down the two remaining horse slaughter plants in the U.S. That act brought discussions about the complexities of animal welfare to the forefront for everyone involved in the equine industry. This past week the GAO released a report asking Congress to either institute a permanent ban on horse slaughter or allow it. This recent report by the GAO has put a renewed light on the horse slaughter debate.

The issue of welfare (the non-entitlement kind) is well beyond the scope of what I can adequately address here. The complexities of the debate about animal welfare is, in large part, fed by individuals different perceptions of what is truly the best welfare option. Last year’s annual meeting of the American Association of Equine Practitioners (AAEP) devoted their keynote address to this topic. As I listened to this presentation it really hit me how stark the disparity is between differing individuals beliefs of what really constitutes the ‘best’ practices of animal welfare. Is protection from natural predators better welfare than free ranging in a ‘natural’ environment? Is a low level of infectious disease better welfare than having social interaction? More poignant to this discussion: is humane slaughter under federal inspection better welfare than malnourishment? is humane slaughter of equids a better option than owner neglect or owner performed euthanasia? is it more humane to use animal products for human consumption or to put a carcass in a landfill? These are complex issues vehemently argued by camps with opposing presuppositions.

Regardless of perspective, this recent GAO report refreshes the discussion of the current stalemate on the horse slaughter issue. According to this most recent GAO report the current plant closures have pushed the horse slaughter market to Canada and Mexico (which do not have the same regulations for humane transport and handling as we do here), have resulted in significantly lower sales prices of lower grade horses and have had a negative impact on the welfare of these horses by greatly increasing the long distance travel times to horse slaughter facilities.

The basic conclusion of the GAO is that we, as a society, need to move out of purgatory and decide on either re-implementing the option of the humane slaughter of horses or move to a formal ban. The current legislation that functionally does an end around on humane slaughter only leaves those seeking to have it overturned, to do so by another legal end around. The result is that the best intentions often end in the worst outcomes.

For a more in depth look at this issue click here

Equine Repro Update

I spent that past couple of days at the Society for Theriogenology annual meeting. If that is a foreign term to you, theriogenology is really just the study of reproduction in animals. This meeting brings together the innovators in this field to present on new and exciting advancements.

One of the most exciting talks I sat in on was discussing the advancements in embryo diagnostics. More specifically, it is now possible to acquire an embryo, biopsy it for genetic testing-either traits or heritable disease-freeze it for indefinite storage and later thaw it for implantation into a recipient mare for her to carry to term. Equine embryos are generally not inherently resilient to manipulation. The group from Texas that presented their advancements in this field have made remarkably astounding advances with embryo biopsy and testing. While much of this is not really commercially available as of yet, just a couple of years ago the levels of success they are now achieving were not even thought possible. Many of these advancements have sprung out of the recent refinement and success of the ICSI procedure, as previously discussed here. Stay tuned.

Another exciting advancement comes out of Colorado. Veterinarians at Colorado State University have developed a PCR test for uterine fungal infections. Uterine infections in horses are usually caused by bacteria. However, on occasion a fungal organism is pegged as the culprit. To this point, fungi have been difficult to reliably culture and identify. Not to mention it can take several weeks to grow them in the lab. This new technology looks for evidence of fungal DNA. They then replicate the DNA in the lab and analyze it to determine the exact type of fungus. This is incredibly useful because results can be achieved in days rather than weeks. Again this test is not yet commercially available, but should be very soon.

Topics that were covered in depth included stallion breeding soundness exams and placentitis. Stallion breeding soundness exams focus on the predictability of a given stallion to be able to produce foals. Despite all of the advancements over the past many years, this still remains a somewhat elusive target. One thing that is becoming increasingly more apparent is that sperm motility does not correlate well with fertility. This goes contrary to historically popular thinking. But the reality is that some stallions have very good motility and poor conception rates, while other stallions have poor motility and yet have reasonable conception rates. That said, we still feel better seeing good motility. The reality is that relating the findings on a breeding soundness exam to future fertility remains ‘complex and multifactorial’- that is medical jargon for we do not yet have a perfect understanding of this. This does not mean that breeding soundness exams are worthless, quite to the contrary. It just means that they are not black and white, and many factors need to be looked at and addressed when considering the current or future breeding soundness of a given stallion.

