Weight and Age at Calving and Weight Change Related to First Lactation Milk Yield
نویسندگان
چکیده
منابع مشابه
Genetic Parameter Estimates for Lactation Curve Parameters, Milk Yield, Age at First Calving, Calving Interval and Somatic Cell Count in Holstein Cows
The objective of this study was to estimates the genetic and environmental components for the lactation curve parameters, milk yield, age at first calving (AFC), calving interval (CI) and somatic cell count (SCC) in Iranian Holstein cows. The dataset consisted of 210625 test day records from 25883 cows with milk yield in the first parity recorded from July 2002 to September 2007 in a total of 9...
متن کاملGenetic (Co)variance between Age from First to Third Calving and Milk Yield of Holstein Cows in the Tropics
A total of 245187 records of the first three lactations of 131126 Holstein cows in tropical conditions were used to estimate the genetic (co)variance components between age at calving and its respective milk productions. A multivariate analysis of six traits was performed. Heritability for age at calving (h2AC) and milk yield (h2MY) decrease from the ...
متن کاملCorrelations among first and second lactation milk yield and calving interval.
Estimates of genetic correlations were .17 between first lactation milk yield and concurrent calving interval, .10 between second lactation milk yield and first calving interval, and .82 between first and second milk yields. Corresponding phenotypic correlations were .27, .16, and .58. Heritability estimates were .27 and .25 for first and second lactations and .15 for calving interval. Estimate...
متن کاملgenetic parameter estimates for lactation curve parameters, milk yield, age at first calving, calving interval and somatic cell count in holstein cows
the objective of this study was to estimates the genetic and environmental components for the lactation curve parameters, milk yield, age at first calving (afc), calving interval (ci) and somatic cell count (scc) in iranian holstein cows. the dataset consisted of 210625 test day records from 25883 cows with milk yield in the first parity recorded from july 2002 to september 2007 in a total of 9...
متن کاملAn analysis of age and body weight at first calving for Holsteins in the United States.
In a national survey of US dairy producers, only 2.7 +/- 0.5% of Holstein dairy operations reported achieving recommended target ranges of age < or = 24 months and body weight (BW) > or = 550 kg at first calving. Allowing for wider target ranges, still only 14.6 +/- 1.3% of Holstein dairy operations reported achieving age < or = 25 months and BW > or = 544.3 kg at first calving. Ages of individ...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1983
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(83)82064-5