Page 1060 - Adams and Stashak's Lameness in Horses, 7th Edition

1026 Chapter 9

THE DRAFT HORSE

VetBooks.ir Jan F. haWKins

INTRODUCTION tests and diagnostic anesthesia are performed as in light
breed horses. Diagnostic nerve blocks are more difficult
Evaluating lame draft horses presents unique chal­ because of the thick skin of the distal extremity. The
lenges due to of their large size, which complicates han­ thick skin may limit diffusion of local anesthetic; there­
dling, routine farriery, and the lameness evaluation. fore, greater amounts of anesthetic solution are often
Fortunately, most draft horses are docile and amenable needed, and observation times should be longer to allow
to restraint. Draft horses are rarely exercised at speeds for greater diffusion. Higher kVp and mAs are required
greater than a trot. This can delay the onset of obvious for radiography due to the increased size and thick­
signs of lameness because of the lower amount of ath­ ness of the foot and distal extremity. Ultrasonography of
letic demand required. This section reviews the anamne­ the lower limb (below the hock or carpus) is compli­
sis, physical and lameness examination findings, cated by the thick skin and dense hair on the distal
diagnostic tests, common lameness disorders, and treat­ extremity, making careful skin preparation necessary.
ments for lameness in the draft horse.

ANAMNESIS COMMON CAUSES OF LAMENESS
Knowing the type of athletic demand placed on the Lameness of the Foot
horse is useful in determining the most likely cause of
lameness. Common uses for draft horses include pulling, The most common cause of lameness in the draft
farm labor, showing in a hitch (either alone or with horse involves the foot due to poor hoof wall quality,
other horses), dressage, or broodmare. Young horses improper or no trimming, and inadequate hoof hygiene
(under 2 years of age) presenting with lameness should (Figure 9.63). Tie stalls and confinement in wet, manure‐
be evaluated for metabolic bone diseases such as osteo­ contaminated stalls can be risk factors for disorders
chondrosis and subchondral bone cysts. such as subsolar abscessation and proliferative pododer­
matitis (canker). It is difficult for owners to regularly
pick up and examine the foot, and many farriers are
LAMENESS EXAMINATION reluctant to provide routine hoof care for draft horses
because of the physical demands of holding up a large
All draft horses should have a complete physical draft horse.
examination because some cases presented for lameness Farriery can be greatly aided with shoeing stocks.
evaluation may have systemic disease (e.g. endocarditis). Some owners possess shoeing stocks and perform rou­
The lameness examination should begin with a visual tine farriery on their own. Feet also can be hoisted with
examination of the limbs and trunk. Next, the limbs, the help of a rope secured to a hobble placed around the
neck, back, and pelvis should be carefully palpated for pastern. Shoes for draft horses are not readily available
evidence of asymmetry and focal pain or swelling.
Chronic forelimb lameness can contribute to foot asym­
metry and muscle atrophy of the shoulder muscles.
Chronic hindlimb lameness can result in gluteal muscle
atrophy.
Palpation of the lower extremities is complicated by
the presence of long hair (feathers) in the fetlock and
pastern regions. Palpation is also hampered because of
the thick nature of the skin covering the distal extremity.
Picking up the foot for applying a hoof tester can be
challenging because not all draft horses willingly allow
the examiner to pick up the foot. If necessary, the horse
can be placed in stocks and a hobble placed around the
pastern of the affected limb. A rope is secured to the
hobble and the foot hoisted. Hoof tester application is
often not helpful because the soles and hoof walls are
typically thick and hard. Nonetheless, hoof testers
should be applied to fully evaluate the hoof capsule,
sole, and frog.
Lameness should be evaluated at the walk and trot.
Horses should be evaluated on a straight line and while
trotted in a circle. If possible, competition hitch horses Figure 9.63. Hoof care can be more difficult in draft horses,
should be evaluated while pulling a cart or wagon. Flexion predisposing to foot problems, including hoof cracks.