Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-24T06:34:27.330Z Has data issue: false hasContentIssue false
  • English
  • Français

Traversing the ovine cervix – a challenge for cryopreserved semen and creative science

Published online by Cambridge University Press:  22 June 2011

J. J. Robinson ,
W. A. C. McKelvey ,
M. E. King ,
S. E. Mitchell ,
M. J. A. Mylne ,
T. G. McEvoy ,
W. S. Dingwall  and
L. M. Williams
J. J. Robinson*
Affiliation:
Animal Biology Division, Scottish Agricultural College, Ferguson Building, Craibstone Estate, Bucksburn, Aberdeen AB21 9YA, UK
W. A. C. McKelvey
Affiliation:
Animal Health Research Group, Scottish Agricultural College, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, Scotland, UK
M. E. King
Affiliation:
Animal Biology Division, Scottish Agricultural College, Ferguson Building, Craibstone Estate, Bucksburn, Aberdeen AB21 9YA, UK
S. E. Mitchell
Affiliation:
Integrative Physiology, Institute of Environmental and Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
M. J. A. Mylne
Affiliation:
East Mains, Ormiston, East Lothian EH35 5NG, UK
T. G. McEvoy
Affiliation:
Animal Health Research Group, Scottish Agricultural College, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, Scotland, UK
W. S. Dingwall
Affiliation:
Animal Health Research Group, Scottish Agricultural College, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, Scotland, UK
L. M. Williams
Affiliation:
Molecular Nutrition Group, Rowett Institute of Nutrition and Health, University of Aberdeen, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
*
†E-mail: [email protected]
Get access

Abstract

This review brings together research findings on cervical relaxation in the ewe and its pharmacological stimulation for enhancement of the penetration needed for transcervical insemination and embryo transfer. On the basis that the success of artificial insemination is the percentage of ewes lambing, a review is made of recent research aimed at understanding and minimising the sub-lethal effects of freezing and thawing on the viability of spermatozoa, their membrane integrity and their ability to migrate through cervical mucus, as these characteristics have a major influence on fertility, particularly when semen is deposited, artificially, in the os cervix. Milestones of achievement are given for transcervical intrauterine insemination, embryo recovery and transfer and the birth of lambs of pre-determined sex, firstly following intracytoplasmic sperm injection, then laparoscopic intrauterine insemination using highly diluted flow-cytometrically sorted fresh semen and subsequently by os cervix insemination using sexed semen that had been frozen and thawed. Diversity of research endeavour (applied, cellular, molecular), research discipline (anatomy, histology, immunology, endocrinology) and research focus (cell, tissue, organ, whole animal) is embraced within the review as each has significant contributions to make in advancing recent scientific findings from the laboratory into robust on-farm transcervical insemination and embryo transfer techniques.

Keywords

ovine cervixsemen cryopreservationartificial inseminationembryo recovery and transfer
Type
Full Paper
Information
animal , Volume 5 , Issue 11 , 26 September 2011 , pp. 1791 - 1804
Copyright
Copyright © The Animal Consortium 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ahmadi, MR, Nazifi, S, Sajedianfard, J, Moathari, G 2007. Impact of oestrous synchronisation methods on cellular proportions in cervical mucus and serum hormone concentration. Theriogenology 67, 598–604.CrossRefGoogle Scholar
