Effects of Estrogens on Domestic Fowl and Applications in the Poultry Industry

Lorenz, F. W.

doi:10.1016/s0083-6729(08)61014-6

Cited by 102 publications

(30 citation statements)

References 163 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The increase in food consumption of 21*5 per cent is comparable with that obtained with hexoestrol by Payne et al (1964) and agrees with the general conclusion of Lorenz (1954) that increased food intake has been consistently observed with implantation of oestrogens. The food conversion data reviewed by Lorenz (1954) indicated results varying from poorer than to no difference between oestrogen treated and untreated birds.…”

Section: As Percentage Of Weight At Slaughtersupporting

confidence: 89%

“…The food conversion data reviewed by Lorenz (1954) indicated results varying from poorer than to no difference between oestrogen treated and untreated birds. The significantly poorer food conversion by hexoestrol treated chickens in our experiment can be explained by the greater deposition of fat in the bodies of the treated chickens.…”

Section: As Percentage Of Weight At Slaughtermentioning

confidence: 99%

“…Although an increase in fat deposition has been a constant feature of reports on oestrogen implantation in poultry (Lorenz, 1954), there are only limited data which allow absolute changes in total body and carcass fat and other components to be determined. Donovan and Sherman (i960) and Bogdonoff, Henson and Thrasher (1961) reported absolute increases in carcass fat following diethylstilboestrol administration, but there do not appear to be comparable data relating to hexoestrol implantation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of hexoestrol implantation and body size on the chemical composition and body components of chickens

Ryley¹,

Moir²,

Pepper³

et al. 1970

British Poultry Science

View full text Add to dashboard Cite

Two groups of meat-type cockerels, 56 d of age, from the same hatch but of different mean live-weights (1135 g ± SD 96.2 and 544 g ± 72.0) due to differences in earlier nutritional treatments were implanted with hexoestrol to determine the effects on food consumption, live-weight gain, carcass gain, chemical composition of carcass and offal, and weight of some body components. Replicate groups were slaughtered prior to implantation and at the end of the 28-d experimental period.Implantation with a single 15 mg hexoestrol pellet resulted in the following significant differences compared with untreated controls: increases in food consumption, live-weight gain, carcass weight and weight of offal of 21.5, 14.2, 8.2 and 16.6 per cent respectively; poorer food conversion, higher total fat in the carcass, offal and total body and, relative to body weight, heavier livers and lighter hearts, gizzards, legs and necks. The increased fat in treated chickens accounted for all the increased body weight and carcass weight.In comparisons of small and large chickens there was no significant difference in live-weight gain during the 28-d experimental period. At both 56 and 84 d of age the dressing percentages were lower and the weights relative to body weight of offal, liver, shanks and gizzards were higher in small than in large chickens. Percentage moisture was significantly higher in the total bodies and carcasses of small chickens, while percentage fat was significantly lower in the carcasses of small chickens at both 56 and 84 d and in the total bodies and offals at 56 d.

show abstract

Section: As Percentage Of Weight At Slaughtersupporting

confidence: 89%

Section: As Percentage Of Weight At Slaughtermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of hexoestrol implantation and body size on the chemical composition and body components of chickens

Ryley¹,

Moir²,

Pepper³

et al. 1970

British Poultry Science

View full text Add to dashboard Cite

show abstract

“…Considerable changes in the blood composition of immature chickens or adult cockerels occur after oestrogen administration (Lorenz, 1954;Urist, 1959). The appearance in the plasma of the egg-yolk protein precursors, phosvitin and lipovitellin (Gruber, 1972), and the increase in the total calcium concen¬ tration are of the most direct relevance to reproduction.…”

Section: Introductionmentioning

confidence: 99%

Oestradiol Concentration in the Peripheral Plasma of the Domestic Hen From 7 Weeks of Age Until the Time of Sexual Maturity

Senior¹

1974

Reproduction

View full text Add to dashboard Cite

Summary. A specific radioimmunoassay technique was used to measure the concentration of oestradiol at weekly intervals in the blood plasma of seven pullets from 7 weeks of age until they were sexually mature. Large differences in oestradiol concentration were observed between birds. The mean concentration was 94 pg/ml plasma 7 weeks before the first egg was laid. The concentration then began to rise sharply 2 to 3 weeks later to reach a peak of mean value 355 pg/ml 2 to 3 weeks before laying began. The mean concentration when egglaying was established was 138 pg/ml. The high oestradiol levels found before the onset of laying may be essential for the synthesis of yolk protein precursors and for the conservation of calcium as medullary bone in preparation for egg-shell formation. The peak may also be an important part ofthe changes which occur at puberty in the interrelationship between the hypothalamus, the pituitary gland and the ovary.

show abstract

“…The administration ofoestrogens to immature pullets [Ramsay and Campbell, 1956] or cockerels [Greengard, Mendelsohn and Gordon, 1965] induces a large increase in plasma iron as well as many other biochemical changes normally observed in the laying bird [for reviews see Lorenz, 1954;Sturkie, 1965]. Among these is the appearance of a phosphoprotein, absent from the plasma of the non-laying bird [Laskowski, 1935a,b;Roepke and Hughes, 1935], but apparently identical with the phosvitin of egg yolk.…”

mentioning

confidence: 99%