Circulating Concentrations of Estradiol, Luteinizing Hormone, and Follicle-Stimulating Hormone during Waves of Ovarian Follicular Development in Prepubertal Cattle1

Melvin, E.J.; Lindsey, B.R.; Quintal-Franco, JA; Zanella, Eraldo Lourenso; Fike, K. E.; Tassell, Curtis P. Van; Kinder, J. E.

doi:10.1095/biolreprod60.2.405

Cited by 56 publications

(29 citation statements)

References 19 publications

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“…Puberty is determined by monitoring plasma progesterone concentrations; when plasma progesterone becomes . 1.0 ng/ml for at least two subsequent samples collected at 3 -4 day intervals it is said that the animal has attained puberty (Ringuet et al 1994, Salama et al 1994, Melvin et al 1999. Although the plasma progesterone of GRF-treated animals was found to be always higher than the control group of buffaloes in this study, the level did not reach $ 1.0 ng/ml even in a single sample collected at 3 -4 day intervals for any animal from either group, suggesting that no animal in this experiment had reached puberty by the time of the last injection of GRF.…”

Section: Plasma Lh In Blood Samples Collected Prior To and After Grf mentioning

confidence: 99%

Effects of long-term GH-releasing factor administration on patterns of GH and LH secretion in growing female buffaloes (Bubalus bubalis)

Mondal¹,

Prakash²

2004

Reproduction

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To investigate the effects of long-term GH-releasing factor (GRF) administration on the patterns of GH and LH secretion in growing female Murrah buffalo (Bubalus bubalis) calves, 12 buffaloes of 6-8 months of age were divided into two groups (treatment and control groups) of six each in such a way that average body weight between the groups did not differ significantly (P > 0.05). Both the groups were administered i.v. with either synthetic bovine GRF (bGRF(1 -44)-NH 2 ) at 10 mg/100 kg body weight (treatment group) or an equal volume of normal saline (control group) at intervals of 15 days until 18 injections had been completed (9 months). Blood samples collected prior to and after the first and last injection of GRF at 260, 245, 230, 215, 2 10, 2 5 min and 1 5, 1 10, 1 15, 1 30 min, and thereafter at intervals of 15 min up to 8 h post-injection, were assayed for plasma GH and LH. Plasma progesterone was also estimated in twice-a-week samples to assess whether either group had begun ovarian cyclicity. The body weight of all animals was recorded twice a week. In all animals, a peak of GH was recorded within 5-20 min and 5-30 min after the first and last GRF injections and post-injection mean values for plasma GH were significantly (P < 0.01) higher compared with the control group of animals. Although peak GH values after the first and last GRF injection did not differ (P > 0.05), GH levels were maintained at a higher level for a longer time after the last GRF injection compared with the first (240 vs 150 min). The area under the GH response curve after the last GRF injection was found to be significantly (P < 0.01) higher than after the first injection (9344 6 199.7 vs 7763 6 112.4 ng/ml 3 min). The mean post-injection plasma LH levels of the treatment group were significantly (P < 0.01) higher after both the first and last GRF injections than in the control group of animals. Interestingly, compared with the first GRF injection, the preinjection plasma LH level was found to be significantly higher (P < 0.01) at the last injection. The plasma LH concentrations around the last injection of GRF were significantly higher (P < 0.01) than those recorded at the time of the first injection in treated buffaloes. Correspondingly, the plasma LH concentrations in controls were also higher (P < 0.01) around the last injection of GRF vis-à-vis the first injection. The hormone concentration exhibited a higher pulsatility with greater amplitude after the last injection as compared with that recorded after the first injection. Although pulses of LH were also recorded in controls following the last injection, these were fewer and of lower magnitude than those seen in treated animals. No animal from either group reached puberty. GRF-treated buffaloes attained higher (P < 0.001) body weight than the controls. In conclusion, long-term administration of GRF induces and even enhances GH release without any sign of refractoriness, and significantly increases plasma LH also. Hence, long-term treatment with GRF may be used to mai...

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Section: Plasma Lh In Blood Samples Collected Prior To and After Grf mentioning

confidence: 99%

Effects of long-term GH-releasing factor administration on patterns of GH and LH secretion in growing female buffaloes (Bubalus bubalis)

Mondal¹,

Prakash²

2004

Reproduction

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“…Plasma was harvested by centrifugation and stored in plastic screw-cap vials at −20°C. Plasma progesterone was determined by RIA (Coat-ACount assay kit; Diagnostic Product Corp., Los Angeles, CA) by the methods of Melvin et al (1999). Animals were considered to be exhibiting normal estrous activity when plasma progesterone was greater than 1 ng/mL.…”

Section: Methodsmentioning

confidence: 99%

Supplementation to meet metabolizable protein requirements of primiparous beef heifers: I. Performance, forage intake, and nutrient balance1

Patterson

Klopfenstein

Adams

et al. 2003

Journal of Animal Science

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“…Plasma was harvested via centrifugation within 4 h of collection and frozen at −20°C until analysis. Plasma concentrations of progesterone were determined by direct solid-phase RIA (Coat-A-Count, Diagnostics Products Corp., Los Angeles, CA), with modifications described by Melvin et al (1999). Intraand interassay CV (n = 7 assays) for samples from yr 1 were 3.1 and 6.8%, respectively.…”

Section: Blood Collection and Assay Proceduresmentioning

confidence: 99%

Utilization of dried distillers grains for developing beef heifers1,2,3

Martin

Cupp

Rasby

et al. 2007

Journal of Animal Science

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A 2-yr study was conducted at 2 locations to determine if supplementing beef heifers with dried distillers grains (DDG) as an energy source affected growth or reproduction. Spring-born crossbred heifers (n = 316) were blocked by age or sire and age and assigned randomly to DDG or control (dried corn gluten feed, whole corn germ, urea) supplement. Heifers received prairie hay in amounts sufficient for ad libitum intake and 0.59% of BW DDG or 0.78% of BW control supplement (DM basis). Supplements were formulated to be isocaloric, but protein degradability differed. Supplemental undegradable intake protein intake from DDG averaged 267 g/animal daily and reached 318 g/animal daily; control supplemental undegradable intake protein intake averaged 90 g/animal daily and peaked at 107 g/animal daily. Initial pubertal status was determined by 2 blood samples collected 10 d apart, and monthly BW were collected from November through January; then biweekly BW and blood samples were collected from February until May yearly. Heifers were synchronized with 2 injections of PGF 2α 14 d apart; estrus was detected and heifers were artificially insemi-

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Circulating Concentrations of Estradiol, Luteinizing Hormone, and Follicle-Stimulating Hormone during Waves of Ovarian Follicular Development in Prepubertal Cattle1

Cited by 56 publications

References 19 publications

Effects of long-term GH-releasing factor administration on patterns of GH and LH secretion in growing female buffaloes (Bubalus bubalis)

Effects of long-term GH-releasing factor administration on patterns of GH and LH secretion in growing female buffaloes (Bubalus bubalis)

Supplementation to meet metabolizable protein requirements of primiparous beef heifers: I. Performance, forage intake, and nutrient balance1

Utilization of dried distillers grains for developing beef heifers1,2,3

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