Season and reproductive status rather than genetic factors influence change in ewe weight and fat over time 2. Spline analysis of crossbred ewes

2014 ◽  
Vol 54 (6) ◽  
pp. 814 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
N. M. Fogarty ◽  
S. Hatcher ◽  
...  
Keyword(s):  
Genetic Factors ◽  
Genetic Effects ◽  
Low Fertility ◽  
Production Cycle ◽  
Fat Reserves ◽  
Variable Environments ◽  
Maternal Performance ◽  
Fat Score ◽  
Sire Breed ◽  
Over Time

The success of slaughter lamb enterprises is heavily influenced by the ability of the breeding ewe to produce a lamb annually across variable environments. It has been shown that by maintaining heavier weight and condition across the annual production cycle producers can make significant improvements in maternal performance. This paper follows on from a previous analysis of crossbred ewes within the Maternal Central Progeny Test and examines the potential to select for reduced fluctuation in weight and fat across the production cycle. A cubic spline model was fitted to the weight and fat score data from the first three parities of 2688 first-cross ewes. The analysis partitioned the influence of environment, reproduction and genetic effects on the shape of the weight and fat score splines across three parities. Yearly and seasonal variation in feed supply and the demands of raising a lamb are the major influences on fluctuations in the weight and fat score of the breeding ewe. The genetic effects were constant across time with 98 and 92% of the genetic variation for weight and fat, respectively, associated with the spline’s intercept. In agreement with the findings of the first paper of the series it can be concluded that genetic lines do not re-rank for weight or fat score over time. The influence of sire breed on weight and fat score was constant across time with sire breeds fluctuating in parallel across time. As a result it is concluded that to avoid low fat reserves and the subsequent low fertility during the ‘tough’ periods, selection to improve ewe body condition could be made at any time and under any environmental conditions.

Season and reproductive status rather than genetics factors influence change in ewe weight and fat over time. 1. Analysis of crossbred ewes

2014 ◽  
Vol 54 (6) ◽  
pp. 802 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
N. M. Fogarty ◽  
S. Hatcher ◽  
...  
Keyword(s):  
Genetic Correlations ◽  
Adult Life ◽  
Production Cycle ◽  
Strong Correlations ◽  
Multiple Production ◽  
Fat Reserves ◽  
Production Cycles ◽  
Australian Sheep ◽  
Maternal Performance ◽  
Fat Score

The Australian sheep industry has historically made rapid advances in the quality and quantity of meat and wool through genetic improvement, but unfortunately, maternal performance, i.e. number of lambs weaned, is well below desired levels. The aim of the present paper is to investigate the potential to select for increased weight and fat across the production cycle to improve maternal performance. The analysis explores the potential to improve the weight and fat score of breeding ewes during ‘tough’ periods (i.e. when nutrient requirements are not met by the pasture), preparing the breeding ewe for the upcoming mating without an increase in overall ewe size. The 2846 ewes within the maternal central progeny test were weighed and scored for fatness 12 times across three production cycles. Low to moderate heritability estimates for weight (0.04–0.23) and fat (0.02–0.06) changes across the production cycle provide little hope for selection against weight loss during tough periods. The analysis showed very strong genetic correlations between time-points across multiple production cycles for both weight (0.99–0.93) and fat score (0.88–0.98). The very strong correlations between measurements suggest that weight and fat score are genetically the same trait throughout the ewe’s adult life. With 74% and 77% of the genetic variation in weight and fat, respectively, constant across the production cycle, there is little opportunity to select against the natural fluctuations in weight and fat reserves. In conclusion, selection for increased fat can be made at any time and it will result in more fat during tough times.

scholarly journals Decreased heritability and emergence of novel genetic effects on pulse wave velocity from youth to young adulthood

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yisong Huang ◽  
Shaoyong Su ◽  
Harold Snieder ◽  
Frank Treiber ◽  
Gaston Kapuku ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Pulse Wave Velocity ◽  
Wave Velocity ◽  
Young Adulthood ◽  
Ethnic Differences ◽  
Genetic Factors ◽  
Pulse Wave ◽  
Environmental Influences ◽  
Genetic Effects ◽  
Over Time

