Conception rate of lactating dairy cows using ovsynch after presynchronization with prostaglandin F2α (PGF2α) or Gonadotropin Releasing Hormone (GnRH)

Authors

  • J.A. Bartolome Department of Large Animal Clinical Sciences, College of Veterinary, University of Florida, Gainesville, FL 32610; Department of Animal Sciences, University of Florida, Gainesville, FL 32610
  • P. Sheerin Department of Large Animal Clinical Sciences, College of Veterinary, University of Florida, Gainesville, FL 32610
  • S. Luznar Department of Large Animal Clinical Sciences, College of Veterinary, University of Florida, Gainesville, FL 32610
  • P. Melendez Department of Large Animal Clinical Sciences, College of Veterinary, University of Florida, Gainesville, FL 32610
  • D. Kelbert North Florida Holstein (NFH) Inc., Bell, FL 32619
  • C.A. Risco Department of Large Animal Clinical Sciences, College of Veterinary, University of Florida, Gainesville, FL 32610
  • W.W. Thatcher Department of Animal Sciences, University of Florida, Gainesville, FL 32610
  • L.F. Archbald Department of Large Animal Clinical Sciences, College of Veterinary, University of Florida, Gainesville, FL 32610

DOI:

https://doi.org/10.21423/bovine-vol36no1p35-39

Abstract

This study compared the pregnancy rate in cows inseminated after two different pre-synchronization protocols based on clinical features of the genital tract and treatment with either PGF2α or GnRH. A total of 340 reproductively normal lactating dairy cows was divided in two groups. Cows in Group 1 (n=216) had a corpus luteum when palpated per rectum on day 0. These cows were administered 25 mg of PGF2α on day 0, 100
υg ofGnRH on day 14, 25 mg of PGF2α on day 21, 100 υg of GnRH on day 23, and time-inseminated 16-h later. Cows detected in estrus from day Oto day 14 were inseminated 10 to 12-h after signs of estrus.

Cows in Group 2 (n=124) either had a large ovarian follicle and uterine tone, or a corpus hemorragicum when
palpated per rectum on day 0. These cows received 100 υg of GnRH on day 0, 100 υg of GnRH on day 8, 25 mg of PGF2α on day 15, 100 υg of GnRH on day 17, and time-inseminated 16-h later. Cows detected in estrus before the end of the treatment protocol were inseminated 10 to 12-h after signs of estrus and removed from the study. Data collected were pregnancy rate for cows time-inseminated in Group 1, cows inseminated at detected estrus in Group 1, and cows time-inseminated in Group 2. Pregnancy rates were compared using logistic regression adjusted for number of previous services, parity, season and days in milk. There was no difference (p=0.83) in pregnancy rate between cows time-inseminated in Group 1 (35.9%) and Group 2 (32.8%). In Group 1, there was no difference (p=0.21) in pregnancy rate between cows time-inseminated (35.9%) and cows inseminated at detected estrus within 14-d after treatment with PGF2α (43.5%). Results of this study suggest that cows in different stages of the estrous cycle, as determined by rectal palpation of the genital tract, had similar pregnancy rates when they were selectively pre-synchronized with either PGF2α or GnRH.

Cover image of Volume 36, No.1 of the Bovine Practitioner: a herd of cattle in a milking barn, facing the camera, grazing placidly while being milked.

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Published

2002-02-01

How to Cite

Bartolome, J., Sheerin, P., Luznar, S., Melendez, P., Kelbert, D., Risco, C., Thatcher, W., & Archbald, L. (2002). Conception rate of lactating dairy cows using ovsynch after presynchronization with prostaglandin F2α (PGF2α) or Gonadotropin Releasing Hormone (GnRH). The Bovine Practitioner, 36(1), 35–39. https://doi.org/10.21423/bovine-vol36no1p35-39

Issue

Vol. 36, No. 1 (2002 February)

Section

Articles