scholarly journals Short communication: Genetic analysis of lactation curves in buffaloes, using Wood’s model

2020 ◽  
Vol 18 (3) ◽  
pp. e04SC01
Author(s):  
Ludmilla A. Marques de Carvalho ◽  
Guilherme F. de Moura ◽  
Dheynne A. Vieira ◽  
Naudin A. Hurtado-Lugo ◽  
Rusbel R. Aspilcueta-Borquis ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Short Communication ◽  
Genetic Correlations ◽  
Peak Time ◽  
Breeding Programs ◽  
High Magnitude ◽  
Lactation Curve ◽  
Heritability Estimates ◽  
The Individual

Aim of study: To estimate the heritability and genetic correlations for lactation curve traits in buffaloes.Area of study: The buffalo cows were raised on properties located in the states of São Paulo, Ceará and Rio Grande do Norte, Brazil.Material and methods: The individual parameters of Wood’s model ( , , and ) were obtained using a non-linear mixed model. Peak yield (PY), peak time (PT) and lactation persistency (LP) were also calculated. These individual parameters were employed in multi-trait analysis with the milk yield (MY) using Bayesian inference.Main results: The heritability estimates were of low to moderate magnitudes, with values ranging from 0.156 ( ) to 0.299 (PY). The estimates for genetic correlation between the Wood’s parameters and MY were of low to high magnitude and ranged from -0.533 (  and MY) to 0.983 (PY and MY).Research highlights: The heritability estimates obtained indicate that the traits studied can be used in animal breeding programs.

scholarly journals Short communication: QTL mapping for ear tip-barrenness in maize

2016 ◽  
Vol 14 (3) ◽  
pp. e07SC01 ◽  
Author(s):  
Junqiang Ding ◽  
Jinliang Ma ◽  
Jiafa Chen ◽  
Tangshun Ai ◽  
Zhimin Li ◽  
...  
Keyword(s):  
Quantitative Trait ◽  
Genetic Basis ◽  
Mixed Model ◽  
Short Communication ◽  
Genotypic Variation ◽  
Interval Mapping ◽  
Mapping Method ◽  
Additive Effects ◽  
Breeding Programs ◽  
Model Composite

Barren tip on corn ear is an important agronomic trait in maize, which is highly associated with grain yield. Understanding the genetic basis of tip-barrenness may help to reduce the ear tip-barrenness in breeding programs. In this study, ear tip-barrenness was evaluated in two environments in a F2:3 population, and it showed significant genotypic variation for ear tip-barrenness in both environments. Using mixed-model composite interval mapping method, three additive effects quantitative trait loci (QTL) for ear tip-barrenness were mapped on chromosomes 2, 3 and 6, respectively. They explained 16.6% of the phenotypic variation, and no significant QTL × Environment interactions and digenic interactions were detected. The results indicated that additive effect was the main genetic basis for ear tip-barrenness in maize. This is the first report of QTL mapped for ear tip-barrenness in maize.

scholarly journals Categorical Visual Score Traits of a Nellore Beef Cattle Population

2017 ◽  
Vol 9 (8) ◽  
pp. 63
Author(s):  
Jairo Azevedo Junior ◽  
Juliana Petrini ◽  
Gerson Barreto Mourão ◽  
José Bento Sterman Ferraz
Keyword(s):  
Variance Components ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Genetic Correlations ◽  
Estimation Method ◽  
Analysis Data ◽  
Suitable Model ◽  
Linear Distribution ◽  
Tropical Regions ◽  
Trait Analysis

