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Evaluation of test day daily milk yield and persistency of different milking times in primiparous Holstein dairy cows in Iran

Indian Agricultural Research Journals

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Title Evaluation of test day daily milk yield and persistency of different milking times in primiparous Holstein dairy cows in Iran
 
Creator TORSHIZI, M ELAHI
MASHHADI, M HOSSEINPOUR
 
Subject Different milking times, Genetic parameters, Heritability, Persistency
 
Description Monthly test day records (morning, noon and night milk; 470,829) from 49,675 Iranian Holstein over 603 herds were used to study the characteristics of genetic parameters of milk yield at different milking times and evaluation of persistency in different milking times. According to the results, residual variance is high at the begining of lactation(4.70 kg) and gradually decreases till the end of lactation in different milking times. Also the additive genetic variance increases till the end of lactation (especially morning milk and estimates are lower at the beginning of lactation (0.35 kg). Permanent environmental variance shows moderate increase, with peak value at the end of lactation. The trends of heritability at different milking times are similar but the morning milk has higher heritability during 260 to 290 days. Peak time of milk yield for morning time was 79 days but for noon and night milking curves was at 62 and 90 DIM. Genetic correlations of different milking times between test days as well as permanent environmental correlation of higher value (close to unity) in adjacent period but decreased with increasing period among test day yield. Morning milk yield was higher compared to noon and night milk but night milk curve showed better persistency.
 
Publisher Directorate of Knowledge Management in Agriculture
 
Contributor —
 
Date 2013-11-14
 
Type info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
—
 
Format application/pdf
 
Identifier http://epubs.icar.org.in/ejournal/index.php/IJAnS/article/view/34773
 
Source The Indian Journal of Animal Sciences; Vol 83, No 11 (2013)
0367-8318
 
Language eng
 
Relation http://epubs.icar.org.in/ejournal/index.php/IJAnS/article/view/34773/15381
 
Rights Copyright (c) 2014 The Indian Journal of Animal Sciences