The X Factor

Reedannland X-Factor American Saddlebred

Each of Reedannland Saddlebred Stallions are out of Double Copy mares. Each stallion's pedigree is color coded for your convenience. Yellow represents the ideal Double Copy mare. Light blue represents Single Copy mares that have a 50-50 chance of passing The X Factor.

Stallions watch out! The mares are strutting their stuff thanks to Marianna Haun and her new book, The X Factor: The Relationship Between Inherited Heart Size and Racing Performance. The findings Haun shares are not limited to racehorses. In her extraordinary research she discovered the significance of Thoroughbred and Standardbred heart scores, and the reason this must be considered when buying and breeding horses. But what does this have to do with the world of Show Horses? What is a "large heart" and "The X Factor"? And why the mares?

There are two sex-linked chromosomes in each horse. The males receive their X chromosome from their dams and pass it to their daughters . The Y chromosome is from their sires and passed to their sons.

The Facts:

Stallions have only one X and Y chromosome
Mares have two X chromosomes, one dominate, one recessive.
The X chromosome is larger and carries more inheritable material such as intelligence, physical characteristics, and large heart - strength and endurance.
Stallions always decide the sex of the foal. The Y chromosome determines a colt, the X a filly.

Most importantly a stallion can only pass his X chromosome to his daughters, and a mare always contributes one of her X chromosomes with a 50-50 chance of passing the dominant X.

Large Heart refers to size of the heart. The larger heart corresponds to greater strength and stamina. A normal size heart averages 8.5 pounds. The heart of the great race horse Secretariat was estimated to weigh 22 pounds! The heart of his rival in the Triple Crown, Sham, was weighed at 18 pounds.

X Factor is a term used to describe the dominant female X chromosome, which is attributed to creating the large hearts.

A Single copy is a broodmare that
carries the large heart factor on only one of her X chromosomes. She has a 50% chance of producing a large-hearted colt.

A Double Copy broodmare is the ideal! She has both of the dominant
large-hearted X chromosomes. If the mare is bred to a large-hearted sire, she will always produce large-hearted foals. Her daughters then will be double copy mares. Double copy mares frequently produce winners.

Only 28% of American Saddlebred horses have the Double X Factor. Knowing these facts, the

goal is to develop a superior line incorporating high intelligence, proven physical characteristics, strength and a large heart through the mare's dominant X. The mare is the answer! The

sire's secret to achieving status is to get the best mares. The genetics that produces a large

heart has been passed down more than 200 years. The large heart got into the American Saddlebred mainly through daughters of sires such as Denmark, Richelieu, Lexington, Montrose, Duroc, Pekina and Lute Boyd.

Reedannland X-Factor American Saddlebred

			Each of Reedannland Saddlebred Stallions are out of Double Copy mares. Each stallion's pedigree is color coded for your convenience. Yellow represents the ideal Double Copy mare. Light blue represents Single Copy mares that have a 50-50 chance of passing The X Factor.

			Phi Slama Jama The Mystery Writer	Reedann's Top Gun Haven's Hero

	Stallions watch out! The mares are strutting their stuff thanks to Marianna Haun and her new book, The X Factor: The Relationship Between Inherited Heart Size and Racing Performance. The findings Haun shares are not limited to racehorses. In her extraordinary research she discovered the significance of Thoroughbred and Standardbred heart scores, and the reason this must be considered when buying and breeding horses. But what does this have to do with the world of Show Horses? What is a "large heart" and "The X Factor"? And why the mares?
		There are two sex-linked chromosomes in each horse. The males receive their X chromosome from their dams and pass it to their daughters . The Y chromosome is from their sires and passed to their sons. The Facts: Stallions have only one X and Y chromosome Mares have two X chromosomes, one dominate, one recessive. The X chromosome is larger and carries more inheritable material such as intelligence, physical characteristics, and large heart - strength and endurance. Stallions always decide the sex of the foal. The Y chromosome determines a colt, the X a filly. *Most importantly a stallion can only pass his X chromosome to his daughters, and a mare always* contributes one of her X chromosomes with a 50-50 chance of passing the dominant X.**


	Large Heart refers to size of the heart. The larger heart corresponds to greater strength and stamina. A normal size heart averages 8.5 pounds. The heart of the great race horse Secretariat was estimated to weigh 22 pounds! The heart of his rival in the Triple Crown, Sham, was weighed at 18 pounds.				X Factor is a term used to describe the dominant female X chromosome, which is attributed to creating the large hearts.

					A Single copy is a broodmare that carries the large heart factor on only one of her X chromosomes. She has a 50% chance of producing a large-hearted colt.


		A Double Copy broodmare is the ideal! She has both of the dominant large-hearted X chromosomes. If the mare is bred to a large-hearted sire, she will always produce large-hearted foals. Her daughters then will be double copy mares. Double copy mares frequently produce winners.



Only 28% of American Saddlebred horses have the Double X Factor. Knowing these facts, the goal is to develop a superior line incorporating high intelligence, proven physical characteristics, strength and a large heart through the mare's dominant X. The mare is the answer! The sire's secret to achieving status is to get the best mares. The genetics that produces a large heart has been passed down more than 200 years. The large heart got into the American Saddlebred mainly through daughters of sires such as Denmark, Richelieu, Lexington, Montrose, Duroc, Pekina and Lute Boyd.