Variance components and genetic parameters of economically relevant traits in livestock, whether continuous or categorical, can be estimated by methods computationally available providing support for the selection and mating of animals in breeding programs. The objectives of this paper were to obtain and compare the variance components estimates for visual traits under continuous or categorical distribution in single-trait analysis and their correlations with continuous productive traits in two-trait analysis. Data of conformation (CONF), precocity of fat deposition (PREC) and muscling (MUSC) visual scores evaluated at 18 months of age as well as the weight at 18 months of age (YW) were collected from animals born from 2000 to 2012, in Nellore cattle herds raised in Southeastern and Central Western tropical regions of Brazil. Methods III of Henderson, Restricted Maximum Likelihood (REML), Bayesian Inference and generalized linear mixed model (GLMM) were tested. Variance components obtained from single-trait analysis were similar to those obtained from two-trait analysis. The estimates of heritability (h2) for the visual scores ranged from 0.1081 to 0.2190. Heritability estimates for traits evaluated by visual scores have moderate to high magnitude justifying the inclusion of visual scores as selection criteria in animal breeding and the selection of animals with higher scores for mating. High genetic correlations between yearling weight and morphological traits were verified. For visual scores of conformation, precocity and muscling, the most suitable model based on one-trait or two-trait analyses considered an animal model, a linear distribution of the data and the estimation method of the components of (co)variance based on Bayesian methodology.

scholarly journals Genetic Variation and Correlation among Resin Yield, Growth, and Morphologic Traits of Pinus massoniana

2013 ◽  
Vol 62 (1-6) ◽  
pp. 38-43 ◽  
Author(s):  
Qinghua Liu ◽  
Zhichun Zhou ◽  
Huihua Fan ◽  
Yurong Liu
Keyword(s):  
Genetic Correlation ◽  
Genetic Correlations ◽  
Tree Height ◽  
Pinus Massoniana ◽  
The Other ◽  
Breeding Programs ◽  
Family Effects ◽  
Breast Height ◽  
Sib Families ◽  
The Individual

AbstractIn breeding programs, the variations and relationships among main traits need to be understood to develop selection and breeding strategies. Resin is considered as one of most important non-timber production of P. massoniana which can privides terpenes used in the chemical industry. The present study assessed the genetic variations in growth, morphologic traits, and resin yield, as well as the phenotypic and genetic correlations between these traits of 45 half-sib families of eight-year-old Pinus massoniana trees. All traits show highly significant family effects. The individual heritability for diameter at breast height (DBH) was the highest (hi2=0.55). Heritabilities for resin yield, tree height, crown depth, and the height to the live crown were slightly lower than DBH, ranging from 0.32 to 0.45. The other traits were under weak genetic control and heritabilities ranged from 0.17 to 0.20. All growth and morphologic traits were significantly correlated genetically with resin yield. Number of living branches had the highest genetic correlation with resin yield (rg=0.99), followed by DBH and number of living whorls (rg=0.73 and 0.70). Only a moderate positive genetic correlation with resin yield was found with the other traits (rg=0.47-0.57), except for height under the living branches (rg=-0.45). The results of this study indicate that both resin yield and growth can be improved simultaneously in the next generation. Of the traits assessed DBH was the optimum trait for indirectly selecting high-yielding resin trees.

scholarly journals Genetic parameters for fatty acids in intramuscular fat from feedlot-finished Nelore carcasses

2018 ◽  
Vol 58 (2) ◽  
pp. 234 ◽  
Author(s):  
Carolyn Aboujaoude ◽  
Angélica Simone Cravo Pereira ◽  
Fabieli Louise Braga Feitosa ◽  
Marcos Vinicius Antunes de Lemos ◽  
Hermenegildo Lucas Justino Chiaia ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Genetic Correlation ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Intramuscular Fat ◽  
Zebu Cattle ◽  
Fa Composition ◽  
Heritability Estimates ◽  
The Individual ◽  
Long Chain

