Animal Reproduction (AR)
https://www.animal-reproduction.org/article/doi/10.1590/1984-3143-AR2023-0123
Animal Reproduction (AR)
ORIGINAL ARTICLE

Does GnRH treatment at TAI regardless of estrus occurrence increase pregnancy rate in crossbred Bos taurus suckled cows?

Vanessa Silva Fernandes; Gabriella dos Santos Velho; Mateus Felipe Osório dos Santos; Kelly Alves Evangelista; Bernardo Garziera Gasperin; Luiz Francisco Machado Pfeifer; Rogério Ferreira; Paulo Bayard Dias Gonçalves; Gustavo Desire Antunes Gastal; André Gustavo Cabrera Dalto; Monique Tomazele Rovani

Downloads: 2
Views: 375

Abstract

Abstract: The impact of GnRH treatment on the day of TAI in beef cows has received limited investigation, especially concerning its association with estrus expression. Consequently, two experiments were conducted to assess the potential of GnRH treatment on the day of TAI to enhance fertility according to the expression or not of estrus in beef cows. Experiment 1 aimed to determine ovulation rate and luteal function, while Experiment 2 aimed to determine the effect of the two GnRH treatment approaches on pregnancy rate. In Experiment 1, multiparous Brangus suckling cows (n = 17) were submitted to an 8-day TAI protocol. Estrus occurrence was evaluated based on chalk removal on D10 (TAI) and cows were assigned to receive GnRH (25µg lecirelin; im) according to the group: GnRH (n = 7), regardless of estrus expression; or selectGnRH (n = 10), only cows not detected in estrus. Ovulation rate occurring until 77h after IVD removal did not differ (p = 0.17) between GnRH (85.7%; 6/7) and selectGnRH (100%; 10/10). Also, corpus luteum size and serum progesterone concentration were not affected (p>0.05) by treatments. In Experiment 2, crossbred taurine suckled cows (n = 384) were submitted to the same protocol as described in Experiment 1 and were randomly allocated to GnRH or selectGnRH groups. There was no difference in P/AI between groups (selectGnRH = 55.6%; GnRH = 54.3%; p = 0.7) 30 days after TAI. As expected, there was a pronounced effect (p<0.0001) of estrus expression on P/AI (Estrus = 61.5%; No estrus = 33.0%), regardless of group. In summary, ovulation timing and rate and luteal function did not differ between groups. Also, GnRH administration only in cows that do not show estrus is recommended, considering hormone savings and similar conception rate.

Keywords

GnRH, estrus, ovulation, conception rate, timed artificial insemination

References

Alves RL, Silva MA, Consentini CEC, Silva LO, Folchini NP, Oliva AL, Prata AB, Gonçalves JRS, Wiltbank MC, Sartori R. Hormonal combinations aiming to improve reproductive outcomes of Bos indicus cows submitted to estradiol/progesterone-based timed AI protocols. Theriogenology. 2021;169:89-99. http://dx.doi.org/10.1016/j.theriogenology.2021.04.007. PMid:33945944.

Barbosa IP, Cestaro JP, Silva SA, Noleto GS, Goncalves RL, Silva GM, Paes FH, Gasperin BG, Rovani MT, Pfeifer LFM. GnRH34: an alternative for increasing pregnancy in timed AI beef cows. Theriogenology. 2022;179:1-6. http://dx.doi.org/10.1016/j.theriogenology.2021.11.014. PMid:34823056.

Bó GA, Baruselli PS, Mapletoft RJ. Synchronization techniques to increase the utilization of artificial insemination in beef and dairy cattle. Animal Reproduction. 2013;10:137-42.

Cedeño AV, Cuervo R, Tribulo A, Tribulo R, Andrada S, Mapletoft R, Menchaca A, Bo GA. Effect of expression of estrus and treatment with GnRH on pregnancies per AI in beef cattle synchronized with an estradiol/progesterone-based protocol. Theriogenology. 2021;161:294-300. http://dx.doi.org/10.1016/j.theriogenology.2020.12.014. PMid:33370598.

Colazo MG, Kastelic JP, Mapletoft RJ. Effects of estradiol cypionate (ECP) on ovarian follicular dynamics, synchrony of ovulation, and fertility in CIDR-based, fixed-time AI programs in beef heifers. Theriogenology. 2003;60(5):855-65. http://dx.doi.org/10.1016/S0093-691X(03)00091-8. PMid:12935863.

Consentini CEC, Alves R, Silva MA, Galindez JPA, Madureira G, Lima LG, Goncalves JRS, Wiltbank MC, Sartori R. What are the factors associated with pregnancy loss after timed-artificial insemination in Bos indicus cattle? Theriogenology. 2023;196:264-9. http://dx.doi.org/10.1016/j.theriogenology.2022.10.037. PMid:36436362.

