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 Quantitative genetic basis of floral design in a natural plant population

2020 ◽  
Author(s):  
Juannan Zhou ◽  
Charles B. Fenste ◽  
Richard J. Reynolds
Keyword(s):  
Genetic Variation ◽  
Genetic Parameters ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Plant Evolution ◽  
Floral Traits ◽  
Floral Trait ◽  
Evolutionary Trajectory

AbstractThe amount of genetic variation of floral traits and the degree to which they are genetically correlated are important parameters for the study of plant evolution. Estimates of these parameters can reveal the effect of historical selection relative to neutral processes such as mutation and drift, and allow us to predict the short-term evolutionary trajectory of a population under various selective regimes. Here, we assess the heritability and genetic correlation of the floral design of a native N. American tetraploid plant, Silene stellata (Caryophyllaceae), in a natural population. Specifically, we use a linear mixed model to estimate the genetic parameters based on a genealogy reconstructed from highly variable molecular markers. Overall, we found significant heritabilities in five out of nine studied traits. The level of heritability was intermediate (0.027 – 0.441). Interestingly, the floral trait showing the highest level of genetic variation was previously shown to be under strong sexually conflicting selection, which may serve as a mechanism for maintaining the observed genetic variation. Additionally, we also found prevalent positive genetic correlations between floral traits. Our results suggest that S. stellata is capable of responding to phenotypic selection on its floral design, while the abundant positive genetic correlations could also constrain the evolutionary trajectories to certain directions. Furthermore, this study demonstrates the utility and feasibility of marker-based approaches for estimating genetic parameters in natural populations.

Genetic parameters for Australian maternal and dual-purpose meatsheep breeds. I. Liveweight, wool production and reproduction in Border Leicester and related types

1994 ◽  
Vol 45 (2) ◽  
pp. 459 ◽  
Author(s):  
LD Brash ◽  
NM Fogarty ◽  
SA Barwick ◽  
AR Gilmour
Keyword(s):  
Genetic Correlation ◽  
Litter Size ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Reproductive Traits ◽  
Phenotypic Correlation ◽  
Data Set ◽  
Reproduction Traits ◽  
Fleece Weight

Analyses of two separate Border Leicester data sets are reported. In the first set, genetic parameters were estimated for 14 month liveweight and greasy fleece weight from 1312 ewe and ram records representing 75 sires of the Border Leicester and Glen Vale breeds (a related genotype) using derivative-free REML procedures. The heritability estimate for liveweight was 0.24 � 0.07 and greasy fleece weight was 0.17 � 0-05, with the genetic correlation being -0 21 � 0 -30 and phenotypic correlation 0.54 � 0.02. In the second data set, reproductive performance was analysed and genetic parameters were estimated from 7395 joining records for 1604 ewes, representing 165 sires, from two Border Leicester stud flocks. Reproduction traits analysed were fertility (ewes lambing of ewes joined), litter size (lambs born per ewe lambing) and lambs born (per ewe joined). The studs differed in performance for all reproductive traits; fertility (67 v. 82%), litter size (1-27 v. 1-43) and lambs born (85 v. 117%). The estimates of heritability and repeatability respectively for ewe performance were: fertility 0.01 � 0.01 and 0.05 � 0 01, litter size 0.01 � 0.02 and 0.05 � 0.01, lambs born 0.00 � 0.01 and 0.06 � 0.01. Estimates of heritability for average ewe lifetime performance were 0.04% 0.05 for fertility, 0-02 �0.05 for litter size and 0.03 � 0.05 for lambs born, based on averages of 4.6 joining and 3.5 litter size records for ewes. The genetic correlations between lambs born and its components fertility (0.96 � 0.18) and litter size (0.83 � 0.44) were high, with the genetic correlation between fertility and litter size being 0.65 � 0.52. Implications for breeding programs for Border Leicester flocks within LAMBPLAN are discussed.

scholarly journals Realized Sampling Variances of Estimates of Genetic Parameters and the Difference Between Genetic and Phenotypic Correlations

