Effect of Age at First Calving on First Lactation Milk Yield, Lifetime Milk Production And Longevity of 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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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 کاملGenetic relationship between the lifetime milk production, longevity and first lactation milk yield in Slovenian Brown cattle breed
To study the genetic relationship between the lifetime milk production (LMP), first lactation milk yield (MY305), and length of productive life (PL) in the Slovenian Brown cattle population, first lactation records from 14,389 cows and lifetime performance records (LMP and PL) from 12,416 cows were used. Records of LMP and PL were normalised using the square root transformation of the raw value...
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...
متن کاملReduced Age at First Calving: Effects on Lifetime Production, Longevity, and Profitability
The time between birth and first calving represents a period in which replacement heifers are not generating income. Instead this rearing period requires considerable capital expenditures including feed, housing, and veterinary expenses. These expenses constitute 15 to 20% of the total expenses related to milk production (Heinrichs, 1993). A basic approach to reducing this cost is to reduce the...
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ژورنال
عنوان ژورنال: Annals of Animal Science
سال: 2019
ISSN: 2300-8733
DOI: 10.2478/aoas-2018-0044