Once a mare has become an adult at the age of three (3), she can be bred to a stallion (who also has to be at least 3 years old). At this time you can only breed horses of the same breed.
When going to a mare's profile and selecting the "summary" tab there will be a heart-shaped icon with the text: "breed this mare". When clicked, the player will be brought to a new screen where they may select a stallion of their own to breed to the selected mare. Alternatively, a mare can get covered by another player's stallion who is up for public stud. In this case, the studding page of the stallion must be accessed by clicking the studding icon (blue-pink gender symbol). On that page, the player can select the mare and preferred payment option.
In reality, only 80% of bred mares deliver a fully grown foal, while the remaining 20% mares will lose the embryo, fetus, or foal prematurely. In Horse Reality we implemented a 5% chance of pregnancies ending in a miscarriage. This is not affected by energy, training, health, or any other factors of the mare and will happen within the first 4 days of a pregnancy.
The semen quality of stallions also has been taken into account. The better the semen quality, the higher the success rate. Depending on what his stats are, the chance of a failed pregnancy can be greater.
At this moment, the quality of the stallion's semen cannot be tested.
These are the current stats:
- 80+ quality = chance +5%;
- 65+ quality = chance +10%;
- 50+ quality = chance +15%;
- 25+ quality = chance +20%;
- <25 quality = chance = 40%;
This means that if you would have a mare bred with a stallion that has good semen, the total chance of a failed pregnancy is 10% (you have always 5% chance + 5% extra because of his semen). This means you have a 90% chance of getting a healthy foal out of this combination, and it is still 10% lower than the official birth rate in equines.
A failed pregnancy happens when you breed with a horse with bad semen. Within 2 days of breeding, you will receive a message that your mare doesn't seem to be carrying an embryo and she isn't pregnant. After these days you can breed her again. Normally you find out in approximately 40-50 days if your mare is or isn't pregnant anymore, which is why you receive the message 2 days after the breeding.
A miscarriage happens due to that 5% chance we started with. This will happen within 4 days. It means that she started to have a foal, but she lost it after 4-5 months of her pregnancy.
Both issues result in the same notification for now. At a later stage, we will implement different notifications with the real explanation. For now, you will receive a message that states your mare doesn't seem to carry an embryo and that she isn't pregnant anymore.
Overo Lethal White Syndrome
Be aware that if two horses are bred with the OLW gene, there is a high chance the foal will get stillborn due to the Overo Lethal White Syndrome. A foal with the OLW syndrome cannot survive more than 3 days. Due to the syndrome being very painful for the foal, in Horse Reality, a foal with that particular syndrome will be euthanized upon birth.
The ultrasound becomes available at the Veterinarian exactly 120 hours (5 real-life days) after the mare was covered. Note that the ultrasound icon will appear on the mare's "Summary" page earlier than that. The icon shows up at 0:00 HR time on the day when the 120-hours mark will be hit. This means that when the icon appears on the mare's page at midnight, you can be sure that sometime throughout the next 24 hours you will be able to actually ultrasound her at the vet. The ultrasound will reveal the gender of the foal, and alert you in case of a twin pregnancy.
In very rare cases, a mare will carry two embyros instead of just one. Twin pregnancy is very risky for mares in real life, as the equine body is not built to carry two developing foals to full-term. In real life, many twin pregnancies result in spontaneous abortion and, even if one or both foals survive, there are great health risks for all horses involved. Thus, a vet normally pinches one embryo in early pregnancy, so that the other foal may develop normally.
While twin pregnancy is planned to come with certain risks on HR as well, and the vet offers the pinching procedure, right now there are no special risks implemented yet. Twin pregnancies can currently be treated like any other pregnancy in-game, just that you potentially get two foals instead of one.
Pregnancy Duration & Giving Birth
Pregnancy takes between 13.5 and 17 REAL LIFE days. The exact duration within that timeframe is random for each pregnancy. Disclaimer: While the age of a horse can be artificially increased (+6 months for 75 DP via the Summary tab), this will not affect the pregnancy duration of mares. Simply put, there is no way to speed up pregnancies.
In the first 4 days after covering, you'll see that the message on the Summary tab says: "Covered X days ago by [Stallion]". This means that the breeding isn't definitive yet and there is still the possibility of a failed breeding, or an embryo loss. When these 4 days have passed and your mare is in the clear, the message will change to: "Due in X days from [Stallion]". Once this happens, you can be sure that the breeding has gone successfully and your mare will actually give birth after all.
On the last day of pregnancy, beginning at midnight, the message on her Summary tab will say "Giving birth within 24 hours from [Stallion]". Actual labor will begin sometime throughout this new day. You will not get a notification for that, but may be able to catch it by checking on the mare every once in a while: As soon as she goes into labor, the message on her Summary tab will change one last time to "Giving birth from [Stallion]". The new foal will then appear at the next half or full hour mark, whichever comes first. This delay is normal and does not have to be reported as a bug in the forums. Once the new foal arrives, you will also get a notification about the event.