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1409-1416 ◽  
Author(s):  
Kenneth R Koots ◽  
John P Gibson
Keyword(s):  
Genetic Correlation ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Parameter Estimates ◽  
Sampling Variance ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

Abstract A data set of 1572 heritability estimates and 1015 pairs of genetic and phenotypic correlation estimates, constructed from a survey of published beef cattle genetic parameter estimates, provided a rare opportunity to study realized sampling variances of genetic parameter estimates. The distribution of both heritability estimates and genetic correlation estimates, when plotted against estimated accuracy, was consistent with random error variance being some three times the sampling variance predicted from standard formulae. This result was consistent with the observation that the variance of estimates of heritabilities and genetic correlations between populations were about four times the predicted sampling variance, suggesting few real differences in genetic parameters between populations. Except where there was a strong biological or statistical expectation of a difference, there was little evidence for differences between genetic and phenotypic correlations for most trait combinations or for differences in genetic correlations between populations. These results suggest that, even for controlled populations, estimating genetic parameters specific to a given population is less useful than commonly believed. A serendipitous discovery was that, in the standard formula for theoretical standard error of a genetic correlation estimate, the heritabilities refer to the estimated values and not, as seems generally assumed, the true population values.

Genetic analysis of docility score of Australian Angus and Limousin cattle

2018 ◽  
Vol 58 (2) ◽  
pp. 213 ◽  
Author(s):  
S. F. Walkom ◽  
M. G. Jeyaruban ◽  
B. Tier ◽  
D. J. Johnston
Keyword(s):  
Adverse Effect ◽  
Animal Model ◽  
Genetic Analysis ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Production Costs ◽  
Breeding Value ◽  
Maternal Behaviour ◽  
Production Traits ◽  
Subjective Score

The temperament of cattle is believed to affect the profitability of the herd through impacting production costs, meat quality, reproduction, maternal behaviour and the welfare of the animals and their handlers. As part of the national beef cattle genetic evaluation in Australia by BREEDPLAN, 50 935 Angus and 50 930 Limousin calves were scored by seedstock producers for temperament using docility score. Docility score is a subjective score of the animal’s response to being restrained and isolated within a crush, at weaning, and is scored on a scale from 1 to 5 with 1 representing the quiet and 5 the extremely nervous or anxious calves. Genetic parameters for docility score were estimated using a threshold animal model with four thresholds (five categories) from a Bayesian analysis carried out using Gibbs sampling in THRGIBBS1F90 with post-Gibbs analysis in POSTGIBBSF90. The heritability of docility score on the observed scale was 0.21 and 0.39 in Angus and Limousin, respectively. Since the release of the docility breeding value to the Australian Limousin population there has been a favourable trend within the national herd towards more docile cattle. Weak but favourable genetic correlations between docility score and the production traits indicates that docility score is largely independent of these traits and that selection to improve temperament can occur without having an adverse effect on growth, fat, muscle and reproduction.

HERITABILITIES AND GENETIC CORRELATIONS FOR ULTRASONIC BACKFAT MEASUREMENTS, GROWTH AND CARCASS TRAITS IN SWINE

1982 ◽  
Vol 62 (3) ◽  
pp. 665-670 ◽  
Author(s):  
D. C. JEFFRIES ◽  
R. G. PETERSON
Keyword(s):  
Key Words ◽  
Genetic Correlation ◽  
Genetic Parameters ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Ultrasonic Measurements ◽  
Yorkshire Pigs ◽  
Daily Gain ◽  
Season Interaction

