The weeks and days leading up to foaling can be exciting and stressful, filled with sleepless nights and middle of the night trips to the barn. Several technologies exist to assist in predicting when parturition is eminent. These devices, which include foaling monitors and milk test kits, may help take some of the anxiety out of the situation.
Milk Test Kits
When foaling is drawing near the mare will typically begin to show signs of mammary gland development, her abdomen will drop, the ligaments and muscles in the perineal area begin to relax, and there is engorgement of the teat ends with waxing of the teats approximately 48 – 72 hours prior to foaling. The mare may also drip milk from her udder 12 – 24 hours prior to foaling.
One way to predict foaling is to test the milk dripping from the mare’s teats. It has been shown calcium in the milk increases as foaling approaches. Typically, when the calcium level is above 200 ppm it is highly likely she will foal within 48 hours. However, it is not a definite timeline. In Dr. David Scofield’s experience (SBS Veterinary Services in Chesapeake City, MD), monitoring the milk calcium levels is a great way to tell when a mare likely isn’t ready to foal. He says, “If the calcium levels are low, she probably isn’t close. However, if the levels are high it can be several days before she will foal.” Another method of testing the mare’s milk is by testing the pH level of her milk. A decrease in pH (becoming more acidic) shows the mare is getting close to foaling.
Two test kits available on the market are Predict-A-Foal® and Foal Watch®. The Predict-A-Foal® system uses rapid test strips. As the number of test squares changing color increase so does the chance of foaling. Foal Watch® (photo right) is used by aspirating small amounts of diluted milk samples into a calibrated titration chamber. When color change occurs there is a scale on the glass chamber which indicates the level of calcium in the milk. If there is greater than 200 ppm of calcium in the mammary secretion there is a 54% chance of foaling within 24 hours, an 84% within 48 hours and a 98% chance she will foal within 72 hours.
There are several labor alert devices available on the market. They are fastened around the mare’s belly, inserted into her vagina/vulva or attached to her halter. These devices include the Birth Alarm® (girth strap transmitter), Birth Alert® (vaginal insert transmitter), Breeder Alert (halter transmitter), Foalert™ (vulva transmitter) and EquiFone (halter transmitter).
Devices, such as Birth Alarm®, Breeder Alert, and EquiFone, which attach to the mare via her halter or a girth strap monitor if the mare is standing up or lying down. Since they monitor the behavior of the mare and not the actual process of foaling there could be many false alarms.
The Foalert™ (photo left) transmitter (sewn into the vulva) tells you when things are passing the vulva. Since it only alerts when things are passing through the vulva it doesn’t give you much lead time to get to the barn. Also, if there is a dystocia that prevents the foal from passing parts through the vulva the alert won’t activate which could result in an emergency situation for the mare and/or foal. A bonus to this system is that it can be connected to a pager or cell phone. This system has a substantial upfront cost but the transmitters can be reused if you purchase the multiple use transmitters (good for ten foalings).
Dr. Scofield uses Foalert™ and monitors the mare’s mammary secretions with pH test strips as well as calcium carbonate tests. He also supplements the Foalert™ with internet based cameras. He said, “I love having internet based cameras on the foaling stalls that allow me to watch from my home computer or iPhone.”
Select Breeders Southwest (SBSW) in Aubrey, TX uses the EquiFone system. This system uses a halter monitor which alerts you when the mare lays flat for 10 seconds or more. The sensor is attached under the throat latch of the halter and transmits a signal to a base which is connected to a phone line. When the sensor is in "foaling position" the base will call phone numbers previously programed into the system. An advantage to this system is that it can be put on or taken off the mare’s halter with little effort and at the discretion of the person who is foal watching. Some mares may lay down prior to actual parturition giving you an earlier alert that foaling is imminent compared to a system that uses a vulvar implant.
EquiFone is relatively inexpensive compared to more intricate systems so it may be better for farms foaling fewer mares. Another use for EquiFone is that it can also be placed on the halter of a horse suspected to be suffering from colic. Thus, giving the system a use for other horses on the property when foaling season is complete.
A disadvantage to the EquiFone is in the simple nature of how the sensor works. There may be several false alarms since the system is not able to distinguish between actual parturition and a mare that has simply laid down for the night. Zach Kahn of SBSW says, “To complement the EquiFone, we have a camera system that can be monitored though an internet connection. This helps to limit the number of trips to the barn as well as allows us to view the mare and new born foal after parturition.”
It may not be possible to pinpoint the exact minute a mare is going to foal. However, using these prediction devices, or a combination of several, may assist in narrowing down when you need to remain close to home.
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