Akinbami, MA, Meredith, S, Warren, JE Jr, Anthony, RV, Day, BN 1990. Cervical dilation, conception rate, and concentrations of progesterone and estradiol-17B in postpartum ewes treated with porcine relaxin. Theriogenology 34, 927–940.CrossRefGoogle ScholarPubMed
Anel, L, Kaabi, M, Abroug, B, Alvarez, M, Anel, E, Boixo, JC, de la Fuente, LF, de Paz, P 2005. Factors influencing the success of vaginal and laparoscopic artificial insemination in Churra ewes: a field study. Theriogenology 63, 1235–1247.CrossRefGoogle Scholar
Audicana, L, Aughey, E, O'Shaughnessy, PJ 1998. Sensitivity of the early luteal phase ovine cervix to prostaglandin E2(PGE2) and expression of EP3 receptor mRNA. Research in Veterinary Science 64, 177–179.CrossRefGoogle ScholarPubMed
Ayad, VJ, Leung, ST, Parkinson, TJ, Wathes, DC 2004. Coincident increases in oxytocin receptor expression and EMG responsiveness to oxytocin in the ovine cervix at oestrus. Animal Reproduction Science 80, 237–250.CrossRefGoogle ScholarPubMed
Bari, F, Khalid, M, Haresign, W, Merrell, B, Murray, A, Richards, RIW 1999. An evaluation of the success of MOET in two breeds of hill sheep maintained under normal systems of hill flock management. Animal Science 69, 367–376.CrossRefGoogle Scholar
Barry, DM, van Niekerk, CH, Rust, J, van der Walt, T 1990. Cervical embryo collection in sheep after ripening of the cervix with prostaglandin E2 and estradiol. Theriogenology 33, 190.CrossRefGoogle Scholar
Beilby, KH, Grupen, CG, Thomson, PC, Maxwell, WMC, Evans, G 2009. The effect of insemination time and sperm dose on pregnancy rate using sex-sorted ram sperm. Theriogenology 71, 829–835.CrossRefGoogle ScholarPubMed
Buckrell, BC, Buschbeck, C, Gartley, CJ, Kroetsch, T, McCutcheon, W, Martin J Penner, WK, Walton, JS 1994. Further development of a transcervical technique for artificial insemination in sheep using previously frozen semen. Theriogenology 42, 601–611.CrossRefGoogle ScholarPubMed
Campbell, JW, Harvey, TG, McDonald, MF, Sparksman, RI 1996. Transcervical insemination in sheep: an anatomical and histological evaluation. Theriogenology 45, 1535–1544.CrossRefGoogle Scholar
Candappa, IBR, Bainbridge, HC, Price, NT, Hourigan, KR, Bartlewski, PM 2009. A preliminary study of the suitability of Cervidil® to induce cervical dilation for artificial insemination in ewes. Research in Veterinary Science 87, 204–206.CrossRefGoogle ScholarPubMed
Cardozo, JA, Fernández-Juan, M, Forcada, F, Abecia, A, Muiño-Blanco, T, Cebrián-Pérez, JA 2006. Monthly variations in ovine seminal plasma proteins analysed by two-dimensional polyacrylamide gel electrophoresis. Theriogenology 66, 841–850.CrossRefGoogle ScholarPubMed
Catt, SL, Catt, JW, Gomez, MC, Maxwell, WMC, Evans, G 1996. Birth of a male lamb derived from an in vitro matured oocyte fertilized by intracytoplasmic injection of a single presumptive male sperm. Veterinary Record 139, 494–495.CrossRefGoogle Scholar
Cavaco-Goncalves, S, Marques, CC, Horta, AEM, Figueroa, JP 2006. Increased cervical activity during oestrus in progestagen treated ewes: possible role in sperm transport. Animal Reproduction Science 93, 360–365.CrossRefGoogle ScholarPubMed
Cognie, Y 1999. State of the art in sheep–goat embryo transfer. Theriogenology 51, 105–116.CrossRefGoogle ScholarPubMed
Cognie, Y, Baril, G, Poulin, N, Mermillod, P 2003. Current status of embryo technologies in sheep and goat. Theriogenology 59, 171–188.CrossRefGoogle ScholarPubMed
Coonrod, SA, Coren, BR, McBride, BL, Bowen, MJ, Kraemer, DC 1986. Successful non-surgical collection of ovine embryos. Theriogenology 25, 149.CrossRefGoogle Scholar