AbstractIncreased arterial stiffness measured by pulse wave velocity (PWV) is an important parameter in the assessment of cardiovascular risk. Our previous longitudinal study has demonstrated that carotid-distal PWV showed reasonable stability throughout youth and young adulthood. This stability might be driven by genetic factors that are expressed consistently over time. We aimed to illustrate the relative contributions of genetic and environmental factors to the stability of carotid-distal PWV from youth to young adulthood. We also examined potential ethnic differences. For this purpose, carotid-distal PWV was measured twice in 497 European American (EA) and African American (AA) twins, with an average interval time of 3 years. Twin modelling on PWV showed that heritability decreased over time (62–35%), with the nonshared environmental influences becoming larger. There was no correlation between the nonshared environmental factors on PWV measured at visit 1 and visit 2, with the phenotypic tracking correlation (r = 0.32) completely explained by shared genetic factors over time. Novel genetic influences were identified accounting for a significant part of the variance (19%) at the second measurement occasion. There was no evidence for ethnic differences. In summary, novel genetic effects appear during development into young adulthood and account for a considerable part of the variation in PWV. Environmental influences become larger with age for PWV.

Heritability of Longitudinal Measures of Body Mass Index and Lipid and Lipoprotein Levels in Aging Twins

2007 ◽  
Vol 10 (5) ◽  
pp. 703-711 ◽  
Author(s):  
Ellen L. Goode ◽  
Stacey S. Cherny ◽  
Joe C. Christian ◽  
Gail P. Jarvik ◽  
Mariza de Andrade
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Genetic Factors ◽  
Significant Proportion ◽  
Lipoprotein Cholesterol ◽  
Equation Modeling ◽  
Shared Environment ◽  
Significant Contributor ◽  
Age Related ◽  
Over Time

AbstractBody-mass index (BMI), total cholesterol (TC), lowdensity lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) levels are known to be highly heritable. We evaluated the genetic and environmental relationships of these measures over time in an analysis of twin pairs. Monozygotic (235 pairs) and dizygotic (260 pairs) male twins were participants in the National Heart Lung and Blood Institute Veteran Twin Study, and were followed with three clinical exams from mean age 48 years to mean age 63 years. Structural equation modeling (SEM) with adjustment forAPOEgenotype (a significant contributor to TC and LDL-C) was used to assess longitudinal patterns of heritability. Results indicated a contribution of genetic factors to BMI, TC, LDL-C, HLD-C, and TG. Modest increases over time were observed in the heritability of BMI (from 0.48 to 0.61), TC (from 0.46 to 0.57), LDL-C (from 0.49 to 0.64), and HDL-C (from 0.50 to 0.62), but this trend was not present for TG. There was a corresponding decrease in shared environmental influences over time for these traits, although shared environment was a significant contributor only for HDL-C. Moreover, we observed that genetic influences for all measures were significantly correlated over time, and we found no evidence of age-specific genetic effects. In summary, longitudinal analyses of twin data indicate that genetic factors do not account for a significant proportion of the variation in age-related changes of BMI or lipid and lipoprotein levels.

scholarly journals Behavioral effects of the neurotoxin ß-N-methylamino-L-alanine on the mangrove rivulus (Kryptolebias marmoratus) larvae

2018 ◽  
Author(s):  
Alessandra Carion ◽  
Julie Hétru ◽  
Angèle Markey ◽  
Victoria Suarez-Ulloa ◽  
Silvestre Frédéric
Keyword(s):  
Genetic Factors ◽  
Prey Capture ◽  
Aquatic Ecotoxicology ◽  
Low Genetic Diversity ◽  
Variable Environments ◽  
Maximal Speed ◽  
Self Fertilization ◽  
Kryptolebias Marmoratus ◽  
Mangrove Rivulus

Mangrove rivulus, Kryptolebias marmoratus, is a hermaphrodite fish capable of self-fertilization. This particularity allows to naturally produce highly homozygous and isogenic individuals. Despite the low genetic diversity, rivulus can live in extremely variable environments and adjust its phenotype accordingly. This species represents a unique opportunity to clearly distinguish the genetic and non-genetic factors implicated in adaptation and evolution, such as epigenetic mechanisms. It is thus a great model in aquatic ecotoxicology to investigate the effects of xenobiotics on the epigenome, and their potential long-term impacts. In the present study, we used the mangrove rivulus to investigate the effects of the neurotoxin ß-N-methylamino-L-alanine (BMAA) on larvae behaviors after 7 days exposure to two sub-lethal concentrations. Results show that BMAA can affect the maximal speed and prey capture (trials and failures), suggesting potential impacts on the organism’s fitness.