Madureira G, Consentini CEC, Motta JCL, Drum JN, Prata AB, Monteiro PLJ Jr, Melo LF, Goncalves JRS, Wiltbank MC, Sartori R. Progesterone-based timed AI protocols for Bos indicus cattle II: reproductive outcomes of either EB or GnRH-type protocol, using or not GnRH at AI. Theriogenology. 2020;145:86-93. http://dx.doi.org/10.1016/j.theriogenology.2020.01.033. PMid:32007636.

Nogueira E, Silva MR, Silva JCB, Abreu UPG, Anache NA, Silva KC, Cardoso CJT, Sutovsky P, Rodrigues WB. Timed artificial insemination plus heat I: effect of estrus expression scores on pregnancy of cows subjected to progesterone-estradiol-based protocols. Animal. 2019;13(10):2305-12. http://dx.doi.org/10.1017/S1751731119000442. PMid:30982488.

Pancarci SM, Jordan ER, Risco CA, Schouten MJ, Lopes FL, Moreira F, Thatcher WW. Use of estradiol cypionate in a presynchronized timed artificial insemination program for lactating dairy cattle. J Dairy Sci. 2002;85(1):122-31. http://dx.doi.org/10.3168/jds.S0022-0302(02)74060-5. PMid:11860104.

Perry GA, Smith MF, Lucy MC, Green JA, Parks TE, MacNeil MD, Roberts AJ, Geary TW. Relationship between follicle size at insemination and pregnancy success. Proc Natl Acad Sci USA. 2005;102(14):5268-73. http://dx.doi.org/10.1073/pnas.0501700102. PMid:15795381.

Perry GA, Smith MF, Roberts AJ, MacNeil MD, Geary TW. Relationship between size of the ovulatory follicle and pregnancy success in beef heifers. J Anim Sci. 2007;85(3):684-9. http://dx.doi.org/10.2527/jas.2006-519. PMid:17060416.

Pfeifer LFM, Moreira EM, Silva GM, Souza VL, Nunes VRR, Andrade JS, Neves PMA, Ferreira R. Effect of estradiol cypionate on estrus expression and pregnancy in timed artificially inseminated beef cows. Livest Sci. 2020;231:103886. http://dx.doi.org/10.1016/j.livsci.2019.103886.

Prata AB, Madureira G, Robl AJ, Ribeiro HS, Sagae M, Elias MCV, Pimenta C, Barrios J, Hartmman D, Schneider AA, Sandoval GAF, Wiltbank MC, Sartori R. Progesterone-based timed AI protocols for Bos indicus cattle III: comparison of protocol lengths. Theriogenology. 2020;152:29-35. http://dx.doi.org/10.1016/j.theriogenology.2020.04.020. PMid:32361304.

Pugliesi G, Santos FB, Lopes E, Nogueira E, Maio JR, Binelli M. Improved fertility in suckled beef cows ovulating large follicles or supplemented with long-acting progesterone after timed-AI. Theriogenology. 2016;85(7):1239-48. http://dx.doi.org/10.1016/j.theriogenology.2015.12.006. PMid:26764150.

Pursley JR, Mee MO, Wiltbank MC. Synchronization of ovulation in dairy cows using PGF2alpha and GnRH. Theriogenology. 1995;44(7):915-23. http://dx.doi.org/10.1016/0093-691X(95)00279-H. PMid:16727787.

Richardson BN, Hill SL, Stevenson JS, Djira GD, Perry GA. Expression of estrus before fixed-time AI affects conception rates and factors that impact expression of estrus and the repeatability of expression of estrus in sequential breeding seasons. Anim Reprod Sci. 2016;166:133-40. http://dx.doi.org/10.1016/j.anireprosci.2016.01.013. PMid:26805603.

Sá Fo MF, Crespilho AM, Santos JE, Perry GA, Baruselli PS. Ovarian follicle diameter at timed insemination and estrous response influence likelihood of ovulation and pregnancy after estrous synchronization with progesterone or progestin-based protocols in suckled Bos indicus cows. Anim Reprod Sci. 2010;120(1-4):23-30. http://dx.doi.org/10.1016/j.anireprosci.2010.03.007. PMid:20395079.

Sales JN, Carvalho JB, Crepaldi GA, Cipriano RS, Jacomini JO, Maio JR, Souza JC, Nogueira GP, Baruselli PS. Effects of two estradiol esters (benzoate and cypionate) on the induction of synchronized ovulations in Bos indicus cows submitted to a timed artificial insemination protocol. Theriogenology. 2012;78(3):510-6. http://dx.doi.org/10.1016/j.theriogenology.2012.02.031. PMid:22503845.

Souza AH, Viechnieski S, Lima FA, Silva FF, Araujo R, Bo GA, Wiltbank MC, Baruselli PS. Effects of equine chorionic gonadotropin and type of ovulatory stimulus in a timed-AI protocol on reproductive responses in dairy cows. Theriogenology. 2009;72(1):10-21. http://dx.doi.org/10.1016/j.theriogenology.2008.12.025. PMid:19269685.
 


Submitted date:
08/30/2023

Accepted date:
12/11/2023

65ef6692a9539558f72f59b4 animreprod Articles
Links & Downloads

Anim Reprod

Share this page
Page Sections