The aim of the present study was to estimate covariance components and genetic parameters for beef fatty acid (FA) composition of intramuscular fat in the longissimus thoracis muscle in Nelore bulls finished in feedlot. Twenty-two FAs were selected. The heritability estimates for individual FAs ranged from 0.01 to 0.35. The heritability estimates for myristic (0.25 ± 0.09), palmitic (0.18 ± 0.07), oleic (0.28 ± 0.09), linoleic (0.16 ± 0.06) and α-linolenic (0.35 ± 0.10) FAs were moderate. Stearic, elaidic, palmitoleic, vaccenic, conjugated linoleic acid, docosahexanoic, eicosatrienoic and arachidonic FAs had heritability estimates below 0.15. The genetic-correlation estimates between the individual saturated FAs (SFAs) were low and negative between myristic and stearic FAs (–0.22 ± 0.84), moderate between palmitic and myristic FAs (0.58 ± 0.56) and negative between palmitic and stearic FAs (–0.69 ± 0.45). The genetic correlations between the individual long-chain polyunsaturated FAs (PUFAs) were positive and moderate (>0.30). However, the genetic-correlation estimates between long-chain PUFAs and α-linolenic acid were low (<0.30), except for the correlation between arachidonic and α-linolenic acids. The genetic correlation estimates of the sums of SFAs with monounsaturated fatty acids and omega 6 FAs were low (0.25 ± 0.59 and –0.02 ± 0.51 respectively), high with PUFAs and omega 9 FAs (–0.85 ± 0.15 and 0.86 ± 0.17 respectively) and moderate with omega 3FAs (–0.67 ± 0.26). The present study demonstrated the existence of genetic variation and, hence, the possibility to increase the proportion of healthy and favourable beef FAs through selection. The results obtained in the study have provided knowledge to elucidate the additive genetic influence on FA composition of intramuscular fat. In addition, genetic-relationship estimates of intramuscular FA profile help seek strategies for genetic selection or genetic-based diet management to enhance the FA profile in Zebu cattle.

scholarly journals Genetic and non genetic effects for lactation curve traits in Holstein-Friesian cows

2012 ◽  
Vol 55 (5) ◽  
pp. 450-457 ◽  
Author(s):  
I. Boujenane ◽  
B. Hilal
Keyword(s):  
Milk Yield ◽  
Genetic Correlations ◽  
Genetic Effects ◽  
Peak Time ◽  
Holstein Friesian ◽  
Lactation Curve ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Calving Season ◽  
Friesian Cows

Abstract. The objective of this study was to determine the genetic and non genetic effects on lactation curve traits determined by the incomplete gamma function of Wood (1967) for Holstein-Friesian cows in Morocco. Data analysed included 49262 monthly records of the test-day milk yield from 4888 lactations of 3932 cows at their 1st, 2nd or 3rd parity collected during 1990 and 1999 in 232 herds enrolled in the official milk recording. In general, lactation curve traits (A, B, C, peak time [Tmax], peak milk yield [Ymax], persistency and 305 day milk yield [MY305]) were affected by herd, parity, age at calving, season of calving and year of calving. Heritability estimates were low and varied from 0.01 for parameter A to 0.10 for Ymax. Genetic and phenotypic correlations among traits varied from −0.79 to 1.00 and from −0.80 to 0.96, respectively. Genetic correlations between MY305 and parameter C were negative, but those between MY305 and all the other lactation curve traits were positive. It was concluded that selection for high peak milk yield and persistency will result in higher 305 day milk yield.

scholarly journals Analysis of Genetic Parameters for Reproductive Traits in Crossbred Dairy Cattle Maintained at Holetta Agricultural Research Center.

2020 ◽  
Vol 39 (01) ◽  
Author(s):  
Kefale Getahun ◽  
Million Tadesse ◽  
Direba Hundie
Keyword(s):  
Dairy Cattle ◽  
Genetic Parameters ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Agricultural Research ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Breeding Value ◽  
Research Center ◽  
Phenotypic Correlation

This study was aimed to generate information on variance components and the resulting genetic parameters (heritability, repeatability, genetic and phenotypic correlations and genetic trends) of some economic traits of Borena and its crosses with Holstein Friesian dairy cattle maintained at Holetta agricultural research center dairy farm. Traits studied were age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSC). Overall, 11331 dairy cattle reproductive performance records were used for the study. WOMBAT, which is a software package for quantitative genetic analysis of continuous traits, fitting a linear, mixed model; estimates of covariance components and the resulting genetic parameters were employed and obtained. Heritability values of reproductive traits were from very low (0.071, 0.082 and 0.012) for CI, DO and NSC to moderate (0.3 and 0.22) for AFC and AFS traits. Repeatability estimate for CI, DO and NSC were low (0.17, 0.17 and 0.129). Strong and positive genetic correlation (0.98) was appeared between AFS and AFC traits. Negative genetic correlations were observed between AFS and DO (-0.001), AFC and DO (-0.05), AFS and NSC (-0.022), AFC and NSC (-0.29) and CI and NSC (-0.31). AFS were negative phenotypic correlation with CI, DO and NSC. Similarly, AFC was negative phenotypic correlation with CI and DO. Low phenotypic correlation was observed between AFC and NSC, CI and DO, CI and NSC and, DO and NSC. Strong and positive phenotypic correlation was appeared between AFS and AFC. The regression coefficient of mean breeding value for NSC, CI, DO, AFC and AFS on year of birth were -0.0066x+13.25 times/year, -1.19x+2387.4 days/year, -1.23x+2445.6 days/year, 0.2x-410 months/year and 0.48x-980 months/year, respectively.

