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Details van artikel 37 van 62 gevonden artikelen
| Titel: |
Lifetime Production and Longevity of Holstein Friesian Cows in Relation to Their Sire Transmitting Ability |
| Auteur: |
H. Atil A. S. Khattab |
| Verschenen in: |
Pakistan journal of biological sciences |
| Paginering: | Jaargang 2 (1999) nr. 1 pagina's 69-73 |
| Jaar: |
1999 |
| Inhoud: |
A total of 193 Holstein Friesian cows sired by 39 bulls at Dena farm in Egypt, during the period from 1987 to 1991 were used to estimate phenotypic and genetic parameters of lifetime production and longevity traits in Friesian cows in Egypt and to study relationship between sire transmitting ability (ETA`s) of sires for first 305 day milk yield and each of lifetime production and longevity traits. Heritability and phenotypic and genetic correlations were estimated by paternal half sibs correlations. Heritability estimates were 0.18, 0.24, 0.04, 0.05 and 0.00 for first 305 day milk yield, total lifetime milk production, total lactation period, productive life and number of lactations completed. All phenotypic (0.14 - 0.97) and genetic (0.90 - 1.00) correlations among different traits studied were significant except the correlations between number of lactations completed and different traits studied. Sires with at least ten daughters were evaluated by best linear unbiased prediction procedures. Sires with positive expected (ETA`s) for first 305 day milk production, have positive values for lifetime production and longevity traits. Product moment correlations of expected ETA`s for first 305 day milk yield with lifetime production and longevity traits ranged from (0.09 to 0.96). Sire selection for higher milk yield in the first lactation would lead to a slight increase in longevity defined as length of productive life. |
| Uitgever: |
Asian Network for Scientific Information (provided by DOAJ) |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 37 van 62 gevonden artikelen
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