scholarly journals Artificial selection and maintenance of genetic variance in the global dairy cow population

2005 ◽  
Vol 360 (1459) ◽  
pp. 1479-1488 ◽  
Author(s):  
S Brotherstone ◽  
M Goddard

Genetic improvement of dairy cows, which has increased the milk yield of cows in the UK by 1200 kg per lactation in 12 years, is an excellent example of the application of quantitative genetics to agriculture. The most important traits of dairy cattle are expressed only in females, but the main opportunity for selection is in males. Despite this, genetic improvement was achieved by the invention of a new statistical methodology, called ‘best linear unbiased prediction’ to estimate the breeding value of bulls. Intense selection of the best bulls, combined with the worldwide use of these bulls through artificial insemination and frozen semen, has created a global population and caused concern that the genetic variation available in the future will be reduced. Maintenance of genetic variation and long-term genetic gains would be aided by rational payment systems, use of crossbreeding where profitable, inclusion of all economically important traits in the breeding objective, recognition of genotype by environment interactions and the use of selection algorithms that balance estimated breeding value against the average relationship among the selected animals. Fortunately, all of these things are happening to some degree.

2003 ◽  
Vol 2003 ◽  
pp. 46-46
Author(s):  
S. Avendaño ◽  
J.A. Woolliams ◽  
B. Villanueva

Dynamic selection algorithms using quadratic indices to optimise the contributions of selection candidates for maximising rates of genetic gain (ΔG) while constraining the rate of inbreeding (ΔF) in the long-term to pre-defined values, are available (Grundy et al, 1998). Avendaño et al (2001 a,b) applied these optimal selection algorithms on the UK Meatlinc (sheep) and Aberdeen Angus (beef cattle) pedigree breeds and found substantial expected increases (of at least 17%) in the average index score at the observed ΔF. Although these algorithms constitute powerful operational tools for breeding schemes, the framework for deterministically predicting ΔG under optimal selection with restricted ΔF is not yet available. This study presents a novel approach to this problem.


2020 ◽  
Author(s):  
Emily Budzynski-Seymour ◽  
James Steele ◽  
Michelle Jones

Physical activity (PA) is considered essential to overall health yet it is consistently reported that children are failing to meet the recommended levels. Due to the bidirectional relationship between affective states and PA, affective responses are a potential predictor to long term engagement. Since late March 2020 the UK government enforced ‘lockdown’ measures to help control the spread of Coronavirus (COVID-19); however, this has impacted children’s PA. Using online resources at home to support PA is now common. The primary aim of this research was to investigate the use of the Change4Life 10-minute Shake Ups to support PA by examining the effects of Disney branding upon children’s (n=32) post activity affective responses and perceived exertion. The secondary was to investigate the effect of the lockdown on PA habits. Children had similar positive affective responses and perceived effort to activities; however, branding was considered to be a key contributing factor based upon qualitative feedback from parents. Children’s PA levels dropped slightly since ‘lockdown’ was imposed; though online resources have been utilised to support PA. The use of immersive elements such as characters and narrative in PA sessions, as well as utilising online resources during ‘lockdown’ appear potentially promising for future research.


Author(s):  
Hunter M. Holzhauer

This chapter begins with a breakdown of recent growth trends for the overall commodities market. However, the long-term future of the market will heavily depend on three pressing issues: excess supply, increased regulations, and algorithmic trading. The section on excess supply explores how traders are changing strategies to adjust to the current imbalance between supply and demand, especially in the steel industry, and how that imbalance might change in the future based on global population trends and climate change concerns. The next section examines several regulatory trends, including the dramatic exodus of some investment banks from certain segments of the commodities market followed by a section focusing on how algorithmic trading is influencing how commodities are traded. A discussion of potential scenarios for the commodities market follows. The chapter concludes by examining a few ways in which the market and commodity traders may both survive and even thrive in the future.


