Foaling is normally a happy time, but occasionally things go wrong. Sadly, there are many reasons why a foal may become orphaned. The mare may die. The mare may be agalactic, meaning she has no milk. The mare may reject her foal for any number of reasons; she may simply be a maiden mare lacking in maternal instincts, she may have sustained a foaling injury that caused her to associate her foal with pain, or she may sense that her foal is ill.
When a foal is orphaned, it can be fed milk replacer or milk replacer pellets, but this is incredibly labor intensive. Such a foal would also miss out on the social education that a mare provides. These foals may be at increased risk for aspiration pneumonia if carelessly fed with a bottle, scours if the milk replacer is not handled correctly, or anaphylaxis if the product used was bovine-derived and the foal must later receive plasma.
A better alternative is a nursemare. There are internet groups dedicated to matching orphaned foals with mares who have lost their foals. Unfortunately, the stars must align perfectly in terms of timing, and sometimes there simply is no mare available within a reasonable driving distance. Additionally, sometimes these mares do not accept a new foal, or their handlers do not have the experience to properly facilitate a match.
The most reliable solution is an ethical nursemare. These mares do not need to give birth to a foal to make milk, instead, their lactation was pharmacologically induced using a combination of medications and udder stimulation. These mares are generally available from January through July, and cost between $3000-$5000. Like all things relating to foaling, an amalgamation of science and art is required to produce an ethical nursemare. The businesses who provide these mares have dedicated their lives to it and will answer the phone at all hours. They are masters at grafting foals onto mares, so their success rate is high and there is no need for blindfolds or hobbles.
Sometimes a breeder will suspect ahead of time that they will need a nursemare; for example, a mare who has a history of rejecting foals, or a mare who has a potentially fatal condition such as prepubic tendon rupture or hydrops. In these situations, the breeder can reserve an ethical nursemare at the beginning of the season so that one is definitely available if they need her.
Nursemares should be treated with the same care and respect as any other horse. They should be in good weight and physical condition with a healthy haircoat. Any pain or unsoundness should be managed so that she is comfortable to perform her duties. A quality ration should be provided in order for the mares to produce a sufficient quantity of quality milk. Typically nursemares will require medication for several days after they are grafted to their new foals, and the treatment plan supplied by the nursemare provider should be followed carefully to ensure optimal milk production.
Due to the existence of ethical nursemares, there is no reason for a mare to ever be bred for the sole purpose of orphaning her foal so that she can feed another mare's foal. Most ethical nursemares are retired broodmares, meaning they are experienced moms who are eager to adopt foals. This service turns a sad situation into a happy ending for everyone; the mares get to have a wonderful forever home and orphaned foals get to be raised by a loving horse mom.