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| Barbosa,Severino B.P.; Ramalho,Ricardo P.; Monardes,Humberto G.; Dias,Flávio M.; Santos,Djalma C. dos; Batista,Ângela M.V.. |
| The productive performance of four Holstein-Gir genetic groups (1/2H, 1/4H, 5/8H, 5/8Hinter se) and the effects of non-genetic factors on production traits was evaluated using a data set of 7,951 test-day samples collected between January 1980 and December 1999 from the Arcoverde Experimental Station in the Brazilian state of Pernambuco (Empresa Pernambucana de Pesquisa Agropecuária). The statistical model included the fixed effects of calving year (1980 to 1999) and month (January to December), genetic group of the cow, age at months of calving (33 to 190) and days in milk at each test-day. Random effects were sire, cow and residual with test-days treated as repeated records within each cow within each lactation. For the four genetic groups the milk yield... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Genetic groups; Epistasis; Genetics groups; Recombination; Repeated measures; Test-day. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000300012 |
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| Biassus,Igor de Oliveira; Cobuci,Jaime Araújo; Costa,Claudio Napolis; Rorato,Paulo Roberto Nogara; Braccini Neto,José; Cardoso,Leandro Lunardini. |
| The objective of this study was to estimate genetic parameters for milk, fat and protein yields of Holstein cows using 56,508; 35,091 and 8,326 test-day milk records from 7,015, 4,476 and 1,114 cows, calves of 359, 246 and 90 bulls, respectively. The additive genetic and permanent environmental effects were estimated using REML. Random regression models with Legendre polynomials from order 3 to 6 were used. Residual variances were considered homogeneous over the lactation period. The estimates of variance components showed similar trends, with an increase of the polynomial order for each trait. The heritability estimates ranged from 0.14 to 0.31; 0.03 to 0.21 and 0.09 to 0.33 for milk, fat and protein yield, respectively. Genetic correlations among milk,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fat yield; Herdability; Milk yield; Protein yield; Test-day. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982011000100012 |
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