HERITABILITY OF NONRETURN RATE OF CANADIAN HOLSTEIN-FRIESIAN BULLS

1983 ◽  
Vol 63 (1) ◽  
pp. 39-48 ◽  
Author(s):  
B. B. MURRAY ◽  
L. R. SCHAEFFER ◽  
E. B. BURNSIDE
Keyword(s):  
Maximum Likelihood ◽  
Artificial Insemination ◽  
Variance Components ◽  
Fixed Effects ◽  
Mixed Model ◽  
Factors Affecting ◽  
Holstein Friesian ◽  
Best Linear Unbiased ◽  
Dairy Bulls ◽  
One Year

Conception rates of Canadian Holstein-Friesian bulls in artificial insemination were recorded as percent 60- to 90-day nonreturns to first service. A total of 5, 923, 974 first services to 784 bulls by 207 sires were analyzed using a mixed model which included age of bull (1–14 yr), years (1956–1976), months and AI units as fixed effects. Bulls and sires of bulls were random. Significant differences were found in all classifications involving fixed effects. Nonreturn rates at one year of age were highest and significantly different from nonreturn rates at 9 yr of age and older. Lowest estimates of nonreturn rates were in January and December, and highest were in September and October. Differences were found among some AI units. Best linear unbiased predictions of differences among all service sires were obtained. Variance components were estimated iteratively by maximum likelihood. Heritability was 0.25 by regression of sire on son with 30 sires having four or more sons. Repeatability was 0.41. Many factors affecting nonreturn rates could not be identified, especially at the cow or herd level. Sire selection programs in AI units for high nonreturn rates in sires of young bulls should be successful. Key words: Fertility, dairy bulls, heritability

Selection on lean growth in a nucleus of Landrace pigs: an analysis using Gibbs sampling

1996 ◽  
Vol 63 (2) ◽  
pp. 243-253 ◽  
Author(s):  
M. C. Rodriguez ◽  
M. Toro ◽  
L. Silió
Keyword(s):  
Gibbs Sampling ◽  
Variance Components ◽  
Fixed Effects ◽  
Prediction Method ◽  
Environmental Parameters ◽  
Linear Unbiased Prediction ◽  
Normal Distributions ◽  
Lean Growth ◽  
Best Linear Unbiased ◽  
Selection For

AbstractData from 4150 Landrace pigs tested during the period 1989-94 for backfat thickness and age at 100 kg in an open selection nucleus were analysed with the standard restricted maximum likelihood/best linear unbiased prediction method and with a Bayesian approach based on the marginal posterior distributions of parameters of interest achieved via Gibbs sampling. Breeding values and fixed effects were sampled from normal distributions and (co)variance components from inverted Wishart distributions. The Bayesian analysis indicated that the selection was effective for both traits. Assuming flat priors for the (co)variance components, the posterior means of the annual rates of response to selection for both traits were −0·473 days and −0·212 mm. The influence of informative priors constructed from (co)variances estimated in the French Landrace breed on inferences about genetic and common environmental parameters, genetic group effects and total and annual responses was also examined.

scholarly journals Factors associated with the weight of individual primal cuts and their inter-relationship in cattle

2019 ◽  
Vol 3 (4) ◽  
pp. 1593-1605 ◽  
Author(s):  
Michelle M Judge ◽  
Thierry Pabiou ◽  
Stephen Conroy ◽  
Rory Fanning ◽  
Martin Kinsella ◽  
...  
Keyword(s):  
Decision Support ◽  
Fixed Effects ◽  
Mixed Model ◽  
Random Effect ◽  
Carcass Weight ◽  
Holstein Friesian ◽  
Support Tools ◽  
Beef Herd ◽  
Fat Score ◽  
The Individual

Abstract Input parameters for decision support tools are comprised of, amongst others, knowledge of the associated factors and the extent of those associations with the animal-level feature of interest. The objective of the present study was to quantify the association between animal-level factors with primal cut yields in cattle and to understand the extent of the variability in primal cut yields independent carcass weight. The data used consisted of the weight of 14 primal carcass cuts (as well as carcass weight, conformation, and fat score) on up to 54,250 young cattle slaughtered between the years 2013 and 2017. Linear mixed models, with contemporary group of herd-sex-season of slaughter as a random effect, were used to quantify the associations between a range of model fixed effects with each primal cut separately. Fixed effects in the model were dam parity, heterosis coefficient, recombination loss, a covariate per breed representing the proportion of Angus, Belgian Blue, Charolais, Jersey, Hereford, Limousin, Simmental, and Holstein–Friesian and a three-way interaction between whether the animal was born in a dairy or beef herd, sex, and age at slaughter, with or without carcass weight as a covariate in the mixed model. The raw correlations among all cuts were all positive varying from 0.33 (between the bavette and the striploin) to 0.93 (between the topside and knuckle). The partial correlation among cuts, following adjustment for differences in carcass weight, varied from −0.36 to 0.74. Age at slaughter, sex, dam parity, and breed were all associated (P < 0.05) with the primal cut weight. Knowledge of the relationship between the individual primal cuts, and the solutions from the models developed in the study, could prove useful inputs for decision support systems to increase performance.

