Studies of hormone patterns during the oestrous cycle of beef cows

Peters, A. R.

doi:10.1051/rnd:19850708

Cited by 3 publications

(1 citation statement)

References 21 publications

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“…The post-partum period is characterized by a low frequency of pulsatile LH release (see review by Peters & Lamming, 1986). During the preovulatory period of the oestrous cycle, plasma LH concentrations rise and a marked increase in LH pulse frequency is observed (Rahe et al, 1980;Schallenberger et al, 1984;Peters, 1985). Repeated injections of low doses of GnRH have been used to induce this pattern of LH release post partum in order to simulate the events of the pre¬ ovulatory period.…”

Section: Introductionmentioning

confidence: 99%

Hormone responses to low-dose GnRH treatment in post-partum beef cows

Jagger¹,

Peters²,

Lamming³

1987

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Acyclic beef cows received 1.0, 2.5 or 5.0 micrograms GnRH/2 h for 48 h as 24 X 2 h repeated i.v. injections or by continuous i.v. infusion. Preovulatory-type LH surges were detected in 9/18 injected and 8/15 infused cows and occurred 30.6 +/- 5.1 h and 3.3 +/- 0.7 h after the start of treatment respectively. Cows receiving the lowest infusion dose did not exhibit gonadotrophin surges. The LH response to individual injections increased with dose but the proportion of injected cows showing preovulatory-type surges at each dose level did not change. A total of 20 cows (10 injected and 10 infused) showed evidence of luteal activity within 7 days of the end of GnRH treatment, although this was transitory in most animals. Cows which exhibited preovulatory-type LH surges in response to treatment had significantly higher plasma oestradiol-17 beta concentrations and lower FSH concentrations before treatment than those which did not. The results suggest that the LH response to GnRH treatment is dependent on follicular status in the immediate pretreatment period.

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Section: Introductionmentioning

confidence: 99%

Hormone responses to low-dose GnRH treatment in post-partum beef cows

Jagger¹,

Peters²,

Lamming³

1987

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Physiological and Pathological Plasma Profiles of Progesterone and LH in Indigenous West African Shorthorn Cows (Bos taurus taurus)

Chicoteau

Humblot²,

Cloe

et al. 1989

Reprod Domestic Animals

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Contents Hormonal profiles (progesterone, LH) were studied in eleven Baoule females in the hot and humid pre‐rainy season. Eight animals showed similar patterns to what is described for other Bos taurus taurus breeds in distinct environmental conditions. Plasma progesterone levels were low at estrus (Day 0), increasing as from Day 4 by 1 ng/ml/Day and reaching its peak (mean = 12 ng/ml approximately) around Day 14. The LH basal level was 1.48 ± .50 ng/ml. The mean duration and maximum concentration of the preovulatory LH peak were respectively of 6 Hand 100 ng/ml. Three animals showed cycles abnormalities (extension of the luteal phase, acyclicity) which could be due to thermal stress. Inhalt Physiologische und pathologkche Plasmaprofile für Progesteron und LH bei einheimischen westafrikanischen Shorthornkühen (BOS taurus taurus) Hormonprofile für Progesteron und LH wurden an 11 Baoulekühen während der heißen und feuchten Vorregensaison untersucht. 8 Tiere zeigten Profile, wie sie auch für andere Bos taurus taurus‐Rassen unter bestimmten Umweltbedingungen beschrieben wurden. Die Progesteronwerte waren während der Brunst (Tag 0) niedrig, stiegen ab Tag 4 täglich um 1 ng/ml an und erreichten mit durchschnittlich 12 ng/ml um den 14. Tag ein Maximum. Der Basalwert fur LH lag bei 1,48 ± 0,50 nglml. Die mittlere Dauer des LH‐peaks wurde mit 6 Std. ermittelt, der Maximalwert mit 100 ng/ml. 3 Tiere zeigten Zyklusabweichungen (verlangerte Lutealphase bzw. Azyklie), was durch Hitzestreß verursacht sein könnte.

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Evidence for a Coupled Oscillator Model of Endocrine Ultradian Rhythms

et al. 2018

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Whereas long-period temporal structures in endocrine dynamics have been well studied, endocrine rhythms on the scale of hours are relatively unexplored. The study of these ultradian rhythms (URs) has remained nascent, in part, because a theoretical framework unifying ultradian patterns across systems has not been established. The present overview proposes a conceptual coupled oscillator network model of URs in which oscillating hormonal outputs, or nodes, are connected by edges representing the strength of node-node coupling. We propose that variable-strength coupling exists both within and across classic hormonal axes. Because coupled oscillators synchronize, such a model implies that changes across hormonal systems could be inferred by surveying accessible nodes in the network. This implication would at once simplify the study of URs and open new avenues of exploration into conditions affecting coupling. In support of this proposed framework, we review mammalian evidence for (1) URs of the gut-brain axis and the hypothalamo-pituitary-thyroid, -adrenal, and -gonadal axes, (2) UR coupling within and across these axes; and (3) the relation of these URs to body temperature. URs across these systems exhibit behavior broadly consistent with a coupled oscillator network, maintaining both consistent URs and coupling within and across axes. This model may aid the exploration of mammalian physiology at high temporal resolution and improve the understanding of endocrine system dynamics within individuals.

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Studies of hormone patterns during the oestrous cycle of beef cows

Abstract: Introduction.

Cited by 3 publications

References 21 publications

Hormone responses to low-dose GnRH treatment in post-partum beef cows

Hormone responses to low-dose GnRH treatment in post-partum beef cows

Physiological and Pathological Plasma Profiles of Progesterone and LH in Indigenous West African Shorthorn Cows (Bos taurus taurus)

Evidence for a Coupled Oscillator Model of Endocrine Ultradian Rhythms

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