HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Interpretive Summary Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Silvestre, A. M. Articles by Colaço, J. Search for Related Content PubMed PubMed Citation Articles by Silvestre, A. M. Articles by Colaço, J.

The Accuracy of Seven Mathematical Functions in Modeling Dairy Cattle Lactation Curves Based on Test-Day Records From Varying Sample Schemes

Departement of Animal Science–CECAV, University of Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal

¹ Corresponding author: asilvest{at}utad.pt

Daily milk yield over the course of the lactation follows a curvilinear pattern, so a suitable function is required to model this curve. In this study, 7 functions (Wood, Wilmink, Ali and Schaeffer, cubic splines, and 3 Legendre polynomials) were used to model the lactation curve at the phenotypic level, using both daily observations and data from commonly used recording schemes. The number of observations per lactation varied from 4 to 11. Several criteria based on the analysis of the real error were used to compare models. The performance of models showed few discrepancies in the comparison criteria when daily or 4-weekly (with first test at days in milk 8) data by lactation were used. The performance of the Wood, Wilmink, and Ali and Schaeffer models were highly affected by the reduction of the sample dimension. The results of this work support the idea that the performance of these models depends on the sample properties but also shows considerable variation within the sampling groups.

Key Words: dairy cow • lactation curve

This article has been cited by other articles:

				A. S. Santos and A. M. Silvestre A Study of Lusitano Mare Lactation Curve with Wood's Model J Dairy Sci, February 1, 2008; 91(2): 760 - 766. [Abstract] [Full Text] [PDF]

				C. M. B. Dematawewa, R. E. Pearson, and P. M. VanRaden Modeling Extended Lactations of Holsteins J Dairy Sci, August 1, 2007; 90(8): 3924 - 3936. [Abstract] [Full Text] [PDF]