¶ Managing Your Studs
¶ Breeding Frequency
Mares obviously can only be bred once a year, but stallions can breed many mares in a year. How many mares they can cover or inseminate depends on their genetics! Each stud will be able to breed 10-20 mares, or be collected that many times, in 1 game month, during the breeding season. Keep in mind, 1 semen collection = 1 mare cover, so if he has 10 breedings available in a month, and you collect him 5 times, he can then only live cover 5 mares in that month.
¶ Age
Stallions can be bred or have semen collected as early as 2 years old, but their fertility does not reach its peak until they are 6 years old. Age also affects their Breeding Frequency as well, and their Breeding Frequency will not peak until they are 6 years old too.
¶ Season
Horses are seasonal breeders, and are most likely to become pregnant late spring to early fall. This ‘breeding season’ lasts from May to September in Legacy, and during this time, stallions will be at their peak fertility.
However, you can still breed in the ‘off-season’ (October to April), but your chance of getting a pregnancy will be cut in half, so you will probably have a difficult time getting mares pregnant. In addition, he won't be able to breed as many mares as he would during the breeding season.
¶ Using a Stud for Live Cover
Stallions can be used to live cover or artificially inseminate a mare. To live cover a mare with one of your studs, simply go to the mare's Breeding tab on her page, and select the stud you want from the drop down, and click Breed.
¶ Artificial Insemination
Using a stud for Artificial Insemination is easy, but also more complicated. The easy part is, you just need to go to your Ranch page, find the Semen Storage tab, select the stud you want, select the number of straws you want to use (4, 8 or 12), select the mare, and click Breed. There is a lot more to it than that though.
¶ Collecting Studs
If you would like to collect semen from a stud, you can easily do so by going to his page, selecting his Breeding tab, use the slider to select how many times you would like to collect that stallion, and then click ‘Collect.’ Each collection will yield 4 straws, and the straws will automatically be put in your Semen Storage on the Ranch page. Also, a single semen collection will cost you a little bit from the vet ($50/collection), and you may need to purchase a liquid nitrogen tank to store the semen ($200).
¶ Semen Sorting ('Test Gender')
When collecting a stud, you can also pay the vet to sort the semen based on which sex chromosome the sperm carry (X or Y). This way, you can use straws that will most likely produce a filly or a colt, depending on what you want! And yes, this is a real thing that is done sometimes in real life!
How is it done? At a basic level, the semen is run through a machine called a Flow Cytometer, which is able to sort cells based on even the tiniest of differences. In this case, it can distinguish X- vs Y-bearing sperm, because the X chromosome is slightly bigger than Y chromosomes. Neat, huh?
So, when you collect a stud in game, you have the option to sort the semen, by checking the ‘Test Gender’ box next to the Collect button, before you click Collect. If you do this, your vet will charge you $200 on top of the usual collection fees, and then they will run the semen through a Flow Cytometer to try to sort the semen. We say try because it's not 100% guaranteed to work, but, if it does, you will receive two sets of straws for your stud. On average the split will be 50/50 X- vs Y- bearing sperm, though not always! For example, here, this stallion was collected 15 times (for a total of 15 x 4 = 60 straws), and we ended up with 32 X-bearing straws (note the female gender icon in the bottom right), and 28 Y-bearing straws (male gender icon in the bottom right).
What happens when you use these straws? You will have a 90% chance of getting a foal with the gender indicated on the straws! Why only 90%? This process isn't perfect, so sometimes some sperm get mixed up into the wrong straws, so there is still a small chance of the foal coming out the opposite gender.
What if the sorting didn't work, and the vet just gave you regular straws (no gender icon)? Unfortunately that happens sometimes too. You'll still have to pay the vet the extra $200 and you will get to keep the regular straws, but you will have to try again to get sorted straws.
¶ Effect of Breeding Frequency and Season on Semen Collection
During the ‘off-season’, stallions can only be bred to or collected half as many times as they would during the breeding season. This is true for both live covers and collecting semen.
¶ Semen Storage
A semen ‘tank’ is created automatically when you collect or purchase straws. Each tank holds up to 120 straws for one stallion, and will cost you $200 to purchase. Each ranch can have an unlimited number of tanks, but you will have to pay $10/tank/game month in order to maintain them (refill them with liquid nitrogen to keep the semen frozen). These charges will be automatic.
¶ Why use artificial insemination vs. live covers?
Each has its pros and cons, or reasons why you might want to pick one method over the other. The benefits of using live cover largely come down to one thing: it's free, if you own the stud. Artificial insemination has two different benefits though:
- You can use it to 'preserve' a stallion's fertility (before gelding, selling, death, etc.).
- You can increase the chance of getting a pregnancy with artificial insemination, by using more straws. See the next section.