Season and reproductive status rather than genetic factors influence change in ewe weight and fat over time. 4. Genetic relationships of ewe weight and fat score with fleece, reproduction and milk traits

2016 ◽  
Vol 56 (4) ◽  
pp. 708 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
N. M. Fogarty ◽  
S. Hatcher ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Fat ◽  
Genetic Relationships ◽  
Fibre Diameter ◽  
Reproductive Traits ◽  
Production Cycle ◽  
Production Traits ◽  
Milk Production Traits ◽  
Milk Traits ◽  
Fat Score

The profitability of a sheep enterprise is greatly influenced by the ability of the ewe to produce a lamb annually. This paper examines the between- and within-breed association between the liveweight and fat score of the adult ewe and key fleece, reproduction and milk production traits. The study analysed the performance of 2846 first-cross Merino and Corriedale ewes from the maternal central progeny test (MCPT) over their first three production cycles. Breed (9 sire breeds) and within-breed (91 sires) correlations were calculated from bivariate correlations of adult liveweight and fat score with fleece, reproduction and milk production traits. The mean liveweight and fatness of the breeds were low to moderately negatively correlated with greasy fleece weight (–0.55 and –0.25, respectively) and moderate to strongly positively correlated with fibre diameter (0.88 and 0.41, respectively). However, the within-breed correlations were generally low to negligible. The genetic relationships between ewe fat score and reproductive traits at the breed and within-breed level was generally low to negligible and, in some cases, negative under production conditions where the ewes were well managed and averaged a fat score of 3.5 pre-joining and became too fat across the production cycle. Strong breed correlations between ewe fat score and milk fat concentration (0.88) suggest that selection of fatter sire breeds will lead to increased fat in their progenies’ milk, which was associated with larger lambs. The potential advantages of selecting for more fat to improve the maternal performance of the ewe seem to be limited in enterprises where the production system can easily be adjusted to restrict the influence of temporary and long-term feed deficiencies, as was achieved within the MCPT research flocks.

Recent trends in pig production: the importance of intake

1989 ◽  
Vol 13 ◽  
pp. 1-5 ◽  
Author(s):  
J. E. Riley
Keyword(s):  
Food Intake ◽  
Growth Traits ◽  
Meat Production ◽  
Production Cycle ◽  
Limiting Factor ◽  
New Production ◽  
Fat Reserves ◽  
Production Cycles ◽  
The Individual ◽  
The Uk

AbstractThe UK pig industry has shown an ability to respond quickly to changing market requirements and improving efficiency of pig meat production. Rapid genetic improvement in breeding stock, particularly in carcass quality and growth traits, together with the adoption of new production strategies, have been the main factors. These changes have had major implications for the way pigs are fed at all stages of the production cycles. Market forces have resulted in a pig population with reduced fat reserves and low appetite. Food intake is a limiting factor at several stages of the production cycle including post weaning, in the case of early-weaned piglets, and the management of young lactating sows. Knowledge of the daily nutrient requirements of the individual animal far exceeds the ability to ensure that those requirements are satisfied by feeding systems in commercial use. Manipulation of food intake to achieve optimum profit is the weakest link in the UK producers' knowledge.

Winter corticosterone and body condition predict breeding investment in a nonmigratory bird

2019 ◽  
Vol 30 (6) ◽  
pp. 1642-1652 ◽  
Author(s):  
Chloé Montreuil-Spencer ◽  
Kelsey Schoenemann ◽  
Ádám Z Lendvai ◽  
Frances Bonier
Keyword(s):  
Life History ◽  
Breeding Season ◽  
Body Condition ◽  
Reproductive Investment ◽  
Phenotypic Traits ◽  
Residual Body ◽  
Life History Stage ◽  
Nonbreeding Season ◽  
Fat Reserves ◽  
Fat Score

Abstract Reproduction is an energetically demanding life history stage that requires costly physiological and behavioral changes, yet some individuals will invest more into reproduction and breed more successfully than others. To understand variation in reproductive investment, previous studies have evaluated factors during breeding, but conditions outside of this life history stage may also play a role. Using a free-ranging population of black-capped chickadees (Poecile atricapillus), we assessed the repeatability of plastic traits relating to energetic condition (circulating initial corticosterone concentrations and body condition) during the nonbreeding season and evaluated whether these traits predicted reproductive investment in the subsequent breeding season. We found that initial corticosterone concentrations and an index of body condition, but not fat score, were moderately repeatable over a 1-week period in winter. This trait repeatability supports the interpretation that among-individual variation in these phenotypic traits could reflect an intrinsic strategy to cope with challenging conditions across life history stages. We found that females with larger fat reserves during winter laid eggs sooner and tended to spend more time incubating their eggs and feeding their offspring. In contrast, we found that females with higher residual body mass delayed breeding, after controlling for the relationship between fat score and timing of breeding. Additionally, females with higher initial corticosterone in winter laid lighter eggs. Our findings suggest that conditions experienced outside of the breeding season may be important factors explaining variation in reproductive investment.