Cran, DG, McKelvey, WAC, King, ME, Dolman, DF, McEvoy, TG, Broadbent, PJ, Robinson, JJ 1997. Production of lambs by low dose intrauterine insemination with flow cytometrically sorted and unsorted semen. Theriogenology 47, 267.CrossRefGoogle Scholar
Croy, BA, Prudencio, J, Minhas, K, Ashkar, AA, Galligan, C, Foster, RA, Buckrell, B, Coomber, BL 1999. A preliminary study on the usefulness of HUIL-8 in cervical relaxation of the ewe for artificial insemination and embryo transfer. Theriogenology 52, 271–287.CrossRefGoogle Scholar
de Graaf, SP, Beilby, K, O'Brien, JK, Osborn, D, Downing, JA, Maxwell, WMC, Evans, G 2007a. Embryo production from superovulated sheep inseminated with sex-sorted ram spermatozoa. Theriogenology 67, 550–555.CrossRefGoogle ScholarPubMed
De Graaf, SP, Evans, G, Maxwell, WMC, Downing, JA, O'Brien, JK 2007b. Successful low dose insemination of flow cytometrically sorted ram spermatozoa in sheep. Reproduction in Domestic Animals 42, 648–653.CrossRefGoogle ScholarPubMed
Dobson, H 1988. Softening and dilation of the uterine cervix. Oxford Reviews of Reproductive Biology 10, 491–514.Google ScholarPubMed
Donovan, A, Hanrahan, JP, Duffy, P, Boland, MP 2000. AI in sheep: breed differences in timing of ovulation. Irish Journal of Agriculture and Food Research 39, 464–465.Google Scholar
Donovan, A, Hanrahan, JP, Duffy, P, Byrne, GP, Boland, MP 1999. Cervical AI with fresh and frozen–thawed semen: effect of ewe breed. Irish Journal of Agriculture and Food Research 38, 267.Google Scholar
El-Hajj Ghaoui, R, Gillan, L, Thomson, PC, Evans, G, Maxwell, WMC 2007a. Effect of seminal plasma fractions from entire and vasectomised rams on the motility characteristics, membrane status, and in vitro fertility of ram spermatozoa. Journal of Andrology 28, 109–122.CrossRefGoogle Scholar
El-Hajj Ghaoui, R, Thomson, PC, Leahy, T, Evans, G, Maxwell, WMC 2007b. Autologous whole ram seminal plasma and its vesicle-free fraction improve motility characteristics and membrane status but not in vivo fertility of frozen–thawed ram spermatozoa. Reproduction in Domestic Animals 42, 541–549.CrossRefGoogle Scholar
Fair, S, Hanrahan, JP, Donovan, A, Duffy, P, O'Meara, CM, Lonergan, P, Evans, ACO 2007. Hormonal relationships during the periovulatory period among breeds known to differ in fertility after cervical artificial insemination with frozen thawed semen. Animal Reproduction Science 97, 284–294.CrossRefGoogle ScholarPubMed
Fair, S, Hanrahan, JP, O'Meara, CM, Duffy, P, Rizos, D, Wade, M, Donovan, A, Boland, MP, Lonergan, P, Evans, ACO 2005. Differences between Belclare and Suffolk ewes in fertilization rate, embryo quality and accessory sperm number after cervical or laparoscopic artificial insemination. Theriogenology 63, 1995–2005.CrossRefGoogle ScholarPubMed
Flohr, SF, Wulster-Radcliffe, MC, Lewis, GS 1999. Technical note: development of a transcervical oocyte recovery procedure for sheep. Journal of Animal Science 77, 2583–2586.CrossRefGoogle ScholarPubMed
Fukui, Y, Roberts, EM 1977. Sperm transport after non-surgical intrauterine insemination with frozen semen in ewes treated with prostaglandin F2α. Journal of Reproduction and Fertility 51, 141–143.CrossRefGoogle Scholar
Fukui, Y, Kohno, H, Okabe, K, Katsuki, S, Yoshizawa, M, Togari, T, Watanabe, H 2010. Factors affecting the fertility of ewes after intrauterine insemination with frozen–thawed semen during the non-breeding season. Journal of Reproduction and Development 56, 460–466.CrossRefGoogle ScholarPubMed
Gilbert, CL, Jenkins, K, Wathes, DC 1991. Pulsatile release of oxytocin into the circulation of the ewe during estrus. Journal of Reproduction and Fertility 91, 337–346.CrossRefGoogle Scholar
Gordon, I 1994. Laboratory production of cattle embryos. CAB International, Wallingford, Oxon, UK.Google Scholar
