I was just emailed a question regarding use of sex-sorted semen, so I thought I would blog my answer since many of you are probably fielding this question out there as well.
Most of the AI studs claim that sex-sorted semen yields fertility in heifers of about 80% to 85% of non-sorted semen. In general, herds with good heifer fertility can achieve good results with sex-sorted semen, whereas herds with poor heifer fertility can experience disastrous results. This variability occurs because there is less room for technical error when using sex-sorted semen. Also, keep in mind that Accelerated Genetics is marketing their own proprietary sex-sorted semen they call Bovatel which only slightly skews sex ratio compared to all of the other studs, which are using the Beltsville method of sorting. The studs only recommend using sex-sorted semen in nonlactating heifers; however, I have run across a few herds that are breeding first lactation cows using sex-sorted semen. This is not something I would recommend, but it is hard to argue against if fertiltiy results are reasonable.
My impression is that there is alot of sex-sorted semen being used in Wisconsin. As for how widely sex-sorted semen is being used, Ryan Sterry, Denise Brusveen, Kent Weigel, and I are going to crunch the results from our sex-sorted semen survey at the Dairy Team meeting the end of this month. Many of you participated in administering this survey. Basically, we asked dairy producers who attended UWEX programs this past winter about whether or not they used sex-sorted semen and their perceptions of sex-sorted semen. The results should be interesting, and we will be getting that information out to the Dairy Team as soon as we can get it analyzed.
Finally, Weigel and I addressed this issue at the 2005 Wisconsin Road Show meetings. I have uploaded a pdf of that slide set entitled "Can We Change the Sex Ratio of Calves?" to my web site at: http://www.uwex.edu/ces/dairyrepro/topics.cfm. This slide set overviews data comparing fertility of sorted vs. non-sorted semen, and Kent included a brief economic analysis. Roy Wilson's MS data is also included in these slides, and there is some other interesting stuff in there as well.