scholarly journals Hybrid of Restricted and Penalized Maximum Likelihood Method for Efficient Genome-Wide Association Study

Genes ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1286
Author(s):  
Wenlong Ren ◽  
Zhikai Liang ◽  
Shu He ◽  
Jing Xiao
Keyword(s):  
Maximum Likelihood ◽  
Variance Components ◽  
Statistical Power ◽  
Mixed Model ◽  
Single Locus ◽  
Genome Wide Association ◽  
Likelihood Method ◽  
Penalized Maximum Likelihood ◽  
Genome Wide ◽  
Estimation Of Variance

In genome-wide association studies, linear mixed models (LMMs) have been widely used to explore the molecular mechanism of complex traits. However, typical association approaches suffer from several important drawbacks: estimation of variance components in LMMs with large scale individuals is computationally slow; single-locus model is unsatisfactory to handle complex confounding and causes loss of statistical power. To address these issues, we propose an efficient two-stage method based on hybrid of restricted and penalized maximum likelihood, named HRePML. Firstly, we performed restricted maximum likelihood (REML) on single-locus LMM to remove unrelated markers, where spectral decomposition on covariance matrix was used to fast estimate variance components. Secondly, we carried out penalized maximum likelihood (PML) on multi-locus LMM for markers with reasonably large effects. To validate the effectiveness of HRePML, we conducted a series of simulation studies and real data analyses. As a result, our method always had the highest average statistical power compared with multi-locus mixed-model (MLMM), fixed and random model circulating probability unification (FarmCPU), and genome-wide efficient mixed model association (GEMMA). More importantly, HRePML can provide higher accuracy estimation of marker effects. HRePML also identifies 41 previous reported genes associated with development traits in Arabidopsis, which is more than was detected by the other methods.

EVALUATION OF BEEF SIRES ACROSS BREEDS FOR CALVING EASE

1977 ◽  
Vol 57 (4) ◽  
pp. 635-645 ◽  
Author(s):  
L. R. SCHAEFFER ◽  
J. W. WILTON
Keyword(s):  
Maximum Likelihood ◽  
Scoring System ◽  
Variance Components ◽  
Error Variance ◽  
Best Linear Unbiased Prediction ◽  
Linear Unbiased Prediction ◽  
Calving Ease ◽  
Best Linear Unbiased ◽  
Maximum Likelihood Prediction ◽  
Unbiased Prediction

Agriculture Canada and Alberta Record of Performance calving ease records on 54,139 calves from 3,338 sires of 18 breeds were used to evaluate sires by comparisons across breeds of sire. An objective scoring system was applied to the calving ease codes to derive appropriate weights for each category rather than using percentage of unassisted births or assuming equal intervals between categories. Common sire and error variance components were assumed for all breeds of sire. Heritability of calving ease under the model used was estimated to be.10 by maximum likelihood. Prediction of sire values for calving ease scores of future calves were calculated by best linear unbiased prediction procedures. Shorthorn, Hereford, and Angus sires caused relatively few calving difficulties, while Maine-Anjou sires caused more difficulties. Age of dam and sex of calf differences were also important. The range of sire evaluations for calving ease was narrow, but the bulls in either extreme could be identified.

scholarly journals Parámetros genéticos de crecimiento y producción de lana en ovinos usando la metodología de modelos mixtos

2009 ◽  
Vol 7 (1) ◽  
pp. 42
Author(s):  
Rodrigo Alfredo Martínez ◽  
Rodrigo Vásquez ◽  
Javier Vanegas ◽  
Marco Suárez
Keyword(s):  
Variance Components ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Mixed Model ◽  
Growth Characteristics ◽  
Random Component ◽  
Wool Production ◽  
Gibbs Sampling Algorithm ◽  
Calving Season ◽  
Number Of Births

<p>En este trabajo se estimaron los parámetros genéticos a partir de datos de campo registrados durante 26 años (1974 a 1999) en un núcleo de las razas ovinas Hampshire, Romney Marsh y Corriedale. Se estimaron los parámetros genéticos de las características de crecimiento, producción de lana y reproducción. Los modelos utilizados incluyeron efectos fijos, como ‘año de parto, ‘época de parto, ‘sexo, ‘número de parto; en el componente aleatorio también se incluyeron los efectos genéticos directo, materno y de ambiente permanente, dependiendo de la característica. Los análisis fueron hechos usando un modelo animal de característica simple mediante el programa MTGSAM® que emplea el algoritmo de muestreo de Gibbs para inferir los componentes de varianza. Se encontraron valores de heredabilidad directa que variaron entre 0,13 y 0,33 para peso al nacimiento y entre 0,16 y 0,35 para peso al destete corregido a 120 días y para caracteres de producción de lana, valores cercanos a 0,25. También se determinaron las tendencias anuales promedio de los valores genéticos y de los índices de consanguinidad para cada una de las razas, encontrando en términos generales valores promedio de consanguinidad de 3,47% para la raza Hampshire, 0,75% para Romney Marsh y 0,76% para Corriedale. Estos resultados sugieren una tendencia levemente creciente de los valores de consanguinidad, pero de acuerdo con lo que se espera para una población de conservación.  </p><p> </p><p><strong>Growth and wool production genetic parameters in sheep using mixed model methodology </strong></p><p>This work was aimed at estimating genetic parameters from field-data recorded over a 26-year period (1974 to 1999) in a flock of Hampshire, Romney Marsh and Corriedale sheep. Genetic parameters were estimated from growth characteristics, wool production and reproduction. The models used included fixed effects, such as birth year, calving season, gender and number of births. Direct, maternal and permanent environmental genetic effects were also included in the random component, depending on the characteristic. MTGSAM® software (using Gibbs’ sampling algorithm) was used on a simple animal model for inferring variance components. Direct heritability values were found, ranging form 0.13 to 0.33 for birth weight, 0.16 to 0.35 for weaning weight (corrected to 120 days) and values around 0.25 for wool production. Annual mean tendency of genetic values and consanguinity indices were also determined for each of the breeds, resulting in 3.47% mean consanguinity for the Hampshire, 0.75% for Romney Marsh and 0.76% for Corriedale breeds. These results suggested a slight tendency for increased consanguinity values, but remaining in line with those expected for a conservation population. </p>

