4/2/2010 - The Prepurchase Exam

Vet tip of the Day: The Prepurchase Examination
Key Words: Intended Use, Physical examination, X-rays

 Today I am going to discuss some theoretical considerations regarding prepurchase examinations.  Tomorrow I will go over the nuts and bolts of the prepurchase exam including what you should expect your veterinarian to do during the exam, and how to determine if x-rays or blood work are indicated.  Right now let's begin with a look at the issue of suitability.

Today I completed a prepurchase examination on a 15 year old arabian endurance horse.  The horse was experienced, with 5,000 competition miles and no history of lameness problems.  The buyers were looking for a safe, experienced horse to do 25 to 50  mile endurance rides, but not at a highly competitive level.  The horse had not been competing for the past two years, but had been consistently ridden as an athletic trail horse.

I share this information with you, and chose this picture of the little cowgirl riding her barrel patterns on what appears to be a very wise old mare, for a reason.  The arabian gelding I saw today, and the old quarter horse poking around the barrel are two very different horses, but each is appropriate for their rider's needs.

A prepurchase exam is a veterinarian's evaluation of a horse's physical well being based on a single evaluation which takes from 45 minutes to a couple of hours to complete. While a tremendous amount of valuable information can be gathered based on a thorough physical examination, lameness evaluation, and diagnostic imaging, even the most rigorous prepurchase exam cannot replace a good history on a horse's past performance record and a buyer's solid understanding of their goals in purchasing this horse.  Obviously the little cowgirl's horse needn't demonstrate the same athletic ability as the 15 year old endurance horse.

As a veterinarian, one of the most challenging situations when performing a prepurchase examination is trying to evaluate a horse with an unknown history which is not performing the job for which it is intended.  For example, last fall I was asked to evaluate a 9 year old thoroughbred mare being purchased as a children's show jumper.  The mare had done some showing as a 5 and 6 year old, and then for an unknown reason had become a brood mare.  She had 2 foals then didn't conceive last year and now was for sale. 

Evaluating a horse like this is really difficult.  She has not been in any kind of exercise program for 3 years and there is no explanation for her change from performance horse to brood mare.  She may have a perfect prepurchase examination on the day I look at her.  She may be sound, have good conformation and pass all my flexion tests and limb palpations with flying colors.  She may have normal x-rays of her hocks, and front feet.  From my perspective, she is a sound horse.  However, I always caution buyers of such animals that the horse is not performing at the level of intended use and has an incomplete history therefore it is impossible for me to have great confidence in assessing the horse's long term prospects for continued soundness.   In fact, when this mare was put back in regular work and began jumping she developed a hind limb lameness that was attributed to a suspensory injury, which very possibly had been the reason she became a brood mare in the first place.

The moral of the story is this:  when purchasing a horse, always look for an animal that is in work, and performing at least close to the level at which you intend to use it.  It is then much more likely that your veterinarian will be able to accurately identify issues of concern and discuss them with you.  Make every effort to obtain a history of the horse's past performance and ask the seller why the horse is for sale.

A prepurchase examination is a very important part of making a wise investment.  Often I identify problems during a prepurchase exam about which the seller was unaware - that is why we subject the horse to unusually rigorous conditions during the examination such as trotting small circles on very hard and very soft surfaces.  But at the end of the day, the ethical horse seller with a complete history on their horse can be equally as valuable as your veterinarian's assessment.  Tomorrow I will discuss in detail what you should expect from your veterinarian during a prepurchase examination.

The wind is howling - Mother Nature has been very restless throughout March and appears to be continuing her mood right into April.  Keep your head down and your spirits high.

4/1/2010 Protecting our Ecology

Vet tip of the Day: Homeostasis- Support the Water Wars

Today's vet tip isn't strictly about veterinary medicine, but it is about the most important concept behind practicing good medicine: Homeostasis.