scholarly journals Genetic amplification and the individualization of the parent–child relationship across adolescence

2012 ◽  
Vol 43 (2) ◽  
pp. 413-422 ◽  
Author(s):  
S. Ludeke ◽  
W. Johnson ◽  
M. McGue ◽  
W. G. Iacono
Keyword(s):  
Criminal Behavior ◽  
Genetic Factors ◽  
Freedom Of Expression ◽  
Genetic Influence ◽  
Self Report ◽  
Parent Child Relationship ◽  
Psychological Traits ◽  
Child Relationship ◽  
Over Time ◽  
Parent Child

BackgroundMany psychological traits become increasingly influenced by genetic factors throughout development, including several that might intuitively be seen as purely environmental characteristics. One such trait is the parent–child relationship, which is associated with a variety of socially significant outcomes, including mental health and criminal behavior. Genetic factors have been shown to partially underlie some of these associations, but the changing role of genetic influence over time remains poorly understood.MethodOver 1000 participants in a longitudinal twin study were assessed at three points across adolescence with a self-report measure regarding the levels of warmth and conflict in their relationships with their parents. These reports were analyzed with a biometric growth curve model to identify changes in genetic and environmental influences over time.ResultsGenetic influence on the child-reported relationship with parent increased throughout adolescence, while the relationship's quality deteriorated. The increase in genetic influence resulted primarily from a positive association between genetic factors responsible for the initial relationship and those involved in change in the relationship over time. By contrast, environmental factors relating to change were negatively related to those involved in the initial relationship.ConclusionsThe increasing genetic influence seems to be due to early genetic influences having greater freedom of expression over time whereas environmental circumstances were decreasingly important to variance in the parent–child relationship. We infer that the parent–child relationship may become increasingly influenced by the particular characteristics of the child (many of which are genetically influenced), gradually displacing the effects of parental or societal ideas of child rearing.

scholarly journals Nutrient Release from Controlled-release Fertilizers in Acid Substrate in a Greenhouse Environment: I. Leachate Electrical Conductivity, pH, and Nitrogen, Phosphorus, and Potassium Concentrations

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 780-787 ◽  
Author(s):  
Donald J. Merhaut ◽  
Eugene K. Blythe ◽  
Julie P. Newman ◽  
Joseph P. Albano
Keyword(s):  
Electrical Conductivity ◽  
Controlled Release ◽  
Nutrient Release ◽  
Low Fertility ◽  
Plant Production ◽  
Production Cycle ◽  
Permissible Levels ◽  
Phosphorus And Potassium ◽  
Acid Substrate ◽  
Controlled Release Fertilizers

Release characteristics of four types of controlled-release fertilizers (Osmocote, Nutricote, Polyon, and Multicote) were studied during a 47-week simulated plant production cycle. The 2.4-L containers containing a low-fertility, acid-based substrate were placed in an unheated greenhouse and subjected to environmental conditions often used for production of azaleas and camellias. Leachate from containers was collected weekly and monitored for pH, electrical conductivity, and concentrations of NH4+ N, NO3–N, total P and total K. Leachate concentrations of all nutrients were relatively high during the first 10 to 20 weeks of the study, and then gradually decreased during the remaining portion of the experiment. Differences were observed among fertilizer types, with Multicote often resulting in higher concentrations of N, P, and K in leachates compared to the leachates from the other fertilizer types during the first half of the study. Concentrations of NO3– and P from all fertilizer types were often above permissible levels as cited in the federal Clean Water Act.

Inter- and intra-individual variation in the response to TMS

2012 ◽  
Author(s):  
Eric M. Wassermann
Keyword(s):  
Genetic Factors ◽  
Motor Evoked Potentials ◽  
Gross Anatomy ◽  
Short Term ◽  
Fields Of Study ◽  
Normal Individuals ◽  
Large Motor ◽  
Neurologically Normal ◽  
Over Time

The variable amplitude of motor cortex is a striking aspect of the muscle response to transcranial magnetic stimulation. It is easy to produce large motor-evoked potentials (MEPs) in some healthy subjects, while others' cortico-muscular pathways seem barely excitable, even by the strongest available stimuli. MEP amplitude and other measures also vary widely within individuals over time. The factors of these differences among and within individuals are age, gross anatomy of the individuals, genetic factors, and physiological differences associated with behavioural and other traits such as personality, conditions like migraine. The MEP varies over time within individuals at rest under laboratory conditions. These variations can be short term or long term. Differences among neurologically normal individuals have important implications for research using TMS. These differences open doors to new fields of study to neurophysiologists in the treatment and etiology of brain disease.

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