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RESEARCH ARTICLE

In vivo embryo production in cows superovulated 1 or 2 days after ovum pick-up

Ricardo S. Surjus A , Alexandre B. Prata A , Marta Borsato A , Fernanda C. S. Z. Mattos B , Mariana C. Martins da Silveira B , Gerson B. Mourão A , Alexandre V. Pires A , Milo C. Wiltbank C and Roberto Sartori A D
+ Author Affiliations
- Author Affiliations

A Department of Animal Science, College of Agriculture ‘Luiz de Queiroz’ (ESALQ), University of São Paulo, Av. Pádua Dias, 11, CP 9, Piracicaba, SP 13418-900, Brazil.

B College of Veterinary and Animal Science, São Paulo State University, Distrito Rubião Júnior, Botucatu, SP 18618-970, Brazil.

C Department of Dairy Science, University of Wisconsin, 1675 Observatory Drive, Madison, WI 53706, USA.

D Corresponding author. Email: robertosartori@usp.br

Reproduction, Fertility and Development 26(4) 527-532 https://doi.org/10.1071/RD12398
Submitted: 13 December 2012  Accepted: 15 March 2013   Published: 9 May 2013

Abstract

The present study evaluated superovulatory responses and in vivo embryo production in cows treated with FSH starting 1 or 2 days after ovum pick-up (OPU). Thirty-three non-lactating Nelore cows were subjected to aspiration of all follicles ≥3 mm for OPU. After OPU, cows were randomly divided into two groups in which the follicle superstimulatory treatments with FSH started 1 or 2 days after OPU (Groups D1 and D2, respectively). Data are presented as the least squares mean ± s.e.m. The number of follicles ≥3 mm before OPU was similar between groups (~34); however, cows in Group D2 had more follicles ≥3 mm on the first day of FSH (15.2 ± 2.3 vs 7.6 ± 1.7; P = 0.04) and a higher ratio of the number of follicles at first FSH/number of follicles before OPU (0.41 ± 0.04 vs 0.24 ± 0.02; P = 0.01). In addition, Group D2 cows had a greater superovulatory response than did cows in Group D1 (18.9 ± 2.8 vs 9.1 ± 1.9 corpora lutea, respectively; P < 0.03). However, there was no difference in the total number of recovered ova and embryos from cows in Groups D2 and D1 (5.1 ± 1.4 vs 4.9 ± 1.3, respectively; P > 0.10). Nevertheless Group D2 cows had more freezable embryos than Group D1 cows (3.2 ± 1.1 vs 1.3 ± 0.5, respectively; P < 0.05). Cows from Group D2 had a much higher proportion (P < 0.001) of follicles ≥8 mm compared with follicles ≥6 mm and <8 mm at the time of the last treatment with FSH. In conclusion, to obtain a greater production of viable embryos in superovulated cows after OPU, it is recommended to wait at least 2 days before starting FSH treatment.

Additional keywords: cattle, follicle aspiration, FSH.


References

Adams, G. P., Matteri, R., Kastelic, J., Ko, J., and Ginther, O. J. (1992). Association between surges of follicle-stimulating-hormone and the emergence of follicular waves in heifers. J. Reprod. Fertil. 94, 177–188.
Association between surges of follicle-stimulating-hormone and the emergence of follicular waves in heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38Xhs1Kltr4%3D&md5=8d985eebfe3fd503de6a661234d1bb3eCAS | 1552480PubMed |

Adams, G. P., Kot, K., Smith, C., and Ginther, O. J. (1993). Selection of a dominant follicle and suppression of follicular-growth in heifers. Anim. Reprod. Sci. 30, 259–271.
Selection of a dominant follicle and suppression of follicular-growth in heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3sXit1Kjsbk%3D&md5=2f47ada1089dd01e504e3f4a7565e9fcCAS |

Adams, G., Nasser, L. F., Bó, G. A., Garcia, A., DelCampo, M., and Mapletoft, R. J. (1994). Superovulatory response of ovarian follicles of wave-1 versus wave-2 in heifers. Theriogenology 42, 1103–1113.
Superovulatory response of ovarian follicles of wave-1 versus wave-2 in heifers.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28zgtVeksw%3D%3D&md5=288246dd929b6ab72459ced858b77d05CAS | 16727614PubMed |