scholarly journals The Design of Early-Stage Plant Breeding Trials Using Genetic Relatedness

2020 ◽  
Vol 25 (4) ◽  
pp. 553-578 ◽  
Author(s):  
Brian R. Cullis ◽  
Alison B. Smith ◽  
Nicole A. Cocks ◽  
David G. Butler
Keyword(s):  
Plant Breeding ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Genetic Relatedness ◽  
Early Stage ◽  
Genetic Effects ◽  
Breeding Programs ◽  
Model Based ◽  
Selection Decisions ◽  
Design Generation

Abstract The use of appropriate statistical methods has a key role in improving the accuracy of selection decisions in a plant breeding program. This is particularly important in the early stages of testing in which selections are based on data from a limited number of field trials that include large numbers of breeding lines with minimal replication. The method of analysis currently recommended for early-stage trials in Australia involves a linear mixed model that includes genetic relatedness via ancestral information: non-genetic effects that reflect the experimental design and a residual model that accommodates spatial dependence. Such analyses have been widely accepted as they have been found to produce accurate predictions of both additive and total genetic effects, the latter providing the basis for selection decisions. In this paper, we present the results of a case study of 34 early-stage trials to demonstrate this type of analysis and to reinforce the importance of including information on genetic relatedness. In addition to the application of a superior method of analysis, it is also critical to ensure the use of sound experimental designs. Recently, model-based designs have become popular in Australian plant breeding programs. Within this paradigm, the design search would ideally be based on a linear mixed model that matches, as closely as possible, the model used for analysis. Therefore, in this paper, we propose the use of models for design generation that include information on genetic relatedness and also include non-genetic and residual models based on the analysis of historic data for individual breeding programs. At present, the most commonly used design generation model omits genetic relatedness information and uses non-genetic and residual models that are supplied as default models in the associated software packages. The major reasons for this are that preexisting software is unacceptably slow for designs incorporating genetic relatedness and the accuracy gains resulting from the use of genetic relatedness have not been quantified. Both of these issues are addressed in the current paper. An updating scheme for calculating the optimality criterion in the design search is presented and is shown to afford prodigious computational savings. An in silico study that compares three types of design function across a range of ancillary treatments shows the gains in accuracy for the prediction of total genetic effects (and thence selection) achieved from model-based designs using genetic relatedness and program specific non-genetic and residual models. Supplementary materials accompanying this paper appear online.

The effect of open plan furniture settings on sustained attention: a randomized crossover trial

2019 ◽  
Author(s):  
Caroline Kelly ◽  
Blake Staat ◽  
Erica Klenz
Keyword(s):  
Response Time ◽  
Work Environment ◽  
Sustained Attention ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Resource Depletion ◽  
Negative Experience ◽  
Individual Work ◽  
Open Plan ◽  
The Individual

Current prevalent discourse suggests that open plan offices provide a negative experience for millions of workers. Since a major dissatisfier in the open plan is the increase in distractions and lack of privacy and the associated lack of ability to concentrate, we conceived of a randomized crossover experimental design that would examine how different furniture settings might affect the performance of a task designed to measure sustained attention. Seventy-three participants completed the Sustained Attention Response Task in two sessions, once at an open Bench workstation and once at a semi-shielded Individual Work Environment (IWE), within the open plan. Data was analyzed in a linear mixed model and showed that participants had significantly fewer errors of commission (p=.0004) and an increased response time for Go trials before a failed No-Go trial (p=.0232) at the Individual Work Environment which indicates better sustained attention than at the Bench. An increased response time for go trials was greater at the Bench, though it did not meet the threshold for significance (p=.0893). The theories of resource depletion and social inhibition may help to explain the findings as the Individual Work Environment provides increased privacy and a more relaxed posture, allowing individuals to conserve cognitive resources as the demand to monitor themselves and others in their surroundings is decreased. This research suggests that the open plan can provide increased density, flexibility and proximity while at the same time, better support the need for sustained attention, by offering a range of furniture settings with different affordances.

