Maturity of a giant: age and size reaction norm for sexual maturity for Atlantic leatherback turtles

2021 ◽  
Author(s):  
Marc Girondot ◽  
Baptiste Mourrain ◽  
Damien Chevallier ◽  
Matthew H. Godfrey
Keyword(s):  
Sexual Maturity ◽  
Reaction Norm ◽  
Leatherback Turtles

Patterns of Marine Turtle Mortality in British Waters (1992–1996) with Reference to Tissue Contaminant Levels

1998 ◽  
Vol 78 (3) ◽  
pp. 973-984 ◽  
Author(s):  
B.J. Godley ◽  
M.J. Gaywood ◽  
R.J. Law ◽  
C.J. McCarthy ◽  
C. McKenzie ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Caretta Caretta ◽  
Marine Turtle ◽  
Dermochelys Coriacea ◽  
Fishing Gear ◽  
Leatherback Turtles ◽  
Marine Turtles ◽  
Causes Of Mortality

Mortality patterns of marine turtles entangled in fishing gear, found dead at sea or stranded dead on and around the coast of Britain in the period 1992–1996 are described. Of a total of 38 dead turtles identified, 35 were leatherback turtles (Dermochelys coriacea) and three were loggerhead turtles (Caretta caretta). All D. coriacea were considered adults or subadults nearing sexual maturity. Six individuals were assessed as females, ten were classified as males and 19 were not sexed. Dermochelys coriacea (N=20 measured) ranged from 120 to 210 cm in curved carapace length (mean, 152 cm). The three C. caretta were juveniles, and ranged from 15 to 30 cm curved carapace length. Possible origins, causes of mortality and interactions with fisheries are discussed. In addition, contaminant levels were determined in the tissues of three D. coriacea. Concentrations of organic contaminants determined were found to be low.

THE »EARLY-ANDROGEN« SYNDROME; ITS DEVELOPMENT AND THE RESPONSE TO HEMI-SPAYING

1964 ◽  
Vol 45 (1) ◽  
pp. 1-12 ◽  
Author(s):  
H. E. Swanson ◽  
J. J. van der Werff ten Bosch
Keyword(s):  
Sexual Maturity ◽  
Compensatory Growth ◽  
Testosterone Propionate ◽  
Single Injection ◽  
Weight Increase ◽  
Corpora Lutea ◽  
Transition Stage ◽  
Adult Females

ABSTRACT The »early-androgen« syndrome in the rat – i. e. anovulatory ovaries in adult females after a single injection of testosterone propionate (TP) within a week of birth – may not become apparent until some time after the attainment of sexual maturity. Large doses (50 or 100 μg) of TP were effective earlier than lower doses (5 or 10 μg). Rats which received 5 μg TP were ovulating at 10 weeks of age, mated but were infertile at 13 weeks of age, and were anovulatory at 21 weeks. In rats between 10 and 13 weeks old there was a marked fall in the number of corpora lutea in the ovaries of animals which had been given 5 μg TP. Hemi-spaying was followed by compensatory growth of the remaining ovary which consisted of corpora lutea in ovulating, and of follicles in anovulatory rats; little or no compensatory weight increase occurred in animals which seemed to be in the transition stage from the ovulatory to the anovulatory condition.

PLASMA LH, TESTOSTERONE AND DHT IN THE PIG FROM BIRTH TO SEXUAL MATURITY

1973 ◽  
Vol 71 (4_Suppl) ◽  
pp. S148 ◽  
Author(s):  
F. Elsaesser ◽  
D. K. Pomerantz ◽  
F. Ellendorff ◽  
K. Kreikenbaum ◽  
A. König
Keyword(s):  
Sexual Maturity

Estimation of Sexual Maturity Based on Morphometrics of Genital Organs in Male Northern Fur Seals, Callorhinus ursinus

Mammal Study ◽  
2020 ◽  
Vol 46 (1) ◽  
Author(s):  
Yukino Hirakawa ◽  
Takanori Horimoto ◽  
Ippei Suzuki ◽  
Yoko Mitani
Keyword(s):  
Sexual Maturity ◽  
Callorhinus Ursinus ◽  
Fur Seals ◽  
Northern Fur Seals