Amiridis, G. S., Tsiligianni, T., and Vainas, E. (2006). Follicle ablation improves the ovarian response and the number of collected embryos in superovulated cows during the early stages of lactation. Reprod. Domest. Anim. 41, 402–407.
Follicle ablation improves the ovarian response and the number of collected embryos in superovulated cows during the early stages of lactation.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28rlvF2jtQ%3D%3D&md5=28d57610637126bbb12791061244dfdcCAS | 16984345PubMed |

Baracaldo, M. I., Martinez, M. F., Adams, G. P., and Mapletoft, R. J. (2000). Superovulatory response following transvaginal follicle ablation in cattle. Theriogenology 53, 1239–1250.
Superovulatory response following transvaginal follicle ablation in cattle.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD3czpsFKitg%3D%3D&md5=a79350cd6dcede7fdbb303f875cf4edbCAS | 10832749PubMed |

Barros, C. M., and Nogueira, M. F. G. (2001). Embryo transfer in Bos indicus cattle. Theriogenology 56, 1483–1496.
Embryo transfer in Bos indicus cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xjslyqtw%3D%3D&md5=f99ce9b291647b13410a11512bc1ff81CAS | 11768812PubMed |

Bergfelt, D. R., Lightfoot, K. C., and Adams, G. P. (1994). Ovarian synchronization following ultrasound-guided transvaginal follicle ablation in heifers. Theriogenology 42, 895–907.
Ovarian synchronization following ultrasound-guided transvaginal follicle ablation in heifers.Crossref | GoogleScholarGoogle Scholar |

Blondin, P., Guilbault, L. A., and Sirard, M. A. (1997). The time interval between FSH–P administration and slaughter can influence the developmental competence of beef heifer oocytes. Theriogenology 48, 803–813.
The time interval between FSH–P administration and slaughter can influence the developmental competence of beef heifer oocytes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXms1Shsrw%3D&md5=41c8008a0fccacc613a41b2fb8034625CAS | 16728173PubMed |

Blondin, P., Bousquet, D., Twagiramungu, H., Barnes, F., and Sirard, M. A. (2002). Manipulation of follicular development to produce developmentally competent bovine oocytes. Biol. Reprod. 66, 38–43.
Manipulation of follicular development to produce developmentally competent bovine oocytes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xht1ylsA%3D%3D&md5=40dd11f59fc74e77fa737ce4840b4fe1CAS | 11751261PubMed |

Bó, G. A., Adams, G. P., Caccia, M., Martinez, M. F., Pierson, R. A., and Mapletoft, R. J. (1995). Ovarian follicular wave emergence after treatment with progestogen and estradiol in cattle. Anim. Reprod. Sci. 39, 193–204.
Ovarian follicular wave emergence after treatment with progestogen and estradiol in cattle.Crossref | GoogleScholarGoogle Scholar |

Boni, R., Roelofsen, M. W., Pieterse, M., Kogut, J., and Kruip, T. A. (1997). Follicular dynamics, repeatability and predictability of follicular recruitment in cows undergoing repeated follicular puncture. Theriogenology 48, 277–289.
Follicular dynamics, repeatability and predictability of follicular recruitment in cows undergoing repeated follicular puncture.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28zgtVykug%3D%3D&md5=58f41192f018d185917735e23e7d76d1CAS | 16728127PubMed |

Bridges, P. J., and Fortune, J. E. (2003). Characteristics of developing prolonged dominant follicles in cattle. Domest. Anim. Endocrinol. 25, 199–214.
Characteristics of developing prolonged dominant follicles in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXntVChsLg%3D&md5=34d70ca5d0aba26aa64bdd6e8468c360CAS | 12972376PubMed |

