The Horse

JAN 2019

The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.

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24 January 2019 The Horse | TheHorse.com penicillin and gentamicin, "pass through the placenta and attain therapeutic concentrations for a period of time in the allantois fluid surrounding the fetus." Antibiotics that do not pass through the placenta well, say Macpherson, in- clude ceftiofur sodium and ceftiofur crys- talline free acid. Based on her research (TheHorse.com/111282), they produce almost undetectable concentrations in fe- tal fluids and fetal tissues and, thus, aren't good treatment choices for placentitis. "The ceftiofur drugs are still useful for treating conditions other than placenti- tis in pregnant mares," she says, "as the pharmacokinetic profiles are not signifi- cantly altered in pregnancy." Other researchers are looking at the ef- fects of the antibiotic enrofloxacin, which appears to have similar effects as genta- micin but isn't as harsh on the kidneys, says Linton. Sedatives Many owners wonder whether sedation is safe for pregnant mares. "The common sedatives used in horses are α 2 agonists (xylazine and detomidine)," says Linton. "Many people also use acepromazine, which is more of a calming agent (tran- quilizer) than a sedative." While none of these are labeled for use in pregnant mares, she says they typi- cally don't cause serious side effects. Still, ask yourself why you are giving sedation and if it's necessary. If it makes the mare more comfortable to have a laceration sutured, says Linton, you might want to use it. If it's just to keep her calm because she doesn't like being confined to a stall, come up with a medication-free way to keep her happy. The downside to sedatives and tran- quilizers are they can potentially affect the mare's blood pressure and, therefore, blood flow to the fetus, says Sheerin. However, "used in moderation, they are probably fairly safe," he says. "A one-time dose of the drugs we typically use for se- dation or tranquilization would probably not cause a problem." Anesthesia—if your mare needs colic surgery, for instance—might be riskier. It can potentially decrease cardiac out- put, depress arterial pressures, and cause respiratory depression. If gen- eral anesthesia must be performed on a pregnant mare, researchers believe the safest window is Days 40-220 of gestation ( TheHorse.com/156897). Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) The NSAIDs, including phenylbutazone (Bute), flunixin meglumine (Banamine), and firocoxib (Equioxx), also aren't labeled for use in pregnant mares, but veterinarians often administer them in moderation without issue, says Sheerin. He says one conservative dose might be safe (if your pregnant mare is colicky, for instance, you can probably safely give her a dose of Banamine), whereas chronic administration might cause kidney prob- lems or endanger the fetus. There's little research backing these drugs' use in broodmares. "We have looked at flunixin meglumine and didn't see whether or not it passed the pla- centa," says Macpherson. "It may have been because the system we were using to measure it prevented it from passing, but we don't know—we couldn't detect it in fetal fluids." Other Colic Medications Sheerin advises against administer- ing more than one moderate dose of the anti-spasmodic and anti-cholinergic (blocks parasympathetic nerve signals) drug N- butylscopolammonium bromide (Buscopan) off-label to pregnant mares to treat spasmodic and gas colic. "The fear is that it might relax the cervix," he says. MEDS FOR MARES BRIEF SUMMARY (For full prescribing information, see package insert.) CAUTION: Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. DESCRIPTION: Domperidone is a D2 dopamine receptor antagonist. The chemical formula is 6-chloro-3-[1-[3-(2- oxo-3H-benzimidazol-1-yl) propyl]piperi- din-4-yl]-1H-benzimidazol-2-one. INDICATION: For prevention of fescue toxicosis in periparturient mares. Contraindication: Horses with hypersen- sitivity to domperidone should not receive EQUIDONE Gel. WARNINGS: Failure of passive transfer of immunoglobulins (IgG) may occur when using EQUIDONE Gel even in the absence of leakage of colostrum or milk. All foals born to mares treated with EQUIDONE Gel should be tested for serum IgG concen- trations. Do not use in horses intended for human consumption. HUMAN WARNINGS: Not for use in humans. For oral use in animals only. Keep this and all drugs out of the reach of children. Pregnant and lactating women should use caution when handling EQUIDONE Gel, as systemic exposure to domperidone may affect reproductive hormones. Consult a physician in case of accidental human exposure. PRECAUTIONS: EQUIDONE Gel may lead to premature birth, low birth weight foals or foal morbidity if administered >15 days prior to the expected foaling date. Accurate breeding date(s) and an expected foaling date are needed for the safe use of EQUIDONE Gel. Do not use in horses with suspected or confirmed gastrointestinal blockage, as domperidone is a prokinetic drug (it stimu- lates gut motility). ADVERSE REACTIONS: The most common adverse reactions associated with treatment with EQUIDONE Gel are premature lactation (dripping of milk prior to foaling) and failure of passive transfer. Distributed by: Dechra Veterinary Products 7015 College Boulevard, Suite 525 Overland Park, KS 66211, 866-933-2472 © 2016 Dechra Ltd. EQUIDONE is a registered trademark of Dechra Ltd. All rights reserved. NADA 141-314, Approved by FDA EQUIDONE ® Gel (domperidone) For oral use in horses only. Read anthelmintic labels before deworming to make sure the one you're getting ready to ad- minister is approved for use in pregnant mares. DUSTY PERIN

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