Whenever I am treating a very sick horse, foremost in my mind is the concept of homeostasis, which is the natural balance of all the elements in the body which when present, produces a healthy organism.

This morning I received a call from a client who has been deeply involved in a fight in the area where I live to stop the exportation of dangerous amounts of water out of our delicate watershed by a land development consortium.  She asked me to post the following message on the blog on behalf of the Northern Nevada Citizens for Water Conservation.  For many of us, riding our horses in the exquisite high desert environment of Northern Nevada nourishes our souls in a manner that defies expression.  The exportation of water proposed by these developers threatens the homeostasis of this delicate ecological system.  Please read Helen's message and do anything you can to support NNCWC in their fight for our precious native ecology.

You are all probably aware that RRR LLC have filed an appeal to the

Nevada Supreme Court with regards to the Washoe County Commission's
decision not to allow them to export water from our valley.
RRR LLC has been denied this on three different occasions; at the
Community Advisory Board, Washoe County Commission, and most recently
in their request for a Judicial Review.
Northern Nevada Citizens for Water Conservation has organized and funded this
fight. We hired an attorney when the Judicial Review was requested, by
doing so we were allowed to have our testimony and concerns heard.
Legal fees have pretty much exhausted our funds. How far we have gotten
in our cause, on fundraisers and donations is remarkable.


NNCWC is working for everyone's water. We need money for round number
four, it's that simple. Please put your donation in perspective with
what you are at stake to lose; if your well levels drop and you are
forced to drill deeper, (hoping to find the diminishing water table);
how that will affect your property value or even your ability to
exist here...


One more thing, be aware that the State Water Engineer has been
severely chastised by the courts for allowing excessive water
exportation permits to the potential devastation of environments and
small rural communities. The message being that their interests are not
necessarily yours, nor are they looking out for you. Please help. Send
contributions to: NNCWC 448 Hill St Reno, Nv 89501.

To learn more about water issues in the West, log on to http://www.greatbasinwater.net/

Thank you,
Helen Mooney

3/31/2010 - Vaccination Reactions II

Vet tip of the Day: "Allergic" reactions to vaccination
Key Words: Urticaria, hives, hypersensitivity, anaphylaxis

Most importantly, remember that severe vaccination reactions are rare.  That's why it was difficult to find a decent picture - sorry for the quality of this one.  True hypersensitivity or anaphylactic reactions to vaccines, while rare, do occur and require immediate attention.  The physiology behind these reactions is very complex and poorly understood in horses. 

Anaphylaxis refers to a shock reaction by the body to some foreign substance.  In the case of vaccines, anaphylaxis can occur the first time a vaccine is administered.  An anaphylactic response can vary from mild hives that appear hours after a vaccine is given, to acute life-threatening cardiovascular collapse which can occur within minutes of vaccination.  Epinephrine is the preferrred initial treatment for severe anaphylasis.  It works by counteracting the immediately life-threatening components of the body's severe inflammatory response.  It is usually administered by intramuscular injection.  In the most severe cases, it may be given intravenously.  Administration may be repeated every 15-20  minutes if necessary.

Hypersensitivity and immune-mediated reactions to vaccines also occur and may have similar clinical signs to anaphylaxis.  When these reactions occur, they usually are less dramatic than acute, severe anaphylaxis.  Signs may include swelling of the muzzle, face and throat region, which can lead to respiratory distress, or may manifest as hives, or urticaria.  Depending on the severity and progression of the clinical signs, treatment may include steroidal or non-steroidal (phenylbutazone, flunixin/banamine) anti-inflammtory agents, and/or anti-histamines.

When a horse experiences an adverse reaction to vaccination, the question always arises, should the horse be vaccinated again?  If the reaction is a very sore neck, sometimes changing vaccine brands, and thus the adjuvant used, will help.  If the horse has a true anaphylactic or severe hypersensitivity response to vaccination, the problem is more complex and the decision to repeat vaccination should be made based on the severity of the reaction and consideration of the true risk of the disease against which vaccination is directed.

