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YOUR GUIDE TO THE 2017 AAEP CONVENTION SPONSORED BY A16 TheHorse.com/AAEP2017 AAEP Wrap-Up THE HORSE March 2018 PMIE mares had rates of about 30%, and treated mares had rates over 60%. Turner suggested vets consider adding PRP intrauterine infusions to their list of potential PMIE treatments. Cipro for Gram-Negative Endometritis? Antibiotic resistance, particularly of Gram-negative organisms (a certain bacterial class), has increased. One family of antimicrobials, fluoroquinolones, has excellent Gram-negative activity, so "it would be really nice if we could have a fluoroquinolone in our toolbox to treat Gram- negative endometritis," said Turner. She said the currently available fluoro- quinolone for horses, enrofloxacin (Bay- tril), is not safe for intrauterine use. But ciprofloxacin, a metabolite of enrofloxa- cin, has an identical spectrum of activity, as well as anti-inflammatory properties. Researchers evaluated ciprofloxacin as a Gram-negative bacterial endometritis treatment. They infused each infected mare's uterus with 60 mL of an intrave- nous ciprofloxacin used in humans. They saw high concentrations of ciprofloxacin in the uterine lumen and endometrial tissue 24 hours later, well above the levels needed to kill the four common types of endometritis-causing bacteria. They noted little to no inflammation or adverse effects. "So ciprofloxacin right out of the bottle might be an option for the treatment of infectious (bacterial) endometritis in mares," said Turner, adding that it's "a big gun and should be reserved for resistant organisms only," reminding vets that the team used extra-label human products. New Help IDing Problem Pregnancies Researchers evaluated the use of mater- nal blood plasma progestin and estrogen concentrations to identify problem preg- nancies. These hormones increase sig- nificantly mid- to late gestation in mares during healthy pregnancies. The research- ers took blood samples from nearly 500 pregnant mares monthly, tested hormone levels, and determined whether the mares showed signs of problems, delivered healthy foals, or experienced foal loss. Based on their findings, they created a chart with recommended normal values for progestins and estrogens in 20-day increments during late gestation. "It gives us a potential diagnostic assay to identify problem pregnancies," said Turner, and shows that serial hormone monitoring can help vets track treatment efficacy. She cautioned against relying heav- ily on hormonal values because of low positive predictive values; vets will end up overdiagnosing problems that don't exist. Also, hormonal changes tend to occur late in a problem's progression, so these tests may not be best for early detection. "How- ever, they are likely to be good for moni- toring the status of problem pregnancies, particularly following treatment," she said. Estradiol to Help Treat Placentitis Next, researchers evaluated the efficacy of various combinations of estradiol cypi- onate (a long-acting estrogen) and a long- acting form of altrenogest (the progestin Regu-Mate) to treat ascending bacterial placentitis (placental inflammation). They studied a group of healthy preg- nant mares and five groups of pregnant mares with induced bacterial placentitis. Group 1 received a traditional treatment of the antimicrobial trimethoprim- sulfamethoxazole (TMS) and the anti- inflammatory flunixin meglumine (FM). Group 2 got TMS, FM, and altrenogest; Group 3 got TMS, FM, altrenogest, and estradiol cypionate; Group 4 got TMS, FM, and estradiol cypionate without altrenogest; and Group 5 was untreated. The untreated group had a significant increase in dystocias (difficult births), preterm deliveries, and foal loss. All treat- ment groups benefited from their treat- ments, and foal survival rates were similar to those of control mares. The group treated with TMS, FM, and estradiol was the only one with no compromised foals and similar foal birth weights as controls. "This suggests that the addition of es- tradiol may benefit mares with placenti- tis," said Turner. Mare and Stallion Factors Affecting Pregnancy Rates Another research group studied the ef- fects of various mare and stallion factors on per-cycle pregnancy rate (PCPR) and pregnancy loss in a large population of Thoroughbreds. In stallions they found: ■ No difference in PCPR whether the mare was the first one bred by a stal- lion on a given day or the fourth; ■ No difference in PCPR whether the stal- lion shuttled between hemispheres; and ■ High-usage stallions that bred more than 21 times in a seven-day period had a 10% decrease in PCPR. In mares they found: ■ A significant decrease in PCPR with advancing age—geriatric mares (18 and older) were 2.9 times less likely to conceive than mares 8 and under; ■ An increase in pregnancy loss rate with advancing age—geriatric mares were 2.6 times more likely to abort; ■ Barren mares were 1.8 times more likely to abort than maiden mares; ■ A significant decrease in PCPR in mares bred on foal heat; and ■ No other effect on PCPR, including be- ing treated for a uterine problem. "These study results show mare age has the greatest effect on fertility," said Turn- er. "We kind of already knew this, but this adds more to your armamentarium when trying to explain to an owner who wants to breed their 21-year-old mare why it could be very difficult." As for breeding on foal heat, "the de- crease in pregnancy rate in mares bred on foal heat (~10%) did not justify a flat-out decision across the board to not breed on foal heat," she said. "If a mare is normal it's still reasonable to proceed with foal heat breeding, knowing there is a some- what reduced chance of pregnancy." h e Visit TheHorse.com/AAEP2017 ■ Top Medicine Studies of 2017, TheHorse.com/40206 ■ Top Surgery Studies of 2017, TheHorse.com/40144 ■ Top Reproduction Studies of 2017, TheHorse.com/40136 So ciprofloxacin right out of the bottle might be an option for the treatment of infec- tious (bacterial) endo- metritis in mares." DR. REGINA TURNER