Gundogan, M, Yeni, D, Avdatek, F, Fidan, AF 2010. Influence of sperm concentration on the motility, morphology, membrane and DNA integrity along with oxidative stress parameters of ram sperm during liquid storage. Animal Reproduction Science 122, 200–207.CrossRefGoogle ScholarPubMed
Gündüz, MC, Turna, Ö, Circt, Ü, Uçmak, M, Çağatay, T, Sabuncu, A, Bacinoğlu, S 2010. Lambing rates and litter size following carazolol administration prior to insemination in Kivircik ewes. Animal Reproduction Science 118, 32–36.CrossRefGoogle ScholarPubMed
Gusmáo, AL, Silva, JC, Bittencourt, TCC, Martins, LEP, Fordiano, HD, Barbosa, LP 2009. Coleta transcervical de embiões em ovinos da raça Dorper no semiárido do nordeste Brasileiro. Arquivo Brasileiro de Medicina Veterinária e Zootecnia 61, 313–318.CrossRefGoogle Scholar
Halbert, GW, Dobson, H, Walton, JS, Buckrell, BC 1990b. The structure of the cervical canal of the ewe. Theriogenology 33, 977–992.CrossRefGoogle ScholarPubMed
Halbert, GW, Dobson, H, Walton, JS, Sharpe, P, Buckrell, BC 1990a. Field evaluation of a technique for transcervical intrauterine insemination of ewes. Theriogenology 33, 1231–1243.CrossRefGoogle Scholar
Hanrahan, JP 2003. Aspects of reproductive performance in small ruminants – opportunities and challenges. In Reproduction in domestic ruminants V (ed. BK Campbell, R Webb, H Dobson and C Doberska), pp. 15–26. Society for Reproduction and Fertility, Cambridge University Press, Cambridge, UK.Google Scholar
Haresign, W, Merrell, BG, Richards, RIWA 1994. Multiple ovulation and embryo transfer in hill ewes. Animal Production 58, 449.Google Scholar
Holt, WV, Lloyd, RE 2010. Sperm storage in the vertebrate female reproductive tract: how does it work so well? Theriogenology 73, 713–722.CrossRefGoogle Scholar
Houdeau, E, Raynal, P, Marnet, PG, Germain, G, Mormede, P, Rossano, B, Monnerie, R, Prud'homme, MJ 2002. Plasma levels of cortisol and oxytocin, and uterine activity after cervical artificial insemination in the ewe. Reproduction, Nutrition, Development 42, 381–392.CrossRefGoogle ScholarPubMed
Husein, MQ, Romano, JE, Bailey, MT, Ababneh, MM, Crabo, BG, Godfrey, RW, Head, WA, Wheaton, JE 1998. Estrous synchronisation and pregnancy rate of transcervically inseminated ewes during the breeding season. Sheep and Goat Research Journal 14, 148–152.Google Scholar
Kaabi, M, Alvarez, M, Anel, E, Chamorro, CA, Boixo, JC, de Paz, P, Anel, L 2006. Influence of breed and age on morphology and depth of inseminating catheter penetration in the ewe cervix: a post-mortem study. Theriogenology 66, 1876–1883.CrossRefGoogle Scholar
Kershaw, CM, Scaramuzzi, RJ, McGowan, MR, Wheeler-Jones, CPD, Khalid, M 2007. The expression of prostaglandin endoperoxide synthase 2 messenger RNA and the proportion of smooth muscle and collagen in the sheep cervix. Biology of Reproduction 76, 124–129.CrossRefGoogle ScholarPubMed
Kershaw, CM, Khalid, M, McGowan, MR, Ingram, K, Leethongdee, S, Wax, G, Scaramuzzi, RJ 2005. The anatomy of the sheep cervix and its influence on the transcervical passage of an inseminating pipette into the uterine lumen. Theriogenology 64, 1225–1235.CrossRefGoogle ScholarPubMed
Kershaw-Young, CM, Khalid, M, McGowan, MR, Pitsillides, AA, Scaramuzzi, RJ 2009. The mRNA expression of prostaglandin E receptors EP2 and EP4 and the changes in glycosaminoglycans in the sheep cervix during the estrous cycle. Theriogenology 72, 251–261.CrossRefGoogle ScholarPubMed
Kershaw-Young, CM, Scaramuzzi, RJ, McGowan, MR, Pitsillides, AA, Wheeler-Jones, CPD, Khalid, M 2010. The effect of estradiol on Cox-2, EP2 and EP4 mRNA expression and the extracellular matrix in the cervix of the hypogonadotrophic, ovariectomised ewe. Theriogenology 73, 620–628.CrossRefGoogle Scholar
