Putting your mare in foal is not a light undertaking and should only be considered if you, or someone you know, feels confident about caring for the mare and foal.
Breeding can be achieved by either Artificial Insemination (AI) or Natural Cover.
Although older mares often prove to be good mothers, breeding is most likely to be successful if the mare is under 12yrs old and has had regular oestrous cycles. A thorough veterinary examination, especially ultrasound scanning of the reproductive tract, before making final arrangements would be money well spent, especially when travelling and livery fees are to be taken into account.
If a mare is travelling to a stud (including ours!) to be covered naturally then the stud is likely to ask for:
1] The mare to be tested for Contagious Equine Metritis and other TVDs before being accepted at stud.
2] The mare to be vaccinated against Flu, and recently wormed. Vaccination against tetanus is strongly recommended.
3] The mare should have the hind shoes removed.
4] All the relevant documentation, including a passport, if the foal is going to be entered into a breed society stud book.
Most of the above are not relevant for mares if AI is selected as the mare typically stays at home.
Most Mares have a breeding season from early spring to late summer, although it is not unusual, for some mares to cycle all year round, especially if they are stabled. Oestrous cycles take approximately 21 days and stallion will show interest in the mare for about 5 days but the mare will only stand for about 48hrs. Once ovulation has taken place the mare rapidly goes out of season.
The first couple of cycles in the year often appear to be normal but the mare may fail to ovulate: this is known as a transitional oestrous and these can also occur at the end of the breeding season.
Once the mare has ovulated the ovum is only viable for about 12hrs. For this reason conception rates are highest when the mare is covered prior to ovulation, preferably within 24hrs.
Fertilisation occurs in the oviduct, close to the ovary, and the conceptus then constantly travels from one horn of the uterus to the other over the next fortnight before finally becoming trapped by the uterine wall around day 15. This constant migration of the embryo seems to be necessary for the mare to recognise the pregnancy.
The pregnancy is generally considered to range from 335-342 days but there are many cases when this has been over a month longer. Generally, foals due to be born in the very early part of the year will have longer gestations than those due to be born in the late spring/early summer.
1] ultrasound scan from day 14.
2] eCG hormone assay from day 45-120.
3 ]Oestrogen hormone assay from day 90-term.
4] Rectal palpation from around day 15 onwards.