YMPOSIUM PAPER: The Estrous Cycle in

Estrous synchronization is a valuable tool to enhance reproductive management in beef cattle. Procedures that facilitate synchronization of estrus in cycling cattle and induce ovulatory estrus in peripubertal heifers and postpartum anestrous cows will increase reproductive rates and expedite genetic progress through use of AI. A better understanding of physiology and endocrinology of the estrous cycle will improve reproductive management of beef cattle and facilitate the successful application of estrous synchronization protocols, which, in turn, will increase the use of AI and hasten genetic improvement in beef cattle production systems. Effective reproductive management requires the successful application of available knowledge to current estrous synchronization protocols. To that end, this review covers the basic physiology and endocrinology of the estrous cycle and provides an overview of our current understanding of follicular waves. Topics to be covered include endocrinology associated with the estrous cycle, follicular development, and the corpus luteum. A review of the utilization of estrous synchronization and AI in the U. S. beef industry is also briefly discussed.

[1]  A. Cupp,et al.  Melengestrol acetate at greater doses than typically used for estrous synchrony in bovine females does not mimic endogenous progesterone in regulation of secretion of luteinizing hormone and 17 beta-estradiol. , 1995, Biology of reproduction.

[2]  M. Diskin,et al.  Effect of immunization against synthetic peptide sequences of bovine inhibin alpha-subunit on ovulation rate and twin-calving rate in heifers. , 1993, Journal of reproduction and fertility.

[3]  M. Boland,et al.  Pattern of growth of dominant follicles during the oestrous cycle of heifers. , 1988, Journal of reproduction and fertility.

[4]  A. L. Goodman,et al.  The ovarian triad of the primate menstrual cycle. , 1983, Recent progress in hormone research.

[5]  D. Schams,et al.  The oestrous cycle of the cow: hormonal parameters and time relationships concerning oestrus, ovulation, and electrical resistance of the vaginal mucus. , 1977, Acta endocrinologica.

[6]  S. Ying.  Inhibins, activins, and follistatins: gonadal proteins modulating the secretion of follicle-stimulating hormone. , 1988, Endocrine reviews.

[7]  W. White,et al.  Gonadotropin-Releasing Hormone: One Polypeptide Regulates Secretion of Luteinizing and Follicle-Stimulating Hormones , 1971, Science.

[8]  E. Bleach,et al.  The ability of steroid-free bovine follicular fluid to suppress FSH secretion and delay ovulation persists in heifers actively immunized against inhibin. , 1993, The Journal of endocrinology.

[9]  F. Bazer,et al.  Thermal changes of the bovine uterus following administration of estradiol-17beta. , 1974, Journal of animal science.

[10]  M. Lucy,et al.  Factors that affect ovarian follicular dynamics in cattle. , 1992, Journal of animal science.

[11]  R. Rodgers,et al.  Purification, morphology, and progesterone production and content of three cell types isolated from the corpus luteum of the sheep. , 1982, Australian journal of biological sciences.

[12]  S. Quirk,et al.  The growth and differentiation of ovarian follicles during the bovine estrous cycle , 1988 .

[13]  R. Pierson,et al.  Ovarian follicular populations during early pregnancy in heifers. , 1986, Theriogenology.

[14]  J. E. Fortune,et al.  Ovarian follicular dynamics during the estrous cycle in heifers monitored by real-time ultrasonography. , 1988, Biology of reproduction.

[15]  J. Kinder,et al.  Hormone concentrations in the caudal vena cava during the first ovarian follicular wave of the oestrous cycle in heifers. , 1995, Journal of reproduction and fertility.

[16]  G. S. Greenwald.  Species differences in egg transport in response to exogenous estrogen , 1967, The Anatomical record.

[17]  D. Baird,et al.  Induction of ovulation and normal luteal function by pulsed injections of luteinizing hormone in anestrous ewes. , 1982, Endocrinology.

[18]  D. Baird,et al.  Prostaglandin F 2 identified as a luteolytic hormone in sheep. , 1972, Nature: New biology.

[19]  J. Ireland,et al.  Selection, dominance and atresia of follicles during the oestrous cycle of heifers. , 1994, Journal of reproduction and fertility.

[20]  J. Ireland,et al.  Accuracy of predicting stages of bovine estrous cycle by gross appearance of the corpus luteum. , 1980, Journal of dairy science.