scholarly journals Multi-breed herd approach to detect breed differences in composition and fatty acid profile of cow milk

2019 ◽  
Vol 64 (No. 1) ◽  
pp. 11-16 ◽  
Author(s):  
C.L. Manuelian ◽  
M. Penasa ◽  
G. Visentin ◽  
A. Benedet ◽  
M. Cassandro ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fixed Effects ◽  
Mixed Model ◽  
Point Of View ◽  
Cow Milk ◽  
Dual Purpose ◽  
Stage Of Lactation ◽  
Holstein Friesian ◽  
Breed Differences ◽  
Trans Fa

The objective of the present study was to estimate the effect of breed on milk fatty acid (FA) composition of dairy (Brown Swiss, Holstein-Friesian, and Jersey) and dual-purpose cows (Simmental and Alpine Grey) in multi-breed herds. Information on individual milk samples was collected during routine cow milk testing between 2011 and 2014, and consisted of 285 606 observations from 17 445 cows in 617 herds. Fixed effects included in the mixed model were breed, parity, stage of lactation and the interaction between parity and stage of lactation, and random effects were cow, herd-test-date and residual. Contrast estimates for the studied traits were used to compare specific sets of breeds. Holstein-Friesian produced more milk than the other cattle breeds, with the greatest trans FA and C18:1 and the lowest C18:0 content. Comparison between the specialised dairy vs the dual-purpose breeds highlighted significant differences for all traits except for polyunsaturated FA and trans FA content. Specialised dairy breeds had greater milk saturated FA, short-chain FA, medium-chain FA, C14:0 and C16:0 content, and dual-purpose breeds produced milk with greater content of monounsaturated FA, long-chain FA, C18:0 and C18:1. Results demonstrated that, although specialised dairy produced more milk than dual-purpose breeds, milk FA profile of the latter was more favourable from a human nutrition point of view.

Estimates of Genetic Variation for Angus Gestation Length

2021 ◽  
Vol 99 (Supplement_2) ◽  
pp. 14-15
Author(s):  
Carson Gilleland ◽  
Kelli J Retallick ◽  
Daniel H Poole ◽  
Zack Peppmeier ◽  
Mark Knauer
Keyword(s):  
Variance Components ◽  
Fixed Effects ◽  
Additive Genetic Variance ◽  
High Capacity ◽  
Gestation Length ◽  
Phenotypic Variance ◽  
Contemporary Group ◽  
Heritability Estimates ◽  
One Year ◽  
Estimate Variance

Abstract The objective of this study was to estimate variance components for gestation length within the American Angus breed. Data (n = 148,649) from the American Angus Association, containing cattle born between 2000 to 2020, were used for the analysis. Based on a cow’s reproductive biology, gestation length records were determined acceptable if between 266 and 290 days (n = 114,857). Gestation length mean and standard deviation were 278.6 and 4.6 days, respectively. Average Information Restricted Maximum Likelihood (AIREML) was used to estimate variance components for the gestation length. A single trait animal model included random effects of direct and maternal additive genetic variance and fixed effects of dam age rounded to the nearest year, calf gender and contemporary group. Contemporary group was determined as herd, year of birth and season of birth combinations. Contemporary groups containing less than five animals were excluded from analysis. Phenotypic variance for gestation length was estimated at 18.9. Direct and maternal heritability estimates for gestation length were 0.59±0.01 and 0.10±0.01, respectively. Further analysis evaluated the fixed effects of year and dam age on gestation length. From 2000 to 2020, an increase in one year decreased (P &lt; 0.01) gestation length by 0.09 days. Gestation length differed (P &lt; 0.01) by age of dam. Gestation length LSMEANS for 2, 3, 4, 5, 6, 7 and 8 year old cows were 277.7, 278.6, 279.0, 279.2, 279.3, 279.5 and 279.6, respectively. Heritability estimates within Angus breed suggest gestation length has a high capacity for genetic change. Results suggest gestation length has decreased over the past two decades and is shorter in younger cows.

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