ORIGINAL PAPER
Age-season lactation curves for production traits of
cows calving in Wielkopolska region of Poland
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August Cieszkowski Agricultural University,
Department of Genetic and Animal Breeding,
Wołyńska 33, 60-637 Poznań, Poland
Publication date: 2004-06-16
Corresponding author
T. Strabel
August Cieszkowski Agricultural University,
Department of Genetic and Animal Breeding,
Wołyńska 33, 60-637 Poznań, Poland
J. Anim. Feed Sci. 2004;13(3):405-416
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ABSTRACT
The objective of this study was to estimate lactation curves for cows of different age at calving
in winter and summer seasons. Data consisted of 1 289 522 test-day records of cows calved in
Wielkopolska region in 1992-1996. Milk, fat and protein yields in first three parities were studied.
Test-day model with 50 classes of days-in-milk by parity was used. Lactation curves were derived
from solutions for this effect. They were flatter for first versus later lactations. Peak yield for milk
production occurred in the second part of the first month of production. Shape of lactation curves for
different age and season classes did not vary substantially. Cows calving in winter season had higher
production. Similarly, older cows had higher yields for all traits and lactations, however the evidence
of age at calving by season of calving interaction was found.
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