King, ME, McKelvey, WAC, Ranilla, MJ, Robinson, JJ 1998. Hysteroscopic observation of cervical response in the oestrous and anoestrous ewe. Proceedings of the British Society of Animal Science, Scarborough, UK, p. 181.CrossRefGoogle Scholar
King, ME, McKelvey, WAC, Dingwall, WS, Matthews, KP, Gebbie, FE, Mylne, MJA, Stewart, E, Robinson, JJ 2004. Lambing rates and litter sizes following intrauterine or cervical insemination of frozen/thawed semen with or without oxytocin administration. Theriogenology 62, 1236–1244.CrossRefGoogle ScholarPubMed
Leahy, T, Marti, JI, Evans, G, Maxwell, WMC 2009. Seminal plasma proteins protect flow-sorted ram spermatozoa from freeze–thaw damage. Reproduction, Fertility and Development 21, 137–146.CrossRefGoogle ScholarPubMed
Leahy, T, Evans, G, Maxwell, WMC, Marti, JI 2010a. Seminal plasma proteins do not consistently improve fertility after cervical insemination of ewes with non-sorted or sex-sorted frozen–thawed ram spermatozoa. Reproduction, Fertility and Development 22, 606–612.CrossRefGoogle ScholarPubMed
Leahy, T, Marti, JI, Evans, G, Maxwell, WMC 2010b. Seasonal variation in the protective effect of seminal plasma on frozen–thawed ram spermatozoa. Animal Reproduction Science 119, 147–153.CrossRefGoogle ScholarPubMed
Leahy, T, Marti, JI, Mendoza, N, Pérez-Pé, R, Muiño-Blanco, T, Cabrián-Pérez, JA, Evans, G, Maxwell, WMC 2010c. High pre-freezing dilution improves post-thaw function of ram spermatozoa. Animal Reproduction Science 119, 137–146.CrossRefGoogle ScholarPubMed
Ledingham, MA, Denison, FC, Kelly, RW, Young, A, Norman, JE 1999. Nitric oxide donors stimulate prostaglandin F2α and inhibit thromboxane B2 production in the human cervix during the first trimester of pregnancy. Molecular Human Reproduction 5, 973–982.CrossRefGoogle ScholarPubMed
Leethongdee, S, Kershaw-Young, CM, Scaramuzzi, RJ, Khalid, M 2010. Intra-cervical application of Misprostol at estrus alters the content of cervical hyaluronan and the mRNA expression of follicle stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR) and cyclo-oxygenase-2 in the ewe. Theriogenology 73, 1257–1266.CrossRefGoogle Scholar
Leethongdee, S, Khalid, M, Bhatti, A, Ponglowhapan, S, Kershaw, C, Scaramuzzi, RJ 2007. The effects of the prostaglandin E analogue Misoprostol and follicle-stimulating hormone on cervical penetrability in ewes during the peri-ovulatory period. Theriogenology 67, 767–777.CrossRefGoogle ScholarPubMed
Leppert, PC 1995. Anatomy and physiology of cervical ripening. Clinical Obstetrics and Gynecology 38, 267–279.CrossRefGoogle ScholarPubMed
Li, QY, Guan, H, Hou, J, An, XR, Chen, YF 2008. Technical note: transfer of ovine embryos through a simplified mini-laparotomy technique. Journal of Animal Science 86, 3224–3227.CrossRefGoogle ScholarPubMed
Macfarlane, SR, Seatter, MJ, Kanke, T, Hunter, GD, Plevin, R 2001. Proteinase-activated receptors. Pharmacology Reviews 53, 245–282.Google ScholarPubMed
Matthews, EL, Ayad, VJ 1994. Characterisation and localization of a putative oxytocin receptor in the cervix of the oestrous ewe. Journal of Endocrinology 142, 397–405.CrossRefGoogle ScholarPubMed
Maxwell, WMC, Evans, G, Mortimer, ST, Gillon, L, Gellatly, ES, McPhie, CA 1999. Normal fertility in ewes after cervical insemination with frozen–thawed spermatozoa supplemented with seminal plasma. Reproduction, Fertility and Development 11, 123–126.CrossRefGoogle ScholarPubMed
McEvoy, TG, McKelvey, WAC, Robinson, JJ, Dingwall, WS, Lindsay, E, King, ME, FitzSimons, J 1996. Treatment of ewes to facilitate transcervical embryo collection does not compromise embryo development. Journal of Reproduction and Fertility, Abstract Series 17, 6.Google Scholar