Bridges, G. A., Mussard, M. L., Burke, C. R., and Day, M. L. (2010). Influence of the length of proestrus on fertility and endocrine function in female cattle. Anim. Reprod. Sci. 117, 208–215.
Influence of the length of proestrus on fertility and endocrine function in female cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhsVGltrnL&md5=b2c40692f34131be2d2cab14a3ba96f8CAS | 19500921PubMed |

Bungartz, L., and Niemann, H. (1994). Assessment of the presence of a dominant follicle and selection of dairy cows suitable for superovulation by a single ultrasound examination. J. Reprod. Fertil. 101, 583–591.
Assessment of the presence of a dominant follicle and selection of dairy cows suitable for superovulation by a single ultrasound examination.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK2M%2FlsFCjtA%3D%3D&md5=e0e0ebd7e7e00b5379a8b328a8dd67f4CAS | 7966012PubMed |

Buratini, J., Price, C. A., Visintin, J. A., and Bo, G. A. (2000). Effects of dominant follicle aspiration and treatment with recombinant bovine somatotropin (BST) on ovarian follicular development in Nelore (Bos indicus) heifers. Theriogenology 54, 421–431.
Effects of dominant follicle aspiration and treatment with recombinant bovine somatotropin (BST) on ovarian follicular development in Nelore (Bos indicus) heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXnsleku7k%3D&md5=475d781de921e61a3a346e8fb41fe258CAS | 11051325PubMed |

Callesen, H., Greve, T., and Hyttel, P. (1987). Premature ovulations in superovulated cattle. Theriogenology 28, 155–166.
Premature ovulations in superovulated cattle.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD283pvFSltQ%3D%3D&md5=282330dc534d0e15fc8746c69024f837CAS | 16726301PubMed |

Carter, F., Forde, N., Duffy, P., Wade, M., Fair, T., Crowe, M. A., Evans, A. C., Kenny, D. A., Roche, J. F., and Lonergan, P. (2008). Effect of increasing progesterone concentration from Day 3 of pregnancy on subsequent embryo survival and development in beef heifers. Reprod. Fertil. Dev. 20, 368–375.
Effect of increasing progesterone concentration from Day 3 of pregnancy on subsequent embryo survival and development in beef heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXjtVKksLg%3D&md5=64ca51d0d9b619dd0572e72474aeae4aCAS | 18402756PubMed |

Castro Neto, A. S., Sanches, B. V., Binelli, M., Seneda, M. M., Perri, S. H., and Garcia, J. F. (2005). Improvement in embryo recovery using double uterine flushing. Theriogenology 63, 1249–1255.
Improvement in embryo recovery using double uterine flushing.Crossref | GoogleScholarGoogle Scholar |

Cavalieri, J., Farin, P. W., Kinder, J. E., Van Camp, S. D., Whitacre, M. D., Washburn, S. P., and Britt, J. H. (2001). Ovarian follicular development following administration of progesterone or aspiration of ovarian follicles in Holstein cows. Theriogenology 55, 805–821.
Ovarian follicular development following administration of progesterone or aspiration of ovarian follicles in Holstein cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXit1emur4%3D&md5=61953e13e8f494722d2f4d5b5bbf1880CAS | 11245267PubMed |

Day, M. L., Mussard, M. L., Bridges, G. A., and Burke, C. R. (2010). Controlling the dominant follicle in beef cattle to improve estrous synchronization and early embryonic development. Soc. Reprod. Fertil. Suppl. 67, 405–419.
| 1:STN:280:DC%2BC3MnosFemtQ%3D%3D&md5=91924f8d2e50eb0674a264b85d8b7cc0CAS | 21755687PubMed |

García Guerra, A., Tribulo, A., Yapura, J., Singh, J., and Mapletoft, R. J. (2012). Lengthening the superstimulatory treatment protocol increases ovarian response and number of transferable embryos in beef cows. Theriogenology 78, 353–360.
Lengthening the superstimulatory treatment protocol increases ovarian response and number of transferable embryos in beef cows.Crossref | GoogleScholarGoogle Scholar | 22494674PubMed |

