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Methodological advances on spermatozoa sexing for using in genetic improvement and animal production

The market demands, since the end of the 1920s the market demands a technology for spermatozoa sexing that can be inserted in the industry to production of frozen semen and that has the following features: a) does not change sperm viability; b) it be compatible with freezing of spermatozoa after treatment for sexing; c) it allows the spermatozoa sexing after their thawing; d) it allows the production of various doses of sexed frozen semen per day at a compatible cost for the market. The importance of this technology to maximize animal production at lower cost is a challenge of the research and it has been studied for many years. The possibility to produce, in commercial scale, semen doses enriched with X or Y spermatozoa will increase the benefits of the use of artificial insemination (AI) for its decisive role to maximize the genetic progress between generations, according to the requirements of each genetic improvement program and livestock capacity. Different technological routes are taken in the attempt to select gender in mammals, both for zootechnical interest species and for endangered species and pet animals. There are two alternatives for that: to separate X-chromosome-bearing spermatozoa from those Y- chromosome-bearing spermatozoa; or to sex pre-implanted embryos.The availability of sexed semen in cattle has been eagerly anticipated for many years, and recent developments have brought this technology to the brink of commercial application. Limitations still exist, namely conception rates in field. This limits the willingness of producers to pay a premium price for the product. The focus of this paper is to discuss potential breeding schemes that can lead to widespread usage of sexed semen, in spite of its aforementioned limitations.

bovine; spermatozoa; sex selection


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