McKelvey, B 1999. AI and embryo transfer for genetic improvement in sheep: the current scene. In Practice 21, 190–195.CrossRefGoogle Scholar
McKelvey, WAC, Robinson, JJ, Aitken, RP 1985. A simplified technique for the transfer of ovine embryos by laparoscopy. Veterinary Record 117, 492–494.CrossRefGoogle ScholarPubMed
McKelvey, WAC, Robinson, JJ, Aitken, RP, Robertson, IS 1986. Repeated recoveries of embryos from ewes by laparoscopy. Theriogenology 25, 855–865.CrossRefGoogle Scholar
McKelvey, WAC, McEvoy, TG, Dingwall, WS, Robinson, JJ, Lindsay, E, King, ME, FitzSimons, J, Mylne, MJA 1997. The use of exogenous hormones to facilitate transcervical embryo recovery in sheep and their effect on embryo development. Theriogenology 47, 369.CrossRefGoogle Scholar
McMillan, WH, Hall, DRH 1994. Laparoscopic transfer of ovine and cervine embryos using the transpic technique. Theriogenology 42, 137–146.CrossRefGoogle ScholarPubMed
Menchaca, A, Vilarino, M, Crispo, M, de Castro, T, Rubianies, E 2009. New approaches to superovulation and embryo transfer in small ruminants. Reproduction, Fertility and Development 22, 113–118.CrossRefGoogle Scholar
Mitchell, SE, Robinson, JJ, King, ME, Williams, LM 2005. Proteinase-activated receptors in ovine cervical function. Reproduction, Fertility and Development 17, 693–699.CrossRefGoogle ScholarPubMed
Mitchell, SE, Robinson, JJ, King, ME, McKelvey, WAC, Williams, LM 2002. Interleukin 8 in the cervix of non-pregnant ewes. Reproduction 124, 409–416.CrossRefGoogle ScholarPubMed
Mocé, E, Purdy, PH, Graham, JK 2010. Treating ram sperm with choloesterol-loaded cyclodextrins improves cryosurvival. Animal Reproduction Science 118, 236–247.CrossRefGoogle ScholarPubMed
Moré, J 1984. Anatomy and histology of the cervix uteri of the ewe: new insights. Acta Anatomica 120, 156–159.CrossRefGoogle ScholarPubMed
Mylne, MJA, McKelvey, WAC, Fernie, K, Matthews, K 1992. Use of a transcervical technique for embryo recovery in sheep. Veterinary Record 130, 450–451.CrossRefGoogle ScholarPubMed
Mylne, MJA, Dingwall, WS, King, ME, McKelvey, WAC, Robinson, JJ 1999. The viability of ovine embryos recovered transcervically and transferred by laparoscope. Proceedings of the British Society of Animal Science, Scarborough, UK, p. 16.CrossRefGoogle Scholar
Naqvi, SMK, Pandey, GK, Gautam, KK, Joshi, A, Geethalakshmi, V, Mittal, JP 2005. Evaluation of gross anatomical features of cervix of tropical sheep using cervical silicone moulds. Animal Reproduction Science 85, 337–344.CrossRefGoogle ScholarPubMed
Nellenschulte, E, Niemann, H 1992. Collection and transfer of ovine embryos by laparoscopy. Animal Reproduction Science 27, 293–304.CrossRefGoogle Scholar
Nemec, LA, Loskutoff, NM, Lesley, BL, Fields, MJ, Bowen, MJ, Kraemer, DC 1988. The influence of relaxin, with steroid treatment, on cervical dilatation in ovariectomised ewes. Theriogenology 29, 282.CrossRefGoogle Scholar
Nur, Z, Zik, B, Ustumer, B, Sagirkaya, H, Ozguden, CG 2010. Effects of different cryoprotective agents on ram sperm morphology and DNA integrity. Theriogenology 73, 1267–1275.CrossRefGoogle Scholar
O'Hara, L, Hanrahan, JP, Richardson, L, Donovan, A, Fair, S, Evans, ACO, Lonergan, P 2010. Effect of storage duration, storage temperature, and diluents on the viability and fertility of fresh ram sperm. Theriogenology 73, 541–549.CrossRefGoogle ScholarPubMed
O'Meara, CM, Donovan, A, Hanrahan, JP, Duff, P, Fair, S, Evans, ACO, Lonergan, P 2007. Resuspending ram spermatozoa in seminal plasma after cryopreservation does not improve pregnancy rate in cervically inseminated ewes. Theriogenology 67, 1262–1268.CrossRefGoogle Scholar
