Table 1. Commonly used analgesic agents and suggested doses in horses. The dose and route of administration used for each
patient must be determined on the basis of the clinical problems, systemic status of the horse, concurrent drug use and other
relevant medical factors.
Pain management in food and fiber producing ruminants is often more problematic than in other domestic species. Analgesic
protocols have not historically been incorporated into routine agricultural animal treatment plans because of the perception
that they are too time-consuming, too costly, and too impractical for routine use. This is further exacerbated by subtle clinical
signs of pain that are often poorly understood and under-recognized. Because there has been relatively little emphasis on
pain management in food and fiber animals, it is not surprising that pharmacologic management of pain is sharply limited by
availability of drugs licensed for use in food-producing animals, a lack of information regarding therapeutic analgesic strategies
in these species, and related concerns regarding drug withdrawal times to avoid residues in meat or milk.
Table 2 Drugs for continuous rate infusion (CRI) for analgesia in horses.
Today the incorporation of analgesic treatments into agricultural animal medicine is slowly increasing world-wide in response
to three very different influences. First, our abilities to recognize the behavioral signs of pain are improving for all animals
species with resultant increasing awareness of the presence of pain in our patients. Second, an enhanced understanding of
the adverse effects of uncontrolled pain on the well-being of animals and hence, on their long term production capacity, has
increased the willingness of producers to spend the time and money required for analgesia in association with routine surgical
procedures. Finally, there is growing world-wide demand for animal products produced in a "cruelty free" environment and increasing
numbers of consumers are willing to pay higher prices for such products.
Behavioral Responses to Pain in Ruminants
Table 3 Drugs used for epidural analgesia in horses.
Behavioral signs of pain in ruminants are often quite subtle and may primarily manifest as an absence of normal behaviors.
Cattle and sheep in pain may appear dull, depressed, and show little interest in their surroundings, separating themselves
from the herd or flock. Unusual behaviors by an individual, not manifested by other animals in the group, may suggest the
presence of pain. In cattle, these unusual behaviors may vary from total inactivity to restlessness to obvious hyperactivity.
Any painful condition may impair rumen motility and cause a sudden decrease in milk yield. Cattle with abdominal pain may
show abdominal splinting, grunting, tooth grinding, or arched back. More specific signs of abdominal pain such as kicking
at the abdomen or rolling are less common in cattle than in horses. In sheep, grinding of teeth, head pressing, lip curling
and cessation or rumination may occur with severe pain. After castration or tail docking indicators of pain in lambs may include
repeatedly laying down and standing up, wagging their tails, or remaining immobile while standing. Goats tend to vocalize
more in response to pain than do cattle or sheep. As with horses, ruminant species may show changes in their responses to
human interaction as a result of pain. This may manifest as rigidity of posture, violent responses, or resentment of handling.
Chronic pain may be manifested as changes in personality, loss of appetite, and decreased grooming behavior.