Pre-Purchase Risk Assessment
Why was my horse assessed as ‘high risk’ at pre-purchase exam one year and then considered ‘low risk’ three years later?
A pre-purchase is a risk assessment based on the clinical findings on the day of examination. The pre-purchase exam will involve a clinical exam and may include blood tests, radiographs and ultrasound examinations. At the conclusion of the pre-purchase examination, all of the information is collated and a risk assessment is given for the horse that takes into account its suitability for the intended purpose and the likelihood of future veterinary issues arising during its working life.
Common things that affect the risk category into which a horse is placed include;
Competition history
Whether the horse is in work.
The intended use of the horse.
Whether the horse is being purchased to be trained on and re-sold.
Whether there is a major issue with the clinical exam.
Whether there are any abnormalities found on one of the diagnostic tests.
The assessment of risk is often personal and situational. In my clinical practice I have observed that it is often heavily influenced by prior experience purchasers have had with previous horses. Prior disappointing or even neutral experiences often influence future decision making. A purchaser who has had to retire a horse with a foot issue will often be very risk adverse when presented with the smallest change on a radiograph of the foot. This purchaser may not tolerate any risk in that area. Equally, a purchaser may have previously purchased a horse with a terrible set of back radiographs that went on to have a successful competition career. This purchaser may decide that they are comfortable proceeding with the purchase of a future horse that has radiographic changes in its back.
When we perform a pre-purchase examination we assess each individual issue found during the examination and assign each issue a risk assessment of Low- Moderate- High. After the total findings of the examination are collated we can then give an overall risk profile for a horse. A horse with a high risk profile will not necessarily go lame and not be able to do the job for which it is intended. We may have just decided, on basis of our clinical assessment that the horse is at a high risk of requiring veterinary management in order for it to perform at an acceptable level for the purchaser. From time to time we will assign a higher risk profile to a horse when we uncover a potential issue that may progress clinically. If that potential issue is one that we know from our experience can be career ending we will assign that particular horse to a high risk category.
I’m going to run through some clinical scenarios to give you, the reader some insight into the decision making process I go through when I am assigning a horse into a risk category after conducting a pre-purchase examination.
Scenario 1.
1. 6 yr old Showjumping mare, jumping 1.00m heights now. Horse has only been in work for 8 months as she had a foal as 4yr old.
a. Clinical exam: Sound, no major concerns seen. Moves well under saddle and not presenting with any abnormalities.
b. X-rays show this mare has a large stifle cyst in the medial femoral condyle
c. Overall this will be assessed as a Moderate -High Risk horse.
d. Explanation: The medial femoral cyst is a developmental abnormality. These lesions can be seen on some weanlings or yearlings and disappear by 2 yrs of age. But this is still present in this mare at 6yrs of age so we know it will stay. Horse is currently sound, but limited performance history. These lesions will often present with lameness when they are first broken in or later in life. To deal with them they have traditionally been frustrating. Injecting the joint of limited benefit. Surgery is often needed. Lately there has been a new surgery where a screw is placed across the cyst to offer stability. The thinking behind this is that the surgery will offer stability across the cyst. However, the long term follow up of these cases has not yet been done for performance horses. How will these horses be in 4, 8, 10 years time? Will there be arthritis of the joint? Surgery requires more money and time off. This will affect the risk category into which we assign this horse.
e. How does a vendor improve the risk profile for this horse?
i. Show a longer history of maintaining soundness
ii. Show that there have been no changes from this date until the next 2/3 years. Taking regularly a series of x-rays to show a vet there has been no change.
iii. This will reduce the risk of this horse down lower. It will probably never reach low risk but will get down to a low moderate risk if the horse is older and been competing for a long time.
Scenario 2.
2. 4 yr old dressage mare, been in work 10 weeks.
a. Clinical exam: Sound at walk and trot, stiff through the back on the lunge, stiff when cantering. No resentment of flexion and extension of the back.
b. X-rays show Radiographic back changes, suggestive of possible kissing spine issues.
c. Risk profile: Moderate for back pain issues.
d. Explanation: We know there is often not a definite link between back X-ray changes and the clinical issue of back pain and kissing spines. The changes are not always linked to work as seen in this horse. It is extremely unlikely that this horse has the changes due to work so they have to be genetic or conformational. So the issue then becomes how do we assess the significance of the changes. The risk for a purchaser is then to decide if these changes may affect their purchase. They may never progress and be fine or they may become a problem down the track. If they become a problem then the road ahead can be difficult.
e. How does the vendor improve the risk profile of this horse? This is disappointing for the vendor of course, but the changes are unlikely to be work related so how do they decrease the level of risk for a purchaser? The vendor needs to show that the horse can do the work and proceed with training. The fact that there are radiographic changes present isn’t the end of the world but if the vendor can show that the horse can do the work and have no back pain. In this situation, many purchasers will be more accepting of the risk associated with buying this horse. Of course some may be wary but the vendor can be hopeful that they may wish to proceed with the purchase if it can be shown that the radiographic changes are not adversely affecting the horses performance.
f. How about if we change the scenario again? Let’s say the horse is a 14yr old Prix St George horse how does this affect the risk profile? Well for me personally, if the horse has been doing all the work happily and competing successfully I would assess this horse as a low-moderate risk and in this situation, most purchasers would proceed. The horse has demonstrated it can perform at the required level.
Scenario 3.
3. 14 yr old Warmblood mare competing at Inter 1 level. Had 12 months off previously when she was 10 yrs old, for a medial suspensory branch injury on the right hind.
a. Clinical exam: Horse is sound with no lameness seen in hand or on the circle on the soft surface. There is thickening of the suspensory branch but no pain on palpation. There is no lameness after flexion tests. It is interesting and worth noting that it is so important to see these horses work on a soft surface. Many horses with suspensory branch issues can appear sound on a hard surface and present lame on a soft surface.
b. Ultrasound shows that there is thickening with a less than ideal fibre pattern evident.
c. So the risk is that the horse has an abnormal suspensory branch. This could go at any time in the future and and could prove difficult to rehabilitate a second time.
d. At this stage the vendor kindly produces the original scans from the injury and a series of images that have been taken at yearly intervals over the last few years. We can now see that over the last few years and the ultrasound image has not changed at all. The cross-sectional area and the fibre pattern is very similar and has not changed in two years.
e. So we can now assess this as a low-moderate risk purchase as there is evidence to show that there have been no further and ongoing changes to the suspensory branch. Yes, it could of course go again but the information we have at hand has shown no changes over the previous few years.
I hope that this series of scenarios shows that the level of risk we assign to a prospective purchase is often situational. Something that presents a risk as a 4yr old can change by the time a horse is 8-10 yrs of age and demonstrated it can perform at the level required. Just because you have an issue on x-ray or ultrasound in a young horse that maybe might put you off as a purchaser does not mean it will cause an issue for the horse. Having said this, purchasers still needs to appreciate the risk associated with purchasing a young horse with radiographic changes.
From a vendor perspective if your horse has an issue the aim should be to present to prospective purchasers evidence that it hasn’t caused an issue. Vendors should aim to provide a regular competition record. If there has been a past injury that has been rehabilitated then the Vendor needs to show that the injury is stable and hasn’t changed over time. The suspensory branch injury described above is a good example.
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Have your pre purchase vet check undertaken by a highly experienced sport horse vet.
Dr Mike Tweedie has a wealth of experience conducting comprehensive horse pre purchase examinations.
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