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Comparative evaluation of a new lactation curve model for pasture-based Holstein-Friesian dairy cows

Citation

Adediran, SA and Ratkowsky, DA and Donaghy, DJ and Malau-Aduli, AEO, Comparative evaluation of a new lactation curve model for pasture-based Holstein-Friesian dairy cows, Journal of Dairy Science, 95, (9) pp. 5344-5356. ISSN 0022-0302 (2012) [Refereed Article]


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Copyright Statement

Copyright American Dairy Science Association 2012.

DOI: doi:10.3168/jds.2011-4663

Abstract

Fourteen lactation models were fitted to average and individual cow lactation data from pasture-based dairy systems in the Australian states of Victoria and Tasmania. The models included a new "log-quadratic" model, and a major objective was to evaluate and compare the performance of this model with the other models. Nine empirical and 5 mechanistic models were first fitted to average test-day milk yield of Holstein-Friesian dairy cows using the nonlinear procedure in SAS. Two additional semiparametric models were fitted using a linear model in ASReml. To investigate the influence of days to first test-day and the number of test-days, 5 of the best-fitting models were then fitted to individual cow lactation data. Model goodness of fit was evaluated using criteria such as the residual mean square, the distribution of residuals, the correlation between actual and predicted values, and the Wald-Wolfowitz runs test. Goodness of fit was similar in all but one of the models in terms of fitting average lactation but they differed in their ability to predict individual lactations. In particular, the widely used incomplete gamma model most displayed this failing. The new log-quadratic model was robust in fitting average and individual lactations, and was less affected by sampled data and more parsimonious in having only 3 parameters, each of which lendsm itself to biological interpretation.

Item Details

Item Type:Refereed Article
Keywords:lactation model , pasture-based , dairy cow, test-day milk yield
Research Division:Agricultural and Veterinary Sciences
Research Group:Animal Production
Research Field:Animal Breeding
Objective Division:Animal Production and Animal Primary Products
Objective Group:Livestock Raising
Objective Field:Dairy Cattle
Author:Adediran, SA (Dr Samuel Adediran)
Author:Ratkowsky, DA (Dr David Ratkowsky)
Author:Donaghy, DJ (Associate Professor Danny Donaghy)
Author:Malau-Aduli, AEO (Associate Professor Aduli Malau-Aduli)
ID Code:63682
Year Published:2012
Web of Science® Times Cited:6
Deposited By:Agricultural Science
Deposited On:2010-05-21
Last Modified:2013-05-10
Downloads:6 View Download Statistics

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