Using a Nurse Mare to Raise an Orphan Foal

Some breeders are faced with the difficult issue of raising an orphan foal. While bottle feeding formula is the most common method of raising orphan foals, a preferred method is to use a nurse mare.

Availability and supply of nurse mares varies depending on locale, but in most Thoroughbred breeding areas of the world, it is not uncommon to see a draft or pinto mare with Thoroughbred foal at foot within a herd of Thoroughbred mares and foals. Some large breeding operations maintain their own herd of nurse mares specifically for their needs, staggering their foaling dates across the season. There are also specific nurse mare producers who lease lactating mares for the season.

Draft breeds and draft crosses are usually used as nurse mares because they have easygoing dispositions and tolerate the adoption process well. Still, there are some considerations that need to be made before this option is chosen to raise an orphan foal.

Milk production in mares is generally proportional to the mare’s body weight with mares producing around 3% of their body weight per day as fluid milk. A 550-kg (1,200-lb) Thoroughbred mare would therefore produce about 16 kg (35 lb) of milk per day and this amount of milk should provide enough energy, protein, and minerals to support her foal’s growth. If this foal is paired with a 650-kg (1,430-lb) Belgian mare that is capable of producing 20 kg (44 lb) of milk per day, this may result in rapid growth rates, potentially putting the foal at risk of a number of skeletal problems including developmental orthopedic disease.

Another consideration is the stage of lactation of the nurse mare. Mares produce higher levels of protein, lipids, and lactose directly after foaling. Those levels decrease over the following weeks and months. If a young foal is placed on a mare that has been lactating for several months, the mare’s milk may not contain the levels of essential nutrients that the adopted foal may need.

In a study done by Kentucky Equine Research, growth rates of foals raised on nurse mares were compared to growth rates of foals raised on their natural dams and growth rates of foals weaned at five days of age and fed milk replacer. The foals raised on nurse mares were larger than the other groups of foals at the end of the six-month study, and they grew faster during the first three months of age. There was no reported skeletal disease in either of the groups.

Using a nurse mare to raise an orphan foal is certainly the preferred method for most breeders, especially as it removes the need to mix formula and feed the foal every few hours. It is important, if nurse mares are available for use, to match her size and stage of lactation to that of the dam of the orphan foal to ensure optimal growth and development.