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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
10/04/1996 |
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Data da última atualização: |
10/04/1996 |
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Autoria: |
WILSON, D. E.; ROTHSCHILD, M. F.; BOGGESS, M. V.; MORRICAL, D. G. |
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Título: |
Adjustment factors for birth weight and 30-day, 60-day, and 90-day weaning weight in sheep. |
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Ano de publicação: |
1996 |
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Fonte/Imprenta: |
Journal of Animal Breed and Genetics, v.113, n.1, p.29-41, 1996. |
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Idioma: |
Inglês |
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Conteúdo: |
The performance record for known sources of environmental variation is often statistically adjusted before genetic evaluation of many commercially produced livestock species. Typically, records are adjusted for effects such as age of dam, sex, and type ,of birth/rearing (BIR), which are consistent for all animaIs, but cannot be fitted into genetic evaluation models because contemporary groups are small. Adjustment factors can be multiplicative or additive. Both types of factors equalize the means of the adjusted subclasses, but multiplicative factors change the variance by the square ratio used. Additive factors do Dot change the variance. The adjustment factors currently used by the National Sheep Improvement Program (NSIP) are multiplicative, and are a combination of factors estimated by the United States Department of Agriculture (UNITED STATES DEPARTMENTOF AGRICULTURE 1968; NOTTER et al. 1975; MARTIN et al. 1980; NATIONAL SHEEP IMPROVEMENT PROGRAM 1986). These adjustment factors are used for aIl weaning ages and across all breeds evaluated by the NSIP. However, the current factors do not satisfactorily account for the effects of sex, BIR, and age of dam in the NSIP data. Therefore, this study aimed to estimate separate adjustment factors for weaning weight at 30, 60, and 90-days to enable lambs records to be evaluated for genetic merit by NSIP. Adjustment factors were estimated by breed type, to provide two sets of factors for use across all 27 breeds currently evaluated by NSIP. Adjustment factors for birth weight were also estimated, by using birth-weight records collecte~ by the NSIP. MenosThe performance record for known sources of environmental variation is often statistically adjusted before genetic evaluation of many commercially produced livestock species. Typically, records are adjusted for effects such as age of dam, sex, and type ,of birth/rearing (BIR), which are consistent for all animaIs, but cannot be fitted into genetic evaluation models because contemporary groups are small. Adjustment factors can be multiplicative or additive. Both types of factors equalize the means of the adjusted subclasses, but multiplicative factors change the variance by the square ratio used. Additive factors do Dot change the variance. The adjustment factors currently used by the National Sheep Improvement Program (NSIP) are multiplicative, and are a combination of factors estimated by the United States Department of Agriculture (UNITED STATES DEPARTMENTOF AGRICULTURE 1968; NOTTER et al. 1975; MARTIN et al. 1980; NATIONAL SHEEP IMPROVEMENT PROGRAM 1986). These adjustment factors are used for aIl weaning ages and across all breeds evaluated by the NSIP. However, the current factors do not satisfactorily account for the effects of sex, BIR, and age of dam in the NSIP data. Therefore, this study aimed to estimate separate adjustment factors for weaning weight at 30, 60, and 90-days to enable lambs records to be evaluated for genetic merit by NSIP. Adjustment factors were estimated by breed type, to provide two sets of factors for use across all 27 breeds currently evaluated... Mostrar Tudo |
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Thesagro: |
Melhoramento; Ovino; Peso. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02166naa a2200193 a 4500
001 1516370
005 1996-04-10
008 1996 bl uuuu u00u1 u #d
100 1 $aWILSON, D. E.
245 $aAdjustment factors for birth weight and 30-day, 60-day, and 90-day weaning weight in sheep.
260 $c1996
520 $aThe performance record for known sources of environmental variation is often statistically adjusted before genetic evaluation of many commercially produced livestock species. Typically, records are adjusted for effects such as age of dam, sex, and type ,of birth/rearing (BIR), which are consistent for all animaIs, but cannot be fitted into genetic evaluation models because contemporary groups are small. Adjustment factors can be multiplicative or additive. Both types of factors equalize the means of the adjusted subclasses, but multiplicative factors change the variance by the square ratio used. Additive factors do Dot change the variance. The adjustment factors currently used by the National Sheep Improvement Program (NSIP) are multiplicative, and are a combination of factors estimated by the United States Department of Agriculture (UNITED STATES DEPARTMENTOF AGRICULTURE 1968; NOTTER et al. 1975; MARTIN et al. 1980; NATIONAL SHEEP IMPROVEMENT PROGRAM 1986). These adjustment factors are used for aIl weaning ages and across all breeds evaluated by the NSIP. However, the current factors do not satisfactorily account for the effects of sex, BIR, and age of dam in the NSIP data. Therefore, this study aimed to estimate separate adjustment factors for weaning weight at 30, 60, and 90-days to enable lambs records to be evaluated for genetic merit by NSIP. Adjustment factors were estimated by breed type, to provide two sets of factors for use across all 27 breeds currently evaluated by NSIP. Adjustment factors for birth weight were also estimated, by using birth-weight records collecte~ by the NSIP.
650 $aMelhoramento
650 $aOvino
650 $aPeso
700 1 $aROTHSCHILD, M. F.
700 1 $aBOGGESS, M. V.
700 1 $aMORRICAL, D. G.
773 $tJournal of Animal Breed and Genetics$gv.113, n.1, p.29-41, 1996.
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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