Heat Cycles: At What Age, How Long, and How Often

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    In order to breed your pigs, it is essential to choose the opportune time. There are several elements to this, all of which must coincide for a successful breeding to take place. If just one part of the plan were to go awry, the opportunity to breed could be missed, resulting in a delay in pregnancy and farrowing for several weeks if not longer.

    The first step in breeding a sow or gilt is for her to be sexually mature. Gilts typically reach puberty at around five months of age and at that time will begin to show signs of a heat cycle, also known as Estrous. While this age is typical for sexually maturity, it is not guaranteed as some do mature earlier or even later. Depending on the life and health of a gilt, there could be a delay in reaching sexual maturity. For example, breeds or even individual pigs may be slow growers that simply take longer to arrive at breeding readiness. Pigs that are underfed or stunted may take longer to reach breeding suitability as well.

    Once your gilt is sexually mature, breeding needs to occur at the right time in order to achieve a successful pregnancy. Sows and gilts normally experience heat cycles every three weeks, at which time they will have to be exposed to a boar. If the exposure times do not align with heat cycles, any efforts at breeding could fail due to nothing more than poor timing. When planning to unite your sow with a boar, keep in mind that the window of opportunity to catch her in heat only lasts between 8-36 hours.

    If your sow is not in heat, it may be possible to encourage a heat cycle to occur. By placing a sow in the vicinity of other sows in heat, you may be able to bring her into heat. If that does not work, relocating a sow to a place where she can see and smell him, which may entice a heat cycle to begin.


    Signs of heat include restlessness and going off feed. She will also adopt a rigid stance when pressure is applied to her back to indicate she is ready for mounting by a boar. Her vulva will also become swollen and pink. Boars in the area will also likely foam at the mouth when the smell a gilt or sow in heat. All of this will occur every 21 days in pigs that are properly maintain and in good health. A deviation from this schedule may indicate a health problem, so it is important to pay attention to the reproductive health of pigs even if they are not being used for breeding.


    A young gilt in her first heat cycle should not be bred. Although it is possible to achieve pregnancy, giving her time to grow a little more is beneficial. Being larger and stronger will enable her to better carry a litter. Remember that the more health and developmental benefits your gilt or sow has on her side, the more she can pass on to her young. Thus, breeding only mature, healthy pigs is best for all involved.

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