Gibbons, J. R., Wiltbank, M. C., and Ginther, O. J. (1999). Relationship between follicular development and the decline in the follicle-stimulating hormone surge in heifers. Biol. Reprod. 60, 72–77.
Relationship between follicular development and the decline in the follicle-stimulating hormone surge in heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXhvFylsw%3D%3D&md5=45db29c44e2068c29df3b639a40d4c4fCAS | 9858488PubMed |

Gong, J. G., Bramley, T. A., and Webb, R. (1993). The effect of recombinant bovine somatotropin on ovarian follicular-growth and development in heifers. J. Reprod. Fertil. 97, 247–254.
The effect of recombinant bovine somatotropin on ovarian follicular-growth and development in heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3sXhs1WhtL4%3D&md5=7de8fd6ab9468471f3cf60f75014b067CAS | 8464017PubMed |

Gong, J. G., Campbell, B., Bramley, T. A., Gutierrez, C. G., Peters, A., and Webb, R. (1996). Suppression in the secretion of follicle-stimulating hormone and luteinizing hormone, and ovarian follicle development in heifers continuously infused with a gonadotropin-releasing hormone agonist. Biol. Reprod. 55, 68–74.
Suppression in the secretion of follicle-stimulating hormone and luteinizing hormone, and ovarian follicle development in heifers continuously infused with a gonadotropin-releasing hormone agonist.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XltlKnsLg%3D&md5=30caca358b0eb1ffee0976b41992d832CAS | 8793060PubMed |

Gong, J. G., Armstrong, D. G., Baxter, G., Hogg, C., Garnsworthy, P. C., and Webb, R. (2002). The effect of increased dietary intake on superovulatory response to FSH in heifers. Theriogenology 57, 1591–1602.
The effect of increased dietary intake on superovulatory response to FSH in heifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XktlWnur8%3D&md5=b03e9bff49519360118956a3e1d97891CAS | 12035971PubMed |

Gutierrez, C. G., Oldham, J., Bramley, T. A., Gong, J. G., Campbell, B., and Webb, R. (1997). The recruitment of ovarian follicles is enhanced by increased dietary intake in heifers. J. Anim. Sci. 75, 1876–1884.
| 1:CAS:528:DyaK2sXkt1Gksrg%3D&md5=1343151538e962a8aad16acfa28a77aaCAS | 9222845PubMed |

Hyttel, P., Callesen, H., and Greve, T. (1986). Ultrastructural features of preovulatory oocyte maturation in superovulated cattle. J. Reprod. Fertil. 76, 645–656.
Ultrastructural features of preovulatory oocyte maturation in superovulated cattle.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaL287pvFyrtQ%3D%3D&md5=2a41163af0f72ae19ee9824a633736e9CAS | 3084771PubMed |

Ireland, J. J., Ward, F., Jimenez-Krassel, F., Ireland, J. L. H., Smith, G. W., Lonergan, P., and Evans, A. C. (2007). Follicle numbers are highly repeatable within individual animals but are inversely correlated with FSH concentrations and the proportion of good-quality embryos after ovarian stimulation in cattle. Hum. Reprod. 22, 1687–1695.
Follicle numbers are highly repeatable within individual animals but are inversely correlated with FSH concentrations and the proportion of good-quality embryos after ovarian stimulation in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXot1ejtLo%3D&md5=fd72acc2474712d3e0d7578ea8ea02bcCAS | 17468258PubMed |

Keller, D., and Teepker, G. (1990). Effect of variability in response to superovulation on donor cow selection differentials in nucleus breeding schemes. J. Dairy Sci. 73, 549–554.
Effect of variability in response to superovulation on donor cow selection differentials in nucleus breeding schemes.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK3c3ivFGmtQ%3D%3D&md5=65fd3693180f3efbb143c98634ce5152CAS | 2329209PubMed |

Kohram, H., Twagiramungu, H., Bousquet, D., Durocher, J., and Guilbault, L. (1998). Ovarian superstimulation after follicular wave synchronization with GnRH at two different stages of the estrous cycle in cattle. Theriogenology 49, 1175–1186.
Ovarian superstimulation after follicular wave synchronization with GnRH at two different stages of the estrous cycle in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXivVWmsbc%3D&md5=dbb34c159509621583ae81ad78fed45dCAS | 10732055PubMed |

