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Ovarian follicular dynamics and endocrine profiles in Polwarth ewes with high and low body condition

Published online by Cambridge University Press:  18 August 2016

C. Viñoles ,
L. J. Harris ,
M. Forsberg ,
G. Banchero  and
E. Rubianes
C. Viñoles
Affiliation:
Sheep Unit, National Research Institute for Agriculture (INIA), La Estanzuela, Colonia, Uruguay Centre for Reproductive Biology, Department of Clinical Chemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden UK Department of Physiology, Faculty of Veterinary Medicine, Montevideo, Uruguay
L. J. Harris
Affiliation:
Sheep Unit, National Research Institute for Agriculture (INIA), La Estanzuela, Colonia, Uruguay
M. Forsberg
Affiliation:
Centre for Reproductive Biology, Department of Clinical Chemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden UK
G. Banchero
Affiliation:
Sheep Unit, National Research Institute for Agriculture (INIA), La Estanzuela, Colonia, Uruguay
E. Rubianes*
Affiliation:
Department of Physiology, Faculty of Veterinary Medicine, Montevideo, Uruguay
*
† Corresponding author present address: Department of Animal Production, Faculty of Agricultural Sciences, Montevideo, Uruguay. E-mail: [email protected]
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Abstract

In this investigation we tested the hypothesis that static body condition (BC) of the ewe affects oestradiol and FSH with implications for subsequent follicular growth and turn-over. Sixteen Polwarth ewes were selected from a flock according to their BC score (scale: 1 emaciated; 5 obese). High BC (HBC) ewes (no. = 8) had a BC score of 4·1 (s.e. 0·1) and low BC (LBC) ewes (no. = 8) had a BC score of 1·9 (s.e. 0·1). Daily ultrasound examinations were performed and blood samples for progesterone, oestradiol and follicle-stimulating hormone (FSH) determination were collected. All HBC ewes (8/8) exhibited three waves of follicular development, while four LBC ewes (4/8) had two waves and the other four (4/8) had three waves of follicular development (P ≤ 0·05) during the interovulatory period. Overall, the emergences of 33 out of 44 follicular waves were preceded by significant increases in FSH concentrations. Maximum FSH concentrations were detected 0·9 ± 0·2 days before wave emergence. Oestradiol concentrations increased significantly during the growing phase in 38 out of 44 large follicles. A negative correlation between oestradiol and FSH was observed in HBC ewes. A similar inhibitory effect of oestradiol on FSH was observed in LBC ewes, irrespective of whether they developed two or three follicular waves. However, a longer period with high FSH was needed to promote the emergence of the second follicular wave in two-wave LBC ewes. Four HBC ewes had twin ovulations but no LBC ewes did (P ≤ 0·05). In HBC ewes, the follicular phase was characterized by lower oestradiol (6·5 (s.e. 1·0) pmol/l) but higher mean FSH concentrations (2·4 (s.e.0·4) μg/l) than in LBC ewes (8·9 (s.e. 1·2) pmol/l and 2·0 (s.e. 0·3) μg/l, respectively; P ≤ 0·05). The present results suggest that BC influences the pattern of follicular dynamics through changes in the endocrine milieu. Higher FSH concentrations during the follicular phase in HBC ewes, which allowed an extended period of follicular recruitment from a significantly larger pool of small antral follicles could explain the higher ovulation rate observed in this group.