Finally, for those of you who adminster your own vaccines, be aware that storage conditions are extremely important for vaccines.  Vaccines that are not stored at proper temperatures are significantly more likely to cause adverse reactions than those kept cool at all times. Also, correct administration of intramuscular shots, both with respect to location of the injection and injection technique, play important roles in the safety of injections.  If you choose to vaccinate your own horses, be sure to obtain instruction from a licensed veterinarian or licensed veterinary technician concerning the correct administration of intramuscular injections.  And be sure that your vaccines have been properly stored before you purchase them, check the expiration date, and keep them carefully stored until they are administered.  Better yet, take advantage of the chance to visit with your vet and have a spring wellness check up and make an appointment with your veterinarian to give your spring vaccinations!

It's cold and snowy on March 31 in Northern Nevada.  What's it like where you are?  Looking forward to spring and good riding weather.

03/30/2004 - Vaccination Reactions

Vet tip of the Day: When Vaccinations go Wrong
Key Words: Vaccine, adjuvant, immune system, clostridium

Vaccination season is drawing to a close, but I thought I would return to this subject one more time to talk about vaccination reactions.  Of course I would like to tell you that I have never had a horse demonstrate an adverse response to vaccination, but that would be a big fat lie.  Fortunately, I can tell you that I have never had a horse suffer a serious vaccination reaction that didn't respond promptly to appropriate treatment. There are several types of adverse reactions to vaccination, and it is important that you understand how they differ, both in onset of signs, and seriousness of consequences.


By far the most common adverse reaction to vaccination is the simple sore neck.  I vaccinate hundreds (literally) of horses every spring, and this year to date I know of only two horses which developed significant signs of neck pain following vaccination.  Typically the day after vaccination the owner notices that these horses are unwilling to move their heads, show signs of pain if one of the vaccination sites is touched, and exhibit swelling at the vaccination site.  Occasionally the discomfort will be so severe that horses will not lower their heads to eat or drink, or will pull back if pressure is applied to a lead rope when they are haltered.  Years ago I had a client call to tell me that her horse was having a seizure when in fact the horse's neck was so painful that when the owner tried to lead her forward she reared over backwards in response to the pain.  The vast majority of inflammatory reactions after vaccination resolve within 48 - 72 hours with palliative therapy including warm compresses and phenylbutazone.

This "sore neck" reaction to vaccination is NOT an allergic response to the vaccine.  It is an exagerrated inflammatory response to the ingredient in the vaccine that stimulates the horse's immune system.  This ingredient is called an adjuvant, and is very important in causing vaccines to elicit a strong antibody response by your horse's immune system.  Without this response, the vaccine will not be effective in preventing the disease against which it is directed.  Drug companies spend a lot of time and money developing different adjuvants.  Their goal is to find an adjuvant that is a potent stimulator of the immune system but does not cause severe local soreness.  Over the years I have used many brands of vaccines, and have come to be a staunch supporter of Intervet vaccines.  I believe that their adjuvant causes very few advers reactions, and I have been impressed with the company's dedication to client education and with their committment to research and development of new products to protect horses' health, such as Prevenile, their DNA based West Nile vaccine.

