Estimates of Some Genetic Parameters of Economic Importance in Angus Cattle

Estimates of Some Genetic Parameters of Economic Importance in Angus Cattle PDF Author: Haymchal Harricharan
Publisher:
ISBN:
Category : Aberdeen-Angus cattle
Languages : en
Pages : 166

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Estimates of Some Genetic Parameters of Economic Importance in Angus Cattle

Estimates of Some Genetic Parameters of Economic Importance in Angus Cattle PDF Author: Haymchal Harricharan
Publisher:
ISBN:
Category : Aberdeen-Angus cattle
Languages : en
Pages : 166

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Estimates of Genetic Parameters Necessary for Constructing Selection Indexes for Beef Cattle

Estimates of Genetic Parameters Necessary for Constructing Selection Indexes for Beef Cattle PDF Author: Lee Evans
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 110

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Estimation of Genetic Parameters and Time Trends in a Herd of Angus Cattle

Estimation of Genetic Parameters and Time Trends in a Herd of Angus Cattle PDF Author: David Wain Schafer
Publisher:
ISBN:
Category : Aberdeen-Angus cattle
Languages : en
Pages : 236

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Growth and Maturation of Angus Cattle

Growth and Maturation of Angus Cattle PDF Author: Miroslav Kaps
Publisher:
ISBN:
Category : Aberdeen-Angus cattle
Languages : en
Pages : 230

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The objective of this study was to estimate genetic parameters for growth, maturity and carcass traits, and to analyze relationship of each of these traits with mature weight. Growth data utilized in the study consisted of repeated weight measurements of 3044 Angus cows. A Brody growth curve was fitted to the data for each cow individually in order to predict asymptotic (mature) weight, age when animal reached 65% of mature weight, and weights, growth rates, degrees of maturity and relative growth rates at 365 and 550 days of age. Carcass data consisted of 3477 records of steers, including hot carcass weight, back fat-thickness, rib-eye area, cutability and marbling score. Genetic parameters of mature weight were estimated from a single-trait animal model for asymptotic weight, a two-trait animal model for asymptotic and weaning weight, and a two-trait animal model for repeated mature weights (measured after 4 y of age) and weaning weight. Heritability estimates for growth and carcass traits were obtained by restricted maximum likelihood from a set of two-trait animal models considering a given trait and weaning weight which was in the model to account for any effect of culling. Similarly, genetic correlations between mature weight and other traits were obtained from a set of three-trait models. A sample of 29943 animals was used for weaning weight measurements. Fixed effects in the models included weaning, cow and carcass contemporary groups. For the carcass traits the effect of slaughter age was included in the model as a covariate. Random effects in the model included direct genetic, maternal genetic and permanent environmental effects for weaning weight, but only direct genetic and repeated measurements (if in the model) for each of the other traits. Estimates of heritability for mature weight were. 44,.51 and. 57 for the single-trait model with asymptotic weight, two-trait model with asymptotic weight and two-trait model with repeated weights, respectively. The reduced heritability estimate from the single-trait model was most likely due to the effect of culling, thus, a genetic evaluation for mature size should be considered in a multiple-trait model including mature weight as well as some earlier measured growth trait. (Abstract shortened by UMI.).

Estimates of Genetic Parameters of Certain Production and Carcass Traits in Beef Cattle

Estimates of Genetic Parameters of Certain Production and Carcass Traits in Beef Cattle PDF Author: Marion Fitzgerald
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 216

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Genetic Parameters in Straightbred and Crossbred Beef Cattle Populations

Genetic Parameters in Straightbred and Crossbred Beef Cattle Populations PDF Author: Richard John Dunn
Publisher:
ISBN:
Category : Cattle
Languages : en
Pages : 210

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Genetic Parameter Estimates for Feet and Leg Traits in Red Angus Cattle

Genetic Parameter Estimates for Feet and Leg Traits in Red Angus Cattle PDF Author: Brady Robert Jensen
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ISBN:
Category :
Languages : en
Pages :

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The objective of this study was to investigate the parameter estimates for feet and leg traits, relationships within feet and leg traits, and between feet and leg traits and production traits in Red Angus cattle. Subjective scores for 14 traits including: Body Condition Score (BCS), Front Hoof Angle (FHA), Front Heel Depth (FHD), Front Claw Shape (FCS), Rear Hoof Angle (RHA), Rear Heel Depth (RHD), Rear Claw Shape (RCS), Size of Hoof (Size), Front Side View (FSV), Knee Orientation (KNEE), Front Hoof Orientation (FHO), Rear Side View (RSV), Rear View (RV), and a Composite Score (COMP) were collected by trained evaluators on 1885 Red Angus cattle at different ranches across the United States. A three-generation pedigree file was obtained from the Red Angus Association of America (RAAA) that contained 13,306 animals, and EPDs on all animals with feet and leg scores were obtained. All traits except COMP were scored as intermediate optimum traits. Data were modeled using a linear bivariate animal model with random additive genetic and residual effects, and fixed effects of age and contemporary group (herd-year). Variances were estimated with ASREML 3.0 and 4.0. Heritability estimates of BCS, FHA, FHD, FCS, RHA, RHD, RCS, Size, FSV, Knee, FHO, RSV, RV, and COMP were 0.11, 0.20, 0.17, 0.09, 0.19, 0.25, 0.17, 0.36, 0.16, 0.17, 0.17, 0.30, 0.14, and 0.12, respectively. These results showed feet and leg traits were lowly to moderately heritable. Strong, positive genetic correlations were found between FHA and FHD (0.89), FHA and RHA (0.88), FHD and RHA (0.85), FHA and RHD (0.85), FHD and RHD (0.94), and FHO and Knee (0.95), indicating these traits may be highly related to one another. Strong negative correlations were found between Knee and FSV ( -0.59) and FHO and FSV ( -0.75). The strongest correlation was between front limb traits (FHA, FHD, FSV, FHO, Knee, and Comp) and the Stayability EPD (STAY) was FSV (r =0.16; r_s =0.20) and for rear limb traits (RHA, RHD, RCS, RSV, RV, and Comp) and STAY was RCS (r = -0.12; r_s=-0.14). This indicates that cattle with more slope to the angle of the shoulder stay in the herd longer and cattle with less curl to the inside of the claw tend to stay in the herd longer. Further studies with more data could help validate the relationship between feet and leg traits and production traits.

Estimates of Genetic, Environmental and Phenotypic Parameters in the Canadian Record of Performance Beef Cattle Population

Estimates of Genetic, Environmental and Phenotypic Parameters in the Canadian Record of Performance Beef Cattle Population PDF Author: Brian Wayne Kennedy
Publisher:
ISBN:
Category : Beef cattle
Languages : en
Pages : 500

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The Effect of Selection on Estimates of Genetic Parameters

The Effect of Selection on Estimates of Genetic Parameters PDF Author: Donald Franklin Butcher
Publisher:
ISBN:
Category : Cattle
Languages : en
Pages : 158

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Estimates of Genetic Parameters for Crossbred Beef Cattle

Estimates of Genetic Parameters for Crossbred Beef Cattle PDF Author: Adolfo Pérez Márquez
Publisher:
ISBN:
Category :
Languages : en
Pages : 324

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