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Comparison of different lactation curve models in Karan Fries cattle of India*

Indian Agricultural Research Journals

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Title Comparison of different lactation curve models in Karan Fries cattle of India*
 
Creator BANU, RASHIA
SINGH, AVTAR
MALHOTRA, R
GOWANE, G
KUMAR, V
JAGGI, SEEMA
VERGHESE, E
GANDHI, R S
CHAKRAVARTY, A K
RAJA, T V
 
Subject Karan Fries; Lactation curve models; Milk yield; Monthly test day;Weekly test day milk yield
 
Description The first lactation weekly test day milk yield (WTDMY) records (57233) and monthly test day milk yield (MTDMY) records (11970) spread over a period of 23 years (1984– 2006) sired by 82 bulls of Karan Fries cattle were used to develop the best lactation curve model. The lactation curve parameters of Quadratic cum log model (QCLM), Gamma function (GF), Cobby Le Du model (CLDM), Polynomial regression function (PRF) and Multiphasic logistic function (MLF) were estimated. The average weekly test day milk yield was predicted with high degree of accuracy (R2 > 85%) by all the models with the maximum accuracy (R2 = 99.50%) obtained by polynomial regression function (PRF) and the least fit (R2 = 87.90%) was obtained by Gamma function (GF). However Quadratic cum log model (R2 = 99.20%) was almost equal to polynomial regression function and was better than Cobby Le Du model (R2 = 92.80%). The average root mean square error (RMSE) was found to be minimum with PRF (0.0121 Kg) followed by MLF (Triphasic). Thus the best fit model was polynomial regression function, which was better than other functions for prediction of first lactation WTDMY. The average monthly test day milk yield was predicted with high degree of accuracy (R2 > 75%) by all the models with the maximum accuracy (R2 > 99.41%) obtained by polynomial regression function (PRF) and the least fit was obtained with gamma function (R2 = 79.05%). However, quadratic-cum-log model (R2 = 99.28%) was almost equal to polynomial regression function and was better than CLDM (R2 = 89.50%). The average root mean square error (RMSE) was found to be minimum with PRF (0.0061 kg) followed by QCLM (0.0620). Thus the best fit model was polynomial regression function for prediction of both weekly and monthly test day milk yield of first lactation in Karan Fries cows
 
Publisher Directorate of Knowledge Management in Agriculture
 
Contributor —
 
Date 2012-11-19
 
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/25158
 
Source The Indian Journal of Animal Sciences; Vol 82, No 11 (2012)
0367-8318
 
Language eng
 
Relation http://epubs.icar.org.in/ejournal/index.php/IJAnS/article/view/25158/11709
 
Rights Copyright (c) 2014 The Indian Journal of Animal Sciences