When a horse develops a sore neck after vaccination, it is important to notice whether or not the horse is systemically ill.  Specifically, will the horse refuse food and water even when it is placed so that the horse can reach it without lowering its head? Is the horse's temperature over 102.5 degrees?  Is the swelling at the vaccination site severe and increasing over time?  When the swelling is palpated, is there a crackling feeling underneath the skin?  Does the horse appear markedly depressed?  If the answer to any of these questions is yes, then the horse should be examined by a veterinarian.  As stated earlier, the vast majority of inflammatory reactions after vaccination are not serious and resolve within 48 - 72 hours with palliative therapy including warm compresses and  phenylbutazone.  However, in rare cases, it is possible for a bacteria called Clostridium to grow deep in muscle tissue at a vaccination site. If this unlikely event does occur, it can be life-threatening.
Clostridial bacteria exist normally in the environment in a spore form which can only grow in the abscence of oxygen.  Even when a clean needle and syringe are used and the vaccination is administered correctly, it is possible for Clostridial spore sitting on the skin to be carried deep into the muscle tissue by the needle during vaccination.  When this happens it is a random, extremely unlucky event, and does not mean that the vaccine was administered improperly.  Clostridial infections can be life threatening and require prompt and aggressive treatment. The Clostridium bacteria grow rapidly in the abscence of oxygen and produce several toxins which invade the horse's blood stream and cause severe systemic illness which can be fatal. Therefore, it is always a good idea to contact your veterinarian if your horse has an adverse reaction to a vaccine and discuss your horse's specific clinical signs so that you and your vet can decide if your horse needs to be examined.  If you take your horse's temperature and do a physical examination (see blog on this!) and carefully observe your horse's behavior before you call your vet you will be best able to provide important information in making that decision.

In tomorrow's Vet tip of the Day I will discuss Allergic reactions to vaccination and the importance of careful storage and administration of  vaccines, for those of you who vaccinate your own horses.

Until then,

I believe that education is the key to evolution.
I believe that animals are the key to compassion.
I believe the learning never stops.

4/25/2010 - How Diseases Spread

Vet tip of the Day: Infectious Disease Control/Equine Herpes Virus
Key Words: EHV-1, EHV-4, neurologic disease, upper respiratory virus

This story is loosely based on actual events that took place in 2007-2008, spanning from Europe to New York, then south to Florida, and west to California. The goal is not to alarm you, or make you an expert on Equine Herpes Virus type-1 (EHV-1), but to provide guidelines on how to protect your horse from infectious diseases. Developing an increased awareness of how diseases can change and spread rapidly will help you to improve the care and well-being of your equine companions. Our story:

An eight-year-old horse that received excellent care in Germany was purchased by a person in the United States. He was vaccinated and dewormed regularly, and received appropriate booster vaccinations three weeks before his transport by air to New York. Upon arrival he was quarantined according to federal regulations. Once released from quarantine, he was transported by truck to Kentucky with one group of horses, and then shipped on to Florida with a different group. When he arrived in Florida 10 days after leaving New York, a handler noticed he seemed depressed and unsteady on his feet. The owner was alerted and a veterinarian was contacted to evaluate the horse.

How are diseases spread?

How and why did the horse become ill? We know the horse received excellent management with booster vaccinations for appropriate infectious diseases three weeks before shipping overseas. The immune system takes at least 10 days to fully respond to a booster vaccine, so ideally they should be given two to four weeks before shipping or change of environment.

It would have been advisable to rest the horse in New York following the flight and quarantine before transporting to Florida, and to avoid the mixing of different groups of horses during travel. Research has shown that horses subjected to long-distance transport are at significantly greater risk of infection with respiratory tract pathogens compared to similar non-transported horses.

The veterinarian exam revealed the horse had a 102.5 ºF fever and neurologic signs manifested as weakness and incoordination of the hind limbs, and a rectal palpation determined the horse’s bladder was distended with urine. The owner was told that a neurologic form of EHV-1 was suspected and immediate isolation was recommended until a diagnosis could be confirmed because a new, highly contagious form of this disease had been reported in other U.S. locations.

What is EHV-1?

Equine Herpes Virus Type-1 (EHV-1) is an old and common disease in horses, most commonly causing an upper respiratory infection in young horses, but also responsible for late term abortion and a sporadic neurologic disease. Luckily, this veterinarian was aware of outbreaks in recent years of neurologic disease affecting multiple horses caused by EHV-1; most notably one in a university hospital in which 46 of 135 in-house patients developed neurologic signs, leading to death in 12 of those horses.

