Taking blood is a procedure very commonly performed and is done for a number of reasons. Sometimes it is to test for a certain disease in particular- for example evidence of strangles, although most of the time we take blood in order to get more information that allows us to work out what condition your horse may be suffering from.
Most of the time we will ask the laboratory to perform two types of test.
Haematology involves testing the cells found in blood (red blood cells, white blood cells, platelets). By measuring these we are able to identify anaemia, infection and inflammation.
Biochemistry involves measuring enzymes and chemicals within blood that are produced by different organs and metabolic processes.
The normal levels of enzymes are well known, so when blood results are produced we compare your horse’s enzyme levels with those deemed normal for another horse of the same age.
The main organs we access are liver, kidneys, and muscles, in addition to inflammatory enzymes sometimes associated with infection.
For example- if we found a horse had elevations in its liver enzymes we may suspect it of having a problem with its liver.
The horse below appeared very stiff and reluctant to move after exercise. Bloods were taken which are shown. AST and CK are both enzymes produced by muscles. As you can see they are massively elevated compared with normal levels. This would be consistent with tying up (exertional rhabdomyolysis).
Normal Reference Range
Sometimes we will monitor the progression of a disease through repeated blood tests. By monitoring enzyme levels we are able to recognise whether a horse is getting better/ worse and hence tailor treatment according to the results obtained.
Ultrasound is a technique we often use to diagnose soft tissue injuries and abnormalities. An ultrasound machine is composed of a probe and a processor. The probe emits ultrasound waves which bounce back off the tissue and are then processed by the processor to create an image on the screen.
The most common situation we would use it is in the examination of suspected tendon and ligament injuries. Many athletic horses will injure their superficial digital flexor tendon at the back of the cannon region. Often a swelling will be evident at the back of the leg, however ultrasound is used to image the area and show any damage present and the extent of it. We often use ultrasound to monitor the healing and repair phases in order to plan a staged recovery and exercise programme.
Older horses often injure the check ligament, which is a ligament that originates at the back of the knee and attaches to the deep digital flexor tendon. These horses often present with a swelling on the outside of the leg below the knee. Ultrasound is used to identify this and monitor the healing of these injuries.
Another use of ultrasound is in the investigation of abdominal disease. The liver is an organ commonly examined with ultrasound, and is situated primarily on the right side of the horse. We use ultrasound to identify the most suitable place to take a biopsy from in horses with liver disease.
The intestine is also imaged using ultrasound. Using ultrasound we are able to measure gut wall thickness and assess for any changes in its structure- often seen in horses with inflammatory bowel disease and lymphoma.
Ultrasound examination is a completely pain free procedure and in the majority of cases is performed on the yard, provided there is a mains electricity supply. Very occasionally we will administer sedation in order to ensure a cooperative patient to get the best images possible! Sometimes we will have to clip the hair off from the area we are scanning in order to get adequate skin contact for high quality images.
We are able to save the digital images acquired and these are then attached to your horse’s record for us to view whenever required. If requested we can often print a copy for you if you wish to keep them for your records.
Testing for Respiratory Disease
Sometimes if we suspect your horse may be suffering from respiratory disease we will recommend further testing. This may include endoscopy, x rays, Tracheal Washes or Broncho Alveolar Lavage. We have included some notes for you to read about these techniques to help understand why we do certain tests and how they are performed.
Endoscopy- This procedure involves passing a camera up the nose into the back of the throat in order for us to examine the anatomy of the nasopharynx and larynx. It allows us to examine where nasal discharge is coming from, any foreign bodies or abnormal masses and allows us to look for evidence of inflammation within the trachea and upper respiratory tract. It is normally performed without sedation, although some horses may be sedated if necessary.
Tracheal Wash– If we suspect your horse of having a lower respiratory tract problem- i.e lungs then we will often perform this test to identify any bacteria growing within the lungs or windpipe. The endoscope is passed into the windpipe and a fluid sample obtained. We then send this sample off to the laboratory for culture and sensitivity. This procedure can be performed at your yard and is often performed under mild sedation.