Keywords

conformationewesfolliclesFSHoestradiol
Type
Reproduction
Information
Animal Science , Volume 74 , Issue 3 , June 2002 , pp. 539 - 545
Copyright
Copyright © British Society of Animal Science 2002

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References

Ahmad, N., Townsend, E. C., Dailey, R. A. and Inskeep, E. K. 1997. Relationships of hormonal patterns and fertility to occurrence of two or three waves of ovarian follicles, before and after breeding, in beef cows and heifers. Animal Reproduction Science 49: 13–28.CrossRefGoogle ScholarPubMed
Baird, D. T., Campbell, B. K., Mann, G. E. and McNeilly, A. S. 1991. Inhibin and oestradiol in the control of FSH secretion in sheep. Journal of Reproduction and Fertility, Supplement 43: 125–138.Google Scholar
Bartlewski, P. M., Beard, A. P., Cook, S. J., Chandolia, R. K., Honaramooz, A. and Rawlings, N. C. 1999. Ovarian antral follicular dynamics and their relationships with endocrine variables throughout the oestrous cycle in breeds of sheep differing in prolificacy. Journal of Reproduction and Fertility 115: 111–124.CrossRefGoogle ScholarPubMed
Boukhliq, R., Adams, N. R. and Martin, G. B. 1996. Effect of nutrition on the balance of production of ovarian and pituitary hormones in ewes. Animal Reproduction Science 45: 59–70.CrossRefGoogle ScholarPubMed
Campbell, B. K., Dobson, H., Baird, D. T. and Scaramuzzi, R. J. 1999. Examination of the relative role of FSH and LH in the mechanism of ovulatory follicle selection in sheep. Journal of Reproduction and Fertility 117: 355–367.CrossRefGoogle ScholarPubMed
De Castro, T., Rubianes, E., Menchaca, A. and Rivero, A. 1999. Ovarian dynamics, serum estradiol and progesterone concentrations during the interovulatory interval in goats. Theriogenology 52: 399–411.CrossRefGoogle ScholarPubMed
Downing, J. A. and Scaramuzzi, R. J. 1991. Nutrient effects on ovulation rate, ovarian function and the secretion of gonadotropin and metabolic hormones in sheep. Journal of Reproduction and Fertility, Supplement 43: 209–227.Google ScholarPubMed
Evans, A. C. O., Duffy, P., Hynes, N. and Boland, M. P. 2000. Waves of follicle development during the estrous cycle in sheep. Theriogenology 53: 699–715.CrossRefGoogle ScholarPubMed
Evans, A. C. O., Komar, C. M., Wandji, S. A. and Fortune, J. E. 1997. Changes in androgen secretion and luteinizing hormone pulse amplitude are associated with the recruitment and growth of ovarian follicles during the luteal phase of the bovine oestrous cycle. Biology of Reproduction 57: 394–401.CrossRefGoogle Scholar
Fry, R. C. and Driancourt, M. A. 1996. Relationships between follicle-stimulating hormone, follicle growth and ovulation rate in sheep. Reproduction, Fertility and Development 8: 279–286.CrossRefGoogle ScholarPubMed
Gibbons, J. R., Kot, K., Thomas, D. L., Wiltbank, M. C. and Ginther, O. J. 1999. Follicular and FSH dynamics in ewes with a history of high and low ovulation rates. Theriogenology 52: 1005–1020.CrossRefGoogle ScholarPubMed
Ginther, O. J., Kot, K. and Wiltbank, M. C. 1995. Associations between emergence of follicular waves and fluctuations in FSH concentrations during the estrous cycle in ewes. Theriogenology 43: 689–703.CrossRefGoogle ScholarPubMed
Leyva, V., Buckrell, B. C. and Walton, J. S. 1998. Regulation of follicular activity and ovulation in ewes by exogenous progestagen. Theriogenology 50: 395–416.Google ScholarPubMed
Lopez Sebastian, A., Gonzalez de Bulnes, A., Santiago Moreno, J., Gomez, Brunet A., Townsend, E. C. and Inskeep, E. K. 1997. Patterns of follicular development during the estrous cycle in monoovular Merino del Pais ewes. Animal Reproduction Science 48: 279–291.CrossRefGoogle Scholar