Genetic parameters were estimated for 2403 purebred Yorkshire pigs over a 2-yr period, representing 21 sires. The traits studied included average daily gain, age adjusted to 90 kg, ultrasonic measurements of backfat at the mid-back and loin positions, total and adjusted total ultrasonic backfat and corresponding carcass backfat measurements. Least squares analyses were used to estimate and adjust for the effects of sex, year-season and sex by year-season interaction. Heritabilities and genetic correlations were calculated for all traits using both half- and full-sib estimates. Adjusted age and adjusted total ultrasonic backfat measurements were found to have the highest heritabilities of the live traits in this study. Estimates of heritability for adjusted age and adjusted total ultrasonic backfat were 0.24 ± 0.10 and 0.26 ± 0.10 based on half-sib and 0.56 ± 0.07 and 0.41 ± 0.06 from full-sib analyses. The genetic correlation between these two traits was −0.07 ± 0.28 based on the half-sib method. The total phenotypic correlation was −0.01 ± 0.02. Key words: Swine, ultrasonic backfat, heritabilities, genetic correlations

scholarly journals Estimation of variance components of milk, fat, and protein yields of Tunisian Holstein dairy cattle using Bayesian and REML methods

2016 ◽  
Vol 59 (2) ◽  
pp. 243-248 ◽  
Author(s):  
Hafedh Ben Zaabza ◽  
Abderrahmen Ben Gara ◽  
Hedi Hammami ◽  
Mohamed Amine Ferchichi ◽  
Boulbaba Rekik
Keyword(s):  
Dairy Cattle ◽  
Bayesian Methods ◽  
Milk Fat ◽  
Variance Components ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Bayesian Procedure ◽  
Milk Traits ◽  
Residual Variances ◽  
Estimation Of Variance

Abstract. A multi-trait repeatability animal model under restricted maximum likelihood (REML) and Bayesian methods was used to estimate genetic parameters of milk, fat, and protein yields in Tunisian Holstein cows. The estimates of heritability for milk, fat, and protein yields from the REML procedure were 0.21 ± 0.05, 0.159 ± 0.04, and 0.158 ± 0.04, respectively. The corresponding results from the Bayesian procedure were 0.273 ± 0.02, 0.198 ± 0.01, and 0.187 ± 0.01. Heritability estimates tended to be larger via the Bayesian than those obtained by the REML method. Genetic and permanent environmental variances estimated by REML were smaller than those obtained by the Bayesian analysis. Inversely, REML estimates of the residual variances were larger than Bayesian estimates. Genetic and permanent correlation estimates were on the other hand comparable by both REML and Bayesian methods with permanent environmental being larger than genetic correlations. Results from this study confirm previous reports on genetic parameters for milk traits in Tunisian Holsteins and suggest that a multi-trait approach can be an alternative for implementing a routine genetic evaluation of the Tunisian dairy cattle population.

Phenotypic and genetic parameters for reproductive performance in a synthetic line of sheep

1981 ◽  
Vol 96 (1) ◽  
pp. 107-113 ◽  
Author(s):  
T. G. Martin ◽  
D. Nicholson ◽  
C. Smith ◽  
D. I. Sales
Keyword(s):  
Reproductive Performance ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Direct Selection ◽  
Sex Distribution ◽  
Regression Methods ◽  
Litter Weight ◽  
Heritability Estimates ◽  
Synthetic Line

SUMMARYData on 902 ewes (1755 records) bom over 7 years in the synthetic ABRO Dam Line were analysed by least squares. Reproductive traits of the ewe were not affected by whether she was a single or a twin or by the age of her dam. Ewe age had major effects on all reproductive traits. Litter weight traits were affected by the sex distribution and the age of the litter when weighed.Heritability estimates, both by half sib and regression methods, were low for litter size, low to moderate for litter weights, and higher for ewe and fleece weights. Genetic correlations among the litter-weight traits were high. Together with the heritability estimates, they indicated that selection on litter weight at birth (and perhaps other traits) might give a greater change in total litter weight at weaning, the main measure of ewe productivity and the objective in improvement, than would direct selection.

scholarly journals Genetic parameters of traits at the juvenile stage of different assai palm tree progenies

2018 ◽  
Vol 53 (7) ◽  
pp. 815-823
Author(s):  
Patricia Cardoso Andrade Navegantes ◽  
Maria do Socorro Padilha de Oliveira ◽  
José Airton Rodrigues Nunes
Keyword(s):  
Genetic Parameters ◽  
Mixed Model ◽  
Genetic Correlations ◽  
Fruit Production ◽  
Leaf Sheath ◽  
Juvenile Stage ◽  
Palm Tree ◽  
Euterpe Oleracea ◽  
Mixed Model Approach ◽  
Randomized Design

