Sex selection of sperm in farm animals: status report and developmental prospects

Abstract

Pre-selection of spermatozoa based on the relative DNA difference between X-and Y-chromosome bearing populations by flow cytometry is an established method that has been introduced into commercial cattle production. Although several important improvements have increased the sort efficiency, the fertilising ability of sexed spermatozoa based on offspring per insemination is still behind farmers' expectations. The main stress factors, especially on mitochondria, that reduce the lifespan of spermatozoa are described, and new technical as well as biological solutions to maintain the natural sperm integrity and to increase the sorting efficiency are discussed. Among these methods are the identification of Y-chromosome bearing spermatozoa by bi-functionalised gold nanoparticles and triplex hybridisation in vivo as well as new laser-controlled deflection system that replaces the deflection of spermatozoa in the electrostatic field. Additionally, as well as a new nonsurgical transfer system of spermatozoa into the oviduct of cows has been developed and allows a significant reduction of spermatozoa per transfer. Altogether, the improvements made in the recent years will allow a broader use of sex-sorted spermatozoa even in those species that require more cells than cows and sheep.Reproduction (2013) 145 R15-R30

Update on sexed semen technology in cattle

“…Although currently available, commercial sexed semen is not yet an ideal product, but improvements will continue to be made (Seidel, 2012;Rath et al, 2013). While I have emphasized how sexed semen is produced and used in the United States, the situation is very similar in Canada and several other countries.…”

“…A published study by Klinc et al (2007) indicated that addition of certain antioxidants to sperm during the sorting process was very beneficial to fertility under European condition, but numbers of inseminations were limited. In any case, fertility of sexed semen likely will continue to improve with further research (Rath et al, 2013). In addition, procedures to optimize timing of AI for sexed semen with ovulation synchronization procedures are being thoroughly researched.…”

“…Hermann et al (1999) have produced a strain of mice that naturally has a 2 : 1 male to female sex ratio in progeny without sorting sperm. Currently, however, there is a reluctance to invest in transgenic foodproducing animals, and making such transgenic cattle would be very expensive.Although currently available, commercial sexed semen is not yet an ideal product, but improvements will continue to be made (Seidel, 2012;Rath et al, 2013). While I have emphasized how sexed semen is produced and used in the United States, the situation is very similar in Canada and several other countries.…”

Will AI in pigs become more efficient?

“…Alternatively, other more efficient procedures than flow cytometry are to be developed. With regard to the first target, research is currently done for identification of Y chromosome-specific sequences by bi-functionalised gold nanoparticles and triplex hybridisation in vivo as well as developing a new laser-controlled deflection system that replaces the deflection of spermatozoa in the electrostatic field [44]. In addition, parallel sorting based on microfluidic chips is being tested to avoid the complex orientation of spermatozoa by the flow-tip, therefore providing much higher rates of sorting [42].…”

Sexing of Spermatozoa in Farm Animals: a Mini Review

“…The demand for livestock products like meat, milk and dairy products have increased globally; to meet this demand, utilization of modern technologies to promote sustainable production of animals assumes paramount importance. Pre -sexed sperm or embryo mediated livestock production along with other genomic, proteomic and phenomics technologies offers a promising breeding strategy to meet the increased demand for food production (Rath et al, 2013). Determination of sex at the earliest stage can reduce the management cost thorough selective management of superior bulls or cows.…”