Broncho-Alveolar Lavage –The most common cause of a chronic cough in an adult horse is Recurrent Airway Obsruction(formally known as COPD). This describes a hypersensitivity of the lungs to inhaled allergens- pollens, dusts etc. This condition is normally diagnosed by performing a bronchoalveolar lavage. This procedure is normally performed under sedation. A tube is placed up the nose all the way into the lungs. We then squirt saline down the tube and then suck it back up to 'wash' cells from the lungs into the fluid. The sample is then sent to the laboratory , whereby a diagnosis is then made depending on the type and number of cells found.
Guttural Pouch Lavage – Used as a diagnostic test to assess whether there is an infectious agent within the guttural pouch. Commonly used in cases of suspected Strangles (Strep Equi var equi) to confirm diagnosis or conformation of cure. This method involves a catheter being placed into the guttural pouches and fluid being flushed in and aspirated. A guttural pouch wash is regarded as the gold standard for diagnosing strangles and confirming its cure.
Liver biopsy is a procedure we perform when we suspect a horse may have a problem with their liver. It is very rare to suspect liver disease simply based on clinical signs, the vast majority of liver disease cases we see are diagnosed following blood tests (see section on blood testing).
Although blood tests will identify that a horse may have a problem with their liver, unfortunately they are unable to give us much more information than that. As you can imagine, if we want to identify what the problem is and how bad it is, the best thing to do is to examine a piece of liver!
The way this is done is by taking a tiny piece (approx. 3mm x 15mm) under ultrasound guidance from the right side of the liver. We do occasionally take some from the left side but more commonly from the right side.
The procedure is performed under standing sedation and as an outpatient, so we will normally perform it at your yard, unless there are limitations with electricity etc.
After a sedative has been given the right side of the abdomen is clipped and ultrasound used to identify the liver and examine it for any obvious abnormalities- size/ shape/ masses etc. Once a suitable site has been identified, local anaesthetic is injected and a tiny incision made in the skin. A biopsy needle is then advanced through the skin and muscle into the liver and a tiny piece of liver collected. We normally collect about 4 pieces in order for the laboratory to assess fully for the cause of the problem and identify how severe the changes are and hence what the prognosis will be.
Antibiotics and pain relief are given at the time, however the procedure presents a minimally invasive technique, allowing us to identify much more information regarding the cause and severity of the problem.
After the procedure we will often place a skin staple at the site of the biopsy which is removed after approximately 10 days. We normally recommend box rest for approximately 12 hours after the procedure, however after this the horse may resume normal activity.
Choke can be a very distressing thing for an owner to see. Fortunately it is not that common and in the majority of cases will resolve either on its own, or with treatment. It is normally seen either during feeding or immediately after.
Choke in horses describes a situation whereby the food pipe (oesophagus) becomes blocked with impacted food material. As a consequence of this the horse will often become distressed and uncomfortable. Frequent attempts to swallow will be seen and often the horse will be gulping repeatedly. In severe cases large volumes of white foamy liquid will come from the horse’s nostrils. This is saliva building up behind the obstruction.
If you suspect your horse has choke then immediately remove all food. Gently massaging the left side of the neck from top to bottom may help reduce spasm of the food pipe. If after 10 minutes your horse still appears uncomfortable then contact the practice to arrange a visit.
Fingers crossed you won’t need a visit however if we do need to attend then treatment of choke normally begins with sedation and muscle relaxants to reduce the spasm of the food pipe. We will usually administer anti-inflammatories and occasionally antibiotics if we are concerned that your horse may have aspirated (breathed in) fluid onto his/her windpipe and respiratory tract.
Should this fail to work then we will then pass a stomach tube to lavage the obstruction clear. This would normally be performed under sedation.
Once we are happy that the obstruction has been cleared it would be normally recommended to starve him/her for the next 12 hours and then gradually reintroduce soft food- grass, mashes etc. before continuing with roughage- soaked hay.
The most common cause for choke is over enthusiastic eating of dry chaff/ unsoaked sugar beet. It is sensible to always check for underlying dental disease though, as sometimes having partially unchewed long fibre can predispose to choke.
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New House Farm, Belbroughton Rd, Blakedown DY103JH