Association between age at first calving and milk production in first lactation on longevity traits in Holstein cows
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...
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Data containing 14,188 lactation and reproductive records of Korean Holstein cows at first parity distributed across 3,734 herd-year-season groups were analyzed to get genetic (co)variance estimates for milk yield, fat yield, calving ease, and days open. Milk and Fat yields were adjusted to 305 d. Heritabilities and genetic correlations were estimated in two different animal models on which wer...
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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 کاملEffect of age at first calving on longevity and fertility traits for Holstein cattle
Effects of age at first calving (AFC) on functional longevity of Czech Holstein cows and their reproduction traits in the first lactation were analyzed using the first lactation data of 605 538 Holstein cows first calved from 1993 to 2008. Three classes were formed for AFC: low age class (16–24 months), average age class (25–30 months), and high age class (33–46 months). Effects of AFC on lengt...
متن کاملAssociation of LEPR gene Polymorphism with milk yield and age at first calv-ing in the Iranian Holstein dairy cows
The LEPR is a glycoprotein expressed mainly in hypothalamus, where it takes part in energy homeostasis and in regulation of the activity of the secretory organs. A transition mutation in this gene results in substitution of cytosine by thymine leading to the substitution of threonine by methionine in the intracellular domain of the LEPR-b isoform. This study investigated the impact of polymorph...
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ژورنال
عنوان ژورنال: Biotechnology in Animal Husbandry
سال: 2020
ISSN: 1450-9156,2217-7140
DOI: 10.2298/bah2001027k