The mating of a stallion and mare should be easy. So it can be if you learn one secret – the necessity of observing the horses and recording these observations accurately. Accurate records reveal subtle patterns in mating behavior that can help get the mare to accept the stallion.

There are two types of breeding: natural and artificial. I have a series of images of an elder statesman gelding who was castrated late in life and continued to show good natural mating behavior, especially when turned out with his new girlfriend. Known as pasture breeding, it is the way nature intended it to occur. However, in professional breeding operations where only natural breeding is allowed, trained handlers hold the stallion and mare, and it is a very specific type of horsemanship. I will discuss this because my training before vet school was on a Thoroughbred farm where hand breeding was the only way allowed.

Artificial breeding details are beyond the scope of this website as the complexities are nuanced and detailed. However, artificial breeding includes 1) the collection of the stallion either on a mare or a dummy mount, 2) the artificial insemination of the mare by a veterinarian, 3) the freezing or cooling of semen for shipment to other farms far away, 4) the collection of fertilized eggs and transfer of these ova (fertilized eggs) into recipient mares.

Complicating things include shy or aggressive mating behavior, venereal diseases, systemic viral diseases, acquired reproductive tract infections, attrition or damaged sperm and eggs, twin fetus development, birth canal damage and abortion (pre-term and full-term). I’ll do my best to touch on these topics, but this subject could be a whole website. However, I have seen all of these topics in my 12 years of full vet practice, and I will have several stories to illustrate them all.

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