Color and type—an elusive combination

Breeders of Paint Horses are involved in an interesting and complicated endeavor. They face challenges that breeders within other horse breeds do not have to consider. That challenge is the production of a horse that not only excels in conformation or performance, but that also sports an attractive color pattern. Other breeders have the much simpler task of concentrating on only the horse's ability or body type.

Any time a breeder selects for multiple traits simultaneously, the task of selection becomes complicated. Single trait selection is much easier. An example is the Thoroughbred breed, in which any color or pattern that pops up is fully acceptable--as long as the horse is fast. Certainly, different portions of the Thoroughbred industry put different emphasis on racing ability, color and the like, but the overall trend is to ignore color and concentrate on athletic ability.

While most Thoroughbreds are somewhat plainly colored, there are examples of the breed sporting some quite unusual colors and patterns. As soon as one of these unique individuals excels in racing and in producing racers, we might see more and more of what are now fairly unusual Thoroughbred horses.

What tactics can a Paint Horse breeder use to produce well-patterned performance horses? The old adage to "breed the best to the best" certainly can guide this effort, although the definition of "best" is going to vary depending on which specific endeavor the breeder is interested in.

The Paint Horse breeder has a few key advantages in the breeding of horses. One is the fact that the various patterns are dominantly inherited. The other is that the breed structure allows outcrosses to the Thoroughbred and Quarter Horse breeds.

One tactic that is reasonably successful is the mating of well-patterned Paint Horses to excellent Quarter Horse or Thoroughbred performers. This is especially useful if the Paint in question is only moderate in performance or conformation.

The drawback to the this approach is the sobering fact that only about 50 percent of these matings will produce the desired Paint-patterned foal, and of these, only a small percentage will be candidates for performance or conformation excellence.

Another tactic breeders use is to utilize only the top end of the Paint Horse breed. Many Paints are surely equal in every way to the outcrosses available, and are critically important to breeders as well as to the Paint Horse breed. These horses can be used on patterned as well as solid-colored mates to produce the next generation of Paint performance and conformation stars.

By breeding these horses with patterned mates, it is possible to generate either homozygotes (in the case of tobiano), or "compound heterozygotes" which are those horses that have multiple patterns in combination, but each in a heterozygous state. These horses are useful in a breeding program, because they will produce well over 50 percent (and more like 75 to 90 percent) patterned foals when bred to solid-colored mates.

These are valuable horses to a breeder, and are all the more so if they are themselves excellent in desirable traits.

Are there stumbling blocks to breeding for both color and performance? Yes, and they are numerous. However, the challenges make the rewards doubly sweet.

One challenge to dual success in both color and performance is that not all foals will be spotted. Genetics is a science of averages and unfortunately does little to predict the precise color, pattern, conformation or behavior of an individual horse.

The law of averages works great when applied to big groups, but only poorly for individuals. As a result, a well-planned breeding program will produce a range of colors, patterns and conformations instead of the highly desired superior combination of all three.

There may be other challenges to breeding for color and performance or conformation. Some Paint breeders have relayed to me the impression that the overo patterns tend to be easier to stamp on a good halter horse conformation than is the tobiano pattern. They indicate that tobianos tend to excel in performance classes, and overos in conformation classes. If this is true, then it might be the case that in addition to color there are other effects of the tobiano and various overo pattern genes.

This is a tantalizing thought, and breeders of long experience may be better able to shed light on this subject. Some genes do indeed have multiple effects throughout the body. If the Paint pattern genes are among these, then this might explain why it is easier to stamp a certain conformation on an overo than on a tobiano. This could be due to the baggage for traits other than color that these genes carry along with them--something inherent in the action of the gene itself.

If this is true, then the production of a certain combination, such as a tobiano that excels as everyone's halter horse ideal, may indeed be quite difficult to achieve.