It was discovered that the EHV-1 virus had undergone a mutation in which a single element in the viral DNA code was altered. The resulting strain was more virulent, contagious, and specifically attacked the horse’s neurologic system. Therefore it was named neuropathogenic EHV-1. With the emergence of this mutated virus, the clinical form of EHV-1 associated with neurologic signs was becoming more common and more. This exemplifies how a tiny change in the genetic code of a virus can have far-reaching and dangerous effects.

In Florida, a nasal swab confirmed the diagnosis of neuropathogenic EHV-1. This first horse was treated and recovered. Meanwhile, another horse off-loaded from the original truck in Kentucky was arriving in Southern California, and a third horse that had accompanied our horse by van to Florida was taken to a farm, and later to a horse show facility nearby. The horse in California walked off the truck with clinical signs similar to the first index horse in Florida, and was quickly assessed and isolated. The third horse never showed signs of illness, but 10 days after arriving at the show grounds, other horses began to develop signs of neurologic disease. Subsequently, the presence of the neuropathogenic form of EHV-1 was confirmed, leading to an extended quarantine of the show grounds. No other cases were detected in Southern California after isolation of the index case, but within the month, a horse was confirmed infected at Golden Gate Race Track. There have been isolated confirmations of neuropathogenic EHV-1 in California horses since, but no multiple case outbreaks have occurred.

Disease control and prevention among horses

How could the spread to the show grounds have been prevented? First, when a contagious disease is suspected, the affected horse should be isolated and other in-contact horses should be quarantined and monitored for signs of disease for an appropriate duration. This would have meant immediately contacting the shipping company and identifying all the horses transported with the original horse in Florida with clinical signs. In the case of EHV-1, the incubation period is typically two to eight days, but can be as short as 24 hours – showing how quickly this becomes a logistical nightmare, and how critical every hour becomes. The horse in Southern California was traced back to the horse in Florida, which was connected to the air transport from Europe – tedious tracking, but important to successfully contain infectious diseases.

Second, rapid diagnosis is critical. Our astute veterinarian in Florida submitted the nasal swab for a state-of-the-art diagnostic technique called PCR (polymerase chain reaction). This test amplifies specific DNA segments in the sample and allows the detection and identification of minute amounts of viral DNA, confirming that this particular viral strain was present in the affected horse.

Finally, how can you as a horse owner reduce the spread of infectious disease? Your first goal is to protect your horse against infection by consulting with your veterinarian to ensure that your horse is appropriately vaccinated. Learn all you can about the safe and comfortable transporting of horses. With these good management techniques, you’re supporting your horse’s immune system and reducing the odds that he will succumb to an infectious disease, even in the face of exposure. Use common sense during competitive events: do not share water, tack, or grooming equipment. EHV-1 is spread primarily by horse to horse contact and by virus transported on equipment and the clothing, hands, and shoes of people moving between horses. If your horse is exposed to fewer viral particles and has a healthy immune system, illness is less likely.

When your horse is at high risk of contracting an infectious disease such as EHV-1, even the best management may not protect him completely. If he does become infected with a contagious disease, your goal is to protect him and other horses with early detection. Fever is the earliest sign of most viral diseases. The single most important thing you can do is to monitor your horse’s rectal temperature twice daily at shows, before and after shipping, and when new horses come on the property. Whenever your horse’s rectal temperature is 102.2 ºF or higher, contact your veterinarian and follow their recommendations.

Don’t abandon your equestrian activities for fear of infectious disease. Just stay informed and use common sense to guide you. Your veterinarian is your best resource for advice on the prevention and control of infectious diseases. Don’t hesitate to ask questions and continue your life-long education as a responsible and caring horse owner.


More Information on EHV-1

www.vetmed.ucdavis.edu/ceh/topics-EHV-1-info

www.cdfa.ca.gov/ahfss/ah/equine_herpes_virus

www.doacs.state.fl.us/ai/ehv1/index.shtml

This story first appeared in Petfolio magazine, published in Reno, Nevada.



