Many of us who have owned broodmares can attest that there are certain signs that indicate foaling time is near. These signs most generally will fit into a time frame ranging from weeks, days, and hours to foaling.
It is best to start out with a general knowledge of when a mare was bred. Foaling is most likely to occur when a pregnancy reaches the gestational age between 320 and 370 days. Some folks may believe their mare is overdue once she reaches 345 days, with day 340 or 341 being the mean average. Remember that the gestational clock is run by the foal's internal battery, which will induce labor once the foal has adequately and sufficiently developed in utero.
- 2 to 6 weeks - the mare's teats and udder will begin to swell and enlarge. Sometimes (in maiden mares, particularly) the udder and teats may swell and recede a couple of times. I've never noticed this occurring with established broodmares.
- 1 week to 2 weeks - The croup muscles around the tail dock and vulva of the mare will begin to relax and feel "spongey." The vulva may appear swollen when it is relaxed.
- 4 to 6 days - The mare's udder will fill with milk and the teats will become engorged.
- 2 to 4 days - Waxing (leaking or streaming of colostrum) will form on the teats.
- Hours to minutes - The mare will appear agitated and restless, even colicky-acting. She may bite or kick at her sides, or lay down repeatedly. Sweating may be obvious.
These signs, in their entirety, may or may not be exhibited by all mares. Most particularly of these are waxing and milk engorgement. Some mares do not wax at all and may not show signs of milk engorgement until shortly before birth.
Of particular noteworthiness is how each mare individually exhibits these signs. The impending birth signs a maiden broodmare exhibits will most likely stay with her throughout her breeding career. Interestingly, a mare will tend to deliver around the same timeframe, give or take an hour or two.
For those who are awaiting new arrivals this spring, good luck to you during your foal watch. I hope you are able to be witness to such a splendid event.