Pedigree Generation Position

Statistically Beneficial Generation Location
for Linebreeding

When practicing linebreeding, what generation position of the pedigree is most effective? Almost all horses, bad performers as well as good, are linebred in some way. However, the extensive research that has been done into successful horses has shown that certain areas of the pedigree have proved more beneficial for linebreeding than others.

Edwin Anthony, Thoroughbred pedigree expert said "...it is not the fact that inbreeding or linebreeding is present, but how it occurs is paramount."

Before we continue let me warn you not to become legalistic about position placement. If you can step back from the pedigree you are trying to construct and become fluid in applying the breeding principles you will find it easier to create that special horse. Remember, we are usually not dealing with pure-bred horses when we breed sport horses, so we will have a harder time getting some of the recommended pedigree patterns. The pedigree equilibrium as a whole is the key, with sex balanced linebreeding, full and 3/4 siblings, with both sides of the pedigree involved, and duplications through as many different siblings as possible.

In general the experts have determined that the focal linebreeding should be in what many call the engine room, which is the  4th through 6th generation positions. Here are a few of their opinions:

The Lesh brothers, early evaluators of Thoroughbred pedigrees, determined that the 3x3 position has only a slightly higher percentage of winners than average, but a very high percentage of good producers. Later researchers have agreed with this finding saying that inbred horses are often extraordinary producers.

David Dink, who entered his research to disprove the benefits of linebreeding, ended up reporting that he found duplications of significant ancestors in the 4x4 position best for winners.

Harold Hampton, who alerted the Thoroughbred breeders "down under" to the benefits of balanced linebreeding, believed the 5x5 position was premier.

Clive Harper, who gathered the results of the previous pioneers to give us a detailed overview, said that better horses have more linebreeding in the 4th, 5th and 6th, and they also need an instance of 3/4 or full siblings within 6 generations.

Harper's research went much farther into this. He also saw that the best horses accumulated multiple lines of an important mare or sire in the far reaches of the pedigree, and had reinforcement for that presence in the engine room area. And of that target ancestor in the far reaches (7th to 14th generation) he rated them as such: good- a tap root mare; better- a pair of full sisters; best- a full brother and sister.

When he was asked what he considered the perfect pedigree, he said that would be 4x4 to a full brother and sister, with each having reinforcement to its ancestors. He particularly liked to see one side of the pedigree develop the dam ancestors of the full siblings and the other side to develop the sire side ancestors. He said the closest he ever saw of his ideal pedigree was in the Thoroughbred Fair Trial.

Close to Perfection- Fair Trial

Pedigree theory is complex, but it is worth pursuing. I suggest that you start your program with baby steps, like sex balancing an important line for your goals that is sitting in the "engine room". Make that your target, and when choosing from mates that have this desired compliment, then look at how else they interact with your mare/stallion pedigree. And pick the mate that overall gives you the most dynamic combination. But focus on the target ancestor first- otherwise it will overwhelm you.

How much linebreeding is too much? Can you overdue it? Probably, but if you balance the duplications and use superior ancestors as targets, then you will not lose hybrid vigor. Inbreeding or linebreeding to male only representatives of good lines is what is shown to cause loss of hybrid vigor.

Pedigree researchers Ken McLean and Edwin Anthony, both admired the massive linebreeding found in the great racehorse Roberto's pedigree. Roberto was a superior race horse and a fantastic sire. Winner of the Epsom Derby and he is a great sire of sires. There was no hybrid vigor lost in this horse.

Roberto- Successful Massive Linebreeding

Be fluid in your pedigree design. If the most dynamic combination you find has a 3x6 duplication, then go for it. When the duplications are 4x4 or 5x5 they are equal in strength, but the reality in mates is not often so clear cut. For instance, the super mare Pocahontas, has her strongest duplication 3x5, her next three strongest are 5x7, 5x6 and 5x6. And she is considered one of the greatest mares ever, even 170 years after her birth. Try to keep the strongest activity in the "engine room" area and involve both sides of the pedigree, and you will do well.

For further depth of understanding in this practice, and the points covered in the other articles, I highly recommend that you investigate some of the writings by the pedigree experts, which you will find listed on the Resources and References page They did all the hard work for us. We have only to study it and then apply it to our own breeding programs.

A word about inbreeding for sport horse breeders: inbreeding is attempted by breeders when they want to create greater potency of a particular type into their herd. The most successful typesetters or 'improvers' in horse breeding are inevitably inbred. It is the fact of their inbreeding that allows them to transfer the potency in the traits that are desired. Most breeds have originated with inbreeding, because it will give a reproducible phenotype quickly. There is a common misconception that inbreeding causes defects or mutations. This is not true, what inbreeding does is concentrate the genetics that are present, so if the individual line chosen for the inbreeding has faults or weaknesses, you will concentrate them into the gene pool along with the sport abilities that were the goal. So we suggest that you do your research before you attempt it. When it succeeds you have set the type and sport ability into your herd- when it fails you have brought negative recessive genes to the fore.
An example of successful inbreeding to a prepotent sire line
An example of successful inbreeding to an Elite Mare

What about outcrossing? Outcrossing can be the right choice for a breeder when they have built up their gene pool and want to bring in something new. We recommend that the individuals chosen for the outcross be of a similiar type for the sake of soundness. And that the respective pedigrees are close in genetic strength. If you chose an individual without strong linebreeding for the cross, you will not get the traits you wanted consistently in your foals. And you will actually be taking a step back for the sport talent. If you choose an individual that has a similiar genetic strength as your horses, but with the different lines that you desire, then you should have success for you will bring in hybrid vigor and add to your potency for sport. An example of a beautifully constructed outcross stallion is Bratt Z..

Key Elements in Potency Building