Evaluation of Reproductive Performance in Lactating Dairy Cows with Prostaglandin F₂, Gonadotropin-Releasing Hormone, and Timed Artificial Insemination

¹ Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061
² Department of Large Animal Clinical Sciences, Virginia Polytechnic Institute and State University, Blacksburg 24061

Nine hundred and twenty Holstein cows from 16 commercial dairy herds to evaluate three systematic breeding protocols: 14-d PGF₂, timed artificial insemination (AI), and GnRH-PGF₂, relative to AI following estrus detection without hormone intervention. The timed AI protocol involved GnRH, followed by PGF₂ 7 d later and GnRH again 2 d after PGF₂, with AI 6 to 18 h after the second GnRH. The GnRH-PGF2 protocol consisted of GnRH followed by PGF₂ 7 d later. Eight herds relied on visual observation to detect estrus, and eight herds utilized the HeatWatch estrus detection system. The average interval to first postpartum AI was shortest for the timed AI protocol (77.1 d) followed by the 14-d PGF₂ protocol (81.6 d). There was no difference in days to first AI between the control (86.1 d) and GnRH-PGF₂ (89.5 d) protocols. Percent pregnant per first AI did not differ among control (45.6%), 14-d PGF₂ (43.7%), or GnRH-PGF₂ (44.0%) protocols, but all protocols had a higher percent pregnant per first AI than the timed AI protocol (30.1%). Response to the GnRH-PGF₂ protocol was limited because 44.0% of the cows submitted to the protocol were not detected in estrus 10 d post-PGF₂ administration and had an interval to first AI of 103.8 d. Cumulative percent pregnant by 120 d postpartum did not differ between control cows (53.1%) and hormonally treated cows (50.6%). Visual observation herds had a shorter interval to first postpartum AI (82.8 d) than the HeatWatch herds (84.8 d), with a higher overall rate of estrus detection across all protocols (75.3 and 67.6%, respectively).

Key Words: estrus synchronization • systematic breeding • prostaglandin F₂ • gonadotropin-releasing hormone

Submitted on September 21, 1999
Accepted on March 30, 2000

This article has been cited by other articles:

				D. J. Brusveen, A. H. Souza, and M. C. Wiltbank Effects of additional prostaglandin F2{alpha} and estradiol-17{beta} during Ovsynch in lactating dairy cows J Dairy Sci, April 1, 2009; 92(4): 1412 - 1422. [Abstract] [Full Text] [PDF]

				D. J. Brusveen, A. P. Cunha, C. D. Silva, P. M. Cunha, R. A. Sterry, E. P. B. Silva, J. N. Guenther, and M. C. Wiltbank Altering the Time of the Second Gonadotropin-Releasing Hormone Injection and Artificial Insemination (AI) During Ovsynch Affects Pregnancies per AI in Lactating Dairy Cows J Dairy Sci, March 1, 2008; 91(3): 1044 - 1052. [Abstract] [Full Text] [PDF]

				A. H. Souza, A. Gumen, E. P. B. Silva, A. P. Cunha, J. N. Guenther, C. M. Peto, D. Z. Caraviello, and M. C. Wiltbank Supplementation with Estradiol-17{beta} Before the Last Gonadotropin-Releasing Hormone Injection of the Ovsynch Protocol in Lactating Dairy Cows J Dairy Sci, October 1, 2007; 90(10): 4623 - 4634. [Abstract] [Full Text] [PDF]

				A. R. Rabiee, I. J. Lean, and M. A. Stevenson Efficacy of Ovsynch Program on Reproductive Performance in Dairy Cattle: A Meta-Analysis J Dairy Sci, August 1, 2005; 88(8): 2754 - 2770. [Abstract] [Full Text] [PDF]

				R. C. Goodling Jr., G. E. Shook, K. A. Weigel, and N. R. Zwald The Effect of Synchronization on Genetic Parameters of Reproductive Traits in Dairy Cattle J Dairy Sci, June 1, 2005; 88(6): 2217 - 2225. [Abstract] [Full Text] [PDF]

				M. A. Portaluppi and J. S. Stevenson Pregnancy Rates in Lactating Dairy Cows After Presynchronization of Estrous Cycles and Variations of the Ovsynch Protocol J Dairy Sci, March 1, 2005; 88(3): 914 - 921. [Abstract] [Full Text] [PDF]

				B.-A. Tenhagen, M. Drillich, R. Surholt, and W. Heuwieser Comparison of Timed AI After Synchronized Ovulation to AI at Estrus: Reproductive and Economic Considerations J Dairy Sci, January 1, 2004; 87(1): 85 - 94. [Abstract] [Full Text] [PDF]

				P. M. Fricke, D. Z. Caraviello, K. A. Weigel, and M. L. Welle Fertility of Dairy Cows after Resynchronization of Ovulation at Three Intervals Following First Timed Insemination J Dairy Sci, December 1, 2003; 86(12): 3941 - 3950. [Abstract] [Full Text] [PDF]

				M. C. Cordoba and P. M. Fricke Initiation of the Breeding Season in a Grazing-Based Dairy by Synchronization of Ovulation J Dairy Sci, July 1, 2002; 85(7): 1752 - 1763. [Abstract] [Full Text] [PDF]