scholarly journals Multi-trait and random regression mature weight heritability and breeding value estimates in Nelore cattle

2010 ◽  
Vol 39 (1) ◽  
Author(s):  
A.A Boligon ◽  
M.E.Z Mercadante ◽  
F Baldi ◽  
R.B Lôbo ◽  
L.G Albuquerque
Keyword(s):  
Random Regression ◽  
Breeding Value ◽  
Mature Weight ◽  
Nelore Cattle

scholarly journals Breeding value accuracy estimates for growth traits using random regression and multi-trait models in Nelore cattle

2011 ◽  
Vol 10 (2) ◽  
pp. 1227-1236 ◽  
Author(s):  
A.A. Boligon ◽  
F. Baldi ◽  
M.E.Z. Mercadante ◽  
R.B. Lôbo ◽  
R.J. Pereira ◽  
...  
Keyword(s):  
Growth Traits ◽  
Random Regression ◽  
Breeding Value ◽  
Nelore Cattle

scholarly journals Description and comparison of growth parameters in Chianina and Nelore cattle breeds

1999 ◽  
Vol 22 (2) ◽  
pp. 187-196 ◽  
Author(s):  
Sônia Mara Carrijo ◽  
Francisco A. Moura Duarte
Keyword(s):  
Inflection Point ◽  
Growth Parameters ◽  
Genetic Correlations ◽  
Von Bertalanffy Model ◽  
Cattle Breeds ◽  
Model Average ◽  
Different Ages ◽  
Mature Weight ◽  
Nelore Cattle ◽  
Weight Data

Weight data from birth to 18 months of age of Nelore and Chianina, both meat-producing cattle breeds, were analyzed. Data were corrected for significant effects of environment and utilized to estimate genetic parameters through the non-linear von Bertalanffy model. Average values found for growth parameters in Nelore were: mature weight (A), 312.87 kg; integration constant (B), 0.49; maturity rate (k), 0.13; age at inflection point (T(I)), 3.29 months; weight at inflection point (P(I)), 92.70 kg, and maturity interval (1/k), 8.04 months. For the Chianina animals, the values were 751.38 kg, 0.59, 0.10, 6.64 months, 222.63 kg, and 10.98 months, respectively. Nelore animals exhibited higher maturity rate, smaller maturity intervals, reaching mature weights younger than Chianina animals, although lighter than these at maturity. Heritability estimates presented low values, mainly for mature weight (0.093 and 0.212), age at inflection point (0.062 and 0.202), weight at inflection point (0.093 and 0.212) and maturity interval (0.057 and 0.309) (for Nelore and Chianina, respectively). The parameters mature weight and weight at inflection point presented positive genetic correlations with weights at different ages and with similar trends, increasing as age increased, in both breeds. Considering the development period analyzed, from birth to 18 months of age, the parameter maturity rate and the weights at different ages showed genetic correlations which increased until the weight at 150 and 205 days in Nelore and Chianina, respectively, and decreased from these ages on, and the genetic correlations among the parameter maturity interval and the weights at different ages were negative. They decreased until the weights at 150 and 205 days, respectively, in Nelore and Chianina, and increased from these ages on.

scholarly journals Reaction norms in weights at 365 days old in nellore bulls in northern Brazil

2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4613 ◽  
Author(s):  
Jorge Luís Ferreira ◽  
Alliny Souza de Assis ◽  
Fernando Brito Lopes ◽  
Thomas Wayne Murphy ◽  
Marcelo Corrêa da Silva ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Reaction Norm ◽  
Genotype By Environment Interaction ◽  
Random Regression ◽  
Residual Effects ◽  
Breeding Value ◽  
Environment Interaction ◽  
Nellore Cattle ◽  
Regression Techniques ◽  
Northern Brazil

