Fertility

Fertility is a craftable item. Users in the Pharmaceutical Sciences stream can craft it using reLH, reFSH and GnRH.

Course Article

Improving Fertility

Both mares and stallions can sometimes suffer from fertility issues, which can make them difficult to collect embryos or semen straws from. There are some hormones that can be given to help these horses so you are able to breed them more successfully!

For mares, the basic principle surrounding improving fertility is superovulation, or increasing the number of follicles released during ovulation. These methods are fairly inconsistent, but they may work for your mare! Superovulating mares currently involves recombinant luteinizing hormone (reLH) and recombinant follicle stimulating hormone (reFSH).

Under normal circumstances, LH would increase to a peak, causing the mare to ovulate. Thus, the principle behind reLH is to stimulate that same LH peak to cause ovulation within 24-48 hours after administration. Therefore, the veterinarian can more accurately predict ovulation, for optimum embryo collection.

reFSH is a synthetic analogue of FSH, which normally acts on the mare's ovary to cause follicles to mature so they can be ovulated. By giving extra FSH, more follicles are able to be matured, meaning that when ovulation occurs, there are more eggs available for collection. reFSH can be combined with reLH in order to optimize both the timing, and the amount, of embryos available.

For the stallions, hormonal supplementation can also help improve their fertility. Like the mares, it is also inconsistent in its effectiveness, but may be an option for your boy. Typically, gonadotropin releasing hormone (GnRH) is used in stallions, because it stimulates the release of LH and FSH, which act on the testicles to increase sperm production. Thus, your stallions who may have had difficulty producing enough sperm for several straws may have an easier time.

In Oxer To Oxer, the above drugs have been combined into the pharmaceutical product Fertility. Fertility lasts for one game year, and can improve the likelihood of successfully gathering embryos from your mares, or increase the number of straws you can gather from your stallions. It can only be given to Breeding horses, and if they have been given Fertility, they cannot return to competition until it wears off.

1. Beckstett, A. New Hormone Therapy to Enhance Fertility in Mares. The Horse. https://thehorse.com/177451/new-hormone-therapy-to-enhance-fertility-in-mares/
2. Seamans, MC, Roser, JF, Linford, RL, Liu, IK, Hughes, JP. Gonadotropin and steroid concentrations in jugular and testicular venous plasma in stallions before and after GnRH injection. J Reprod Fertil Suppl 1991;44:57-67.