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 Block, J. Articles by Hansen, P. J. Search for Related Content PubMed PubMed Citation Articles by Block, J. Articles by Hansen, P. J.

Use of insulin-like growth factor-I during embryo culture and treatment of recipients with gonadotropin-releasing hormone to increase pregnancy rates following the transfer of in vitro-produced embryos to heat-stressed, lactating cows¹

J. Block^*, M. Drost, R. L. Monson, J. J. Rutledge, R. M. Rivera^*, F. F. Paula-Lopes^*, O. M. Ocon^*,2, C. E. Krininger, III^*, J. Liu and P. J. Hansen^*,3

^* Departments of Animal Sciences and and Large Animal Clinical Sciences, University of Florida, Gainesville 32611; and Department of Animal Sciences, University of Wisconsin, Madison 53706;and and Vicam, Watertown, MA 02472

³ Correspondence:
P.O. Box 110910 (phone: 352-362-5590; fax: 352-392-5595; E-mail:
hansen{at}animal.ufl.edu).

An experiment was conducted to determine whether pregnancy rates following the transfer of in vitro-produced embryos to heat-stressed cows could be improved by 1) culturing embryos in the presence of IGF-I and 2) treating recipients with GnRH. Lactating Holstein cows (n = 260) were synchronized using a timed ovulation protocol. Embryos were produced in vitro and cultured with or without 100 ng/mL of IGF-I. On d 7 after anticipated ovulation (d 0), a single embryo was transferred to all recipients with a palpable corpus luteum (n = 210). A subset of recipients (n = 164) was injected with either GnRH or placebo on d 11. Plasma progesterone concentrations on d 0 and 7 were used to determine the synchrony of recipients. Pregnancy was diagnosed at d 53 and 81 by rectal palpation. Among all recipients, transfer of IGF-I-treated embryos increased pregnancy rate at d 53 (P < 0.05) and tended to increase pregnancy rate at d 81 (P < 0.06). Calving rate also tended to be higher for recipients that received IGF-I-treated embryos (P < 0.07). Among the subset of synchronized recipients (n = 190), pregnancy rate at d 53 and d 81 and calving rate were higher (P < 0.05) for IGF-I-treated embryos. The GnRH tended to increase pregnancy rate at d 53 for all recipients (P < 0.08) and the subset of synchronized recipients (P < 0.10). There were no effects of GnRH (P > 0.10) for pregnancy rate at d 81 and calving rate. The overall proportion of male calves was 64.3%. There was no effect (P > 0.10) of embryo treatment or GnRH on the birth weight or sex ratio of calves. Results of this experiment indicate that treatment of embryos with IGF-I can improve pregnancy and calving rates following transfer of in vitro-produced embryos. Further research is necessary to determine whether the treatment of recipients with GnRH is a practical approach to increase pregnancy rates following in vitro embryo transfer.

Key Words: Cattle • Embryo Transfer • Gonadotropin-Releasing Hormone • Heat Stress • Insulin-Like Growth Factor

This article has been cited by other articles:

				F. D. Jousan, L. A. de Castro e Paula, J. Block, and P. J. Hansen Fertility of Lactating Dairy Cows Administered Recombinant Bovine Somatotropin During Heat Stress J Dairy Sci, January 1, 2007; 90(1): 341 - 351. [Abstract] [Full Text] [PDF]

				F.D. Jousan and P.J. Hansen Insulin-like Growth Factor-I as a Survival Factor for the Bovine Preimplantation Embryo Exposed to Heat Shock Biol Reprod, November 1, 2004; 71(5): 1665 - 1670. [Abstract] [Full Text] [PDF]