What affects fertility of sexed bull semen more, low sperm dosage or the sorting process?

Frijters, A.; Mullaart, E.; Roelofs, R.M.G.; Hoorne, R.P. van; Moreno, J. F.; Moreno, Óscar; Merton, J.S.

doi:10.1016/j.theriogenology.2008.09.025

Cited by 94 publications

(69 citation statements)

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“…Frijters et al (2009) estimated that two-thirds of the decrease is due to fewer sperm, and the balance is due to damaged sperm. Although few other experiments have been done to partition the causes of the low fertility, the consensus is that for most bulls, both factors are involved in lowered fertility.…”

Section: Fertilitymentioning

confidence: 99%

Update on sexed semen technology in cattle

Seidel

2014

Animal

117

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The technology in current use for sexing sperm represents remarkable feats of engineering. These flow cytometer/cell sorters can make over 30 000 consecutive evaluations of individual sperm each second for each nozzle and sort the sperm into three containers: X-sperm, Y-sperm and unsexable plus dead sperm. Even at these speeds it is not economical to package sperm at standard numbers per inseminate. However, with excellent management, pregnancy rates in cattle with 2 million sexed sperm per insemination dose are about 80% of those with conventional semen at normal sperm doses. This lowered fertility, in part due to damage to sperm during sorting, plus the extra cost of sexed semen limits the applications that are economically feasible. Even so, on the order of 2 million doses of bovine semen are sexed annually in the United States. The main application is for dairy heifers to have heifer calves, either for herd expansion or for sale as replacements, often for eventual export. Breeders of purebred cattle often use sexed semen for specific matings; thawing and then sexing frozen semen and immediately using the few resulting sexed sperm for in vitro fertilization is done with increasing frequency. Beef cattle producers are starting to use sexed semen to produce crossbred female replacements. Proprietary improvements in sperm sexing procedures, implemented in 2013, are claimed to improve fertility between 4 and 6 percentage points, or about 10%.Keywords: sexed semen, cattle, fertility, economics ImplicationsOver the next few years, it is unlikely that any fundamentally new technology will become available for sexing sperm commercially. However, incremental improvements in flow cytometer/cell sorting procedures almost certainly will result in faster speeds of sexing sperm and improved fertility. However, fertility of sexed semen is unlikely to exceed 90% of unsexed semen for most situations for several years, so profitable applications for cattle will be limited. Longer term prospects are encouraging; since sperm are evaluated one at a time, some defective sperm are discarded during sexing, and this may become more sophisticated, increasing fertility. IntroductionMost companies and cooperatives selling bovine semen in the United States sell sexed semen from a subset of their bulls. For reasons to be explained later, it is impossible to know the precise volume of sexed semen sales, but a consensus figure is on the order of 2 million doses annually, averaged over beef and dairy sires and domestic and export sales. This represents something < 5% of bovine semen sales volume.To interpret the sexed semen industry, it will be useful to consider a bit of history plus some intellectual property issues. Sexing sperm is still a developing technology, so changes in the product continue to be made, such as improving fertility, increasing accuracy of sexing, adding flexibility to delivery systems and reducing costs. Intellectual property issuesThere is only one useable, reasonably accurate method of sexing mammalian sperm availab...

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Section: Fertilitymentioning

confidence: 99%

Update on sexed semen technology in cattle

Seidel

2014

Animal

117

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“…There is evidence that the reduction in fertility due to the sexing process is not consistent across sires (Borchersen and Peacock, 2009;Frijters et al, 2009). With the advent and widespread uptake of genomic selection, an increasing proportion of the highest genetic merit sires available to producers are young sires evaluated based on genomic proofs (ICBF, 2013).…”

Section: Economics Of Sexed Semen Usementioning

confidence: 99%

Applications and cost benefits of sexed semen in pasture-based dairy production systems

