Secondary Sex Ratio, Body Weight and Length and Mortality Rate Among Infants

1951 ◽  
Vol 85 (823) ◽  
pp. 267-267
Author(s):  
Mohamed M. Oloufa
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Sex Ratio ◽  
Secondary Sex Ratio

The Biology of the Common Sheath-Tail Bat, Taphozous-Georgianus (Chiroptera, Emballonuridae), in Central Queensland

1990 ◽  
Vol 38 (1) ◽  
pp. 65 ◽  
Author(s):  
S Jolly
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Sex Ratio ◽  
Field Study ◽  
Seasonal Variations ◽  
Post Partum ◽  
Temperature And Humidity ◽  
Eyes Open ◽  
The Common ◽  
The Mean

A field study was carried out over a 4-year period on the common sheath-tail bat, Taphozous georgianus, in central Queensland. Mating occurred in late August and early September, and females gave birth to a single young in late November or early December. Females mated at about 9 months of age. Spermatogenesis commenced in males at about 9 months but they were not able to take part in mating until they were approximately 21 months old. Bats were born well furred with their eyes open, and weighed an average of 24% of their mother's post-partum weight. Young bats attained independence at 3-4 weeks old when they reached 50% of their mothers' body weight. At 3 months old young bats were within a few millimetres of adult dimensions. Marked seasonal variations in body weight resulted from the deposition of fat. Peak weights were recorded in April and minimum weights in September. The mean annual survivial rate was estimated to be 0.61. Mature males have a mortality rate substantially greater than females and this is reflected in a sex ratio strongly biased towards females in older bats. The sex ratio was nearly even in young bats. Most roost caves were occupied by less than 20 individuals. There was little difference between the temperature and humidity at which bats roosted, and the temperature and humidity of available roosts. Most bats were known from only one cave, and few movements of more than 2 km were recorded. Bats appeared to regularly relocate their roosting site, however, and they may have been utilising roosts outside the study area.

scholarly journals Maternal exposure to airborne polychlorinated biphenyls (PCBs) and risk of adverse birth outcomes

2021 ◽  
Author(s):  
Ane Bungum Kofoed ◽  
Laura Deen ◽  
Karin Sørig Hougaard ◽  
Kajsa Ugelvig Petersen ◽  
Harald William Meyer ◽  
...  
Keyword(s):  
Birth Weight ◽  
Preterm Birth ◽  
Sex Ratio ◽  
Polychlorinated Biphenyls ◽  
Birth Outcomes ◽  
Gestational Age ◽  
Small For Gestational Age ◽  
Maternal Exposure ◽  
Adverse Birth Outcomes ◽  
Secondary Sex Ratio

AbstractHuman health effects of airborne lower-chlorinated polychlorinated biphenyls (LC-PCBs) are largely unexplored. Since PCBs may cross the placenta, maternal exposure could potentially have negative consequences for fetal development. We aimed to determine if exposure to airborne PCB during pregnancy was associated with adverse birth outcomes. In this cohort study, exposed women had lived in PCB contaminated apartments at least one year during the 3.6 years before conception or the entire first trimester of pregnancy. The women and their children were followed for birth outcomes in Danish health registers. Logistic regression was performed to estimate odds ratios (OR) for changes in secondary sex ratio, preterm birth, major congenital malformations, cryptorchidism, and being born small for gestational age. We performed linear regression to estimate difference in birth weight among children of exposed and unexposed mothers. All models were adjusted for maternal age, educational level, ethnicity, and calendar time. We identified 885 exposed pregnancies and 3327 unexposed pregnancies. Relative to unexposed women, exposed women had OR 0.97 (95% CI 0.82, 1.15) for secondary sex ratio, OR 1.13 (95% CI 0.76, 1.67) for preterm birth, OR 1.28 (95% CI 0.81, 2.01) for having a child with major malformations, OR 1.73 (95% CI 1.01, 2.95) for cryptorchidism and OR 1.23 (95% CI 0.88, 1.72) for giving birth to a child born small for gestational age. The difference in birth weight for children of exposed compared to unexposed women was − 32 g (95% CI—79, 14). We observed an increased risk of cryptorchidism among boys after maternal airborne LC-PCB exposure, but due to the proxy measure of exposure, inability to perform dose–response analyses, and the lack of comparable literature, larger cohort studies with direct measures of exposure are needed to investigate the safety of airborne LC-PCB exposure during pregnancy

Does preconception stress alter the secondary sex ratio?

2011 ◽  
Vol 96 (3) ◽  
pp. S154
Author(s):  
R.J. Chason ◽  
R. Sundaram ◽  
G.M. Buck Louis ◽  
J.H. Segars ◽  
C. Pyper
Keyword(s):  
Sex Ratio ◽  
Secondary Sex Ratio

THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: REPRODUCTIVE PERFORMANCE

1988 ◽  
Vol 68 (1) ◽  
pp. 69-81 ◽  
Author(s):  
MOHAMED H. FAHMY ◽  
JACQUES J. DUFOUR
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Key Words ◽  
Litter Size ◽  
Reproductive Performance ◽  
Conception Rate ◽  
Ovulation Rate ◽  
Genetic Groups ◽  
Linear Regressions ◽  
Size At Birth

