If you have a pregnant mare in your barn, plan ahead to collect and freeze some of her colostrum — that all-important first milk — so you have it on hand if a foal is born without access to this essential liquid.

Colostrum is produced within the first 24 hours after a mare has foaled and the best quality colostrum is available in the first eight hours post-foaling. Unlike other species that pass antibodies and immunoglobulins across the placenta into the fetus, the foal’s immune system does not kickstart until it receives colostrum during the first 24 hours of life. Newborn foals are able to absorb the life-giving antibodies and nutrients for that first day. After the first 12 hours, colostrum absorption begins to decline, and after 24 hours the foal’s digestive tract changes so the antibodies can no longer be absorbed.

Every foaling season, foals are born without access to this life-giving liquid. Sometimes a mare dies while giving birth. Another mare will reject her foal, or leak milk and colostrum before the foal is born. Another foal may be too weak to stand and nurse. When a foal does not obtain enough quality colostrum to be protected from viruses and bacteria, it is referred to as failure of passive transfer of immunity. Often, the mare can be milked and colostrum either provided to the foal through a bottle or tube, or stored in the freezer until needed.

Related: How to Care for Your New Foal

To collect this magic milk, first allow the newborn foal to properly nurse several times (assuming that he can) and wait until he is resting, ideally about eight hours after birth. Then follow these basic steps:

1. Wash your hands and then gently wash the mare’s udder with warm water. Have a clean, reasonably wide plastic container or stainless steel mixing bowl on hand to collect the milk. 
2. Calmly approach the mare, holding the container in your left hand (or right hand if you are left-handed). Put the container under her udder and gently put your right thumb and forefinger on her teat. 
3. Push the milk bag upward to trigger the flow, the way the foal would, then gently squeeze and pull down on the teat, causing the milk to spray into the container.
4. Stop collecting when the pressure on the mare’s udder is relieved, or when you have collected between eight to ten ounces, whichever comes first. Two collections are usually enough. If the mare is also nursing a foal, do not collect more than a pint of milk or you risk depleting the mare’s colostrum supply for her own newborn.
5. Filter the colostrum prior to freezing with a kitchen filter or cheesecloth. Place the colostrum in a clean plastic screw-top container or sealable plastic bag, and label it with the name of the mare, the date, and the amount of time since foaling.

Freeze the supply immediately to keep as many antibodies intact as possible, and it can remain frozen at minus 20 degrees C for a year or more. Alert your local equine veterinarians and breeders that you have colostrum available in case of emergency.

To use the colostrum, defrost it at room temperature or by running cold water over it. Thawing in a microwave or in hot water will kill the antibodies.

While a horse owner in need will gladly accept any offering of colostrum you have available, the colostrum should be tested prior to freezing to find out what antibody levels it contains, and to test for anti-Aa or anti-Qa antibodies, which can result in an uncommon colostrum cross-match abnormality called neonatal isoerythrolysis (or jaundiced foals). 

Related: Should You Breed Your Mare?

Main Photo: Dreamstime/Janian Mcmillan