[21]  S. Quirk,et al.  Growth and regression of ovarian follicles during the follicular phase of the oestrous cycle in heifers undergoing spontaneous and PGF-2 alpha-induced luteolysis. , 1986, Journal of reproduction and fertility.

[22]  J. Kesner,et al.  Interaction of estradiol and luteinizing hormone releasing hormone on follicle stimulating hormone release in cattle. , 1982, Journal of animal science.

[23]  R. Shanks,et al.  Evidence for an oscillator other than luteinizing hormone controlling the secretion of progesterone in cattle. , 1983, Biology of reproduction.

[24]  W. B. Currie,et al.  Prostaglandin F and progesterone concentrations in the utero-ovarian venous plasma of the ewe during the oestrous cycle and early pregnancy. , 1973, Journal of reproduction and fertility. Supplement.

[25]  G. Niswender,et al.  Progesterone production, LH receptors, and oxytocin secretion by ovine luteal cell types on days 6, 10 and 15 of the oestrous cycle and day 25 of pregnancy. , 1987, Journal of reproduction and fertility.

[26]  J. Kastelic,et al.  Ovarian follicular dynamics in heifers during early pregnancy. , 1989, Biology of reproduction.

[27]  J. Kastelic,et al.  Composition and characteristics of follicular waves during the bovine estrous cycle , 1989 .

[28]  D. Patterson,et al.  Procedures that support reproductive management of replacement beef heifers , 2000 .

[29]  H. Kaneko,et al.  Inhibin is involved in the suppression of FSH secretion in the growth phase of the dominant follicle during the early luteal phase in cows. , 1997, Domestic animal endocrinology.

[30]  J. Wiltbank,et al.  Duration of estrus, time of ovulation and fertilization rate in beef heifers synchronized with dihydroxyprogesterone acetophenide. , 1967, Journal of animal science.

[31]  M. Wise,et al.  Ontogeny of pulsatile secretion of gonadotropin-releasing hormone in the bull calf during infantile and pubertal development. , 1989, Endocrinology.

[32]  J. Ireland,et al.  Effect of progesterone on basal LH and episodic LH and FSH secretion in heifers. , 1982, Journal of reproduction and fertility.

[33]  M. Fritz,et al.  The endocrinology of the menstrual cycle: the interaction of folliculogenesis and neuroendocrine mechanisms. , 1982, Fertility and sterility.

[34]  P. G. Knight,et al.  Treatment of ovariectomized heifers with bovine follicular fluid specifically suppresses pituitary levels of FSH-beta mRNA. , 1989, Journal of molecular endocrinology.

[35]  J. Kinder,et al.  Effect of 17beta-estradiol on the preovulatory surge of LH in the bovine female. , 1991, Theriogenology.

[36]  M Hamon,et al.  Prostaglandin F-2 alpha is transferred from the uterus to the ovary in the sheep by lymphatic and blood vascular pathways. , 1985, Journal of reproduction and fertility.

[37]  P S Kalra,et al.  Transitory changes in plasma progestins, estradiol, and luteinizing hormone approaching ovulation in the bovine. , 1975, Journal of dairy science.

[38]  I. Clarke,et al.  THE TEMPORAL RELATIONSHIP BETWEEN GONADOTROPIN RELEASING HORMONE (GnRH) AND LUTEINIZING HORMONE (LH) SECRETION IN OVARIECTOMIZED EWES1 , 1982 .

[39]  J. Ireland,et al.  Effect of charcoal-treated bovine follicular fluid on secretion of LH and FSH in ovariectomized heifers. , 1983, Journal of animal science.

[40]  A. Nalbandov,et al.  Ovulation and Its Relation to Estrus in Cows , 1942 .

[41]  D. H. Williams,et al.  Active immunization of heifers against a synthetic fragment of bovine inhibin. , 1993, Journal of reproduction and fertility.

[42]  D. Schams,et al.  Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during the luteal phase of the oestrous cycle in the cow. , 1984, Journal of reproduction and fertility.

[43]  H. Newton,et al.  Pattern of plasma luteinizing hormone in the cyclic cow: dependence upon the period of the cycle. , 1980, Endocrinology.

[44]  Roger A. Pierson,et al.  Follicular populations during the estrous cycle in heifers. I. Influence of day , 1987 .

[45]  D. Wishart.  Observations on the oestrous cycle of the Friesian heifer , 1972, Veterinary Record.

