Best Crosses: Leading Horse Breeders Weigh In

Best Crosses: Leading Horse Breeders Weigh In

Choosing the right stallion for your mare is an art form. These are eight essentials for horse breeding research.

mare and foal in grass pasture in front of purple mountain range (Credit: Kati Clyde)

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How could you ever narrow it down to one perfect stallion for your mare? Finding the best cross for your mare and your program is part research, part science and, sometimes, part luck.

The Journal sat down with AQHA Past President and American Quarter Horse Hall of Fame inductee Frank Merrill of Purcell, Oklahoma, and 40-year American Quarter Horse breeder Carol McWhirter of Doniphan, Nebraska, to get their input on how to take luck out of the breeding equation.

The Game Plan

Four of the most important things to know when you start to research a stallion for your mare are pedigree, conformation, the stallion’s performance records and prepotency.


When you’re talking pedigree, always be aware not to cross on a stallion that has close to the same genetic makeup as your mare. Line-breeding and in-breeding have long been a debate among AQHA breeders. Before you cross certain lines, you need to be aware of the characteristics those horses are known for and the consequences of crossing your mare on a stallion that is within the first or second generation. Make sure you are also aware of any genetic flaws that a certain stallion might carry. Every American Quarter Horse stallion that has already bred mares has a genetic panel test on file with AQHA. Compare the stallion's test results with the genetic test results of your mare to ensure genetic defects don't slip into the mix.


When it comes to conformation, evaluate your mare and determine an area that she might lack and find a stallion that is strong in that area. For example, if your mare has a long back, find a stallion that has a short back and comes from a family that is consistent for that trait. Find a stallion that has physical characteristics that complement your mare’s weak points, and remember that two negatives never make a positive. Try to personally view every stallion you breed to. Pictures can be deceiving when it comes to conformation. You want to make sure everything looks right, so if you are not able to see the stallion in person, make sure to get a photograph or video of the horse from all angles on level ground. You want a straight-legged horse that has overall balance.

Need help discerning Quarter Horse conformation? AQHA's Structure in Detail e-book is your ultimate resource.


Make it a point to watch stallions and their offspring through the year. Evaluate things like disposition over time. You can have all the talent in the world, but if the horse doesn’t have the nature to cooperate, it’s going to be a never-ending uphill battle.  Also look at athletic performance over time. For example, take a mare that needs a little help in her stop and breed to a stallion whose get is known for big stops.


The sign of a great sire is his prepotent ability to stamp his foals. Just because stallions are good show horses or performers does not mean they are going to pass their superior quality to their foals. Do not be satisfied just to see stallions. Look at their offspring. Ideally, you want to breed to a sire who throws a consistent product. You can walk in a pen of foals and be able to pick out the offspring of a prepotent stallion. Even though you can’t predict exactly what a foal will look like, when you breed to a prepotent stallion, there is a higher degree of consistency.


Become a bloodline expert. Do not make market-driven decisions and breed to a certain stallion that is the hot commodity this year. He might be the most-promoted stallion out there, but it doesn’t necessarily mean he’s the best for your mare. Know your facts. Learn the traits that certain lines of horses carry and find the right match for your mare’s traits.


Nicking is the crossing of a sire with the daughters of another sire, then studying those results. A "nick" occurs when a sire does significantly better with the daughters of a particular sire. The stallion directory provides a nicking report for every stallion with a foal crop of competition age. Try the QStallions nicking report to study the best crosses for your mare. 


“People must breed with a conscience and always have improvement in mind. We have a responsibility to not bring defective horses into this world,” Carol says.