The Egg-Laying Bird: Major Physiological Changes in Calcium Associated With Oestrogen Control

Thaeler, Deborah A.

doi:10.1079/wps19790005

Cited by 2 publications

(2 citation statements)

References 37 publications

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“…Steroid hormones have been implicated in the regulation of calcium and phosphorus metabolism in the laying hen through several modes of action which may affect eggshell quality (Thaeler, 1979). A line of hens laying thick-shelled eggs has been demonstrated to have significantly greater amounts of serum calcium-binding protein, vitellogenin, and diffusible and nondiffusible calcium than a line laying thin-shelled eggs (Grunder et al, 1980a).…”

Section: Introductionmentioning

confidence: 97%

Preovulatory Concentrations of Progesterone and Estradiol in Plasma and Their Relationships with Eggshell Quality in the Laying Hen

et al. 1985

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Laying hens were divided into high and low shell quality groups on the basis of egg specific gravity during the 5th, 7th, and 9th months of egg production. Concentrations of progesterone and estradiol-17 beta in the plasma were determined by radioimmunoassay in blood samples taken by cardiac puncture from hens at either 18, 21, or 24 hr postoviposition. Egg production and egg weight were not significantly different between shell quality groups; however, hens in the low shell quality group were heavier (P less than .05), had longer clutches (P less than .05), and lower egg specific gravity (P less than .0001) than hens in the high shell quality group. Egg production and clutch size declined (P less than .01) in both groups with increased age. Plasma estradiol and progesterone concentrations were not different between shell quality groups or among periods of production, though progesterone and estradiol concentrations were greater (P less than .005) at 21 hr postoviposition than at 18 or 24 hr. The correlation coefficient between plasma concentrations of estradiol and progesterone was significant. There was no significant association between the plasma concentrations of these hormones and egg shell quality. These data suggest that concentrations of estradiol and progesterone in plasma, during the 6 hr before ovulation, are not highly related to shell quality in the laying hen.

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Section: Introductionmentioning

confidence: 97%

Preovulatory Concentrations of Progesterone and Estradiol in Plasma and Their Relationships with Eggshell Quality in the Laying Hen

et al. 1985

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“…The effect probably resulted from the loss of vitellogenin (Thaeler, 1979) and other calcium-binding proteins in the plasma due to rapid blood removal. Approximately 3% of plasma constituents were removed with each blood sample and were not returned with the red blood cells, resulting in the loss of approximately 67% of total plasma constituents within 24 h. Mongin and Sauveur (1979) saw a similar trend in their hens, but not in cockerels bled at the same times.…”

Section: Discussionmentioning

confidence: 97%

Comparison of Two Multiple Blood Sampling Regimens Using an Indwelling Vascular Access Device for Investigations of the Hen's Ovulatory Cycle and Calcium Metabolism ,

et al. 1993

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The objectives of the present study were to compare the effects of two regimens of serial blood sampling on the concentrations of hormones and ions during the ovulatory cycle of the domestic hen, and to examine the effectiveness of an indwelling vascular access device for repeated collection of blood samples. Single Comb White Leghorn hens were bled every 2 h over a period of 24 to 26 h, either from one oviposition to the next oviposition (OVIP-OVIP), or from 10 h prior to ovulation until the same time 24 h later (AFTN-AFTN). Whole blood was analyzed for ionized calcium concentration. Plasma was analyzed for total calcium, inorganic phosphorus, 1,25-dihydroxycholecalciferol, estradiol-17beta, and progesterone concentrations. The OVIP-OVIP regimen, using oviposition as a reference point, provided more accurate measurements of ionized calcium, inorganic phosphorus, and estradiol-17beta than did the AFTN-AFTN regimen. Either bleeding regimen was suitable for observing the patterns of 1,25-dihydroxycholecalciferol and progesterone concentrations. The decrease in bound calcium concentration observed with both regimens appeared to be an artifact of repeated blood sampling. The chance of a bird laying an egg following her second oviposition was lower following the OVIP-OVIP regimen than the AFTN-AFTN regimen. The vascular access device was a helpful tool in procuring multiple blood samples for measurement of ions and hormones during the ovulatory cycle of the domestic fowl.

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The Egg-Laying Bird: Major Physiological Changes in Calcium Associated With Oestrogen Control

Cited by 2 publications

References 37 publications

Preovulatory Concentrations of Progesterone and Estradiol in Plasma and Their Relationships with Eggshell Quality in the Laying Hen

Preovulatory Concentrations of Progesterone and Estradiol in Plasma and Their Relationships with Eggshell Quality in the Laying Hen

Comparison of Two Multiple Blood Sampling Regimens Using an Indwelling Vascular Access Device for Investigations of the Hen's Ovulatory Cycle and Calcium Metabolism ,

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