I believe that education is the key to evolution.
I believe that animals are the key to compassion.
I believe the learning never stops.

3/24/2010 Normal Physical Exam

Vet tip of the Day: The Normal Horse
Key Words: Heart rate, Respiratory Rate, Temp, Gut sounds, mucous membranes

I performed a prepurchase examination for a new horse owner this week.  She had lots of good questions about her horse husbandry.  One thing she was interested in was learning normal physical examination findings, so I thought I would go over some basics which all horse owners should know.  In case of emergency, or if your horse simply isn't feeling well, being able to do a basic asssessment of your horse's physical parameters can be extremely useful.  Not only does it give you factual information to convey to your veterinarian over the telephone, it also gives YOU factual information to allow you to determine just how serious your horse's condition may be.

First you need some equipment.  Go to any nursing supply store and by a CHEAP stethoscope.  The most basic model is perfectly adequate for obtaining a heart rate.  To listen to your horse's heart, place the flat side of the stethoscope bell against your horse's chest just behind the point of the elbow, then push the stethoscope head forward as far as you can so it slides in underneath the triceps muscle.  Close your eyes and listen carefully.  The heart beat has two parts - lubdub...lubdub...lubdub.  Practice until you can hear it clearly.

Next go to the drug store and buy a regular old human digital thermometer - I prefer the non-flexible ones. 

Finally, purchase a small, LED flashlight and cheap watch with a second hand and store them, along with your stethoscope, thermometer, and a small notebook with a pen attached to it by a piece of string in a handy place in your feed or tack room or horse trailer.

Here are some normal numbers - write them down in your notebook so in an emergency you don't have to remember them. 

Heart rate: 28- 44 beats per minute.  I usually count the heart rate for 15 seconds and multiply by 4 to get beats/minute. Heart rates over 52 beats per minute are definitely abnormal.  Heart rates over 80 beats per minute indicate severe cardiovascular distress.  Remember, exercise, nervousness or excitement may cause your horse's heart rate to be elevated without any serious illness present.
Respiratory rate: 8-16 breaths per minute.  The best way to count the respiratory rate is to stand back from the horse and watch the abdomen just behind the ribcage.  In a normal horse you will see a gentle rise of the abdomen with each breath.  Taking an accurate resting respiratory rate in a normal horse can be difficult, because as soon as you approach them they begin sniffing and snuffling, thereby disrupting the quiet, resting breathing rate.  If your horse has a wide flare to the nostrils with each breath and an deep movement of the abdomen with each breath coinciding with the nostril flare, this is a sign of labored breathing and is abnormal.
Gut Sounds: Using your stethoscope, listen to your horse's abdomen in 4 places - up high and down low on each side, behind the ribs and in front of the hip.  Gut sounds vary tremendously even in a normal horse, but if you listen for 30 seconds in each location, you should hear at least one good, rumbling gurgle in each of your 4 listening zones.
Mucous membranes: Standing beside your horse's head (not in front), lift your horse's lip just enough to see the gums above the incisors on one side.  Normal gums are quite pale pink, with a glistening surface.  If you press against the gums firmly with your finger for a few seconds, when you remove your finger the gums should be white, and should refill with the normal pale pink color in less than 2 seconds.  This is called the capillary refill time (crt).
Attitude:  When I record my physical examination findings, I will often note: BAR.  This is code for Bright, Alert, and Responsive.  When you do your physical exam, note your horse's attitude, expression, head position and body position. Look in the stall or pen and check for fresh manure, or signs of distress such as areas where your horse may have been pawing or rolling.  Check to see if the water trough is full and if the last feeding has been consumed.
Gait/Posture:  Finally, move your horse around a bit and check for lameness and willingness to move forward.

Now you are prepared to do a comprehensive physical examination on your horse.  The best way to recognize abnormal is to know normal, so practice performing physical examinations on your horse frequently so that when you are concerned that something isn't right, you will be confident in your assessment.

