When it’s time to do vaccinations, injections or blood draws, a needle-shy horse can make a veterinarian’s job more difficult and put handlers at risk. But researchers at the University of Pennsylvania’s New Bolton Center have found a simple way to minimize the horse’s discomfort: Apply topical anesthetic to the injection site beforehand.
Noting that a horse can become resistant to injections after even a single unpleasant experience—and punishment or aggressive restraint can cause needle shyness to become more deeply ingrained—the New Bolton Center veterinarians began to numb injection sites with topical lidocaine years ago. They recently organized a study to evaluate the efficacy of the practice.
A study of needle shyness
For the study, the researchers divided 78 ponies into three groups. In the first group, a 5 percent lidocaine topical solution was applied to the injection sites. In the second, the researchers applied a 10 percent lidocaine solution to the site. Finally, a solution that contained no lidocaine was applied to the third (control) group . After two minutes, handlers—who were unaware of which treatment each pony had received—administered the injections.
The researchers watched video recordings of the procedures. They then assigned each animal a score on a four-point scale gauging the intensity of the reactions. (0 = no perceptible reaction; 1 = a slight flinch; 2 = mild-to-moderate head, neck, body and/or limb movement; and 3 = more than moderate movement).
What the data showed about stopping needle shyness
The scores indicated that lidocane made a difference. When either lidocaine solution was applied, 85 percent of ponies showed little or no reaction to the injection. Their response scores were 1 or 0. By contrast, more than half of the ponies in the control group scored 2 or more on the reaction scale. Those scores indicated greater reactions to the injections.
Thus, the researchers concluded, “these findings confirm our clinical impression that application of topical anesthetic just two minutes in advance of intramuscular injection can effectively reduce the behavioral reaction of horses.”
Reference: “Efficacy of lidocaine topical solution in reducing discomfort reaction of horses to intramuscular vaccination,” Animals, June 2022
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