144 EFFECT OF ANTRAL FOLLICLE COUNT IN BEEF HEIFERS ON IN VITRO FERTILIZATION/PRODUCTION

Authors

C. C. Chase Jr., USDA-ARSFollow
R. A. Freeland, USDA-ARSFollow
A. K. McNeel, USDA-ARS
E. C. Wright-Johnson, USDA-ARS
G. A. Perry, South Dakota State UniversityFollow
S. C. Tenley, University of Nebraska-LincolnFollow
J. R. Wood, University of Nebraska-LincolnFollow
A. S. Cupp, University of Nebraska-LincolnFollow
J. L. Vallet, USDA-ARSFollow
J. R. Miles, USDA-ARSFollow

Date of this Version

2017

Citation

Reproduction, Fertility and Development 29(1), 2017, pp. 180-180, http://dx.doi.org/10.1071/RDv29n1Ab144.

Comments

Copyright 2017 at Authors. Used by permission.

Abstract

Our objective has been to compare the IVF and in vitro production (IVP) of embryos from low and high antral follicle count (AFC) heifers. This is the fourth year of the study with years 1 to 3 reported individually. For this report, we add data for the fourth year and present a combined analysis (years 1 to 4) for the first time. Each year, AFC was determined on ~120 Angus heifers using transrectal ultrasonography. Ten heifers with the lowest AFC and 10 heifers with the highest AFC and all with evidence of oestrous cyclicity were synchronized with two 5-mL injections of PGF2α 11 days apart. Half were harvested on Day 5 to 6 and half on Day 15 to 16 of the oestrous cycle. The IVF procedure was slightly modified each year. For year 4, the IVF procedure included protocols for semi-defined media and was as described (IVP Protocol, P. J. Hansen’s Laboratory, University of Florida). Cumulus-oocyte complexes (COC) from follicles less than 8 mm in diameter were cultured in maturation medium (5% CO2; 38.5°C) for 24 h.