Equine Reproductive System
Equine Reproductive System
Tim Heckart
In exploring the reproductive system of the horse we must first understand that this system is made up of physical structures and hormonal or chemical secretions, actions, and reactions. While the physical structures are readily identifiable, the hormonal systems are a bit more obscure. Some of these hormonal actions and reactions are still not fully understood today.
We begin with the delivery of a Filly. At this stage in her life she already has all the eggs, or ova, that will last her through her entire life cycle. These ova reside on the ovaries in small bubble like containers called follicles. Here the ova will remain until the filly matures and begins her reproductive cycle. In the meantime let’s take a look at the physical reproductive structures involved in the female of the species.
The Vulva and Vagina
The entrance to the reproductive tract is the vulva, which is a five to six inch vertical slit located below the anus. On either side of the vulva are the labia or lips of the vulva. Upon entering the vulva we find the vagina, a six to eight inch long tubal musculature structure lined with mucus membranes. The tissues that make up the vagina are very elastic; this elasticity accommodates the stallion’s penis during breeding and also allows for the passage of the foal during parturition. The vagina is the point of sperm deposition for the stallion.
The Cervix
At the end of the vagina is the cervix. The cervix is the entrance to the uterus and provides a physical barrier that protects the uterus from foreign materials. The cervix is approximately 4 inches long and is a highly distensible muscle. The shape and characteristics of the cervix will change extensively as the body’s hormonal environment changes. During estrus, in response to higher levels of estrogen the cervix will appear pink in color due to an increase in vascularity. It will also produce thin, watery mucus. During this time it may be so
Tim Heckart
In exploring the reproductive system of the horse we must first understand that this system is made up of physical structures and hormonal or chemical secretions, actions, and reactions. While the physical structures are readily identifiable, the hormonal systems are a bit more obscure. Some of these hormonal actions and reactions are still not fully understood today.
We begin with the delivery of a Filly. At this stage in her life she already has all the eggs, or ova, that will last her through her entire life cycle. These ova reside on the ovaries in small bubble like containers called follicles. Here the ova will remain until the filly matures and begins her reproductive cycle. In the meantime let’s take a look at the physical reproductive structures involved in the female of the species.
The Vulva and Vagina
The entrance to the reproductive tract is the vulva, which is a five to six inch vertical slit located below the anus. On either side of the vulva are the labia or lips of the vulva. Upon entering the vulva we find the vagina, a six to eight inch long tubal musculature structure lined with mucus membranes. The tissues that make up the vagina are very elastic; this elasticity accommodates the stallion’s penis during breeding and also allows for the passage of the foal during parturition. The vagina is the point of sperm deposition for the stallion.
The Cervix
At the end of the vagina is the cervix. The cervix is the entrance to the uterus and provides a physical barrier that protects the uterus from foreign materials. The cervix is approximately 4 inches long and is a highly distensible muscle. The shape and characteristics of the cervix will change extensively as the body’s hormonal environment changes. During estrus, in response to higher levels of estrogen the cervix will appear pink in color due to an increase in vascularity. It will also produce thin, watery mucus. During this time it may be so