Researchers continue to explore the complex disease that we have come to call placentitis. Placentitis is an infection of the placenta. The vast majority of the time, bacteria gain entry into the placenta through the cervix of a mid to late term pregnancy. Mares with poor vulvar conformation are particularly at risk. Early identification is crucial to successful treatment. If the injection becomes too extensive the foal can quickly become compromised. The more extensive the infection is the more difficult it is to treat. The best way to look for evidence of a placental infection is ultrasound evaluation of the placenta. This remains our best tool for assessment of placentitis. Treatment usually involves long term antibiotics, anti-inflammatories and progesterone supplementation. There is a lot of new research looking at what are the best medications to use. However, the reality is that successful treatment is tightly correlated with early identification of infection. With this in mind, it may be prudent to screen at high risk mares with ultrasound evaluations of the placenta in late pregnancy.

The last talk I wanted to highlight from this meeting was a presentation by a veterinarian in Argentina who has perfected a large scale embryo transfer program in horses. Embryo transfer is becoming increasing more common. The success rates with embryo transfer continues to improve. The ability to ship recovered embryos to large recipient herds available throughout the U.S. has made this whole venture considerably more practical. There is now an embryo recipient herd here in Michigan (Saginaw) that has been very good for Michigan breeders. The major advantage of a ‘local’ recipient operation is that the cost of shipping and transport of recipient mares is greatly diminished. It also makes it much easier to transport recovered embryos to an ideal recipient because we can now just hop in the car and drive the embryo to its destination, rather than having to rely on the airlines for same day shipment to a recipient herd. Cryopreservation of equine embryos continues to be a challenge. Techniques for improving embryo transfer success and improving efficiencies was covered in great depth.

Even as we are just wrapping up this breeding season, this meeting has reinvigorated me, as I sit in anticipation of next year’s breeding season. The continued advancements in equine reproduction are astounding.

Michigan Coggins Testing Rules Change.....again

The requirements for Coggins testing in Michigan has changed yet again. Earlier this year the prior requirement of annual calendar year testing for horses that are shown or sold expired. That left us without any legal requirement to test. However, shows and fairs still could still require a negative test. Last week the state legislature passed P.A.121 which reinstated the Coggins testing requirement, with a few changes.

A Coggins test is a blood test for a contagious viral disease that affects horses called Equine Infectious Anemia (EIA). EIA is a disease for which there currently is no treatment or vaccine for. As such, infected horses only serve a source of infection to other horses. Testing is the only method of disease control that is available. The disease is a federally regulated disease which requires the test to be submitted and reported on a federally approved form.

Here is the short version of the new law:

1. The following requirments for a negative EIA test do not apply to foals 6 months old or younger.

2. A negative EIA test is now considered current if the blood sample was obtained within the prior 12 months.

2. All horses entered in shows, exhibitions or fairs must have a negative EIA test.

3. Any horse that changes ownership AND location within the State of Michigan must also have a negative EIA test.

4. Any horse entering, remaining or on the premise of any horse auction or market must have a negative EIA test within the previous 12 months.

5. All horses entering the State of Michigan must also be accompanied by a negative EIA test.

The most significant change from the old law is that there is no longer a calendar year requirement. The calendar year requirement was not without reason, but it was a logistical frustration for all of us. This is a welcome change to the law. The caveat to this, is that under the old law many people had their Coggins tests done in January so they would not have to worry about it the rest of the year. Under the new law, your Coggins test for next year will expire one year from when it was drawn. So those who had a Coggins done this past January will have to have next year's Coggins done in January again, if their circumstances meet the requirements of the new law. Click here if you care to know the details of what the requirements used to be.

Look how far we've come

I stumbled across this video that I think you would enjoy. It's really just a quick overview of some of the advances in equine veterinary medicine in recent years. Click here for the link, or go to http://www.myvnn.com/page.asp?id=39&media_type=11&story_id=127

Along the way...

I realize it has been a while since I've made time for a post. This is my best attempt at playing catchup. These are some images I've acquired in my recent travels, that I hope you will enjoy.

Further evidence that veterinarians never know what they will encounter in the course of the day.

This was a large ulcer in the cornea, as demonstrated by the large green area in the center of the cornea. The green area is a stain that we put in the eye that gets taken up by the cornea when the superficial layers of the cornea have been disrupted. You can tell this has been going on for quite a while because of the blood vessels that you can see starting to migrate from the margin of the cornea. The blue haze on the left side of the eye is the result of edema within the cornea. This horse has an unstable tear film which made this a very difficult case to manage.

