If a small amount of Acetaminophen makes your horse feel better, a little more could make him feel even better for a little longer. Owners of horses with persistent aches and pains will be relieved to hear this.

Acetaminophen is a low-cost, effective over-the-counter pain medicine that can be used instead of NSAIDs, which can cause stomach ulcers and kidney damage. According to researchers, Acetaminophen is safe for horses at higher doses than previously evaluated, even when given for weeks at a time.

The study, led by Melissa Mercer, DVM, Dipl. ACVIM-LA, a resident at the Virginia-Maryland College of Veterinary Medicine in Blacksburg, Virginia, pursuing a Ph.D. in veterinary clinical pharmacology, found that 30 milligrams per kilogram of body weight of body acetaminophen twice daily for 21 days had no adverse effects. In practical terms, this equates to around 15,000 milligrams (30 500-milligram tablets) administered at 12-hour intervals to a 1,100-pound horse. The study builds on a previous study that found Acetaminophen was safe for horses when given twice daily at a dose of 20 milligrams per kilogram of body weight for two weeks. Mercer presented these findings at the 2021 American Association of Equine Practitioners Convention, which took place in Nashville, Tennessee, from December 4 to 8.

The newest trial comprised 12 therapy and lesson horses from the Ride-A-Rescue/Winterfrost Farm program, ranging from 13 to 23. All were in good health but had minor, chronic lameness for which they were given NSAIDS regularly to keep them comfortable. Before the start of the trial, they were taken off all drugs. As they trotted in a straight line on the pavement, each horse was rated for lameness using body-mounted electrical sensors and human evaluators. Six horses had their stomachs scoped for gastric ulcers, and their livers were biopsied before and after treatment to look for signs of toxicity.

The researchers proved that Acetaminophen is absorbed quickly and easily in horses, and its pain-relieving qualities are already at work in less than an hour. It’s still unclear how it works, but it’s thought to affect the endocannabinoid, opioid, and serotonergic systems in some of the same ways that scientists believe cannabidiol (CBD) does, according to Mercer. While it doesn’t have the same anti-inflammatory properties as phenylbutazone (bute), it’s gentler on the stomach. In fact, after 21 days of Acetaminophen, some horses in the trial with stomach ulcers exhibited significant recovery. According to Mercer, the break from NSAIDs allowed their preexisting ulcers to heal.

Another advantage is that even after three weeks of twice-daily dosing, Acetaminophen does not build up in the horse’s system. Researchers believe that a greater dose might maintain a therapeutic level until the next dose is delivered since it clears the system quickly. The drug’s peak concentration occurs around an hour after ingestion, and most of the horses looked to feel and move better as a result. They also kept their regular riding schedules throughout the research.

According to Mercer, researchers are currently studying the data, but preliminary studies showed “transient improvement” in lameness scores after 21 days. She concluded that while Acetaminophen may not be the greatest stand-alone treatment for chronic lameness, it is proven to be a safe and efficient way to relieve our horses’ everyday aches and pains.

Why is it that my horse chews on wood?

This served as a nice reminder that horses eat more in the pasture, even if it is sparse than we realize. You may need to make further management changes if you remove pasture access.

If you haven’t already, you should be able to increase your mare’s hay intake to compensate for the lack of pasture without too much concern about weight gain. You’re effectively replacing calories she was previously consuming up until recently. However, because she’s stalled rather than wandering about a field, her energy needs may have decreased slightly, even with the additional round penning. Experiment with different amounts of hay to see how much you can feed without causing weight growth.

You should already be feeding her hay with a reduced nutritional content because she’s an easy keeper. Even if you increase her consumption, this should lower the chance of unwanted weight gain. You might also want to use a slow feeder for your hay so she can eat her ration more slowly. Depending on how much room she is kept in, a few of these could be set out to encourage her to move around.

If you increase her hay intake and continue to gain weight, you may want to reevaluate her grain/concentrate intake. I’m not sure what kind of grain you’re giving or how much she’s eating, but this will be an additional source of calories that forage may replace. If you want the grain to supply vitamins and minerals that the forage in the diet doesn’t, you should look for a ration-balancing supplement. These often feature smaller serving sizes (three to four ounces per day) and provide fewer calories than ration balancing feeds.