Data/hora: 17/06/2024 04:04:25

Biblioteca(s): | Embrapa Caprinos e Ovinos.
Data corrente: | 07/04/2005
Data da última atualização: | 13/04/2022
Autoria: | LEGARRA, A.; UGARTE, E.
Título: | Genetic parameters of milk traits in Latxa dairy sheep.
Ano de publicação: | 2001
Fonte/Imprenta: | Animal Science, v. 73, pt 3, p. 407-412, 2001.
Idioma: | Inglês
Conteúdo: | A total of 7444 lactation records which include milk, fat and protein yields (MY, FY, PY) and fat and protein content (F%, P%) from 6429 Black-Faced Latxa ewes were employed to estimate genetic parameters for milk traits. Traits were standardized to 120 days of lactation. For the calculation of composition traits, not alI test-days had their composition measured and therefore a correction taking this into account was included in lhe analysis. A first- derivative restricted maximum likelihood algorithm was used on an animal model with repeatability analysis, using models including fixed effects (flock-year-season of lambing, age-parity at lambing, number of lambs, interval between lambing and first milk recording and the combination of sampled test-days) and random effects (the additive genetic effect and the permanent environmental effect). The resulting heritabilities were 0.20, 0.16, 0.18, 0.14 and 0.38 for MY, FY, PY, F% and P% respectively. Heritability of F% was much lower than expected, probably due to problems derived from the recording method. Genetic correlations were high and positive between yields and moderately positive between F% and P%, ànd negative or null between yields and composition, as has been reported for other European dairy sheep breeds. As most of the milk produced by Latxa dairy sheep is processed into cheese, the inclusion of milk sampling in official milk recording and a change in the selection criterion are recommended to avoid a long-term worsening in milk composition.
Palavras-Chave: | Composição; Herdabilidade; Ovino leiteiro.
Thesagro: | Genética Animal; Leite; Parâmetro Genético.
Categoria do assunto: | L Ciência Animal e Produtos de Origem Animal
Registro original: | Embrapa Caprinos e Ovinos (CNPC)
Exemplares: | CNPC - (17623-1) - ADD - AP - -- -  -  - v.73,p.407 - DIS