HOW-TO SESSION: PRE-PURCHASE EXAM FOR THE WESTERN HORSE


sale and to performance, it is important to begin a discussion about navicular bone radiology with a horse buyer describing the range of normal findings. The author prefers to see 4 or fewer centrally located vascular channels in the navicular bone. The au- thor tends to shy away from vascular channels on the periphery of the bone and increased vascularity beyond 4 vascular channels or horses having no vascular channels in one foot and many in the other even though they may be of the proper size and shape. The author has seen examples of horses with vas-


cular channels that are atypical but has no history of coffin joint injections, is bare foot, negative to hoof testers, negative to flexion tests, not lame on the hard ground in a circle, and negative to a drug screen can still fail a pre-purchase exam when the radiographs are sent to a buyer’s primary care veterinarian.


Hocks


The predominant discussion for the author regard- ing hock radiographs revolves around the absence or presence or the degree of OA in the distal intertarsal (DIT) and tarsal metatarsal (TMT) joints. Many western performance horses have some degree of OA in the lower hock joints. Again, for the author per- formance vs resale is the dominant theme in regard to prognosing findings. Age of the horse is impor- tant in this discussion as the appearance of OA signs in the younger horse affects its resale as an older horse in the author’s opinion. The discussion around a yearling with radiographic OA frequently revolves around the degree and speed of advance- ment and how the radiographs might look as a 2-year-old. The same can be true for the author when evaluating a 2-year-old with radiographic OA and how it will affect its resale as a 3-year-old. The author believes most veterinarians feel com- fortable managing OA in the DIT and TMT. In the older (3 years and up) show horse, discussion fre- quently moves into the realm of the buyer’s veteri- narian’s recommendations for management of the OA and the subsequent cost of this management on an annual basis. In the author’s opinion, OA of the DIT and TMT


joints has the greatest impact on the stop of a reiner, cutter, or cow horse. In terms of influencing the scoring it’s the author’s opinion the greatest impact is seen in the reiner or the cow horse reining pat- tern. Not holding the ground in a stop, picking a hind foot up in a stop, collapsing instead of easing into a stop, and increased tail activity during a stop, all have been indicative of hock soreness in a reiner or cow horse as is with not holding the inside pivot leg in the ground while spinning in a reining pat- tern, in the author’s experience.


Stifles


Osteochondrosis or other radiographic abnormali- ties of the medial femoral condyle cause concern on


pre-purchase exams. In the author’s experience, they have a dramatic impact on the resale of the horse because when the letters “OCD” are men- tioned during a pre-purchase exam most buyers be- come skeptical. If this does not prevent the buyer from proceeding with their due diligence during a sale, it frequently causes them to reevaluate the horse’s price, level of ability, and mentation before moving forward. Similar issues arise in the sale of the horse with navicular vascular channel irregular- ities, a horse with no stifle effusion, no lameness, and negative to flexion test can still have difficulty being sold with osteochondrosis of the stifle, in the author’s opinion. In the author’s opinion, there are more soft-tissue problems not apparent on radiographs of the stifle that have the potential to affect its long-term prog- nosis for performance than the osseous changes so frequently debated. Again, the horse’s history of stifle intra-articular medication treatment and the lameness exam findings along with ultrasonography can frequently be more insightful than radiographs of the stifle alone. Stifle effusion indicative of sy- novitis, cartilage injuries, and meniscal injuries have been noted by the author to result in a pro- found impact on the long-term prognosis for the athletic performance of the reiner, cutter, and cow horse. The greatest impact being the cutter than the cow horse because of the draw they are expected to perform while cutting.


Ultrasonography of the Stifle


In the author’s opinion, ultrasonography of the stifle is very useful in a pre-purchase exam. In the au- thor’s opinion, ultrasonic findings such as thicken- ing of the synovial capsule and abnormalities of the cranial ligament of the medial meniscus can influ- ence prognosis for ability to perform. Free-floating cartilage fragments in the joint fluid are also con- cerning. Meniscal injuries are recognized as chal- lenging to diagnosis in the author’s opinion and familiarity with normal stifle ultrasound appear- ance is critical if this modality is used in prognosti- cating stifle health.


Fetlocks and Carpus


The author typically includes a flexed lateral of each front fetlock and carpus along with a standing lat- eral of the hind fetlocks in his pre-purchase exams. Again, in the author’s experience, carpal injuries


are very common in reining horses and cow horses. The fast rundowns along with concussions received from turning have the potential to produce lameness and radiographic findings of the carpus. The au- thor finds osteochondral fragments to be an infre- quent cause of lameness but feels they often cause horses to fall out of lead, which causes decreased success in the show pen. In the author’s opinion, caudal eminence P1 osteo- chondral fragments, particularly of the hind fetlock, frequently cause reining and cow horses to fall out of


AAEP PROCEEDINGS  Vol. 65  2019 475


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