Foaling: Late Term Pregnancy — Coming Down the Home Stretch

Foaling is an exciting time, and the wait can seem interminable (for you and the mare). But taking good care of your mare can make the wait go by faster and can help keep your mare healthy while getting her foal off to strong start. From nutrition to foot care, here are the things you should be thinking about as foaling season approaches.

Nutrition

Clean water and quality forage (hay) are the barest basics of animal care. During pregnancy, good nutrition becomes even more important, and supplements may be appropriate. Feed well, but don’t overfeed. There is very little increase in caloric need until about five months into gestation. Mares are expected to gain approximately 12-15% of their initial body weight during pregnancy, mostly from nine to eleven months. By the last month of pregnancy, an average mare will consume roughly 20-22% more calories. If the mare is overconditioned, her late gestational calorie needs may not increase as much. Obesity at the time of delivery can contribute to a difficult delivery. 

Deworming 

Only use deworming products labeled “safe for use in any stage of gestation/ safe for use in pregnant mares.” During gestation, the mare should be dewormed as directed by a veterinarian according to findings on fecal egg counts. She should be dewormed 1-2 weeks prior to delivery or immediately after foaling to limit the transfer of parasites to the foal via the milk or the environment. 

Vaccination 

Vaccination with a killed Herpes virus vaccine at 5, 7, and 9 months of gestation is generally recommended. All routine vaccinations should be boostered 4-6 weeks prior to foaling. This maximizes the antibodies passed to the foal via ingestion of colostrum in the first few hours of life. 

Housing 

Mares should have a large stall of at least twice their body length in any direction. The stall should be free of hazards for both mare and foal. It should be kept clean of manure, cleaned several times a day, and ideally would be disinfected prior to each mare using the stall for foaling. It should have good ventilation but be free of drafts. If the weather is expected to be cold at the time of delivery, a safe heating source should also be available. 

After delivery, water buckets should be elevated off the ground to prevent the foal’s inadvertently becoming trapped. I prefer for mares to foal on a low-dust bedding like straw. The bedding can be changed back to shavings once the foal is a few days old and dust or shavings will no longer stick to the umbilicus. If the time of year allows, mares can also be allowed to foal in a grassy field free of mud, dust and hazards. 

Exercise 

Mares should be regularly exercised if possible. They should have access to clean, mud-free turnout with plenty of space to move around to improve circulation. Mares can often develop edema under the abdomen in late gestation. This can be minimized when there is plenty of room to move around. 

Foot Care 

Broodmares should be kept on a routine hoof care schedule. This is especially important in the last 2 months of pregnancy. Trim about 2-3 weeks prior to delivery. Foot pain can negatively impact foal development; foals may not reach as large a size due to the increased stress of discomfort. Be alert for lameness, which can increase as mares become heavy in late pregnancy. 

Problems 

The mare’s food and water intake, as well as manure and urine production should be monitored closely. From around day 320 of gestation, begin to monitor her temperature at the same time daily to establish what is normal for her. Changes in diet, excretion, or temperature can indicate issues and should be evaluated by your veterinarian. 

Watch the udder and the vulva for any issues. Premature udder development can be associated with fetal stress due to cord compression, placentitis, positional issues or nutritional issues. Udder development prior to 5-6 weeks before the due date should always be evaluated by your veterinarian. A measurement of the combined thickness of uterus and placenta (CTUP) should be taken with the ultrasound to assess for evidence of placentitis. 

Any discharge from the vulva should also be investigated by your veterinarian. Swelling that is localized to the area between the udder and the mare’s belly button warrants a call to your veterinarian. This is a true emergency. Often accompanied by bloody discharge from the teats, it could mean a serious and most often fatal injury to the abdominal muscles/prepubic tendon. 

If the mare had a caslicks that closed part of her vulvar opening, it should be reopened between day 310 and 320 of gestation. If the caslicks is not opened it can result in dystocia or severe vulvar injury. 

Foaling Supplies 

Prepare everything you will need in advance of delivery. You should have straw bedding for the stall, your vet’s contact information, towels, fleet type enema, dental floss or other string for tying off baby’s umbilicus, and a secure container to save the fetal membranes/placenta for the veterinarian to inspect. Have a timer so that you can record the stages of labor from when the water breaks. Mares foal quickly and if it takes longer than 20-25 minutes from her water breaking you should consult your veterinarian. For disinfectant navel dip, a 10% Nolvasan solution is best; betadine can be used, but not strong iodine. Prepare in advance a baby milk bottle, a clean container to milk the mare into and a filter in case you need to offer the baby a bottle to nurse. If it is going to be colder than 45F have a heat source or at least a foal blanket handy. 

A well-cared for mare will deliver a healthy foal most of the time. A little preparation will help the process goes as smoothly as possible, and even improve the chances of survival during a difficult delivery. 

Brandi Holohan is a large animal ambulatory veterinarian specializing in reproductive management at Pilchuck Veterinary Hospital in Snohomish, Washington

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