McNatty, K. P., McNeilly, A. S. and Tsonis, C. G. 1993. A model for follicle selection and the determination of ovulation rate in the ewe. Reproduction, Fertility and Development 5: 459–478.Google Scholar
Meikle, A., Tasende, C, Rodriguez, M. and Garófalo, E.G. 1997. Effects of oestradiol and progesterone on the reproductive tract and uterine sex steroid receptors in females lambs. Theriogenology 48: 1105–1113.CrossRefGoogle ScholarPubMed
Ravindra, J. P., Rawlings, N. C., Evans, A. C. O. and Adams, G. P. 1994. Ultrasonographic study of ovarian follicular dynamics in ewes during the oestrous cycle. Journal of Reproduction and Fertility 101: 501–509.CrossRefGoogle ScholarPubMed
Rhind, S. M. and McNeilly, A. S. 1986. Follicle populations, ovulation rates and plasma profiles of LH, FSH and prolactin in Scottish Blackface ewes in high and low levels of body condition. Animal Reproduction Science 10: 105–115.CrossRefGoogle Scholar
Rhind, S. M. and McNeilly, A. S. 1998. Effects of level of food intake on ovarian follicle number, size and steroidogenic capacity in the ewe. Animal Reproduction Science 52: 131–138.CrossRefGoogle ScholarPubMed
Rhind, S. M., McMillen, S., McKelvey, W. A. C, Rodriguez Herrejon, F. F. and McNeilly, A. S. 1989. Effect of the body condition of ewes on the secretion of LH and FSH and the pituitary response to gonadotropin-releasing hormone. Journal of Endocrinology 120: 497–502.CrossRefGoogle Scholar
Rhind, S. M., McMillen, S. and McKelvey, W. A. C. 1991. Effects of levels of food intake and body condition on the sensitivity of the hypothalamus and pituitary to ovarian steroid feedback in ovariectomized ewes. Animal Production 52: 115–125.Google Scholar
Rubianes, E., Beard, A., Dierschke, D., Bartlewski, P., Adams, G. P. and Rawlings, N. C. 1997. Endocrine and ultrasound evaluation of the response to PGF2a and GnRH given at different stages of the luteal phase in cycling ewes. Theriogenology 48: 1093–1104.CrossRefGoogle Scholar
Scaramuzzi, R. J., Adams, N. R., Baird, D. T., Campbell, B. K., Downing, J. A., Findlay, J. K., Henderson, K. M., Martin, G. B., McNatty, K. P, McNeilly, A. S. and Tsonis, C. G. 1993. A model for follicle selection and the determination of ovulation rate in the ewe. Reproduction, Fertility and Development 5: 459–478.CrossRefGoogle Scholar
Schrick, F. N., Surface, R. A., Pritchard, J. Y., Dailey, R. A., Townsend, E. C. and Inskeep, E.K 1993. Ovarian structures during the estrous cycle and early pregnancy in ewes. Biology of Reproduction 49: 1133–1140.CrossRefGoogle ScholarPubMed
Statistical Analysis Systems Institute. 1989. SAS user’s guide: statistics. SAS Institute Inc., Cary NC.Google Scholar
Suiter, J. 1994. Body condition scoring of sheep and goats. Agriculture Western Australia Farmnote 69: 94.Google Scholar
Viñoles, C., Forsberg, M., Banchero, G. and Rubianes, E. 2001. Effect of long-term and short-term progestagen treatment on follicular development and pregnancy rate in cyclic ewes. Theriogenology 55: 993–1004.CrossRefGoogle ScholarPubMed
Viñoles, C., Meikle, A., Forsberg, M. and Rubianes, E. 1999. The effect of sub-luteal levels of exogenous progesterone on follicular dynamics and endocrine patterns during the early luteal phase of the ewe. Theriogenology 51: 1351–1361.CrossRefGoogle Scholar
Zarco, L., Stabenfeldt, G. H., Kindahl, H., Quirke, J. F. and Granström, E. 1984. Persistence of luteal activity in the non-pregnant ewe. Animal Reproduction Science 7: 245–267.CrossRefGoogle Scholar