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| Registros recuperados: 10 | |
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| Nobre,P.R.C.; Lopes,P.S.; Torres,R.A.; Silva,L.O.C.; Regazzi,A.J.; Torres Júnior,R.A.A.; Misztal,I.. |
| Growth curves of Nellore cattle were analyzed using body weights measured at ages ranging from 1 day (birth weight) to 733 days. Traits considered were birth weight, 10 to 110 days weight, 102 to 202 days weight, 193 to 293 days weight, 283 to 383 days weight, 376 to 476 days weight, 551 to 651 days weight, and 633 to 733 days weight. Two data samples were created: one with 79,849 records from herds that had missing traits and another with 74,601 from herds with no missing traits. Records preadjusted to a fixed age were analyzed by a multiple trait model (MTM), which included the effects of contemporary group, age of dam class, additive direct, additive maternal, and maternal permanent environment. Analyses were carried out by a Bayesian method for all... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Beef cattle; Multiple trait; Random regression. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352003000400015 |
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| Cruz,Diego Augusto Campos da; Savegnago,Rodrigo Pelicioni; Santana,Annaíza Braga Bignardi; Peixoto,Maria Gabriela Campolina Diniz; Bruneli,Frank Angelo Tomita; Faro,Lenira El. |
| ABSTRACT: The aim of this study was to explore the pattern of genetic lactation curves of Guzerá cattle using cluster analysis. Test-day milk yields of 5,274 first-lactation Guzerá cows were recorded in a progeny test. A total of 34,193 monthly records were analyzed with a random regression animal model using Legendre polynomials to fit additive genetic and permanent environmental random effects and mean trends. Hierarchical and non-hierarchical cluster analyses were performed based on the EBVs for monthly test-day milk yield, peak yield, lactation persistency, and partial cumulative and 305-day yields. The heritability estimates for test-day milk yields ranged from 0.24 to 0.52. Cluster analysis identified animals in the population that belong to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Breeding values; Lactation curve; Random regression. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016000701281 |
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| 三浦, 伸也; 鈴木, 三義. |
| (社)北海道酪農検定検査協会の検定日記録を用い，体細胞スコアに対する影響要因を明らかにし，遺伝率を推定した．データは北海道酪農検定検査協会により，1991年2月から2003年3月までに集積された初産の869,114頭からの8,986,351の検定日記録，2産は619,883頭（6,370,190記録），3産は409,320頭（4,194,475記録）に関する泌乳量と体細胞スコアである．体細胞スコアの上昇により，乳量，乳成分量は減少を示し，とくにスコア6以上で急激な減少を示した．体細胞スコアの遺伝率は，Wilminkの泌乳曲線を利用した反復率モデルで，初産〜3産まで0.08，0.07，0.07と推定され，産次間での大きな変動は認められなかった．ルシャンドル多項式を利用した変量回帰モデルを用いた遺伝率推定値は，Wilminkの関数により得られたものより高く，とくに分娩直後および，乾乳前において高く推定された．モデル内の次数を2次から5次まで変化させることによる大幅な遺伝率の変化は認められなかったので，計算時間等を考慮すると3次程度が妥当な次数と考えられる．閾値モデルによる推定遺伝率は分析の中ではもっとも高く推定され，その有効性が示唆されたが，これに関してはさらに実用的な見地からの研究が望まれる． |
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Palavras-chave: Somatic cell score; Heritability; Random regression; Threshold model; Holstein. |
| Ano: 2006 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2598 |
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| Nobre,P.R.C.; Rosa,A.N.; Silva,L.O.C.. |
| Expected progeny differences (EPD) of Nellore cattle estimated by random regression model (RRM) and multiple trait model (MTM) were compared. Genetic evaluation data included 3,819,895 records of up nine sequential weights of 963,227 animals measured at ages ranging from one day (birth weight) to 733 days. Traits considered were weights at birth, ten to 110-day old, 102 to 202-day old, 193 to 293-day old, 283 to 383-day old, 376 to 476-day old, 551 to 651-day old, and 633 to 733-day old. Seven data samples were created. Because the parameters estimates biologically were better, two of them were chosen: one with 84,426 records and another with 72,040. Records preadjusted to a fixed age were analyzed by a MTM, which included the effects of contemporary... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Beef cattle; Multiple trait; Random regression. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352009000400026 |
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| Lôbo,Raimundo N.B.; Vieira,Luiz S.; Oliveira,Amaury A. de; Muniz,Evandro N.; Silva,José M. da. |
| Worm infection is one of the main factors responsible for economic losses in sheep breeding in Brazil. Random regression analysis was used to estimate genetic parameters for the factors faecal egg-count (FEC), packed-cell volume (PCV) and body weight (BW) in Santa Inês lambs. Data from 119 female, offspring of nine rams, were collected between December, 2005 and December, 2006, from the experimental flock of Embrapa Tabuleiros Costeiros, the Brazilian Agricultural Research Corporation located in Frei Paulo, SE, Brazil. After weaning, females were drenched until the faecal egg count had dropped to zero. Two natural challenges were undertaken. FEC heritability was extremely variable, this increasing from 0.04 to 0.27 in the first challenge and from 0.01 to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Genetic correlations; Heritability; Legendre polynomials; Random regression. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000200014 |
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| 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 |
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| Pereira,Rodrigo Junqueira; Ayres,Denise Rocha; Santana Junior,Mário Luiz; Faro,Lenira El; Vercesi Filho,Aníbal Eugênio; Albuquerque,Lucia Galvão de. |
| Abstract: The objective of this work was to compare genetic evaluations of milk yield in the Gir breed, in terms of breeding values and their accuracy, using a random regression model applied to test-day records or the traditional model (TM) applied to estimates of 305-day milk yield, as well as to predict genetic trends for parameters of interest. A total of 10,576 first lactations, corresponding to 81,135 test-day (TD) records, were used. Rank correlations between the breeding values (EBVs) predicted with the two models were 0.96. The percentage of animals selected in common was 67 or 82%, respectively, when 1 or 5% of bulls were chosen, according to EBVs from random regression model (RRM) or TM genetic evaluations. Average gains in accuracy of 2.7, 3.0,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Accuracy; Persistency; Random regression; Rank correlation. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2019000104305 |
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| Registros recuperados: 10 | |
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