[46]  E. Payne,et al.  Radioimmunoassay of 13, 14-dihydro-15-keto prostaglandin F in bovine peripheral plasma. , 1975, Prostaglandins.

[47]  C. J. Wilcox,et al.  Physiological, environmental, and hormonal factors at insemination which may affect conception. , 1973, Journal of dairy science.

[48]  G. Niswender,et al.  Morphometric analysis of cell types in the ovine corpus luteum throughout the estrous cycle. , 1986, Biology of reproduction.

[49]  H. Henderson,et al.  Analyses of the variation in the interval from an injection of prostaglandin F2α to oestrus as a method of studying patterns of follicle development during dioestrus in dairy cows , 1984 .

[50]  P. Franchimont,et al.  Regulation of inhibin production by bovine ovarian cells in vitro. , 1981, Journal of reproduction and fertility.

[51]  W. Hansel,et al.  Plasma LH levels after ovariectomy, corpus luteum removal and estradiol administration in cattle. , 1972, Endocrinology.

[52]  H. R. Tervit,et al.  Jugular levels of 13, 14-dihydro-15-keto-prostaglandin F and progesterone around luteolysis and early pregnancy in the ewe. , 1976, Prostaglandins.

[53]  S. Quirk,et al.  Plasma concentrations of gonadotrophins, preovulatory follicular development and luteal function associated with bovine follicular fluid-induced delay of oestrus in heifers. , 1986, Journal of reproduction and fertility.

[54]  L. Guilbault,et al.  Relationship of 15-keto-13,14-dihydro-prostaglandin F2 alpha concentrations in peripheral plasma with local uterine production of F series prostaglandins and changes in uterine blood flow during the early postpartum period of cattle. , 1984, Biology of reproduction.

[55]  H. Kaneko,et al.  Immunoneutralization of inhibin and estradiol during the follicular phase of the estrous cycle in cows. , 1995, Biology of reproduction.

[56]  E. Rajakoski.  The ovarian follicular system in sexually mature heifers with special reference to seasonal, cyclical, end left-right variations. , 1960, Acta endocrinologica. Supplementum.

[57]  J. Kinder,et al.  Luteinizing hormone secretion and corpus luteum function in cows receiving two levels of progesterone. , 1989, Biology of reproduction.

[58]  J. Kinder,et al.  Corpus luteum development and function in cattle with episodic release of luteinizing hormone pulses inhibited in the follicular and early luteal phases of the estrous cycle. , 1999, Biology of reproduction.

[59]  J. Kastelic,et al.  Ovarian follicular dynamics in heifers: test of two-wave hypothesis by ultrasonically monitoring individual follicles. , 1989, Domestic animal endocrinology.

[60]  G. Niswender,et al.  Analysis of cell types in the corpus luteum of the sheep. , 1989, Journal of reproduction and fertility. Supplement.

[61]  E. Bleach,et al.  Active immunization of heifers against inhibin: effects on plasma concentrations of gonadotrophins, steroids and ovarian follicular dynamics during prostaglandin-synchronized cycles. , 1994, Journal of reproduction and fertility.

[62]  K. Imakawa,et al.  Regulation of pulsatile LH secretion by ovarian steroids in the heifer. , 1986, Journal of animal science.

[63]  E. Bleach,et al.  Effect of active immunization of heifers against inhibin on plasma FSH concentrations, ovarian follicular development and ovulation rate. , 1992, The Journal of endocrinology.

[64]  J. E. Fortune.  Ovarian follicular growth and development in mammals. , 1994, Biology of reproduction.

[65]  D. B. Laster,et al.  Oestrus, LH, ovulation and fertility in beef heifers. , 1975, Journal of reproduction and fertility.

[66]  R. Pierson,et al.  Ultrasonography of the bovine ovary. , 1984, Theriogenology.

[67]  R. Pierson,et al.  Follicular populations during the estrous cycle in heifers. II. Influence of right and left sides and intraovarian effect of the corpus luteum , 1987 .

[68]  V. Warbritton.  The cytology of the corpora lutea of the ewe , 1934 .

[69]  M. F. Smith,et al.  Effect of active immunization of pre-partum and post-partum cows against prostaglandin F-2 alpha on lifespan and progesterone secretion of short-lived corpora lutea. , 1989, Journal of reproduction and fertility.

[70]  I. Rothchild.  The regulation of the mammalian corpus luteum. , 1981, Recent progress in hormone research.