Lonergan, P. (2011). Influence of progesterone on oocyte quality and embryo development in cows. Theriogenology 76, 1594–1601.
Influence of progesterone on oocyte quality and embryo development in cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXhsVanurzI&md5=15dc7ed19b3ee1cf310458ebea657936CAS | 21855985PubMed |

Lonergan, P., Monaghan, P., Rizos, D., Boland, M. P., and Gordon, I. (1994). Effect of follicle size on bovine oocyte quality and developmental competence following maturation, fertilization, and culture in vitro. Mol. Reprod. Dev. 37, 48–53.
Effect of follicle size on bovine oocyte quality and developmental competence following maturation, fertilization, and culture in vitro.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK2c7ns1Wltw%3D%3D&md5=3cdc8fe2c1982f468b8a85790cda6dd8CAS | 8129930PubMed |

Lonergan, P., Woods, A., Fair, T., Carter, F., Rizos, D., Ward, F., Quinn, K., and Evans, A. C. (2007). Effect of embryo source and recipient progesterone environment on embryo development in cattle. Reprod. Fertil. Dev. 19, 861–868.
Effect of embryo source and recipient progesterone environment on embryo development in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtVWhtrzK&md5=b115d5a2a77a98e3ea507592fc7e20d1CAS | 17897589PubMed |

Looney, C. (1986). Superovulation in beef females. In ‘Proceedings of the Fifth Annual Convention of the American Embryo Transfer Association’. pp. 16–29. (Fort Worth, TX.)

Mapletoft, R. J., Steward, K., and Adams, G. (2002). Recent advances in the superovulation in cattle. Reprod. Nutr. Dev. 42, 601–611.
Recent advances in the superovulation in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXit1ymtr8%3D&md5=b57236bd178309e76ff0e39a5d940091CAS | 12625424PubMed |

Mattos, M. C. C., Bastos, M. R., Guardieiro, M. M., Carvalho, J. O., Franco, M., Mourao, G. B., Barros, C. M., and Sartori, R. (2011). Improvement of embryo production by the replacement of the last two doses of porcine follicle-stimulating hormone with equine chorionic gonadotropin in Sindhi donors. Anim. Reprod. Sci. 125, 119–123.
Improvement of embryo production by the replacement of the last two doses of porcine follicle-stimulating hormone with equine chorionic gonadotropin in Sindhi donors.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXnsVyrtb8%3D&md5=94909a83658fa1dc4484481bf7305e01CAS |

Mussard, M. L., Burke, C. R., Behlke, E. J., Gasser, C. L., and Day, M. L. (2007). Influence of premature induction of a luteinizing hormone surge with gonadotropin-releasing hormone on ovulation, luteal function, and fertility in cattle. J. Anim. Sci. 85, 937–943.
Influence of premature induction of a luteinizing hormone surge with gonadotropin-releasing hormone on ovulation, luteal function, and fertility in cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXjslWlu7c%3D&md5=b6eadec65584bd8b8a7bee7e9e38541aCAS | 17145968PubMed |

Nasser, L. F., Adams, G., Bó, G. A., and Mapletoft, R. J. (1993). Ovarian superstimulatory response relative to follicular wave emergence in heifers. Theriogenology 40, 713–724.
Ovarian superstimulatory response relative to follicular wave emergence in heifers.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28zgtVWitg%3D%3D&md5=ead5b630765dc2acf08a3002e5d84f0bCAS | 16727353PubMed |

National Research Council (2000). ‘Nutrient requeriments of beef cattle.’ (Updated 7th Ed.) (National Academy Press, Washington, DC.)