<p>Genotype by environment interaction (GxE) studies are of particular interest in Brazil because of the regional diversity of environmental effects and the wide variety of management systems. The present study evaluates GxE effects on 365 d weight (365W) of Nellore cattle raised on pasture in northern Brazil. The analysis utilized random regression techniques to model the reaction norm. Fixed effects consisted of sex, contemporary group, and the covariate of age of cow at calving. The environmental gradient, defined by the concatenation of a bull and the state in which the calf was born, was modeled by second order Legendre polynomials. Direct additive genetic and residual effects were fit as random. Results showed differences in the magnitude of expression of genotype in proportion to decreasing favorability of the environment. As the environment became more unfavorable, the correlation of breeding value to different environments decreased. The correlations between the intercept and the level slope for 365W feature were of moderate magnitude, predominantly indicating the reclassification of sires in different environments. Reaction standard model was coherent from a technical and biological view point and enabled the perception of GxE in the genetic evaluation of Nellore cattle in the states of Maranhão, Pará and Tocantins.</p><p> </p>

scholarly journals Konstruktion von Indizes mit Restriktionen in Random Regression Modellen zur Veränderung der Wachstumskurve

2007 ◽  
Vol 50 (6) ◽  
pp. 619-627
Author(s):  
N. Mielenz ◽  
L. Schüler
Keyword(s):  
Body Weight ◽  
Growth Curve ◽  
Regression Models ◽  
Test Period ◽  
Regression Coefficients ◽  
Random Regression ◽  
Breeding Value ◽  
Time Interval ◽  
Final Body Weight ◽  
Index Construction

Abstract. Title of the paper: Index construction with restrictions in random regression models to change the pattern of the growth curve Random regression models provide estimated breeding values (EBV) for the complete growth curve for any target age. The animal-specific curves can be described as the weighted sum of continuous covariates with random regression coefficients. By using the covariance matrix K of the additive genetic regression coefficients the response to index selection can be calculated for any age or time of the test period. In this study selection indexes with equality restrictions based on the eigenvectors of matrix K were used to modify the growth curve of the population. In order to demonstrate the index construction a matrix K was used, estimated from repeated measurements for body weight of bulls by using Legendre polynomials as covariates. Indexes for high and low growth rate until age at the reflection point were derived subject to the restriction of zero gain for initial and final body weight. Selection strategies for improving body weight at the end of the test period while holding the daily gain in a certain time interval on a desired level were compared. By using so-called "restrictive economic values", an aggregate breeding value for body weight was derived from EBV for individual growth curve.

scholarly journals Estimation the Genetic Parameters for Milk Yield in Romanian Spotted, Simmental Type Cattle Breed

2021 ◽  
Vol 24 (2) ◽  
pp. 105-121
Author(s):  
Rodica Stefania Pelmuș ◽  
Mircea Cătălin Rotar ◽  
Cristina Lazăr ◽  
Răzvan Alexandru Uță
Keyword(s):  
Animal Model ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Cattle Breed ◽  
Random Regression ◽  
Breeding Value ◽  
Regression Test ◽  
Fat Yield ◽  
Heritability Estimates

Abstract The aim of this study was to estimate the genetic parameters for test-day traits milk yield and the breeding value in Romanian Spotted, Simmental type cattle. Random regression test-day animal model was used to estimate the genetic parameters. The number of records were 2062 test-day from 302 cows. The data were obtained from Romanian Breeding Association Romanian Spotted, Simmental type. The heritability estimates values for milk yield ranged between 0.377 and 0.417. The heritability for fat test-day yield in our study was low the values ranged between 0.117 and 0.236 and for protein test-day yield was medium, the values ranged between 0.308 and 0.372. The breeding value for the best ten cows for milk yield ranged from 1946.57 to 3250.38 kg, for fat yield were between 64.92 and 98.86 kg and for protein ranged from 67.26 to 102.21 kg. The correlations between test-day milk yields ranging from 0.28 to 1. Genetic correlations between test day fat and protein yields were high.

Sign in / Sign up

Export Citation Format

Share Document