[71]  J. Valet,et al.  Prediction of bovine ovulation by a rapid radioimmunoassay for plasma LH. , 1983, Journal of reproduction and fertility.

[72]  W. Hansel,et al.  Concurrent changes in bovine plasma hormone levels prior to and during the first postpartum estrous cycle. , 1973, Journal of animal science.

[73]  G. Niswender,et al.  Effects of luteinizing hormone on luteal cell populations in hypophysectomized ewes. , 1990, Journal of reproduction and fertility.

[74]  J. Ireland.  Control of follicular growth and development. , 2019, Journal of reproduction and fertility. Supplement.

[75]  B. Lunenfeld,et al.  Follicular development and its control. , 1993, Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology.

[76]  W. Hansel,et al.  The effects of prostacyclin (PGI2) and 6-keto-PGF1 alpha on bovine plasma progesterone and LH concentrations. , 1980, Prostaglandins.

[77]  F. C. Greiss,et al.  Effect of ovarian hormones on the uterine vascular bed. , 1970, American journal of obstetrics and gynecology.

[78]  R. Webb,et al.  Steroid control of gonadotropin secretion and ovarian function in heifers. , 1988, Endocrinology.

[79]  W. J. Silvia,et al.  Effects of progestagen treatment on concentrations of prostaglandins and oxytocin in plasma from the posterior vena cava of post-partum beef cows. , 1991, Journal of reproduction and fertility.

[80]  J. Ireland,et al.  Development of antral follicles in cattle after prostaglandin-induced luteolysis: changes in serum hormones, steroids in follicular fluid, and gonadotropin receptors. , 1982, Endocrinology.

[81]  W. Hansel,et al.  Evidence for preferential transfer of prostaglandin F2alpha to the ovarian artery following intrauterine administration in cattle. , 1974, Biology of reproduction.

[82]  J. Kinder,et al.  Progesterone, 17 beta-estradiol, and opioid neuropeptides modulate pattern of luteinizing hormone in circulation of the cow. , 1993, Biology of reproduction.

[83]  Swanson Lv,et al.  LH and prolactin in blood serum from estrus to ovulation in Holstein heifers. , 1971 .

[84]  J. E. Fortune,et al.  Lengthening the bovine estrous cycle with low levels of exogenous progesterone: a model for studying ovarian follicular dominance. , 1990, Endocrinology.

[85]  M. Fisher,et al.  A comparison of plasma LH concentrations in milked and suckling post-partum cows. , 1981, Journal of reproduction and fertility.

[86]  R. Rajamahendran,et al.  Follicular dynamics, corpus luteum growth and regression in lactating dairy cattle , 1991 .

[87]  R. Schwall,et al.  Changes in the distribution of sizes of ovine luteal cells during the estrous cycle. , 1986, Biology of reproduction.

[88]  Potential local regulatory functions of inhibins, activins and follistatin in the ovary. , 2001, Reproduction.

[89]  G. S. Pope,et al.  Concentrations of oestradiol-17 beta, oestrone and progesterone in jugular venous plasma of cows during the oestrous cycle and in early pregnancy. , 1973, Acta endocrinologica.

[90]  E. Schallenberger,et al.  Effect of ovariectomy on tonic gonadotrophin secretion in cyclic and post-partum dairy cows. , 1982, Journal of reproduction and fertility.

[91]  R. Goodman,et al.  Importance of variations in behavioural and feedback actions of oestradiol to the control of seasonal breeding in the ewe. , 1981, The Journal of endocrinology.

[92]  A. Cupp,et al.  Secretion of gonadotrophins change during the luteal phase of the bovine oestrous cycle in the absence of corresponding changes in progesterone or 17β-oestradiol , 1995 .

[93]  R. Wettemann,et al.  Estradiol and progesterone in blood serum during the bovine estrous cycle. , 1972, Journal of animal science.

[94]  J. Kastelic,et al.  Temporal associations among ovarian events in cattle during oestrous cycles with two and three follicular waves. , 1989, Journal of reproduction and fertility.

[95]  G. Niswender,et al.  Luteinizing hormone, progesterone and the morphological development of normal and superovulated corpora lutea in sheep , 1975, Cell and Tissue Research.

[96]  J. Stevenson,et al.  Advances in reproduction in dairy cattle. , 1981, Journal of dairy science.

