HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hiers, E. A. Articles by Yelich, J. V. Search for Related Content PubMed PubMed Citation Articles by Hiers, E. A. Articles by Yelich, J. V.

Synchronization of Bos indicus x Bos taurus cows for timed artificial insemination using gonadotropin-releasing hormone plus prostaglandin F₂ in combination with melengestrol acetate^1,2

E. A. Hiers^*, C. R. Barthle^*, MK. V. Dahms^*, G. E. Portillo^*, G. A. Bridges^*, D. O. Rae, W. W. Thatcher^* and J. V. Yelich^*,3

^* Department of Animal Sciences and and College of Veterinary Medicine, University of Florida, Gainesville, 32611

³ Correspondence:
phone 352-392-7560; fax 352-392-7652; E-mail:
yelich{at}animal.ufl.edu.

Nonlactating Bos indicus x Bos taurus cows were used in three herds to determine the efficacy of different PGF₂ treatments in combination with GnRH and melengestrol acetate (MGA) for a timed artificial insemination protocol. The start of the experiment was designated as d 0, at which time cows were assigned a body condition score and received 100 µg of GnRH. Cows were fed MGA (0.5•mg•cow^-1•d^-1) on d 1 to 7. On d 7, cows received either a single injection of PGF₂ (Lutalyse sterile solution; 25 mg; n = 297), a single injection of cloprostenol sodium (Estrumate; 500 µg; n = 297), or half the recommended dose of PGF₂ (12.5 mg; n = 275) on d 7 and 8. On d 10, all cows were artificially inseminated and received 100 µg of GnRH. Pregnancy rates to the timed artificial insemination (39%) were not affected by treatment, herd, or treatment x herd. There was an effect (P < 0.01) of artificial insemination sire on timed artificial insemination pregnancy rate for one herd, but not the other two herds. Herd influenced (P < 0.05) 30-d pregnancy rates, but there were no treatment or treatment x herd effects as 72.3% of the cows became pregnant during the first 30 d of the breeding season. Results indicate that the type of PGF₂ treatment administered 7 d after GnRH did not influence timed artificial insemination pregnancy rates in nonlactating Bos indicus x Bos taurus cows.

Key Words: Artificial Insemination • Bos indicus • Gonadotropin-Releasing Hormone • Synchronization

This article has been cited by other articles:

				O. G. S. Filho, E. R. Vilela, T. W. Geary, and J. L. M. Vasconcelos Strategies to improve fertility in postpartum multiparous Bos indicus cows submitted to a fixed-time insemination protocol with gonadotropin-releasing hormone and prostaglandin F2{alpha} J Anim Sci, September 1, 2009; 87(9): 2806 - 2814. [Abstract] [Full Text] [PDF]

				J. P. Saldarriaga, D. A. Cooper, J. A. Cartmill, J. F. Zuluaga, R. L. Stanko, and G. L. Williams Ovarian, hormonal, and reproductive events associated with synchronization of ovulation and timed appointment breeding of Bos indicus-influenced cattle using intravaginal progesterone, gonadotropin-releasing hormone, and prostaglandin F2{alpha} J Anim Sci, January 1, 2007; 85(1): 151 - 162. [Abstract] [Full Text] [PDF]

				R. Flores, M. L. Looper, D. L. Kreider, N. M. Post, and C. F. Rosenkrans Jr. Estrous behavior and initiation of estrous cycles in postpartum Brahman-influenced cows after treatment with progesterone and prostaglandin F2{alpha} J Anim Sci, July 1, 2006; 84(7): 1916 - 1925. [Abstract] [Full Text] [PDF]

				J. M. DeJarnette, C. E. Marshall, R. W. Lenz, D. R. Monke, W. H. Ayars, and C. G. Sattler Sustaining the Fertility of Artificially Inseminated Dairy Cattle: The Role of the Artificial Insemination Industry J Dairy Sci, July 1, 2004; 87(13_suppl): E93 - 104. [Abstract] [Full Text] [PDF]