Data/hora: 26/05/2024 20:14:36

Biblioteca(s): 	Embrapa Gado de Corte; Embrapa Pantanal; Embrapa Suínos e Aves.	
Data corrente: 	07/05/1997	
Data da última atualização: 	15/01/2014	
Autoria: 	IRGANG, R.	
Título: 	Direct and correlated responses to selection for weaning weight and postweaning gain in Hereford cattle.	
Ano de publicação: 	1984	
Fonte/Imprenta: 	Raleigh: North Carolina State University, 1984.	
Páginas: 	165p.	
Idioma: 	Inglês	
Notas: 	Tese Doutorado.	
Conteúdo: 	Single trait selection was practiced in three lines of Hereford cattle derived from a common base population. Bulls were selected within sire families for increased weaning weight (WW) in line WWL, increased postweaning gain (PG) in line PGL and ramdomly selected in the control line (CTL). The data consist of 2,467 progeny produced from 1967 to 1981 by 125 sires and 922 dams. After 3 years of stablishing the foundation population, 12 years of continuous selection resulted in slightly less than two generations of selection of selection and in low inbreeding coefficients. Direct selection applied to either WW or PG improved both traits. However, selection for PG increased both PG and WW faster than selection for WW. Selection for WW and for PG increased milk production, preweaning daily gain, yearling weight and feed intake. Correlated responses in these traits were larger in PGL than in WWL. Selection for either WW or PG also increased the amount of fatness in bulls in feedlot. However, it did not result in any or PG also increased the amount of fatness in bulls in feedlot. However, it did not result in any significant change in feed efficiency. Increased birth weight was observed from PG selection but not from WW selection. Realized heritabilities and regression coefficients of correlated responses on cumulative selection differentials, estimated from "quasi-replicates" generated by grouping individual descendents from sires utilized in different years of the foundation population, indicated that genetic drift affected responses to selection and suggest that replication of selection experiments is necessary...	
Palavras-Chave: 	Beefcattle; Fat; Feed efficiency; Growth; Production; Selection.	
Thesagro: 	Alimentação; Crescimento; Desmama; Gado; Gado de Corte; Gordura; Leite; Peso; Produção Animal; Seleção; Zootecnia.	
Thesaurus Nal: 	beef cattle; cattle; milk; weaning weight.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Gado de Corte (CNPGC)	
Exemplares: 	CNPGC - (7911-1) - ADD - TS - PP - T472/84 - IRG - T472/84 - DIS
CNPSA - (4513-1) - ADD - TS - -- -  -  - 1997.00466 - DIS
CPAP - (33875-1) - ADD - TS - PP - TS89.00299 -  - 1989.00299 - DIS