Abstract: The objective of this work was to estimate genetic parameters of traits at the juvenile stage of different assai palm (Euterpe oleracea) tree progenies, as well as to select among and within the most promising for fruit production. A total of 34 half-sib and 16 full-sib progenies were evaluated in a completely randomized design with eight replicates and one plant per plot. Nine traits were measured in five harvests, and the data were analyzed using the mixed model approach. The genetic variance was significant for most of the traits. Progeny-mean heritabilities showed moderate magnitudes, ranging from 51% for number of dead leaves to 59% for leaf sheath length. In general, the genetic correlations were positive and had magnitudes varying from moderate to very high. The genetic gains were more expressive for the traits plant height, leaf sheath length, and girth circumference. The full-sib progenies P33, P37, and P42 are promising for fruit production.

scholarly journals Reconsidering the Energy Homeostasis Hypothesis. the Proposed Role of Fat-Free Mass (FFM) and Resting Metabolic Rate (RMR) Driving Increased Energy Intake After Weight Loss (OR09-04-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Chris Pankey ◽  
Kyle Flack ◽  
Kelsey Ufholz ◽  
LuAnn Johnson ◽  
James Roemmich
Keyword(s):  
Weight Loss ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Agricultural Research ◽  
Food Reinforcement ◽  
Fat Free Mass ◽  
Interactive Effects ◽  
United States Department ◽  
Schedules Of Reinforcement ◽  
Service Project

Abstract Objectives Hypotheses of appetite control and food reinforcement are based on gut and adipose peptide signaling to central appetite centers. Contemporary models propose that RMR and FFM changes modify food reinforcement and this may be best observed after weight loss when body mass is purported to be regained until pre-weight loss FFM is restored. Here we assess the associations of change (∆, post-training value minus pre-training value) in food reinforcement with ∆ fat mass (FM), ∆FFM, and ∆RMR after exercise-induced weight loss. Methods Subjects (n = 29, BMI = 25–35 kg/m2) engaged in a 6-wk aerobic exercise protocol expending either 300 or 600 kcal, 5 d/wk. Relative reinforcement value of food (RRVfood) was measured via a computer-based operant responding task, in which subjects could “earn” access to food or sedentary reinforcers. Schedules of reinforcement for each alternative started at 4 and doubled after every 5 points. Completed schedules were recorded for each alternative (PMaxfood, PMaxsed) and the ratio ((PMaxfood/(PMaxfood + PMaxsed)) determined RRVfood. RMR was determined by indirect calorimetry. FFM was determined by DEXA. Spearman correlation analysis determined correlations between variables at pre and post, and between ∆ scores. A generalized linear mixed model tested the main and interactive effects of ∆FFM and ∆RMR on ∆PMaxfood. Results At baseline, there were no correlations between outcome measures. At post-training, FFM correlated to PMaxfood (P < 0.01, r = 0.52). ∆RMR negatively correlated with ∆PMaxfood (P < 0.01, r = −0.48) and with ∆RRVfood (P < 0.06, r = −0.36). ∆PMaxfood did not associate with ∆FFM (P = 0.71, r = 0.07). ∆RMR predicted (P < 0.05) ∆PMaxfood when controlling for ∆FFM and ∆PMaxfood*∆FFM. Conclusions FFM correlated with PMaxfood post-training; however, ∆PMaxfood did not correlate to ∆FFM, so, ∆FFM may be necessary, but insufficient to increase PMaxfood after weight loss. ∆RMR inversely predicted ∆PMaxfood when controlling for FFM, suggesting that reductions in RMR with weight loss increases ∆PMaxfood perhaps as a means of restoring pre-weight loss FFM and RMR. This model would predict that limiting reductions in RMR during weight loss could benefit weight loss maintenance by limiting increases in food reinforcement. Funding Sources United States Department of Agriculture, Agricultural Research Service project 3062-51000-51-00D.

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.

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