Reproductive performance and body weight were studied on 361 ewes, representing Finnsheep (F), DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. Conception rate in yearlings was 61.5% for DLS compared to 89.0% for F with the crosses being intermediate. Conception rate in older ewes was similar in the different genetic groups (avg. 94%). Ovulation rate and litter size at birth of DLS ewes were 1.72 and 1.44 lambs, which was less than half those of F ewes (3.51 and 2.86 lambs, respectively). Both traits increased progressively with an increase in F breeding in crosses and with advances in age. DLS ewes weaned 1.22 lambs compared to 2.03 lambs for F ewes and 1.84 lambs for 4/8 F ewes. The heaviest litters at weaning (31.7 kg) were raised by 4/8 F ewes, followed by 7/8 F (30.8 kg) while those raised by DLS ewes weighed 23.0 kg and F ewes 29.1 kg. Percentage of ova lost per ewe mated averaged 24% and ranged between 18% (DLS and 1/8 F) and 29% (6/8 F). About 3.6% of lambs were born dead and a further 13.8% died before weaning. Preweaning mortality rate was highest in F (22.9%) and lowest in 3/8 F (9.4%). Average kilograms of lambs weaned per ewe exposed was highest in 4/8 F (27.6 kg) followed by F (26.0 kg), whereas that of DLS was the lowest at 18.1 kg. The 4/8 F cross showed 25% heterosis in kg of lambs weaned per ewe exposed and 52.5% increase over DLS. Significant positive linear regressions were calculated for ovulation rate, litter size and preweaning mortality rate on proportion of Finnsheep breeding in crosses. The relation was quadratic for percent ova lost and lamb mortality at weaning. Yearling DLS females weighted 36 kg compared to 44 kg for F yearlings. However, at 5 yr of age DLS ewes weighed 62 kg, 5 kg heavier than F ewes. The heaviest ewes at all ages were the 4/8 F (45 kg at 1 yr, 65 kg at 5 yr). Key words: Reproduction, DLS sheep, Finnsheep, crossbreeding, heterosis, repeatabilities

scholarly journals Is biasing offspring sex ratio adaptive? A test of Fisher's principle across multiple generations of a wild mammal in a fluctuating environment

2018 ◽  
Vol 285 (1891) ◽  
pp. 20181251 ◽  
Author(s):  
Andrea E. Wishart ◽  
Cory T. Williams ◽  
Andrew G. McAdam ◽  
Stan Boutin ◽  
Ben Dantzer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
Adult Sex Ratio ◽  
Secondary Sex Ratio ◽  
North American Red Squirrels ◽  
Negative Frequency Dependent Selection ◽  
Fisher’S Principle

Fisher's principle explains that population sex ratio in sexually reproducing organisms is maintained at 1 : 1 owing to negative frequency-dependent selection, such that individuals of the rare sex realize greater reproductive opportunity than individuals of the more common sex until equilibrium is reached. If biasing offspring sex ratio towards the rare sex is adaptive, individuals that do so should have more grandoffspring. In a wild population of North American red squirrels ( Tamiasciurus hudsonicus ) that experiences fluctuations in resource abundance and population density, we show that overall across 26 years, the secondary sex ratio was 1 : 1; however, stretches of years during which adult sex ratio was biased did not yield offspring sex ratios biased towards the rare sex. Females that had litters biased towards the rare sex did not have more grandoffspring. Critically, the adult sex ratio was not temporally autocorrelated across years, thus the population sex ratio experienced by parents was independent of the population sex ratio experienced by their offspring at their primiparity. Expected fitness benefits of biasing offspring sex ratio may be masked or negated by fluctuating environments across years, which limit the predictive value of the current sex ratio.

scholarly journals Secondary sex ratio of nestlings of the blackbird (Turdus merula)

2016 ◽  
Vol 23 ◽  
pp. 69-73
Author(s):  
Piotr Nowacki ◽  
Piotr Piliczewski ◽  
Tomasz Rek ◽  
Beata Kirjaka ◽  
Dariusz Wysocki
Keyword(s):  
Sex Ratio ◽  
Turdus Merula ◽  
Secondary Sex Ratio

scholarly journals Sex Ratio and Growth Pattern of Coconut Crabs Birgus latro (Crustacea, Decapoda, Cianobitidae) in North Moluccas Province, Indonesia

Omni-Akuatika ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Rugaya Serosero ◽  
Sulistiono Sulistiono ◽  
Nurlisa A. Butet ◽  
Etty Riani
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Growth Pattern ◽  
B Value ◽  
Strongly Correlated ◽  
Thorax Length ◽  
Large Size ◽  
Cephalothorax Length ◽  
Relationship Of ◽  
The Relationship

Coconut crab (Birgus latro) is a crustacean that has a large size until four kilograms. The study  aimed to analyze sex ratio and growth pattern including the relationship of thorax length - body weight, thorax width - body weight and cephalothorax length plus rostrum - body weight in Daeo (Morotai Island), Laigoma (South Halmahera District) and Fitako (North Halmahera District). The sex ratio was determined using χ2 test and the growth pattern was tested by the b value through t test. The results showed sex ratio of 1: 0.9 in Daeo (n = 581), 1: 0.6 in Laigoma (n = 24), and 1: 2 in Fitako (n = 31). The relationship of thorax length, thorax width and cephalothorax length plus rostrum with body weight were strongly correlated (R2> 70%). The growth pattern of coconut crab in Daeo was negative allometric, while in Laigoma and Fitako were negative allometric and isometric.

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