First Sexed Offspring of the World's First Sexed Mare and Stallion Born

Researchers led by XY Inc., a global biotech company in Fort Collins, Colo., were recently successful in their quest to produce the first sex-selected offspring of the world’s first sex-selected mare and first sex-selected stallion. “First Lady” was born April 20. The filly was produced via artificial insemination (AI) using an extremely low dose of fresh, sexed sperm.

First Lady’s dam, "Call Me Madam," captured global attention in 1998 as the first horse in the world to have her sex selected prior to conception via a cutting-edge cell-sorting technology developed by researchers led by XY Inc. (see article #1012).

The sperm-sorting technology separates sperm that carry the X chromosome and produce females from sperm that carry the Y chromosome and produce males.

First Lady’s sire is "Augustus Primus," born Aug. 1, 1999 at XY. "Gus" is the first sexed male horse ever produced, using AI and low-dose sexed sperm. Typically 500 million sperm are needed to impregnate a mare. Gus was conceived using sperm dosages of just 25 million sperm, which is 5% of the dosage regarded, until his conception, as necessary for AI impregnation of horses.

Only 17 million sexed sperm were used via AI to impregnate Call Me Madam to conceive First Lady. The dose is 3% of the recognized “standard” dosage used with AI in horses.

Call Me Madam was artificially inseminated by XY scientists on May 21, 2002, at Colorado State University’s Animal Reproduction Biotechnology Laboratory. She was settled by June 4, 2002, and had a normal pregnancy and delivery. Gus was collected for the first time—without flushing--to impregnate Call Me Madam.

"First Lady’s birth is solid evidence that the technology XY is offering does not adversely affect the reproductive capabilities of the horses we’re producing," said Mervyn Jacobson, MBBS, XY Inc. chief executive officer and president.

XY researchers have made rapid progress since 1998 when they successfully combined surgical techniques and sexed semen to produce Call Me Madam. The first foal ever produced with sorted sperm which had been frozen and thawed before AI was born in 2000. The following year marked the moving of specialty equine breeding from the research lab into the commercial arena when another sexed foal was born at XY Inc.'s equine breeding facility. That colt was also the first live foal produced from "fresh-shipped," sorted, low-dose, sperm via artificial insemination, which proved that even 18-hours after collection and shipment without cooling, equine sperm can be sorted and artificially inseminated to produce a live foal of the desired sex.

In 2002, XY Inc. working with Australian researchers combined sexed equine sperm with embryo transfer to successfully produce offspring from high quality polo mares.
Applications of AI using advanced sperm sorting could be in excess of $300 million a year for the U.S. horse industry alone, said Jacobson. The market outside the U.S. could more than double those projections, he added.

XY Inc. anticipates signing its first equine commercial license in the United States this year. XY Inc. issued its first equine license to a leading horse breeder in Argentina in 2002.

XY, which holds exclusive global rights to sperm sorting in all non-human mammals, was formed in 1996 as a joint venture of the Colorado State University Research Foundation and Cytomation Inc., of Fort Collins, Colo.

"The birth of this lovely filly is justification to go forward with additional development work to bring to market these sex-selection breeding techniques for horses," Jacobson noted.

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