O'Meara, CM, Hanrahan, JP, Donovan, A, Fair, S, Rizos, D, Wade, M, Boland, MP, Evans, ACO, Lonergan, P 2005. Relationship between in vitro fertilization of ewe oocytes and the fertility of ewes following cervical artificial insemination with frozen–thawed ram semen. Theriogenology 64, 1797–1808.CrossRefGoogle ScholarPubMed
Papadopoulos, S, Hanrahan, JP, Donovan, A, Duffy, P, Boland, MP, Lonergan, P 2005. In vitro fertilization as a predictor of fertility from cervical insemination of sheep. Theriogenology 63, 150–159.CrossRefGoogle ScholarPubMed
Perry, K, Haresign, W, Wathes, DC, Khalid, M 2010a. Intracervical application of hyaluronan improves cervical relaxation in the ewe. Theriogenology 74, 1685–1690.CrossRefGoogle ScholarPubMed
Perry, K, Haresign, W, Wathes, DC, Khalid, M 2010b. Hyaluronan (HA) content, the ratio of HA fragments and the expression of CD44 in the ovine cervix vary with the stage of the oestrous cycle. Reproduction 140, 133–141.CrossRefGoogle ScholarPubMed
Read, CP, Word, RA, Ruscheinsky, MA, Timmons, BC, Mahendoo, MS 2007. Cervical remodelling during pregnancy and parturition: molecular characterization of the softening phase in mice. Reproduction 134, 327–340.CrossRefGoogle ScholarPubMed
Rexroad, CE Jr, Barb, CR 1977. Cervical mucus in estrous ewes after treatment with estrogen, progesterone and intrauterine devices. Journal of Animal Science 44, 102–105.CrossRefGoogle Scholar
Richardson, LR, Hanrahan, JP, Donovan, A, Fair, S, O'Hara, L, O'Sullivan, M, Lonergan, P, Evans, A 2009. Sperm penetration and viscosity of cervical mucus in sheep breeds differing in pregnancy rate to cervical AI with frozen thawed semen. Biology of Reproduction, Supplement S, Abstract 302, p. 116.CrossRefGoogle Scholar
Robinson, JJ, King, ME, Williams, LM, Mitchell, SE, Mylne, MJA, McKelvey, WAC 1999. Towards improved reproductive technologies for sheep. In Animal and food science research report (ed. sine nomine), pp. 2–5. Scottish Agricultural College, Edinburgh, Scotland.Google Scholar
Salamon, S, Maxwell, WMC 1995. Frozen storage of ram semen. 2. Causes of low fertility after cervical insemination and methods of improvement. Animal Reproduction Science 38, 1–36.CrossRefGoogle Scholar
Sanchez-Partida, LG, Windsor, DP, Eppleston, J, Setchell, BP, Maxwell, WMC 1999. Fertility and its relationship to motility characteristics of spermatozoa in ewes after cervical, transcervical, and intrauterine insemination with frozen–thawed ram semen. Journal of Andrology 20, 280–288.CrossRefGoogle ScholarPubMed
Sayre, BL, Lewis, GS 1997. Fertility and ovum fertilization rate after laparoscopic or transcervical intrauterine artificial insemination of oxytocin-treated ewes. Theriogenology 48, 267–275.CrossRefGoogle ScholarPubMed
Scudamore, CL, Robinson, JJ, Aitken, RP, Kennedy, DJ, Ireland, S, Robertson, IS 1991. Laparoscopy for intrauterine insemination and embryo recovery in superovulated ewes submitted to a commercial embryo transfer unit. Theriogenology 35, 329–337.CrossRefGoogle ScholarPubMed
Sheldrick, EL, Flint, APF 1981. Circulating concentrations of oxytocin during the oestrous cycle and early pregnancy in sheep. Prostaglandins 22, 631–636.CrossRefGoogle Scholar
Smith, JF 1971. Ewe fertility-production of cervical mucus. Journal of Reproduction and Fertility 24, 132.CrossRefGoogle ScholarPubMed
Smith, JF, Allison, AJ 1971. The effect of exogenous progestagen on the production of cervical mucus in the ewe. Journal of Reproduction and Fertility 24, 279.CrossRefGoogle ScholarPubMed