Butler

Hutchinson

Cromie

et al. 2014

Animal

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Sexed semen technology is now commercially available in many countries around the world, and is primarily used in dairy cattle breeding. Sperm are sorted by flow cytometry on the basis of a 4% difference in DNA content between sperm containing X and Y chromosomes. Despite reliably producing a 90% gender bias, the fertility of the sexed semen product is compromised compared with conventional semen. The negative implications of the reduced fertility of sexed semen are amplified in seasonal systems of dairy production, as the importance of fertility is greater in these systems compared with year-round calving systems. A review of the literature indicates that conception rates (CR) to 1st service with frozen-thawed sexed semen are~75% to 80% of those achieved with conventional frozen-thawed semen. Preliminary results from a large-scale field trial carried out in Ireland in 2013 suggest that significant improvements in the performance of sexed semen have been made, with CR of 87% of those achieved with conventional semen. The improved fertility of a sexed semen product that delivers a 90% gender bias has considerable implications for the future of breeding management in pasture-based dairy production systems. Sexed semen may facilitate faster, more profitable dairy herd expansion by increasing the number of dairy heifer replacements born. Biosecurity can be improved by maintaining a closed herd during the period of herd expansion. In a non-expansion scenario, sexed semen may be used to increase the value of beef output from the dairy herd. The replacement heifer requirements for a herd could be met by using sexed semen in the 1st 3 weeks of the breeding season, with the remaining animals bred to beef sires, increasing the sale value over that of a dairy bull calf. Alternatively, very short gestation sires could be used to shorten the calving interval. Market prices have a considerable effect on the economics of sexed semen use, and widespread use of sexed semen should be restricted to well managed herds that already achieve acceptable herd fertility performance.

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“…However, after fertilization with sex-sorted spermatozoa, lower fertility rates have been observed both in vivo [9 -13] (after AI) and in vitro [14 -16]. Thus, in a recent large field trial of AI using sexed spermatozoa from seven Holstein bulls, Frijters et al [17] reported a 13.6% decline in the 56-day no return rate; many works also reported decreases in blastocysts rates after IVF of oocytes with sex-sorted sperm [18,19]. Proposed factors for the reduced fertility rates in vivo include not only the damage to the spermatozoa caused by the sorting procedure [11], but also the lower doses of spermatozoa used [9], and sire effects [20] (for review, see Rath et al [21]).…”

Section: Introductionmentioning

confidence: 99%

In vitro and in vivo quality of bovine embryos in vitro produced with sex-sorted sperm

et al. 2012

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In this work we analyzed the effects of three culture systems on developmental ability of bovine embryos in vitro produced with sexed sperm, the survival to vitrification (cryologic vitrification method) of such blastocysts, and their pregnancy rates after embryo transfer to recipients, both as fresh and after vitrification/warming. Finally, we measured the accuracy of the sorting protocol by a polymerase chain reaction-based method to validate the embryo sex at blastocyst stages. We confirmed an individual effect of the bull as well as development rates of embryos produced with sorted sperm lower than embryos with unsorted sperm, independent of the culture system used. The cryoresistance to vitrification of embryos produced with sexed sperm did not differ from that of conventionally produced embryos (re-expansion rates at 24 and 48 h: 74.6% vs. 75.5%, and 64.5% vs. 68.1% for embryos produced with conventional and sorted sperm, respectively; hatching rates at 48 h: 63.55% vs. 55.5% for embryos produced with conventional and sorted sperm, respectively). Finally, no significant differences were found in pregnancy rates after the embryo transfer of fresh and vitrified/warmed blastocysts (52.8% vs. 42.0%, respectively; P Ͼ 0.05). Male and female embryos produced with sorted sperm showed the same quality in terms of developmental ability, cryoresistance, and pregnancy rates after transfer. Our culture system, coupled with the vitrification in fiber plugs, provides good quality sex-known embryos which survive vitrification at similar rates than embryos produced with conventional unsorted sperm; also it produces good pregnancy rates after transfer of sexed embryos both fresh and after vitrification and warming.

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What affects fertility of sexed bull semen more, low sperm dosage or the sorting process?

Cited by 94 publications

References 4 publications

Update on sexed semen technology in cattle

Update on sexed semen technology in cattle

Applications and cost benefits of sexed semen in pasture-based dairy production systems

In vitro and in vivo quality of bovine embryos in vitro produced with sex-sorted sperm

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