The mare is a fifty fifty partner in this enterprise and so care should be taken at the beginning of the breeding process to present her in the best possible health for insemination by the vet or a qualified AI technician (It is illegal for an unqualified person to inseminate a mare)

A healthy mare
The first priority is to assess her state of health – she should be in good but not fat condition and have been swabbed to show that she is free from Klebsiella, Contagious Equine Metritis and Pseudomonas.
Select a mare that is free from any hereditary problems that she may pass on to her offspring - consult your vet as to her suitability if at all unsure. Permanent injury should not preclude breeding but she must be able to comfortably carry her foal to term and actively care for him for at least six months. Adjust the worming programme to cover all worm species as some wormers are not recommended for use on pregnant or lactating mares. We recommend that the breeding process is started as early in the season as practical, to give the maximum number of cycles to get the mare in foal.

The barren mare or older maiden mare may require more help from the veterinary surgeon to assess the genealogical health of the reproductive track. All mares that have been barren for more than one year should have a uterine culture, cytology and in most cases a uterine biopsy. The vet will than be able to prescribe an appropriate course of action prior to the breeding season. Older mares can continue to breed successfully but most mare owners find that conception rates drop if the mare is older that 15

The Oestrous cycle
Depending on the mares’ condition, the length of daylight and ambient temperature the mare should develop a regular oestrous cycle. Very early cycles can generally be discounted as the mares tend not to ovulate until a regular pattern has been established but skilled examination and scanning can help to determine an accurate pattern of her individual behaviour. Most mare owners will notice the onset of the mares season by changes of behaviour but generally you should expect the mare to show repeated cycles of approximately 22 days in length; 3 to 7 days of oestrus; followed by 15 to 17 days of dioestrus when she will naturally reject the stallion. Hormonal treatment is available to induce ovulation during estrus with most mares ovulating within 24 to 48 hours of treatment. This will be the optimum time for the insemination technique to take place.

Preparing for insemination (see further notes on the A.I process)
The mare will be identified from her passport information and matched against those supplied with the semen. She should then be prepared by scrupulously washing the vulva and perineal area with a dilute povidone-iodine solution or mild soap then thoroughly rinsed off with fresh warm water prior to drying with clean, soft disposable (paper) towels. Do not open the semen container until all preparations are complete

Determining pregnancy.  The most obvious sign would be the mare ceasing to cycle but to ensure the best rate of success most vets recommend scanning the mare 14 – 16 days after insemination to determine whether or not she is in foal.