"Horses with lameness in more than one limb are a diagnostic challenge, especially if both a forelimb and a hindlimb are involved," said Sue J. Dyson, FRCVS, of the Center for Equine Studies at the Animal Health Trust, during her presentation on the topic at the 43rd British Equine Veterinary Association Congress, held Sept. 15-18 in Birmingham, U.K. "The first key to successful diagnosis is determination of which are the lame limbs.

"This is particularly difficult if the horse moves with a short, shuffling gait rather than overt lameness," she went on. "Very careful evaluation of the horse under a variety of circumstances, straight lines, circles on soft and hard surfaces, and if necessary ridden, and assessment of response to flexion tests, are crucial. The investigator should first evaluate the overall way the horse moves, focusing first on the forelimbs and then on the hindlimbs. Watch the horse carefully as it turns to change direction; discomfort while turning may reflect foot pain."

She noted that practitioners should pay close attention to the rider's hands when a horse is worked under saddle, as some riders can induce a head nod in a sound horse, making him appear lame. "You need a skilled rider to help you assess response to nerve blocks," she said.

Dyson offered several more tips for practitioners on assessing lameness, including the following:

  • Clinical appraisal before assessing movement might give some clues; for example, obvious muscle asymmetry might reflect hindlimb lameness.
  • Hindlimb lameness may have an associated head nod mimicking ipsilateral (the same side) forelimb lameness. The challenge is this: Are there two lamenesses or one?
  • A head nod might accompany moderate to severe hindlimb lameness, but not always.
  • After blocking the obvious lameness, you might see more! Re-evaluate the whole horse after blocking limbs.
  • If lameness is only apparent when the horse is ridden, be sure that you determine if it is influenced by the diagonal on which the rider sits.
  • Unilateral forelimb lameness is typified by a head nod as the sound limb bears weight, but bilateral forelimb lameness similar in degree might result only in a shortened stride or might be completely inapparent when the horse trots in straight lines.
  • Unilateral hindlimb lameness is typified by a greater up and down excursion of the ipsilateral (the same side) hindquarter than the sound limb.
  • Bilateral forelimb or hindlimb lameness might not be obvious if one limb is considerably more lame than the other, and might be identified only after pain has been removed from the lamer limb.
  • Bilateral hindlimb lameness similar in degree can result in restricted hindlimb impulsion and might not be obvious unless you know the horse, or you are very aware of how a horse of that type should move.
  • Variable lameness characteristics under different circumstances might indicate more than one focus of pain.
  • If lameness is bilaterally symmetrical (in both front or hind limbs), if one limb is blocked, you might see overt lameness in the other. But not always--consider blocking both simultaneously.
  • Limiting factors include time, experience of the clinician, and the horse's tolerance of repeated injections.

"I strongly advocate targeted rather than systematic blocking based upon the clinical signs, type of horse, and prevalence of different sources of pain in a horse used for that discipline," Dyson concluded. With tough cases, scintigraphy can he helpful for confirming positive findings or targeting further investigation, she added.

About the Author

Christy M. West

Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.

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