A mare will not go through heat during the winter or the early time of the spring. Some mares are able to continue their cycle all around the year. In the winter months the reproductive system of the male horses will rest. This period of rest is called anoestrus. The period usually last from the first signs of fall (September) until the sometime in the month of way. Many mares are not able to become pregnant during the cold winter months.
The reproductive cycles of the horses will become active again during the months of the spring. The mare will enter the transitional phase in which her cycle will once again become active. The amount of time a mare will stay in this phrase will vary. Once the mare is able to breed , her cycle will last for a period of 22 days. During this time conception must take place in order for the horse to have her foal.
Nature will work on its own to determine when the mare is ready to reproduce. The amount of daylight has a great influence on the reproductive system of the mares. They need to wait until the days are long to be able to reproduce. The mare is at her most fertile on a midsummer day when the days are the longest.
Due to the reproductive cycles of the horses the foals are usually born at the start of the spring or the early part of the summer. The days are warm and there is enough food to give the foal the best chance to survive and to thrive.
While the summer is the best time for breeding , professional breeders have created their own breeding dates and they tend not to follow the natural patterns. Breeders especially those that are breeding thoroughbreds prefer a breeding season from the middle of the month of February until the first week of the month of July. A foal that is born in the month of February and a baby that is born during the month of August will both be considered to be a year old in January. This is true even those there is a difference in the real age of the foals.
The exposure to light can cause the natural cycle of the mare to start earlier. Some breeders uses artificial light to allow the mare to get 16 hours of light a day. This light should be bright and should be started several weeks before the breeding is set to begin. The horse will need eight to ten weeks of this light in order to their natural cycle to begin once again. It is important to plan ahead when breeding in this manner. The mare should be healthy before being exposed until this extra light. In order to get the mare in her best shape she should be given some extra feedings. This will help make sure her body is healthy enough to begin the reproductive cycle .
For those that do not want to wait a long time to see if the mare will become pregnant they can speak to their vet about other ways to help nature along. In some cases the vet can prescribe the hormone progesterone which will help start the cycle at a faster date. This should be given to the mare near the end of her time of being exposed to the light. This will help start their cycle. In order for this hormone to work it should be given around the time that the mare is fed beach day. This way the horse will not have a problem taking this hormone.
The best time to mate the horses is between the months of May and August. The summer months are when the mares are naturally fertile and they have the best chance of conception. Natural has its own breeding seasons and they should be followed.