The measurement of ground reaction force in dogs trotting on a treadmill

2006 ◽  
Vol 19 (02) ◽  
pp. 81-86 ◽  
Author(s):  
J.-P. Valette ◽  
M. Sanaa ◽  
D. Grandjean ◽  
L. Fanchon
Keyword(s):  
Ground Reaction Force ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Reaction Force ◽  
Training Session ◽  
Peak Time ◽  
Entire Body ◽  
Vertical Force ◽  
Coefficients Of Variation ◽  
Ct Data

SummaryWe studied the time necessary to obtain reliable kinetic data from healthy dogs trotting on a treadmill. Ten adult male Malinois Belgian Shepherd dogs were made to trot on an instrumented treadmill to record the ground reaction force for the entire body and to determine the vertical force variables (peak [PFz], impulse [IFz], stride time [Str], peak time [Tz] and contact time [Ct]). Data were collected from each dog, during three sequences per day, on three consecutive days. In order to determine the contribution of the ‘sequence’, ‘day of measurement’, and ‘dog’ factors and the percentage of variance attributable to dogs, data were analyzed with a linear mixed model. The curve shapes were similar to those obtained with a floor-mounted force platform. Intra-dog coefficients of variation were between 1.57 and 3.46%. Inter-dog coefficients of variation were between 4.18 and 7.82%. A sequence effect was not noted. Each day had a significant effect on all of the data. All variables differed significantly from the first day compared to the other days. However there was not any difference between days 2 and 3. The percentage of the total variance attributable to dogs ranged from 37 to 88%. The coefficients of variation were lower than those obtained with common protocols. The treadmill locomotion remained consistent during a single session. Even if interday variation needs to be accounted for, reliable data can still be obtained after a single training session. The majority of the variation was attributable to the dog. An instrumented treadmill may be used for kinetic analysis.

scholarly journals Conventional and HD-tDCS May (or May Not) Modulate Overt Attentional Orienting: An Integrated Spatio-Temporal Approach and Methodological Reflections

2021 ◽  
Vol 12 (1) ◽  
pp. 71
Author(s):  
Lorenzo Diana ◽  
Giulia Scotti ◽  
Edoardo N. Aiello ◽  
Patrick Pilastro ◽  
Aleksandra K. Eberhard-Moscicka ◽  
...  
Keyword(s):  
Posterior Parietal Cortex ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Right Hemisphere ◽  
Visual Exploration ◽  
Frontal Eye Field ◽  
Baseline Performance ◽  
Spatio Temporal ◽  
The Individual ◽  
The Right

Transcranial Direct Current Stimulation (tDCS) has been employed to modulate visuo-spatial attentional asymmetries, however, further investigation is needed to characterize tDCS-associated variability in more ecological settings. In the present research, we tested the effects of offline, anodal conventional tDCS (Experiment 1) and HD-tDCS (Experiment 2) delivered over the posterior parietal cortex (PPC) and Frontal Eye Field (FEF) of the right hemisphere in healthy participants. Attentional asymmetries were measured by means of an eye tracking-based, ecological paradigm, that is, a Free Visual Exploration task of naturalistic pictures. Data were analyzed from a spatiotemporal perspective. In Experiment 1, a pre-post linear mixed model (LMM) indicated a leftward attentional shift after PPC tDCS; this effect was not confirmed when the individual baseline performance was considered. In Experiment 2, FEF HD-tDCS was shown to induce a significant leftward shift of gaze position, which emerged after 6 s of picture exploration and lasted for 200 ms. The present results do not allow us to conclude on a clear efficacy of offline conventional tDCS and HD-tDCS in modulating overt visuospatial attention in an ecological setting. Nonetheless, our findings highlight a complex relationship among stimulated area, focality of stimulation, spatiotemporal aspects of deployment of attention, and the role of individual baseline performance in shaping the effects of tDCS.

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