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Omega-3s And Inflammation In Athletic Horses

Inflammation is part and parcel to building strength and fitness in equine athletes. One key to training, however, is keeping inflammation at controllable levels after exercise so recovery occurs quickly and training continues unhindered. New findings from Kentucky Equine Research (KER) suggest long-chain omega-3s may be useful in managing inflammation in hard-working horses.

Using eight Thoroughbreds in race training, the researchers designed a 28-day study to determine the effect of long-chain omega-3 (EO-3) supplementation and exercise on blood serum gamma-glutamyl transferase (GGT) levels and inflammation. The enzyme GGT breaks down glutathione, a potent antioxidant. As levels of GGT rise, less glutathione is available to neutralize free radicals, leaving more cells susceptible to the damaging effects of oxidation.

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“Interest in the effect of omega-3s on inflammation stemmed from consistently high concentrations of the enzyme GGT in blood samples of some racing Thoroughbreds,” said Laura Petroski-Rose, B.V.M.S., a veterinarian with Kentucky Equine Research.

In the study, four of the horses were supplemented daily with 60 mL (2 ounces) of EO-3, while four horses served as controls and received the same feed without EO-3. All horses were fed 13to 15 pounds (6-7 kg) of a commercial racing feed (12 percent protein, 8 percent fat) with free-choice timothy hay. During the study, the horses were galloped three times per week (1-1.5 miles per session) on a racetrack and jogged three times per week (30 minutes per session) on a mechanical exerciser. At the conclusion of the 28 days, the horses performed an exercise test on the racetrack that consisted of a warm-up jog, ten-furlong (2,000-meter) gallop, and a two-furlong (400-meter) breeze. Blood samples were taken before exercise as well as two and four hours post-exercise.

The horses supplemented with EO-3 had significantly lower GGT levels two and four hours post-exercise compared to the control horses. This may have resulted from a reduction in inflammation observed post-exercise in the horses fed EO-3. Read more about the study.

New Test Can Detect Bisphosphonate Three Years After Administration

A new study may give regulators the key to better regulate bisphosphonate use in racing. Controversy has surrounded bisphosphonate use since the drug became approved by the Food and Drug Administration (FDA) for use in horses. Bisphosphonates are labeled for adult horses battling navicular syndrome and similar chronic conditions that don't respond to other types of treatment.

The FDA has licensed two bisphosphonates, which are sold under the trade names Tildren and Osphos. The Horse reports that there are other, non-licensed versions of bisphosphonates marketed for horses which are not FDA-approved. Those non-approved products are advertised as being more powerful than the two approved versions.

The FDA prohibits the use of bisphosphonates in horses younger than four years old, but some owners and trainers continue to use the product off-label on young horses. Bisphosphonates impact the build-up/breakdown cycle in bone, which veterinarians say could have negative effects on growing animals.

Dr. Christopher Riggs, chief advisor in veterinary science at The Hong Kong Jockey Club, studied 24 Thoroughbreds who had received a single therapeutic dose of tiludronate disodium between one month to three years earlier. The research team then tested blood plasma and urine samples using ultra‐high‐performance liquid chromatography high‐resolution mass spectrometry, a new testing technology. The tests found traces of tiludronate disodium in every sample.

Previously, testing was only able to detect bisphosphonates in equine blood or urine if it had been administered in the last 40 days. Hair testing could detect an administration from months prior, but is limited in its ability to pinpoint the time of administration.

Researchers believe the drug lingers on the surface of bone, occasionally releasing back into the horse's body for months or years, but little is known about how long that effect could go on. The drug may be more detectable in horses that are going through training and rest periods that affect bone remodeling.

Study: Ophthalmic Atropine Use May Increase Risk Of Colic

Atropine is a commonly used drug in horses with eye issues – specifically with equine uveitis – but a new study has found that it can affect more than just the equine eye: it can also increase a horse's risk of colic.

Dr. Lena Ström and her research team investigated how the drug interacts with the horse's body and found that frequent administration of atropine may reduce intestinal action, increasing colic risk. The team suggests allowing for additional time between atropine treatments to minimize colic risk, but the frequency of medication administration must focus on the horse's comfort.

The research team used two different dosing protocols on four horses to assess the effects of manually delivered atropine on the gastrointestinal system. The research team monitored the frequency of gut noise on all horses to estimate gut action.

The scientists found a decrease in intestinal action after 1 mg of atropine was given every three hours, however there was no change to gut action after the drug was given every six hours. No signs of colic were seen.

The researchers determined that atropine eye drops given at one- or three-hour intervals will accumulate in the plasma over 24 hours and cause possible intestinal complications. Atropine administered in six-hour intervals allows for the removal of the drug from plasma and limits the possibility of colic.

Read the full study here.

Hormones Play A Role In Foal Rejection

Foaling can be a high-stress situation with a lot of variables that may go wrong, from dystocias to ill foals. Though most mares have an innate mothering mentality, some mares reject their offspring and the exact reason is unclear, making it difficult to prevent.

Drs. Dalia Berlin, Amir Steinman and Tal Raz conducted a study using eight Arabian mares who behaved normally after foaling and 15 Arabian mares who typically “rejected” their foals. Rejection includes refusing to let the foal nurse, indifference toward the foal and even attacking the foal. The Arabian was chosen specifically for the study as rejection behavior in mares has been well documented in the breed.

Each mare had blood drawn at the first and third day after foaling; the blood was tested for progesterone, prolactin and estradiol, which are reproductive hormones. The most significant difference between the two groups was the estradiol-to-progesterone ratio the first day after foaling was significantly lower in mares that rejected their foals than in mares with normal maternal behavior.

The exact role the hormones play in maternal behavior is unclear, but the ratio of hormones in mare that rejected their foals increased in the three days post foaling, suggesting that the hormones may normalize and the rejection behavior may diminish.

The study team notes that the creation of hormonal treatments for rejecting mares is premature as the optimal concentration for each hormone is yet unknown.