Rites of Passage

2018 ◽  
Author(s):  
Axel Michaels
Keyword(s):  
Life Cycle ◽  
Old Age ◽  
Sexual Maturity ◽  
Rites Of Passage ◽  
Life And Death ◽  
Transformational Process ◽  
Local Contexts ◽  
Vulnerable Community ◽  
History Of ◽  
The Individual

This chapter examines the classical Hindu life-cycle rites, the term saṃskāra and its history, and the main sources (Gṛhyasūtras and Dharma texts). It presents a history of the traditional saṃskāras and variants in local contexts, especially in Nepal. It describes prenatal, birth and childhood, initiation, marriage, old-age, death, and ancestor rituals. Finally, it analyzes the transformational process of these life-cycle rituals in the light of general theories on rites of passage. It proposes, in saṃskāras, man equates himself with the unchangeable and thus seems to counteract the uncertainty of the future, of life and death, since persons are confronted with their finite existence. For evidently every change, whether social or biological, represents a danger for the cohesion of the vulnerable community of the individual and society. These rituals then become an attempt of relegating the effects of nature or of mortality: birth, teething, sexual maturity, reproduction, and dying.

Isolating Gene E' for Early Sexual Maturity

1945 ◽  
Vol 79 (783) ◽  
pp. 372-377 ◽  
Author(s):  
F. A. Hays
Keyword(s):  
Sexual Maturity

scholarly journals Genotype-by-environment interaction in Holstein heifer fertility traits using single-step genomic reaction norm models

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rui Shi ◽  
Luiz Fernando Brito ◽  
Aoxing Liu ◽  
Hanpeng Luo ◽  
Ziwei Chen ◽  
...  
Keyword(s):  
Heat Stress ◽  
Dairy Cattle ◽  
Candidate Genes ◽  
Heat Tolerance ◽  
Reaction Norm ◽  
Single Step ◽  
Conception Rate ◽  
Critical Periods ◽  
Genotype By Environment ◽  
Fertility Traits

Abstract Background The effect of heat stress on livestock production is a worldwide issue. Animal performance is influenced by exposure to harsh environmental conditions potentially causing genotype-by-environment interactions (G × E), especially in highproducing animals. In this context, the main objectives of this study were to (1) detect the time periods in which heifer fertility traits are more sensitive to the exposure to high environmental temperature and/or humidity, (2) investigate G × E due to heat stress in heifer fertility traits, and, (3) identify genomic regions associated with heifer fertility and heat tolerance in Holstein cattle. Results Phenotypic records for three heifer fertility traits (i.e., age at first calving, interval from first to last service, and conception rate at the first service) were collected, from 2005 to 2018, for 56,998 Holstein heifers raised in 15 herds in the Beijing area (China). By integrating environmental data, including hourly air temperature and relative humidity, the critical periods in which the heifers are more sensitive to heat stress were located in more than 30 days before the first service for age at first calving and interval from first to last service, or 10 days before and less than 60 days after the first service for conception rate. Using reaction norm models, significant G × E was detected for all three traits regarding both environmental gradients, proportion of days exceeding heat threshold, and minimum temperature-humidity index. Through single-step genome-wide association studies, PLAG1, AMHR2, SP1, KRT8, KRT18, MLH1, and EOMES were suggested as candidate genes for heifer fertility. The genes HCRTR1, AGRP, PC, and GUCY1B1 are strong candidates for association with heat tolerance. Conclusions The critical periods in which the reproductive performance of heifers is more sensitive to heat stress are trait-dependent. Thus, detailed analysis should be conducted to determine this particular period for other fertility traits. The considerable magnitude of G × E and sire re-ranking indicates the necessity to consider G × E in dairy cattle breeding schemes. This will enable selection of more heat-tolerant animals with high reproductive efficiency under harsh climatic conditions. Lastly, the candidate genes identified to be linked with response to heat stress provide a better understanding of the underlying biological mechanisms of heat tolerance in dairy cattle.

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