Smith, JF, Parr, J, Beaumont, S, Oliver, JE, Upreti, GC 1995. Comparison of cervical, transcervical and laparoscopic insemination of ewes with chilled stored and frozen ram semen. Proceedings of the New Zealand Society of Animal Production 55, 248–250.Google Scholar
Stellflug, JN, Wulster-Radcliffe, MC, Hensley, EL, Cowardin, EA, Seals, RC, Lewis, GS 2001. Oxytocin-induced cervical dilation and cervical manipulation in sheep: effects on laparoscopic artificial insemination. Journal of Animal Science 79, 568–573.CrossRefGoogle ScholarPubMed
Timmons, B, Akins, M, Mahendroo, M 2010. Cervical remodelling during pregnancy and parturition. Trends in Endocrinology and Metabolism 21, 353–361.CrossRefGoogle ScholarPubMed
Tschugguel, W, Schneeberger, C, Lass, H, Stonek, F, Zaghlula, MB, Czerwenka, K, Schatten, C, Kaider, A, Husslein, P, Huber, C 1999. Human cervical ripening is associated with an increase in cervical inducible nitric oxide synthase expression. Biology of Reproduction 60, 1367–1372.CrossRefGoogle ScholarPubMed
Vu, TK, Hung, DT, Wheaton, VI, Coughlin, SR 1991. Molecular cloning of a functional thrombin receptor reveals a novel proteolytic mechanism of receptor activation. Cell 64, 1057–1068.CrossRefGoogle ScholarPubMed
Wathes, DC, Guldenaar, SEF, Swann, RW, Webb, R, Porter, DG, Pickering, BT 1986. A combined radioimmunoassay and immunocytochemical study of ovarian oxytocin production during the periovulatory period in the ewe. Journal of Reproduction and Fertility 78, 167–183.CrossRefGoogle ScholarPubMed
Windsor, DP 1997. Variation between ejaculates in the fertility of frozen ram semen used for cervical insemination of Merino ewes. Animal Reproduction Science 47, 21–29.CrossRefGoogle ScholarPubMed
Windsor, DP, White, IG 1995. Mitochondrial injury to ram sperm during procedures associated with artificial insemination or frozen storage. Animal Reproduction Science 40, 43–58.CrossRefGoogle Scholar
Windsor, DP, Szell, AZ, Buschbeck, C, Edward, AY, Milton, JTB, Buckrell, BC 1994. Transcervical artificial insemination of Australian Merino ewes with frozen–thawed semen. Theriogenology 42, 147–157.CrossRefGoogle ScholarPubMed
Wolf, BT, McDougall, I 1994. Comparison of MOET in Texel ewe lambs and yearling ewes. Animal Production 58, 448.Google Scholar
Wolf, BT, Mylne, MJA 1994. Influence of age of donor ewe on MOET in Texel sheep. Animal Production 58, 448.Google Scholar
Wulster-Radcliffe, MC, Lewis, GS 2002. Development of a new transcervical artificial insemination method for sheep: effects of a new transcervical artificial insemination catheter and traversing the cervix on semen quality and fertility. Theriogenology 58, 1361–1371.CrossRefGoogle ScholarPubMed
Wulster-Radcliffe, MC, Costine, BA, Lewis, GS 1999. Estradiol-17β-oxytocin-induced cervical dilation in sheep: application to transcervical embryo transfer. Journal of Animal Science 77, 2587–2593.CrossRefGoogle ScholarPubMed
Wulster-Radcliffe, MC, Wang, S, Lewis, GS 2004. Transcervical artificial insemination in sheep: effects of a new transcervical artificial insemination instrument and traversing the cervix on pregnancy and lambing rates. Theriogenology 62, 990–1002.CrossRefGoogle ScholarPubMed
Yue, W, Shi, L, Bai, Z, Ren, Y, Zhao, Y 2009. Sodium dodecyl sulphate (SDS) – polyacrylamide gel electrophoresis of ram seminal plasma proteins and their correlation with semen characteristics. Animal Reproduction Science 116, 386–391.CrossRefGoogle ScholarPubMed
Zhao, Y, Williams, LM, Hannah, LT, Ross, AW, McKelvey, WAC, Robinson, JJ 1999. Oestrogen and progesterone receptor immunoreactivity and c-fos expression in the ovine cervix. Journal of Reproduction and Fertility 115, 287–292.CrossRefGoogle ScholarPubMed