[97]  L. Swanson,et al.  Ovarian characteristics and serum LH, prolactin, progesterone and glucocorticoid from first estrus to breeding size in Holstein heifers. , 1972, Journal of animal science.

[98]  R. Randel,et al.  Induced LH release in spayed cows. , 1973, Journal of animal science.

[99]  B. Barcikowski,et al.  The identification of prostaglandin F2 alpha as a uterine luteolytic hormone and the hormonal control of its synthesis. , 1981, Acta veterinaria Scandinavica. Supplementum.

[100]  G. Niswender,et al.  Characterization of two steroidogenic cell types in the ovine corpus luteum. , 1982, Biology of reproduction.

[101]  R. Sharpe,et al.  Evidence for inhibin-like activity in bovine follicular fluid , 1976, Nature.

[102]  R. Scaramuzzi,et al.  Growth of Graafian follicles in cows following luteolysis induced by the prostaglandin F2 alpha analogue, cloprostenol. , 1980, Australian journal of biological sciences.

[103]  T. Beck,et al.  Bovine serum LH, GH and prolactin following chronic implantation of ovarian steroids and subsequent ovariectomy. , 1976, Journal of animal science.

[104]  J. Ireland,et al.  Follicular development during four stages of the estrous cycle of beef cattle. , 1979, Journal of animal science.

[105]  W. R. Butler,et al.  On the negative feedback regulation of gonadotropins in castrate and intact cattle with comparison of two FSH radioimmunoassays. , 1983, Journal of animal science.

[106]  E. Granström,et al.  Prostaglandin levels in peripheral plasma during the reproductive cycle. , 1976, Advances in prostaglandin and thromboxane research.

[107]  H. Meyer,et al.  Improvement of radioimmunoassays for prostaglandins in bovine blood plasma and their application to monitor reproductive functions. , 1989, Theriogenology.

[108]  H. Kaneko,et al.  Ovarian follicular dynamics and concentrations of oestradiol-17 beta, progesterone, luteinizing hormone and follicle stimulating hormone during the periovulatory phase of the oestrous cycle in the cow. , 1991, Reproduction, fertility, and development.

[109]  K. Imakawa,et al.  Circulating concentrations of 17-estradiol influence pattern of LH in circulation of cows. , 1991, Domestic animal endocrinology.

[110]  D. G. Cran,et al.  Fate of the theca interna following ovulation in the ewe , 2004, Cell and Tissue Research.

[111]  B. Bindon,et al.  Inhibin immunization for increasing ovulation rate and superovulation , 1994 .

[112]  J. Kesner,et al.  Evidence that estradiol induces the preovulatory LH surge in cattle by increasing pituitary sensitivity to LHRH and then increasing LHRH release. , 1981, Endocrinology.

[113]  J. Vane,et al.  Prostaglandins: Their Disappearance from and Release into the Circulation , 1967, Nature.

[114]  A. Mcneilly,et al.  Is there an FSH-releasing factor? , 2001, Reproduction.

[115]  A. Cupp,et al.  Exogenous progesterone and progestins as used in estrous synchrony regimens do not mimic the corpus luteum in regulation of luteinizing hormone and 17 beta-estradiol in circulation of cows. , 1992, Biology of reproduction.

[116]  J. Kinder,et al.  Effect of estradiol on secretion of luteinizing hormone during the follicular phase of the bovine estrous cycle. , 1989, Biology of reproduction.

[117]  J. E. Fortune,et al.  Suppression of the secondary FSH surge with bovine follicular fluid is associated with delayed ovarian follicular development in heifers. , 1990, Journal of reproduction and fertility.

[118]  W. Hansel,et al.  HISTOLOGICAL STUDY OF BOVINE CORPORA LUTEA. , 1965, Journal of dairy science.

[119]  R. Randel,et al.  Factors affecting estrogen-induced LH release in the cow. , 1979, Biology of reproduction.

[120]  D. Schams,et al.  Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during prostaglandin-induced regression of the corpus luteum in the cow. , 1984, Journal of reproduction and fertility.

[121]  P. Concannon,et al.  Corpora Lutea of the Large Domestic Animals , 1973 .

[122]  Y. Couture,et al.  Growth and replacement of the bovine ovarian follicles during the estrous cycle. , 1981, Journal of animal science.

[123]  H. Kaneko,et al.  Evidence that inhibin is an important factor in the regulation of FSH secretion during the mid-luteal phase in cows. , 1993, The Journal of endocrinology.