Skip to main content
ARS Home » Research » Publications at this Location » Publication #156088
Title: PRE-SELECTION OF SEX OF OFFSPRING IN SWINE FOR PRODUCTION:CURRENT STATUS OF THE PROCESS AND ITS APPLICATION

Author
item JOHNSON, L - Retired ARS Employee
item RATH, D - INST ANIM SCI GERMANY
item VAZQUEZ, J - UNIV OF MURCIA SPAIN
item MAXWELL, W - UNIV OF SYDNEY AUSTRALIA
item Dobrinsky, John

Submitted to: Theriogenology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2004
Publication Date: 1/15/2005
Citation: Johnson, L.A., Rath, D., Vazquez, J.M., Maxwell, W.M., Dobrinsky, J.R. 2005. Pre-selection of sex of offspring in swine for production:current status of the process and its application. Theriogenology. 63:615-624.

Interpretive Summary: In the past five years over 30,000 offspring, mostly cattle, have been produced with artificial insemination (AI) of sex-sorted sperm. The worldwide method is the Beltsville Sperm Sexing Technology based on flow cytometric separation of flourescent labeled sperm indicating the relative difference in DNA content of X- and y-chromosome bearing sperm. Current production of sex-sorted sperm is 15 to 20 million sperm per hour in livestock, laboratory and zoo animals, and humans with success of 90 to 95% in shifting the sex ratio of offspring. Conventional AI, intra-uterine (IUAI), oviductal insemination or in vitro fertilization are used to obtain pregnancies. While sperm from all species can be sorted with high purity, pregnancies with low numbers of sperm needed for commercial application remains elusive for swine. Deep IUAI with 50-100 million sexed boar sperm yielded pregnancies with when specialized catheters were used. Further development of swine AI equipment and cryopreservation protocols are needed before routine AI with sexed sperm can be conducted in swine. The future advancements made in low-dose sperm cryopreservation and AI will be instrumental in developing a commercial sex-sorted sperm technology for the swine industry. These developments will revolutionize global pig production.

Technical Abstract: In the past five years it is estimated that as many as 30,000 offspring, mostly cattle, have been produced using artificial insemination with spermatozoa sexed by flow cytometric sperm sorting and DNA differentiation. It is well documented that the only marker in sperm that can be effectively used for the separation of X- and Y-chromosome bearing spermatozoa is DNA. The method as it is currently used worldwide is commonly known as the Beltsville Sperm Sexing Technology. The method is based on the separation of sperm using flow cytometric sorting to sort fluorescently (Hoechst 33342) labeled sperm based on their relative content of DNA within each population of X and Y spermatozoa. Currently sperm can be produced at a rate of 15 to 20 million X- and an equal number of Y-sperm per hr. The technology is being applied in livestock, laboratory animals, zoo animals and in humans with a success rate of 90 to 95% in shifting the sex ratio of offspring. Delivery of sexed sperm to the site of fertilization varies with species. Conventional artificial insemination (AI), intra-uterine insemination, intra-tubal insemination, in vitro fertilization with embryo transfer and deep intra-uterine insemination are effectively used to obtain pregnancies dependent on species. Although sperm of all species can be sorted with high purity, achieving pregnancies with the low numbers of sperm needed for commercial application remains particularly elusive in swine. Deep intra-uterine insemination with 50 to 100 million sexed boar sperm per AI has given encouragement to the view that insemination with one-fiftieth of the standard insemination number will be sufficient to achieve pregnancies with sexed sperm when specialized catheters are used. Catheter design, volume of inseminate, number of sexed sperm are areas where further development is needed before routine inseminations with sexed sperm can be conducted in swine. Cryopreservation has been successfully applied to sexed sperm routinely in cattle. Piglets have been born from frozen sex-sorted boar sperm however, freezing and processing protocols in combination with sex-sorted sperm are not yet optimum for routine use. This review will discuss the most recent results and advances in sex-sorting swine sperm with emphasis on what developments must take place for the sexing technology to be applied in commercial practice.