This is a pair of ultrasound images from a fetal gender determination. This is an incredibly reliable method of determining the gender of a fetus, in utero. It is best done between 60 and 70 days of pregnancy. At this stage of pregnancy gender can be determined by the location of the genital tubercle (labled as GT in these images). In this case the GT is immediately behind the umbilical cord. It can also be seen in the image all the way to the left between the hind legs. This fetus is a colt. If it were a filly the GT would be up under the base of the tail.

The owner of this establishment is presumably is an Appaloosa breeder.

One of the joys of getting up early in the morning is the ability to appreciate the handiwork of God. Note the symmetry in the clouds.

This was a case of cellulitis I saw the other day. The skin was leaking serum, giving the leg a wet, shiny appearance. What looks like wounds are actually areas where the skin is trying to die. This horse responded well to therapy, and is well on his way to a full recovery.

This is an image of a horse's hoof 2 weeks after a hoof wall resection. The severity of this case required that a portion of hoof wall be removed. After removal of the hoof wall, the tissue will fairly quickly keratinize, which is what you see now at the site of the resection. This is a very interesting case that is ongoing. At some point in the future this case will be worthy of its own post. Stay tuned.

"I'm the king of the mountain."

Further evidence of the limitless creativity of horses to incessantly find new and exciting ways to injure themselves.

This is what the wound above looked like after it was put back together.

I love this picture. Count the number of locks on the door. A couple of days before I was at this farm, I was out at another farm at 10:PM treating 5 horses for grain overload. A well secured feed room door represents a significant cost saving over seeing me at 10:PM.

What is your diagnosis? When I arrived at this farm the pony was out on pasture. This was the first thing I saw when I looked in the stall. Notice all of the saliva mixed with chewed up feed. Horses produce an incredible amount of saliva. When the esophagus (the tube that goes from the mouth to the stomach) becomes obstructed, as in a 'choke,' feed and saliva are no longer able to be swallowed. As a result large amounts of saliva and feed will pour out of the mouth. In such cases, a veterinarian should be called immediately.

One of the challenges of dealing with wounds in the summer months is baby flies (otherwise known as maggots).

Baby horses are a lot cuter than baby flies.

Wolf Teeth

The picture to the right is of the right upper dental arcade. The small little tooth at the very front is a wolf tooth. These small little teeth do not serve any known function, other than to get in the way of the bit. For this reason they are typically removed before a young horse goes into training. Occasionally we will encounter an older horse with bit related issues as a result of a wolf tooth left in place.

They can be highly variable in their eruption pattern. Most are about the size of the one in this picture, but they can also be larger or smaller. Most horses have upper wolf teeth, some only have one, and yet some horses never develop them at all. Very rarely will they appear on the lower jaw. They are almost exclusively only on the upper jaw.

Many people get wolf teeth confused with canine teeth. The wolf tooth is technically the first premolar. They sit just in front of the second premolar, which is a very large tooth, and the first major cheek tooth in the dental arcade. The canines sit quite a bit further forward in the mouth, much closer to the incisors. Canine teeth do not appear in the mouth until 4 or 5 years of age. Another difference from wolf teeth is that they are present on both the upper and lower jaws. A properly placed bit would sit behind the canines, but just in front of the wolf teeth. Most mares do not develop canines, but if they do, they are typically quite a bit smaller than what their male counterparts would have. Canine teeth are considerably large than wolf teeth. They are extremely difficult to extract. Canine teeth are only removed if they are diseased. We do not remove healthy canine teeth.

Because wolf teeth do not serve any known function and because they only serve to be a source of irritation in the bitted mouth, we typically removed them prior to a young horse going into training. The picture to the right is the same horse pictured above, except now the wolf tooth has been removed. To extract the tooth we first numb up the area, cut the gum around the tooth and then gradually work to slide it out with an elevator. The small hole left heals over quickly and uneventfully.

Here is what the tooth looks like out of the mouth. You can see that while they have a very small crown, there is a very long root present.

EHV Outbreak: Update

Here is a link to the latest situation report by USDA of the ongoing outbreak of EHV-1. The exciting thing is that in the past week there have been no new cases on any premise that is not under quarantine. It would appear that this latest outbreak is being brought under control.

