Journal of Animal Science, Vol 75, Issue 7 1876-1884, Copyright © 1997 by American Society of Animal Science

JOURNAL ARTICLE

The recruitment of ovarian follicles is enhanced by increased dietary intake in heifers

C. G. Gutierrez, J. Oldham, T. A. Bramley, J. G. Gong, B. K. Campbell and R. Webb
Roslin Institute (Edinburgh), Midlothian, UK.

The objective of this study was to determine whether dietary-induced changes in growth hormone (GH), insulin, and IGF-I alter the pattern of ovarian follicular development in heifers. Twenty-eight 2- to 3-yr-old Hereford-Friesian heifers were equally allocated (n = 7) to one of four dietary treatments: 1) Control (C) fed a maintenance diet as two meals per day; 2) twice maintenance (2M2) given as two meals per day; 3) twice maintenance (2M6) given as six meals per day; 4) feed-deprived (F) fed maintenance requirements as for C, changed to straw ad libitum for 3 d from a synchronized estrus. On d 4 (estrus = d 0) heifers were transferred to grass silage (ad libitum access) until the end of the experiment. Blood samples were collected hourly for 10 h on d 1 and 3 and daily for an additional 14 d. Follicular development was monitored daily by ultrasonography until d 14. The number of small follicles (< 4 mm) was increased (P < .05) by 37% on d 1 and 2 in 2M2 and 2M6 heifers, with no carryover effect of nutrition to the second follicular wave. Number of medium-sized (4 to 8 mm) and large (> 8 mm) follicles did not vary (P > .05) among treatments. The FSH concentrations were not different (P > .05) among treatments. Insulin concentrations were higher (P < .05) in 2M2 and 2M6 heifers than in C or F heifers, with no carryover after the diet was changed. Increase in number of small follicles was independent of changes in FSH and IGF-I, negatively associated with GH, but positively associated with circulating insulin. These results indicate that a short-term increase in nutritional plane can affect follicular recruitment in cycling heifers.

This article has been cited by other articles:

				P. C. Garnsworthy, A. Lock, G. E. Mann, K. D. Sinclair, and R. Webb Nutrition, Metabolism, and Fertility in Dairy Cows: 1. Dietary Energy Source and Ovarian Function J Dairy Sci, October 1, 2008; 91(10): 3814 - 3823. [Abstract] [Full Text] [PDF]

				P. C. Garnsworthy, A. Lock, G. E. Mann, K. D. Sinclair, and R. Webb Nutrition, Metabolism, and Fertility in Dairy Cows: 2. Dietary Fatty Acids and Ovarian Function J Dairy Sci, October 1, 2008; 91(10): 3824 - 3833. [Abstract] [Full Text] [PDF]

				C Letelier, F Mallo, T Encinas, J M Ros, and A Gonzalez-Bulnes Glucogenic supply increases ovulation rate by modifying follicle recruitment and subsequent development of preovulatory follicles without effects on ghrelin secretion Reproduction, July 1, 2008; 136(1): 65 - 72. [Abstract] [Full Text] [PDF]

				H. Kadokawa, N. Tameoka, M. Uchiza, Y. Kimura, and M. Yonai Short Communication: A Field Study on the Relationship Between Body Condition and Embryo Production in Superovulated Holstein Yearling Heifers J Dairy Sci, March 1, 2008; 91(3): 1087 - 1091. [Abstract] [Full Text] [PDF]

				A. A. Fouladi-Nashta, C. G. Gutierrez, J. G. Gong, P. C. Garnsworthy, and R. Webb Impact of Dietary Fatty Acids on Oocyte Quality and Development in Lactating Dairy Cows Biol Reprod, July 1, 2007; 77(1): 9 - 17. [Abstract] [Full Text] [PDF]

				S Freret, B Grimard, A A Ponter, C Joly, C Ponsart, and P Humblot Reduction of body-weight gain enhances in vitro embryo production in overfed superovulated dairy heifers. Reproduction, April 1, 2006; 131(4): 783 - 794. [Abstract] [Full Text] [PDF]

				H. V. Leon, J. Hernandez-Ceron, D. H. Keisler, and C. G. Gutierrez Plasma concentrations of leptin, insulin-like growth factor-I, and insulin in relation to changes in body condition score in heifers J Anim Sci, February 1, 2004; 82(2): 445 - 451. [Abstract] [Full Text] [PDF]

				K. K. Kane, D. E. Hawkins, G. D. Pulsipher, D. J. Denniston, C. R. Krehbiel, M. G. Thomas, M. K. Petersen, D. M. Hallford, M. D. Remmenga, A. J. Roberts, et al. Effect of increasing levels of undegradable intake protein on metabolic and endocrine factors in estrous cycling beef heifers J Anim Sci, January 1, 2004; 82(1): 283 - 291. [Abstract] [Full Text] [PDF]

				R. Webb, P. C. Garnsworthy, J.-G. Gong, and D. G. Armstrong Control of follicular growth: Local interactions and nutritional influences J Anim Sci, January 1, 2004; 82(13_suppl): E63 - 74. [Abstract] [Full Text] [PDF]

				D.G. Armstrong, T.G. McEvoy, G. Baxter, J.J. Robinson, C.O. Hogg, K.J. Woad, R. Webb, and K.D. Sinclair Effect of Dietary Energy and Protein on Bovine Follicular Dynamics and Embryo Production In Vitro: Associations with the Ovarian Insulin-Like Growth Factor System Biol Reprod, June 1, 2001; 64(6): 1624 - 1632. [Abstract] [Full Text]