Author: Kurt Eberhard Sittmann
Publisher:
ISBN:
Category :
Languages : en
Pages : 322
Book Description
Estimation of Genetic and Environmental Parameters of Weaning Weight and Weaning Grade in Hereford Cattle
Genetic Parameters For Docility, Weaning Weight, Yearling Weight And Intramuscular Fat Percentage In Hereford Cattle
Author: José Antonio Torres Vázquez
Publisher:
ISBN:
Category :
Languages : en
Pages : 52
Book Description
Temperament in cattle can be described as the reactivity or fear response to human handling, and it is important to beef cattle producers not only from a human safety but also due to potential correlations with other economically traits. Before a docility selection metric can be added to a genetic evaluation, any potential antagonisms with economically relevant traits should be quantified. The objective was to estimate genetic parameters, including genetic correlations, for chute score (CS), weaning weight (WW), yearling weight (YW), and intramuscular fat percentage (IMF) in Hereford cattle. Single-trait and bivariate animal models were used to estimate heritabilities and genetic correlations. Models included fixed effects of sex and contemporary group, defined as herd–year–season. Direct genetic and residual components were included as random effects. For CS and WW, also additional random effects of maternal genetic and maternal permanent environment were fitted. For CS, WW, YW, and IMF, heritability estimates were 0.27 ± 0.02, 0.35 ± 0.03, 0.36 ± 0.02, and 0.27 ± 0.02, respectively. Genetic correlations between CS and WW, CS and YW, CS and IMF, WW and YW, WW and IMF, and YW and IMF were –0.12 ± 0.06, –0.10 ± 0.05, –0.08 ± 0.06, 0.47 ± 0.05, –0.19 ± 0.09, and –0.41 ± 0.05, respectively. Heritability estimates for all traits suggest that they would respond favorably to selection, although the selection for increased WW or YW could decrease marbling, which is often associated with favorable meat quality. Genetic correlations between CS and WW, YW, and IMF were all favorable but weak, suggesting that selection for improved docility will not have negative consequences on growth or meat quality. Maternal additive and maternal permanent environmental variances for CS were close to zero, suggesting that their inclusion in National Cattle Evaluations is not warranted.
Publisher:
ISBN:
Category :
Languages : en
Pages : 52
Book Description
Temperament in cattle can be described as the reactivity or fear response to human handling, and it is important to beef cattle producers not only from a human safety but also due to potential correlations with other economically traits. Before a docility selection metric can be added to a genetic evaluation, any potential antagonisms with economically relevant traits should be quantified. The objective was to estimate genetic parameters, including genetic correlations, for chute score (CS), weaning weight (WW), yearling weight (YW), and intramuscular fat percentage (IMF) in Hereford cattle. Single-trait and bivariate animal models were used to estimate heritabilities and genetic correlations. Models included fixed effects of sex and contemporary group, defined as herd–year–season. Direct genetic and residual components were included as random effects. For CS and WW, also additional random effects of maternal genetic and maternal permanent environment were fitted. For CS, WW, YW, and IMF, heritability estimates were 0.27 ± 0.02, 0.35 ± 0.03, 0.36 ± 0.02, and 0.27 ± 0.02, respectively. Genetic correlations between CS and WW, CS and YW, CS and IMF, WW and YW, WW and IMF, and YW and IMF were –0.12 ± 0.06, –0.10 ± 0.05, –0.08 ± 0.06, 0.47 ± 0.05, –0.19 ± 0.09, and –0.41 ± 0.05, respectively. Heritability estimates for all traits suggest that they would respond favorably to selection, although the selection for increased WW or YW could decrease marbling, which is often associated with favorable meat quality. Genetic correlations between CS and WW, YW, and IMF were all favorable but weak, suggesting that selection for improved docility will not have negative consequences on growth or meat quality. Maternal additive and maternal permanent environmental variances for CS were close to zero, suggesting that their inclusion in National Cattle Evaluations is not warranted.