USDA's EHV-1 Situation Report (June 8)

Barbaro, Laminitis & 5 yrs.

How can you not remember Barbaro. Can you believe it has been 5 years since he defeated the field in the Kentucky Derby. He brought the world along on his journey through a catostrophic racing injury. However, that is not what ultimately led to his demise. It was laminitis in the other limb that they were not able to get under control which became the last hurdle he could not clear. Check out this video that USA Today put together about Barbaro and the ongoing war on laminitis.

Neuro Herpes Outbreak Update

Here is a link to the USDA's most recent update on the ongoing EHV-1 outbreak. In includes lots of interesting statistics, with breakdowns by state.

http://www.aphis.usda.gov/vs/nahss/equine/ehv/ehv_2011_sitrep_060211.pdf

For more details on the neuro form of EHV-1 see the posting on this blog from May 25.

How Many?

I had a 4-H leader ask me the other day how many teeth do horses have? Sounds like a simple enough question, but the answer is not. It is influenced by several different variables such as age, gender, if any have ever been removed, and if there are any extra ones present. Let me explain.

Let’s start with the basic dentition pattern of the horse. The major teeth of the horse are the incisors, canines, premolars and molars. There should be 6 incisors top and bottom. These are the teeth at the very front of the mouth that are very easy to see. There are 4 canine teeth, two on the top and two on the bottom (one on each side of the mouth). These teeth sit behind the incisors, but in front of the premolars. The bit sits in the space behind the canines, but in front of the pre-molars. The typical adult horse has 12 premolars and 12 molars. They are oriented in a straight row, front to back, top and bottom, on each side of the mouth, with the 3 premolars in front of the 3 molars. With the two top rows, one row on each side, and the two bottom rows all of 6 each, we end up with 24 cheek teeth in all. So in the normal adult male horse we should have 24 cheek teeth (12 molars and 12 premolars), 4 canines, and 12 incisors for a total of 40 teeth. But that is not the whole story.

How many teeth a given horse is influenced by his/her age. The canine teeth do not usually erupt until 4-6 years of age. The last molar does not come in until about 3.5 years of age. The last ‘baby tooth’ is replaced by an adult tooth around 4 years of age.

Gender plays a role in all of this as well, primarily because most mares usually do not develop canine teeth. If they are one of the 28% of mares that have them, they are usually much smaller than those in a stallion or gelding.

Wolf teeth are typically removed at a very young age. They are technically a rudimentary first premolar and can vary tremendously in their eruption pattern. Some horses never get them, some have only one, but most have 2 (one on each side). They are almost always just on the top. It is rare to see wolf teeth on the lower jaw. They do not serve any function for eating or chewing. They often cause bit related problems due to their location and small size. If present, they will sit just in front of the cheek teeth, but well behind the canines. This is the same place that the bit rests in the mouth. We occasionally see them in older adult horses, but most horses have them removed when they are young.

On rare occasion we will encounter a horse with a supernumerary tooth (an extra one). Here is a picture of one I saw just yesterday. It is hard to tell from the picture, but the really long tooth way in the back is actually the seventh tooth back (remember there are only supposed to be 6). Since there is not a seventh tooth on the bottom the upper one just keeps growing and growing. This tooth was an otherwise normal appearing tooth, so we just shortened it with the aid of a motorized burr so that it is no longer rubbing on the opposing gum. This tooth will have to be maintained throughout this horse’s life because it will continue to grow.

So there is the long answer to how many teeth a horse has. The short answer is 36 to 44 in an adult, depending on if canine and wolf teeth are present. If you really want to know exactly how many teeth your horse has, ask your vet next time your horse’s teeth are done and they can give you the exact count for your horse. Of course, that may not be the answer your 4-H judge is looking for.

Outbreak of Neuro form Herpes

I realize I am a little late weighing in on this, but I wanted to make sure you are aware. There is currently an on ongoing outbreak of Equine Herpesvirus Myeloencephalopathy (EHM) affecting horses throughout the United States and Canada. The initial cases were identified at a cutting horse show in Ogden, UT. So far, most of the cases are centered around the western United States. There are, as of yet, no identified cases in Michigan. The challenge with these outbreaks occurring at large shows like this, is that horses from all of the United States can come, be exposed and return home before the first diagnosis is made. This lends to transmission of the virus across wide geographical areas.