Author(s):  
Paul Brooker ◽  
Margaret Hayward

The Armani high-fashion example illustrates the importance of adaptive rational methods in his founding and developing of an iconic high-fashion firm. Armani adapted stylistically to fashion’s new times in the 1970–80s by creating a new style catering for the career woman. His stylistic adaptation is compared with that of another famous Italian fashion designer, Versace, who instead modernized haute couture fashion and created a succession of glamourous styles. Both leaders exploited the same opportunity but in different ways. The third section compares these leaders’ legacies in the 1990s–2000s and assesses from a long-term perspective how capably they had used adaptive rational methods. The final section shifts the focus from fashion to the cosmetics industry and from Italy to the UK. Anita Roddick used adaptive rational methods to establish The Body Shop corporation in the 1970s–80s. However, she then abandoned rational methods with dire results for her corporation in the 1990s.


2019 ◽  
Vol 14 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Sarah Hutchinson ◽  
Paul Ellison ◽  
Andrew Levy ◽  
David Marchant

Objective Concussion is a common injury in ice hockey, and previous research suggests some misconceptions and unsafe attitudes amongst players. The purpose of this study was to assess sport concussion knowledge, attitudes and the effect of sport concussion history in UK-based male ice hockey players across three levels of competition: professional, semi-professional and amateur. Methods Sixty-one participants across a number of UK ice hockey teams completed the Rosenbaum Concussion Knowledge and Attitudes Survey and reviewed a series of statements to assess knowledge (concussion knowledge index), attitudes (concussion attitude index) and misconceptions of concussion. Results Level of competition and concussion history had no significant effect on concussion knowledge index or concussion attitude index. A positive significant relationship exists between playing experience and concussion knowledge index and concussion attitude index. Statements identified common misconceptions and areas of accurate knowledge regarding concussion symptoms suggesting that male ice hockey players have a higher level knowledge compared to a sample of the UK general public. Playing experience was associated with increased knowledge and increasingly safe attitudes towards concussion. Conclusion Despite knowledge relating to loss of consciousness and correct management of symptoms being generally accurate, there are worryingly unsafe attitudes regarding aspects of concussion. Such attitudes may well pose significant threats to players’ safety and long-term health.


Genetics ◽  
1997 ◽  
Vol 146 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Michael Travisano

The effect of environment on adaptation and divergence was examined in two sets of populations of Escherichia coli selected for 1000 generations in either maltose- or glucose-limited media. Twelve replicate populations selected in maltose-limited medium improved in fitness in the selected environment, by an average of 22.5%. Statistically significant among-population genetic variation for fitness was observed during the course of the propagation, but this variation was small relative to the fitness improvement. Mean fitness in a novel nutrient environment, glucose-limited medium, improved to the same extent as in the selected environment, with no statistically significant among-population genetic variation. In contrast, 12 replicate populations previously selected for 1000 generations in glucose-limited medium showed no improvement, as a group, in fitness in maltose-limited medium and substantial genetic variation. This asymmetric pattern of correlated responses suggests that small changes in the environment can have profound effects on adaptation and divergence.


2021 ◽  
Vol 10 (7) ◽  
pp. 1444
Author(s):  
William Myles ◽  
Catherine Dunlop ◽  
Sally A. McFadden

Myopia will affect half the global population by 2050 and is a leading cause of vision impairment. High-dose atropine slows myopia progression but with undesirable side-effects. Low-dose atropine is an alternative. We report the effects of 0.01% or 0.005% atropine eye drops on myopia progression in 13 Australian children aged between 2 and 18 years and observed for 2 years without and up to 5 years (mean 2.8 years) with treatment. Prior to treatment, myopia progression was either ‘slow’ (more positive than −0.5D/year; mean −0.19D/year) or ‘fast’ (more negative than −0.5D/year; mean −1.01D/year). Atropine reduced myopic progression rates (slow: −0.07D/year, fast: −0.25D/year, combined: before: −0.74, during: −0.18D/year, p = 0.03). Rebound occurred in 3/4 eyes that ceased atropine. Atropine halved axial growth in the ‘Slow’ group relative to an age-matched model of untreated myopes (0.098 vs. 0.196mm/year, p < 0.001) but was double that in emmetropes (0.051mm/year, p < 0.01). Atropine did not slow axial growth in ‘fast’ progressors compared to the age-matched untreated myope model (0.265 vs. 0.245mm/year, p = 0.754, Power = 0.8). Adverse effects (69% of patients) included dilated pupils (6/13) more common in children with blue eyes (5/7, p = 0.04). Low-dose atropine could not remove initial myopia offsets suggesting treatment should commence in at-risk children as young as possible.


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