Theriogenology 42: 1303-I 310,1994 THE PHYSIOLOGICAL STATUS OF THE OVARIAN DONOR AFFECT’S lN VITRO DEVELOPMENT OF ISOLATED BOVINE PREANTRAL FOLLICLES J.R. Figueiredo, l,a S. C. J. Hulshof,4 R. Van den HurkP M.M. Bevers,’ M. Thiry,3,b B. Nusgens2 and J.F. Beckers’ t Department of Animal Endocrinology and Reproduction Faculty of Veterinary Medicine 2 Laboratory of Experimental Dermatology 3 Laboratory of Cell Biology and Tissue University of Li&ge, B4ooO Li&ge, Belgium 4 Department of Functional Morphology and 5 Department of Herd Health and Reproduction Faculty of Veterinary Medicine, University of Utrecht The Netherlands Received for publication: zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIH July 1, 1994 Accepted: September 14, 19% ABSTRACT Described in the present paper is the effect of the physiological status of the ovarian donor on the development of isolated bovine preantral follicles during 5 d of culture. The preantral follicles were isolated mechanically from ovaries of calves, or nonpregnant, pregnant and postpartum cows collected at the slaughterhouse. There were no differences observed among calves, nonpregnant and pregnant cows, neither in the percentages of morphologically normal follicles, nor in the mean diameter increase during culture. However, preantral follicles isolated from postpartum animals had a lower viability during culture, as demonstrated by significantly lower percentages of morphologically normal and growing follicles as well as by a lower mean diameter increase. Our findings show that the ovarian source may affect development of bovine preantral follicles in vitro, especially when preantral follicles from postpartum zyxwvutsrqponmlkjihgfed COWS were used. Key words: physiological states, preantral follicles, ovaries, bovine Acknowledgments This work was supported by an IRSIA grant from the Faculty of Veterinary Medicine, University of Li≥ by FRSM; and by les Actions de Recherche Concert&s de la Communaut6 Fran@se de Belgique. We thank Dr. M.McNamara for helpful contribution to this paper. aJ.R. Figueiredo is a recipient of a grant from CNPq-BIOAGRO (UFV), Brazil. bM. Thiry is a research associate with the National Fund for Scientific Research, Belgium. Copyright Q 1994 Butterworth-Heinemann