¶ Determining the number of straws to use for artificial insemination
When using artificial insemination, you are given the option to use 4, 8 or 12 straws to breed 1 mare. Using 4 straws is the equivalent to 1 live covering, both in chance of getting a pregnancy, and by the number of breedings/collections it took from the stud to get the straws. If you use 8 straws, then that took 2 collections from the stud to get, but you will only get to breed 1 mare. Similar for using 12 straws, which takes 3 collections, but only breeds 1 mare. So, why would you want to do this?
Well, when breeding, both the mare's and the stallion's fertility affect your overall chance of pregnancy, but using more straws increases the stallion's chances specifically. But, this benefit is greater for stallions with poor fertility, and the increase in pregnancy chance will probably be small for stallions with great fertility. It will be up to you to you to decide then, if it is worth using the extra straws.
¶ How big is the boost if I use more straws?
Well, that's difficult to answer, because the mare's fertility also comes into play. Let's take a look at some charts though to help answer this.
Let's say we have a mare whose individual fertility rating is 70%, but we have a whole lot of stallions with different fertility ratings. Below is the chance of pregnancy (y-axis), depending on the stallion's fertility rating (x-axis). The 3 colored lines represent pregnancy chance depending on how many straws you use. Also, remember, 4 straws = 1 live cover, so you can think of the blue line as the chance with live cover too.
You may have looked at the above graph and thought, artificial insemination is so much better! Why would anyone want to use live covers then?? Well, that graph is a bit deceptive.
You see, it just compares pregnancy chance of using different numbers of straws. But, that comparison really isn't fair, because 8 straws actually is equivalent to using a stallion twice, and using 12 straws is like using a stallion 3 times. Your odds of getting a mare pregnant from two or three liver covers are much higher than just one live cover. So, how does 8 straws compare to 2 live covers, and 12 straws compare to 3 live covers?
Again, let's use a mare with 70% fertility, and the x-axis will be stallion fertility, and the y-axis will be their chance of pregnancy.
The important comparison here is the red and yellow lines, 8 straws vs. 2 live covers, respectively. The blue line, 4 straws/1 live cover, is just for reference. As you can see, 8 straws is still better than 2 liver covers, but the benefit is much smaller, and is better for poor fertility stallions. The next graph will do the same for 12 straws vs. 3 live covers.
Again the benefit of 12 straws (red line) isn't that much higher than 3 live covers (yellow line), but it is better, considerably for low fertility studs.
So, as you can see, there is no simple answer. Yes, using more straws does increase your chances no matter how you look at it, but, you also have to pay to collect those straws, pay to store them, and, if you no longer have the stallion and have a limited supply of semen, is using more really worth it? That will be up to you.
If you are like us and you like graphs, here's one more, showing the data a different way. This graph shows the % increase you would receive over the equivalent amount of live covers if you were to use 8 or 12 straws, depending on the stallion's fertility. Mare fertility was again kept at 70% for this.
Basically this graph just shows how poor fertility studs benefit from using 8 or 12 straws more than high fertility studs.
¶ Calculating Chance of Pregnancy
Like pretty much everything in Legacy, Fertility is genetic, and each horse has their own hidden Fertility number. Horses will never be fully infertile, or fully fertile in Legacy, but they can have such poor fertility that they may be difficult to get a foal from. Don't worry though, you can breed away from this so long as you are careful. See our page on Fertility under the Horses tab for more information.
As for the change of pregnancy for a specific mare and stud pairing, both horses' fertility are multiplied by each other to get their pregnancy chance. But, keep in mind, if you are having trouble getting a mare pregnant, it may not be because she or the stud have poor fertility. Be sure to check the Season, the mare's Condition, and the stud's Age too. All that is to say, it's complicated!
¶ Cryptorchidism
Cryptorchidism is a genetic trait where one or both of a stallion's testicles fail to descend. The undescended testis will fail to produce sperm, making the stud less fertile or completely sterile.
In the game, stallions will only ever be partial cryptorchids and will have reduced monthly breedings/collections available. If one of your stallions is a cryptorchid, it will be displayed on their health tab, and this condition cannot be fixed. Because the condition is genetic, you will want to be careful breeding to a cryptorchid stallion. It may be better to geld him, but the choice is up to you!
¶ Gelding
You have the option of gelding any stallion you own, once they are 6+ months old. Gelding a stallion will mean he can no longer be used to live cover mares, and you won't be able to collect any more semen from him, but you can still use straws you previously collected.
Why would you want to geld though? There are two benefits:
- Can be Pasture kept with other horses without risk. Geldings won't breed your mares, and they won't fight and injure themselves and other horses.
- They will score more consistently at shows.
No, gelding will not increase their maximum achievable score. It just decreases their variability a bit. This means their average show score will be a bit higher, but their maximum stays the same.
You can geld a stallion on their Management tab on their page.