نتایج جستجو برای: maternal environmental
تعداد نتایج: 470255 فیلتر نتایج به سال:
Restricted maximum likelihood estimates of covariance components and the resulting genetic parameters were obtained for birth, weaning, yearling and final weights and postweaning gain of Australian Charolais cattle fitting an animal model including genetic or permanent environmental maternal effects. No 'carry-over' of maternal effects till weaning on postweaning weights w& found. Direct herita...
Fertility is a discrete trait with two categories (1, successful mating, 0, unsuccessful mating). A Bayesian analysis with a binary threshold animal model has been performed with 18 695 AI mating records from 1987 to 1997, concerning 4085 sows and 187 boars. The pedigree included all individuals genetically linked with data. The binary response was modeled under a probit approach. The model for...
The yellow, orange, or red colors of salmonid eggs are due to maternally derived carotenoids whose functions are not sufficiently understood yet. Here, we studied the significance of naturally acquired carotenoids as maternal environmental effects during embryo development in brown trout (Salmo trutta). We collected eggs from wild females, quantified their egg carotenoid content, fertilized the...
Many lines of data, initial epidemiologic studies as well as subsequent extensive experimental studies, indicate that early-life events play a powerful role in influencing later suceptibility to certain chronic diseases. Such events might be over- or undernutrition, exposure to environmental toxins, but also changes in hormones, in particular stress hormones. Typically, those events are trigger...
the purpose of this study was to investigate the relationship of maternal breeding values of the weight of day-old chick chicks in a commercial broiler line with egg traits including yolk fatty acids. maternal breeding values of 63 hens of known pedigree were estimated through an animal model, containing direct additive genetic effect, maternal additive genetic effect, maternal common environme...
1. Maternal and environmental factors influence embryo development and offspring phenotypes in ways that are likely to impact fitness. Most studies that address this issue, however, fail to mimic the complexities of natural environmental parameters and only quantify selection during a single season. 2. In this study, we examined year-to-year variation in how maternal factors (egg mass, nesting ...
Variation in fitness generated by differences in functional performance can often be traced to morphological variation among individuals within natural populations. However, morphological variation itself is strongly influenced by environmental factors (e.g., temperature) and maternal effects (e.g., variation in egg size). Understanding the full ecological context of individual variation and na...
Maternal effects are ubiquitous in nature and affect a wide range of offspring phenotypes. Recent research suggests that maternal effects also contribute to ageing, but the theoretical basis for these observations is poorly understood. Here we develop a simple model to derive expectations for (i) if maternal effects on ageing evolve; (ii) the strength of maternal effects on ageing relative to d...
Background: Many factors affect exclusive breastfeeding, include method of delivery, parity, maternal age and education, smoking, ethnicity, pregnancy complications, infant health, and environmental factors such as hospital practices, and social support. Recently, maternal obesity has been suggested as a risk factor for poor breast-feeding practices whose role has not...
Evolution of size and growth depends on heritable variation arising from additive and maternal genetic effects. Levels of heritable (and nonheritable) variation might change over ontogeny, increasing through "variance compounding" or decreasing through "compensatory growth." We test for these processes using a meta-analysis of age-specific weight traits in domestic ungulates. Generally, mean st...
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