Enjoy!

3/28/2010: More on Vaccines

Vet Tip of the Day: Vaccinating old horses
Key Words:  geriatric, immune system
A client called this week asking about recommendations for vaccinating old horses and mules.  She was wondering if her old retirees still needed all the same vaccinations that her younger, active, travelling horses receive.  I thought I would answer her question with a blog post so you could all share this information.  Please first review the two previous blog entries on vaccinations posted earlier this spring.  To find them you can type  - vaccination - into the search bar at the top of the blog home page  OR click on - vaccination - in the label group in the top left margin on the blog home page.
Let me reiterate that the decision to vaccinate any horse should be made based on an assessment of risk of disease to that horse and to the other horses in that horse's population group.  With this in mind, let's look at the geriatric horse in particular.  Your old horse's immune system is likely to look pretty much like your old horse does: it ages along with the rest of his body, inside and out.  When deciding whether or not to vaccinate the old fellow, consider the following: his body condition, his mobility, and his population dynamics.  Then think about each disease against with we vaccinate in the terms discussed in the previous blog posts.
Let's consider a contagious disease (spread from horse to horse) such as the upper respiratory viruses - Flu/Rhino.  Keep in mind that immunity to these viruses in general is relatively short lived in all horses.  Should your old horse contract influenza it may take longer for him to recover, and, under certain circumstances he may be at greater risk of developing complications such as pneumonia.  What are these circumstances? Living as part of a  large group of horses in a small area is probably the most threatening to an old horse.  If your horse has chronic lameness issues that cause him to spend significant periods of time lying down, again he is at increased risk of  secondary pneumonia.  If your horse is in poor body condition or has poor dentition, he is at greater risk of having difficulty shaking the flu.  If, however, your retired horse or horses are in good health, living in a large field without much contact with other horses, then their liklihood of contracting a contagious disease such as influenza or rhinopneumonitis is decreased, and should they "catch a cold", it is likely it will run its course without complication.  Under these conditions, you may choose not to vaccinate against Influenza or Rhinopneumonitis.

Concerning Strangles (Strep Equi)  the situation is somewhat different.  While Strangles is a highly contagious disease spread from horse to horse, it also is a disease which causes a powerful and long-lasting immune response in those exposed to the disease.  Because Strangles is common in our area of northern Nevada, most older horses have good naturally aquired immunity.  Therefore, Strangles is uncommon in older horses.  Unfortunately,  old, debilitated horses which do contract Strangles are definitely at higher risk of potentially life threatening complications.  I recommend Stranges vaccination in old horses only if they are living in a high risk environment such as a concentrated boarding barn with high turnover of population or on a breeding farm with high number of foals in close contact.

All older horses should be vaccinated against West Nile Virus.  The disease is sporadic and unrelated to population dynamics.  To contract West Nile Virus, an infected bird flies over your horse's location, a mosquito bites the bird and within a short period of time that same mosquite flies down and bites your old horse.  Old horses definitely are at greater risk of death should they contract West Nile Virus.

Tetanus?  Sleeping Sickness?  The killed vaccines used against these diseases are very effective and afford long lasting immunity.  If you have owned your old friend for years and know for sure that annual tetanus/encephalitis vaccine has been administered, I would be comfortable decreasing the frequency of that vaccination to every 3 years rather than annually.  If you select this route, BE SURE that your horse receives a tetanus toxoid (not tetanus antitoxin) should he develop a foot abscess or deep puncture wound.

Hopefully this information will be of use to you when deciding which vaccines are appropriate for your old horses.

Forward this blog entry to all your friends with old horses.  Become a fan of HighDesertEquine on Facebook - and sign up as a follower of this blog! Your participation is vital to the success of these internet information efforts - every new fan and member moves us up on the search engine list and means that these educational articles will reach more people trying to become better informed caretakers to their horses.