Some Factors Affecting Weaning Weights and Weaning Scores in Beef Calves
Author: James S. Brinks
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 102
Book Description
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 102
Book Description
Evaluation of Response to Selection and Inbreeding in a Closed Line of Hereford Cattle
Author: J. S. Brinks
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 40
Book Description
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 40
Book Description
Effects of Sire Misidentification on Estimates of Genetic Parameters for Birth Weight and Weaning Weight in Hereford Cattle
Estimation of Phenotypic, Genetic, and Environmental Parameters in Two Beef Cattle Populations
Author: Theodore R. Rounsaville
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 202
Book Description
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 202
Book Description
The Effect of Genetic and Environmental Factors on Weaning Weight of Hereford Calves
Author: James Andrew Carpenter
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
Book Description
Moment-type Estimation of Genetic Parameters and Their Variances for Calving Date and Production Traits from Hereford Data Using Multi-way Models
Author: Edward J. Otieno-Rege
Publisher:
ISBN:
Category :
Languages : en
Pages : 424
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 424
Book Description
The Effect of Inbreeding and Environmental Factors on the Weaning Weight and Post-weaning Growth of Range Hereford Cattle
Author: Geoffrey Oswald Harwin
Publisher:
ISBN:
Category : Cattle
Languages : en
Pages : 158
Book Description
The present study was initiated to determine the effects of inbreeding and certain environmental and genetic factors on the weaning weight of range Hereford calves. The study was also extended to include an investigation of the effect of these variables on post-weaning traits of range Hereford females including yearling gain and weight at 18 months, 2 1/2 years and 3 1/2 years of age. The data used in the study were obtained from a long term cattle breeding project initiated by Colorado State University in 1946 at the San Juan Basin Experiment Station and included onservations from 16 inbred lines of Hereford cattle, crosses between yhese lines and a control herd. The preliminary phase of the study was concerned with the development of appropriate mathematical models enabling minimum variance unbiased estimates of the various genetic and ebvironmental factors under investigation. The interactions between the various main effects as they affect weaning weight were investigated simultaneously by means of a least squares analysis. The interactions of sex x mating system, sex x age of dam and year x age of dam were significant. Investigation of the within year regression of weaning weight on age of calf also indicated a significant interaction between age of calf and year. Preleminary investigation indicated a marked curvilinear decline in weaning weight with inbreeding and differential response to inbreeding of both lines and sexes. The results of the preliminary studies were used in developing the final models...
Publisher:
ISBN:
Category : Cattle
Languages : en
Pages : 158
Book Description
The present study was initiated to determine the effects of inbreeding and certain environmental and genetic factors on the weaning weight of range Hereford calves. The study was also extended to include an investigation of the effect of these variables on post-weaning traits of range Hereford females including yearling gain and weight at 18 months, 2 1/2 years and 3 1/2 years of age. The data used in the study were obtained from a long term cattle breeding project initiated by Colorado State University in 1946 at the San Juan Basin Experiment Station and included onservations from 16 inbred lines of Hereford cattle, crosses between yhese lines and a control herd. The preliminary phase of the study was concerned with the development of appropriate mathematical models enabling minimum variance unbiased estimates of the various genetic and ebvironmental factors under investigation. The interactions between the various main effects as they affect weaning weight were investigated simultaneously by means of a least squares analysis. The interactions of sex x mating system, sex x age of dam and year x age of dam were significant. Investigation of the within year regression of weaning weight on age of calf also indicated a significant interaction between age of calf and year. Preleminary investigation indicated a marked curvilinear decline in weaning weight with inbreeding and differential response to inbreeding of both lines and sexes. The results of the preliminary studies were used in developing the final models...
An Evaluation of Environmental Parameters and the Response to Selection for Weaning Weight in Hereford Range Cattle
Author: Charles Thorne Gaskins
Publisher:
ISBN:
Category : Hereford cattle
Languages : en
Pages : 62
Book Description
Publisher:
ISBN:
Category : Hereford cattle
Languages : en
Pages : 62
Book Description