The process of mating a stallion with a mare is called "mounting" or "covering." Before starting the breeding process, consider the mare and stallion carefully and make sure there are no genetic faults on either side. Have a veterinarian give both animals a health check, particularly if the mare has not foaled before. The gestation period of a foal is about 11 months, and the mare will need regular vet checks throughout her pregnancy, as well as a suitable diet and vitamin supplements.
Check that your mare is ready to breed, otherwise she will not be receptive to the stallion and may injure it. Mares come into season during their oestrus cycle, which occurs in spring and summer and lasts about three weeks. At commercial studs, mares will be tested with a "teaser stallion," a horse of lower value that is presented to the mare to check how receptive she is. For a private breeder, the easiest way to tell if a mare is receptive is to have a check done by a veterinarian.
Halter the mare, clip a long rope to her halter and have one assistant take her into an enclosed area. Ideally, this should be a large shed rather than a field so that there will be no distractions.
Bridle the stallion. Clip a rope to either side of the bit, and have two people lead him into the breeding shed. The assistants must control the stallion and not allow him to charge directly before the mare. As the stallion approaches the mare, she should start to turn her hindquarters toward him and lift her tail to the side, known as "presenting." Allow the two horses to approach slowly. Allow the stallion to nuzzle the mare's hindquarters to establish her readiness to be mounted. If the mare's ears flatten back suddenly or either horse starts to become agitated, separate them immediately.
Ensure that the stallion mounts the mare directly from behind rather than from the side. A fourth person should be ready at the mare's hindquarters to guide the stallion in if necessary. The stallion may bite at the mare's neck to balance; this is normal but should not be too aggressive. Once the mating process is finished the stallion will slide backward off the mare and should be immediately taken out of the breeding shed.
Lead the mare round for a few minutes until she has settled. Repeat the breeding process every day during the mare's season or until there are indications that she is no longer receptive to the stallion.
In addition to having the stallion cover the mare in a controlled environment, you could turn the two horses out together for a few days to breed naturally. This is often seen as a less desirable option, as there is a strong risk of one or both horses becoming injured. It is also difficult to know whether the covering has taken place. In addition to having your mare covered by a stallion, you could also consider artificial insemination.
When mounting the mare, the stallion's hooves will come up onto the mare's shoulders, so the mare's handler needs to be ready to step to the side out of the way. Some stallions can become aggressive when mating. Make sure that everyone involved is wearing protective gear and is aware of both horses' body language.