Nogueira, M. F. G., Fragnito, P. S., Trinca, L. A., and Barros, C. M. (2007). The effect of type of vaginal insert and dose of pLH on embryo production, following fixed-time AI in a progestin-based superstimulatory protocol in Nelore cattle. Theriogenology 67, 655–660.
The effect of type of vaginal insert and dose of pLH on embryo production, following fixed-time AI in a progestin-based superstimulatory protocol in Nelore cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXitl2jtw%3D%3D&md5=0c18f3b5bdd65d052a73997c67a462edCAS |

Perry, G. A., Smith, M. F., Lucy, M. C., Green, J. A., Parks, T. E., MacNeil, M. D., Roberts, A. J., and Geary, T. W. (2005). Relationship between follicle size at insemination and pregnancy success. Proc. Natl Acad. Sci. USA 102, 5268–5273.
Relationship between follicle size at insemination and pregnancy success.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXjsFemurk%3D&md5=cd3d5cf5c75833739dd71348c2b84a56CAS | 15795381PubMed |

Pursley, J., Mee, M., and Wiltbank, M. C. (1995). Synchronization of ovulation in dairy-cows using PGF (2-ALPHA), and GnRH. Theriogenology 44, 915–923.
Synchronization of ovulation in dairy-cows using PGF (2-ALPHA), and GnRH.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXpvFymu7w%3D&md5=db793bd7fb4aa2021b86011b6f7c754cCAS | 16727787PubMed |

Robertson, I., and Nelson, R. E. (1998). Certification and identification of the embryo. In ‘Manual of the International Embryo Transfer Society’. (Eds D. Stringfellow and S. M. Seidel.) pp. 103–134. (International Embryo Transfer Society: Savoy, IL.)

Sartori, R., and Barros, C. M. (2011). Reproductive cycles in Bos indicus cattle. Anim. Reprod. Sci. 124, 244–250.
Reproductive cycles in Bos indicus cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXlvFWhur4%3D&md5=361ff1d0757ff520f75a4c30cd7fe901CAS | 21388755PubMed |

Shaw, D. W., Farin, P. F., Washburn, S. P., and Britt, J. H. (1995). Effect of retinol palmitate on ovulation rate and embryo quality in superovulated cattle. Theriogenology 44, 51–58.
Effect of retinol palmitate on ovulation rate and embryo quality in superovulated cattle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXnt1Cjt7o%3D&md5=6ef4b3ed614222f12432c5243aad576fCAS |

Singh, J., Dominguez, M., Jaiswal, R., and Adams, G. P. (2004). A simple ultrasound test to predict the superstimulatory response in cattle. Theriogenology 62, 227–243.
A simple ultrasound test to predict the superstimulatory response in cattle.Crossref | GoogleScholarGoogle Scholar | 15159116PubMed |

Twagiramungu, H., Guilbault, L., and Dufour, J. (1995). Synchronization of ovarian follicular waves with a gonadotropin-releasing-hormone agonist to increase the precision of estrus in cattle: a review. J. Anim. Sci. 73, 3141–3151.
| 1:CAS:528:DyaK2MXovVGqsLs%3D&md5=2a777042f9b39900f41dcf476cc65cfbCAS | 8617687PubMed |

Vasconcelos, J. L., Sartori, R., Oliveira, H., Guenther, J. J., and Wiltbank, M. C. (2001). Reduction in size of the ovulatory follicle reduces subsequent luteal size and pregnancy rate. Theriogenology 56, 307–314.
Reduction in size of the ovulatory follicle reduces subsequent luteal size and pregnancy rate.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD3Mvjt1ymtA%3D%3D&md5=e03abeae986c130a2bdc127f52f2b135CAS | 11480622PubMed |

Viana, J. H., Palhao, M. P., Siqueira, L. G., Fonseca, J. F., and Camargo, L. S. (2010). Ovarian follicular dynamics, follicle deviation, and oocyte yield in Gyr breed (Bos indicus) cows undergoing repeated ovum pick-up. Theriogenology 73, 966–972.
Ovarian follicular dynamics, follicle deviation, and oocyte yield in Gyr breed (Bos indicus) cows undergoing repeated ovum pick-up.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3c3gsVShtg%3D%3D&md5=19c6628aa4758f4bb278f559df25c483CAS | 20071017PubMed |