It has long been an established practice in the equine field to use artificial light sources as a mechanism to shorten the winter anestrus, during which the mare is not ovulating. But, can this same concept be used to stimulate fertility in the stallion? The Horse published a fantastic article on their blog considering this concept. We present a portion of this article to engage the industry in dialogue related to artificial lighting and the potential impacts, both positive and negative, to the industry. The full article on The Horse can be found here. What are your thoughts on this topic?
“With stallions…when days are short the pineal gland within the brain releases melatonin which it is believed inhibits the hypothalamus from releasing GnRH. A failure to release GnRH has something of a domino effect inhibiting the secretion of LH and as a result the production of testosterone in the testes.
The limited supply of testosterone in the testes results in a quieting of the stallion’s reproductive system. Libido is reduced along with testicular size and the manufacture of spermatozoa. Once again there is a similarity with what occurs within a mare’s reproductive system when the ovaries diminish in size and eggs do not mature during anestrus.
As is the case with mares, lights can be used to stimulate a stallion’s reproductive system. After first allowing the system to shut down as the result of lack of light it can be reawakened by placing the stallion under photostimulation for about 16 hours a day usually beginning sometime in December. However it has been found that a stallion will “shut down” earlier in the season after being under lights which could curtail his libido and fertility at the peak breeding period.”
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