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6 results on '"Rorato, P. R. N."'

1. Egg production evaluation of laying hens by multivariate analysis.

Author

Ferreira, P. B., Rorato, P. R. N., Mello, F. C. B., Bevilaqua, B., Macedo, A., and Brittes, L. B. P.

Abstract

Copyright of Arquivo Brasileiro de Medicina Veterinária e Zootecnia is the property of Universidade Federal de Minas Gerais, Escola de Veterinaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2017
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2. Variance Caused by Cytoplasmic Line and Sire by Herd Interaction Effects for Milk Yield Considering Estimation Bias

Author

Rorato, P. R. N., Keown, Jeffrey F, Van Vleck, L. Dale, Rorato, P. R. N., Keown, Jeffrey F, and Van Vleck, L. Dale

Abstract

A total of 138,869 lactation milk yields (305 d, milked twice daily, mature equivalent) from the first three parities of 68,063 New York Holstein cows were used to estimate variance components that were due to additive direct genetic effects, cow permanent environmental effects (cow within sire for sire model), sire by herd interaction effects, and cytoplasmic line effects. The original data were assigned to 10 random samples, which were each analyzed using an animal model and a sire model. From each sample of original data, 20 other samples were analyzed with levels assigned randomly to cytoplasmic and interaction effects (data with randomly simulated levels). Ten of those samples were analyzed with an animal model and 10 with a sire model. The models also included fixed effects of herd-year-seasons. For the animal model and sire model, average fractions of phenotypic variance and average standard errors were, respectively, for additive direct genetic effects 0.300 (0.029) and 0.228 (0.040) for original data and 0.325 (0.025) and 0.262 (0.039) for data with randomly simulated levels. For cow permanent environmental effects the respective averages were 0.242 (0.024) and 0.444 (0.014) for original data and 0.235 (0.025) and 0.492 (0.016) for data with randomly simulated levels. The averages for sire by herd interaction effects were 0.015 (0.008) and 0.018 (0.007) for original data and 0.003 (0.007) and 0.004 (0.009) for data with randomly simulated levels. For cytoplasmic line effects, the respective averages were 0.011 (0.007) and 0.043 (0.008) for original data and 0.003 (0.006) and 0.003 (0.007) for data with randomly simulated levels. The differences between estimates of variance components for original data and data with randomly simulated levels suggest that estimates of fractions of total variance caused by sire by herd interaction and cytoplasmic effects estimated with REML may be biased upward by 0.003 to 0.004.

Published
1999

6. Finishing precocity visual score and genetic associations with growth traits in Angus beef cattle.

Author

Everling DM, Bresolin T, Rorato PR, Araujo RO, Boligon AA, Weber T, Dornelles MA, and Campos LT

Subjects
Animals, Cattle genetics, Monte Carlo Method, Cattle growth & development
Abstract

Finishing precocity visual score selection was adopted to estimate the time from birth to reach slaughter age. This study estimated (co)variance components and genetic correlations for the finishing precocity score at weaning (WP) and yearling (YP) stages by using daily weight gain (BWG = from birth to weaning; WYG = from weaning to yearling) and speed of weight gain (BWR = from birth to weaning; WYR = from weaning to yearling) as support for a genetic evaluation program for Angus beef cattle. Genetic parameters were estimated using Bayesian inference, considering multi-trait analysis and assuming a nonlinear model for WP and YP and linear model for all other traits. Direct heritability estimates were 0.17 (WP), 0.19 (YP), 0.15 (BWG), 0.16 (WYG), 0.15 (BWR), and 0.16 (WYR). The genetic correlation between the finishing precocity score at two ages (weaning and yearling) was 0.61. Positive and moderate genetic correlations were obtained between WP and BWG (0.47) and WP and BWR (0.46). In contrast, negative and low genetic associations were estimated between WP and yearling growth traits (-0.16, WYG; -0.15, WYR). Genetic correlations between YP and other traits were positive 0.29 (BWG), 0.28 (BWR), 0.48 (WYG), and 0.47 (WYR). The selection response for the finishing precocity score at weaning and yearling ages would be low. Selection to increase WP and YP should result in favorable genetic changes in daily weight gains as a correlated response. Therefore, to obtain animals suited for beef cattle production systems, finishing precocity score and growth traits should be considered as selection criteria.

Published
2014
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