|
|
|
| Registros recuperados: 14 | |
|
| |
|
| |
|
|
| Toral,Fábio Luiz Buranelo; Torres Júnior,Roberto Augusto de Almeida; Lopes,Paulo Sávio; Silva,Luiz Otávio Campos da; Reis Filho,João Cruz. |
| The objective of this study was to evaluate alternatives for modeling the age of dam at calving (AOD) effect on the weaning weight of Charolais-Zebu crossbred calves. Data from 56,965 calves were analyzed, using statistical models considering the fixed effects of the contemporary groups, sire and dam genetic groups, and AOD. The AOD effect was fitted to models using annual age classes, and ordinary quadratic to quintic-ordered polynomials (OP) or segmented polynomials (SP) with two, three, four, six and twelve evenly spaced intervals. In the case of segmented polynomials, general linear and quadratic effects and only one quadratic additional term from each knot were considered. The AOD effects were nested within sex of calf in all cases. According to the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Beef cattle; Environmental effects; Genetic evaluation; Least square. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982009000700011 |
| |
|
|
| Cardoso,Leandro Lunardini; Braccini Neto,José; Cardoso,Fernando Flores; Cobuci,Jaime Araújo; Biassus,Igor de Oliveira; Barcellos,Júlio Otávio Jardim. |
| It was evaluated statistical models with different assumptions to define the one that best describes the presence of genotype × environment interaction on adjusted post-weaning weight gain (PWG345) of Hereford cattle, through the study of reactions norms to the environment, obtained by random regression using a Bayesian approach. Four reaction norms hierarchical models (RNHM) were used through the INTERGEN program. The RNHM K uses the solutions of contemporary groups previously estimated by the standard animal model (AM) and considers them as environmental level for predicting the reaction norms and the RNHM S, which jointly estimate these two sets of unknowns. For both models, two versions were considered, one with a homogeneous (hm) and another with a... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Adaptability; Bayesian inference; Environmental sensitivity; Genetic evaluation; Random regression. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982011000200009 |
| |
|
|
| Bertrand,Joseph Keith. |
| Increased movement toward alliances and grid pricing in the U.S. has led to an increase interest in genetic values for carcass traits. The literature suggests that carcass genetic values are an effective tool to enhance selection for carcass traits, and that it is possible to select sires within a breed that can increase marbling score without adversely affecting external fat thickness or percent retail product relative to the breed mean. Ultrasound has been investigated as a cheaper means of collecting carcass information. The literature indicates that carcass traits measured via ultrasound on yearling seedstock will respond to selection. Although the literature is variable on the subject, there are reported genetic correlation (r g) estimates between... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Beef carcass traits; Genetic evaluation; Multi-breed models; Ultrasound. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982009001300007 |
| |
|
| |
|
| |
|
|
| Araújo,Ronyere Olegário de; Rorato,Paulo Roberto Nogara; Weber,Tomás; Everling,Dionéia Magda; Lopes,Jader Silva; Dornelles,Mariana de Almeida. |
| Genetic parameters and genetic and phenotypic trends were estimated for weight at weaning (WW) and visual scores (VS) of conformation (C), precocity (P), musculature (M) and navel (N) for Angus × Nellore crossbred calves. It was used 39,676 records from pre-weaning phase of animals born from 1992 to 2002 in mid-western, southeastern and southern Brazil. The components of covariance were estimated using REML, in animal model, considering as random the maternal and direct additive genetic effects, and as fixed, the effects of contemporaneous group, the genetic group of the animal and of the cow, and as covariates the age of the calf at weaning and the age of the cow at calving, both on days and with linear and quadratic effects, besides direct (DH) and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Beef cattle; Cross-breeding; Genetic evaluation; Genetic progress; Morphologic evaluation. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982010001100012 |
| |
|
| |
|
| |
|
| |
|
| |
|
|
| Ribeiro,Jeferson Corrêa; Silva,Luciano Pinheiro da; Soares,Aline Camporez Crispim; Caetano,Giovani da Costa; Leite,Carla Daniela Suguimoto; Bonafé,Cristina Moreira; Sousa,Mariele Freitas; Torres,Robledo de Almeida. |
| ABSTRACT: We estimated genetic and phenotypic parameters for egg production in meat-type quails aiming to propose an optimal age for selection through partial record egg production. Data of 3,503 female quails from two strains (namely, UFV1, with 1,811 and UFV2 with 1,692 females) were used. Egg production was assessed by the number of eggs recorded after 42 days of age and each partial period consisted on 35 days of egg production forward. Covariance components were estimated by using single and bivariate animal model, comprising each partial period of egg production and full egg production period (one year of egg laying). Regarding strain UFV1, heritability estimates ranges from 0.03 to 0.16, and for strain UFV2 0.20 to 0.25. The highest genetic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coturnix coturnix; Genetic correlation; Genetic evaluation; Heritability; Variance components. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782017000400653 |
| |
|
|
| Moreira,Heverton Luis; Buzanskas,Marcos Eli; Munari,Danisio Prado; Canova,Érika Breda; Lôbo,Raysildo Barbosa; Paz,Claudia Cristina Paro de. |
| Genetic breeding programs of beef cattle in Brazil are including new features, mainly related to reproductive efficiency.Thus, it is necessary to study the effectiveness of selection and quantify genetic gain for these traits in herds. This study estimated genetic and phenotypic parameters and genetic trends for reproductive traits used in breeding programs for Nelore beef cattle. The traits studied were the scrotal circumference (SC) at 365 and 450 days of age (SC365 and SC450), age at first calving (AFC) and gestation length, as a cow trait (GLcow) and a calf trait (GLcalf). The (co)variance components were obtained with the Restricted Maximum Likelihood Methodology in a single and double-trait analysis of the animal model. For scrotal circumference... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Reproductive efficiency; Genetic evaluation; Precocity. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542015000400355 |
| |
| Registros recuperados: 14 | |
|
|
|
