| Titles |
|
English :
|
Random regression test day model for estimation of genetic parameters for milk yield and protein percentage of primiparous friesian cows in egypt
|
|
| Abstract |
Both fixed and random linear and quadratic regressions were used to model test day records that are measured over the trajectory from DIM = 5 to 320-d of primiparous Friesian cows. The (co)variance components were estimated with a single trait animal model with REML algorithm for each of daily milk yield and protein percentage using the computer package DF-REML (Version 3β) of Meyer (1998a) for a total of 1226 records. Records were taken from Sakha Animal Production Research Station belonging to Animal Production Research Institute (Sakha, Kafr El-Shaiekh Governorate, Egypt between 1997 and 2000).
Heritabilities for milk yield and protein percentage were higher for early lactation (< 35 DIM) and gradually decreased as DIM advanced. Genetic correlations through DIM were generally high and tended to decrease as the interval throughout the lactation increased for both traits. Permanent environmental and phenotypic correlations had the same trend. Varied heritability estimates for milk yield and protein percentage along with DIM and the wide range of genetic correlation estimates between records could suggest that yield pattern in first lactation Friesian cows are genetically different.
Keywords: random regression, test day model, genetic parameters, primiparous Friesian cows
|
| Publication year |
2004
|
| Pages |
1-10
|
| Availability location |
معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
|
| Availability number |
|
| Organization Name |
Animal Production Research Institute (APRI)
|
| serial title |
Egyptian Journal of Animal Production
|
| Author(s) from ARC |
|
| Agris Categories |
Animal husbandry
|
AGROVOC
TERMS |
Cows.
Egypt.
Genetic correlation.
Genetic parameters.
Milk yield.
Phenotypes.
Proteins.
|
| Proposed Agrovoc |
random regression;test day model;primiparous Friesian cows;
|
| Publication Type |
Journal
|