Symptoms include fever, decreased coordination, nasal discharge, urine dribbling, loss of tail tone, hind limb weakness, leaning against a wall or fence to maintain balance, lethargy and the inability to rise. First symptoms of a fever and runny nose are usually seen about 2 days after initial exposure. Neurologic deficits do not usually appear until 10-12 days after exposure. The severity of neurologic deficits this virus can cause is what really makes this infection so vicious.

We do not yet fully understand this disease. It is caused by equine herpes virus-1 (EHV-1), more commonly referred to as a rhino virus. This virus is a common cause of upper respiratory infections. However, on seemingly rare occasion, it can mutate and then cause fairly severe neurologic symptoms. There is a point mutation of the virus that has been linked to the neurologic form, but not all horses who become infected with the neurologic form go on to develop neurologic deficits. There is a piece to this puzzle we have not yet found.

This complexity of the virus mutation and variation in symptoms lends to a lot of confusion about what actually constitutes a case of EHM. EHM implies neurologic symptoms, but most agencies define an EHM case based on identification of the mutation in the virus. The problem with this is that a lot of horses that become infected with the mutated form never go on to develop any neurologic symptoms. So a lot of the stats you may be hearing in the press are likely very misleading as to how many horses were ever actually infected with the neurologic form of EHV-1.

Another frustrating point about the neurologic form of EHV-1 is that vaccination is not effective. We do believe that vaccination, with a high antigen vaccine, will lessen the amount of virus circulating and thus lessen the potential for the development of the neurologic form to develop, but we also know that vaccination does not prevent the neurologic form. Vaccination does protect against the respiratory and abortion forms of the disease.

Not all Rhino vaccines are created the same. The high antigen vaccines do a better job a limiting virus shedding. Calvenza is the high antigen EHV vaccine that we use and recommend. There is also a modified live vaccine for EHV, which may be better still at limiting spread. However, there are additional considerations with the use of the modified live vaccine that go beyond the scope of the discussion here. It is best to talk directly with your veterinarian about which vaccine may be best in a given situation. The long and short of it is that over the counter Rhino vaccines are not very good at limiting transmission.
EHV-1 is one of those viruses that can develop into latent infections. Cold sores in humans do this same thing. The virus is always there, but at times of stress (or some other reason) the virus all of the sudden becomes active again. For this reason, seemingly healthy horses potentially could be latently infected and then when placed in a stressful environment, like a horse show, start shedding virus again.

This, is really intended to only be a brief summary about some of the complexities of this virus and the challenges we face in dealing with such outbreaks. The neurologic form of EHV-1 is not anything to mess with. It is a truly nasty disease. Our best strategy for control at this point is good biosecurity practices (see the links below). Vaccination may be of some benefit in limiting the spread of virus, but does not currently protect against the neurologic form. As you can image, there is a ton of more information about this. Here are a couple of good resources if you want to learn more.

USDA info and updates
FAQ’s, provided by AAEP
USDA Equine Biosecurity brochure
AAEP Biosecurity Guidelines
AAEP EHV Control Guidelines

COW: Keep an Eye Out For...

Wow, I did not realize it has been well over a month since my last posting. I will try to make up for it over the next week or so.

Here is an eye that was presented to me recently. What do you think?

This is a tumor, more specifically a squamous cell carcinoma (SCC), involving the nicitans, or more commonly refered to as the third eyelid. The nicitans is a structure that, when the eye is open, hides is the front corner of the eye. In fact, most people do not even realize it is there. It acts as a third eyelid and can slide over the eye. It is mostly made up of conjunctiva with a cartilidge frame that gives it its shape and structure. Below is a picture of the retracted third eyelid. Sorry that it is a little out of focus, but I think you can get the idea.

SCC's are not uncommon tumors of the eye. They have a strong propensity to develop in nonpigmented skin. Horses with white skin around the eye are at higher risk. They rarely spread to other parts of the body, but they can become locally invasive and will rapidly expand into adjoining tissues. This can become a significant problem especially when the eye becomes involved.

Fortunately, this SCC only involved the third eyelid, so we were able to surgically remove it before it invaded the eye itself. Here is what it looked like immediately following surgical removal.

This was a big horse. This last picture pretty much explains why we have such substantial stocks at the clinic.