The Horse

FEB 2018

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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17 February 2018 THE HORSE Indeed, the mare feels internal changes and becomes more pre- occupied with these sensations than her regular routine. "A lot depends on whether you are observing a mare on pasture, out with other horses, or in a stall," Tibary says. "Each case is different. Perhaps she is too quiet today or spending more time with her head down and is just not herself. Then the signs prog- ress to more increased alertness, circling, etc." If the mare is with other horses, she might go off by herself or stay behind the group. If she is confined she might become frustrated and start pacing her pen or stall. "We tell mare owners to be looking for any of these subtle signs during preg- nancy and not just before she is supposed to foal, because those are also signs you might see if she's about to lose the fetus or foal prematurely," Tibary says. He points out that these behavioral signs are quite variable from one mare to another. "We've seen mares that just continue to do what they've been doing; they munch on hay and go on about business as usual and then suddenly go into second-stage labor," he says. Others might appear to have mild discomfort for several days before labor begins. Picking up on these signs becomes more difficult at a veterinary clinic, where the observer isn't familiar with the mare. "We don't know her normal routine," says Tibary. "We changed it, and she may be more nervous anyway or may not want to show any signs. This is when the biochemical tests (more on these in a minute), particularly the strip tests for calcium and pH, become very helpful for monitoring." Monitoring Devices A number of signaling devices (e.g., Foal-Alert, Birth Alert, Foal Alarm, etc.) are available to notify the owner, farm manager, or foaling attendant that a mare is or could be in labor. Some attach to the mare's halter, while others are stitched to her vulva. When she lies flat or her vulva lips begin to spread apart, respec- tively, each device transmits a signal to a receiver that sounds an alarm or calls your phone. "These devices can be helpful, but can't fully replace visual observation," says Tibary. "Most electronic techniques are triggered by the second stage of labor, and in some instances these alarms might be a little too late, since mares foal so quickly. The mare could foal before you are able to get to the barn." Also, in the case of a dystocia (difficult birth), the sensor sutured to the vulva might not work because the foal can't reach the vulva to trigger an alert, says Ellerbrock. "There is also a company working on devices on the halter that monitor the mare's heart rate as well as when she is getting up and down—looking at the horse's vital parameters," says Ellerbrock. "This would signal that the mare is either foaling or colicking." Other monitoring methods include closed-circuit TV or webcam, which allow you to watch the mare from your house or smartphone. You can observe signs of early labor before the other types of monitoring kick in. "Here at our hospital we constantly watch (on webcam) all the mares being monitored for foaling, particularly those that have had a difficult preg- nancy," says Tibary, adding that this allows you to watch the mare from a distance, without disturbing her. Ellerbrock describes the con- venience of apps that connect to the webcams: "You could be out for dinner and pull up the mare on your phone to watch what she is doing," as long as the barn has Wi-Fi access. "Night-vision cameras are the best option because you don't have to leave a light on in the barn all night, which could interfere with the mare's natural circadian rhythm and when she decides to foal," she adds. Mammary Secretion Tests Owners and veterinarians can use a variety of biochemical tests to determine when a mare is near foaling. The tradi- tional one is based on electrolyte changes in mammary secretions. "To do a full monitoring (which must be done at a lab) we can look at calcium, sodium, and potassium levels," says Tibary. "The real trigger in knowing when the mare is going to foal is when we see the level of sodium and level of potas- sium invert. At first the sodium would be very high, then as the mare gets close to foaling the sodium will be lower than potassium. That point of inversion … tells us the mare is within about 24 hours of foaling." At this point you can intensify your visual monitoring. "Other tests focus primarily on cal- cium, which is also a good indicator of imminent foaling," he says. "Calcium in mammary secretions progressively in- creases in concentration as the mare gets closer to foaling. There are many types of test strips (e.g., Predict-A-Foal, Foal- Watch) that are commercially available." When these tests show the secretions' calcium content reaches 200 parts per million, the mare has about a 50% chance of going into labor within 24 hours; about an 85% chance within 48 hours; and about a 95% chance within 72 hours. "Another method we are starting to use in combination with the calcium strip test looks at pH of the secretions," says Tibary, which decrease progressively leading up to foaling. "Research over the last five years has shown that pH of mammary gland secretions is highly correlated with electrolyte changes. When Some foaling signaling devices can be stitched to the mare's vulva. PAULA DA SILVA Breeders can monitor mares from their smartphones via continuous closed-circuit television or webcam. ELLEN PONS

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