Open Access Repository

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

Downloads

Downloads per month over past year

Adediran, SA, Ratkowsky, DA, Donaghy, DJ and Malau-Aduli, AEO 2012 , 'Comparative evaluation of a new lactation curve model for pasture-based Holstein-Friesian dairy cows' , Journal of Dairy Science, vol. 95, no. 9 , pp. 5344-5356 , doi: http://dx.doi.org/ 10.3168/jds.2011-4663.

[img] PDF
2012_Adediran_e...pdf | Request a copy
Full text restricted
Available under University of Tasmania Standard License.

[img]
Preview
PDF (Authors Version)
JDS-11-4663_Rev...pdf | Download (323kB)
Available under University of Tasmania Standard License.

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 lends itself to biological interpretation.

Item Type: Article
Authors/Creators:Adediran, SA and Ratkowsky, DA and Donaghy, DJ and Malau-Aduli, AEO
Journal or Publication Title: Journal of Dairy Science
ISSN: 0022-0302
DOI / ID Number: http://dx.doi.org/ 10.3168/jds.2011-4663
Additional Information:

Copyright 2012 American Dairy Science Association

Related URLs:
Item Statistics: View statistics for this item

Actions (login required)

Item Control Page Item Control Page
TOP