Advances In Semen Sexing

Rens, Welch, and Johnson of Beltsville, Md., reported significant improvements in their flow cytometric semen sexing procedure at the American Society of Animal Science's meeting.

The sexing of sperm with the Beltsville method is based on the fact that the X-chromosome is larger than the Y-chromosome. Hence, the amount of DNA is greater in the X-chromosome. The size difference in the male and female oriented spermatozoa is about 4% in horses.

The authors of the report said they now can achieve an efficient sex identification of spermatozoa with intact viable sperm.

The Beltsville method of sexing uses the difference in DNA quantity of the sex chromosomes X and Y, the ability to measure the amount of DNA in individual sperm, and hi-tech equipment to sort the spermatozoa.

While not in use yet as a routine method of in vitro fertilization because the sorting speed of spermatozoa are not fast enough, this does represent "a giant leap forward." Research studies at Minitube are planned for "sexed" equine semen in in vitro fertilization.

Currently, this technique has already been successfully used for in vitro fertilization studies in cattle and swine, and for AI in cattle.

For more information on about this technique contact Minitube of America at 800/646-4882;

About the Author

Tim Brockhoff

Tim Brockhoff was Staff Writer of The Horse:Your Guide to Equine Health Care from 1995 to 1999. His degree is in Agricultural Communications from the University of Kentucky, and his equine experience is with American Saddlebreds.

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