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<meta content="Roche, J.R." name="eprints.creators_name" />
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<meta content="Malau-Aduli, A.E.O." name="eprints.creators_name" />
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<meta content="2008-01-24 00:10:39" name="eprints.datestamp" />
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<meta content="Predictive characteristics of lactation models for pasture-based Holstein-Friesian dairy cows" name="eprints.title" />
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<meta content="In: DF Chapman, DA Clark, KL Macmillan, DP Nation (Editors). Dairy Science 2007, Meeting the Challenges for Pasture-
Based Dairying’, Proceedings of the 3rd Australasian Dairy Science Symposium, The University of Melbourne, Victoria,
Australia, 3:423-430 (2007)" name="eprints.note" />
<meta content="Mathematical functions to describe a series of milk test day records have the advantage of minimizing random variation, while simultaneously summarizing the lactation profile. Five empirical functions and two mechanistic models were used to model herd and individual milk yield profiles of multiparous Holstein-Friesian cows on 113, 290 milk yield records (8438 lactations) collected from 1994-2005. The models tested were the incomplete gamma (IG), a modified gamma (MG), an exponential (EXP), a polynomial regression (PR), a mixed log (ML), the bi-compartmental (BC), and Dijkstra (DJ) functions, the latter two being mechanistic models. Each model was fitted using the non-linear (NLIN) function of SAS. Model accuracy was evaluated based on residual mean square (RMS), the magnitude and distribution of residuals, and the correlation between the observed and predicted values. All the models, except MG, did equally well in portraying the lactation profile. Parameter estimates were significant (P<0.05), with large serial correlations indicating biased predictions, especially during mid-lactation. Correlations of residuals and observed herd average lactations ranged between -0.13 (MG) to 0.19 (IG), while that between observed and predicted was between 0.76 and 0.99 for the same models. Lactation curves of individual cow milk yields were more varied, exhibited the tendency for a second peak which were not accurately modeled. Mechanistic models performed best with herd data, the PR model fitted overall best, while the MG model fitted the profile least accurately in this study. " name="eprints.abstract" />
<meta content="2007-09-18" name="eprints.date" />
<meta content="In: DF Chapman, DA Clark, KL Macmillan, DP Nation (Editors). Dairy Science Symposium, 'Meeting the Challenges for Pasture-Based Dairying’, Proceedings of the 3rd Australasian Dairy Science Symposium, The University of Melbourne, Victoria, Australia." name="eprints.publication" />
<meta content="3" name="eprints.volume" />
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<meta content="Dairy Science 2007" name="eprints.event_title" />
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<meta content="18-20 September" name="eprints.event_dates" />
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<meta content="Ali, T.E; Schaeffer, L.R; 1987: Accounting for covariances among test day milk yields in dairy cows. Canadian Journal of Animal Science 67: 637-644.
Beever D.E; Rook, A.J; France, J; Danoa, M.S; Gill, M; 1991: A review of empirical and mechanistic models of lactation performance by the dairy cow. Livestock Production Science, 29: 115-130.
Cobby, J.M; Le Du. L.P; 1978: On fitting curves to lactation data. Anim. Prod. 26:127–133.
Dijkstra, J; France, J; Dhanoa, M.S; Maas, J.A; Hanigan, M.D; Rook, A.S; Beever, D.E; 1997: A model to describe growth patterns of the mammary gland during pregnancy and lactation. Journal of Dairy Science 80:2340–2354.
Ferguson J.D; Boston, R; 1993: Lactation curves analysis: Comparison of gamma function, polynomial and exponential methods towards a mechanistic model of milk production. Journal of Dairy Science. 76(Suppl. 1): 268. (Abstr.)
Garcia, S.C; Holmes, C.W; 2001: Lactation curves of autumn- and spring-calved cows in pasture-based dairy systems. Livestock Production Science 68:189-203
Guo, Z; Swalve, H.H; 1995: Modelling of the lactation curve as a sub-model in the evaluation of test day records. Paper presented at the INTERBULL open meeting, 7-8 September, 1995, Prague, Czech Republic.
Jenkins, T.G; Ferrell, C.L; 1984: A note on lactation curves of crossbred cows. Animal Production 39: 470-482.
Kolver, E.S; Muller, S.B; 1998: Performance and nutrient intake of high producing Holstein cows consuming pasture or a Total Mixed Ration. Journal of Dairy Science 81:1403–1411
Papajcsik, I.A; Bodero, J; 1988: Modelling lactation curves of Friesian cows in a subtropical climate. Animal Production 47(2)
Olori, V. E., S. Brotherstone, et al. (1999). Fit of standard models of the lactation curve to weekly records of milk production of cows in a single herd. Livestock Production Science 58(1).
Pollott, G. E. 2000. A biological approach to lactation curve analysis for milk yield. Journal of Dairy Science. 83:2448–2458.
Rowlands, G.J; Lucey, S; Russell, A.M; 1982: A comparison of different models of the lactation curve in dairy cattle. Animal Production 35, 135-144.
SAS. 2005: User’s Guide Version 9.1: SAS Institute, Cary NC, USA.
Saxton, A. ed. 2004: Genetic analysis of complex traits using SAS. Cary, NC SAS Institute Inc.
Tozer, P.R; Huffaker; R.G; 1999: Mathematical equations to describe lactation curves for Holstein-Friesian cows in New South Wales. Australian Journal of Agricultural Research 50:431-440
Val-Arreola, D; Kebreab, E. Dijskra, J; France, J; 2004: Study of the lactation curve in dairy cattle on farms in Central Mexico. Journal of Dairy Science 87:3789-3799
Wilmink, J.B.M. 1987: Adjustment of test-day milk, fat and protein yield for age, season and stage of lactation. Livestock Production Science 16: 335-348
Wood, P.D.P. 1967: Algebraic model of the lactation curve in cattle. Nature 216:164-165
Wood, P.D.P. 1969: Factors affecting the shape of the lactation curve in cattle. Animal Production 11:307-316.
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<meta content="Adediran, S.A. and Roche, J.R. and Donaghy, D.J. and Rawnsley, R. and Freeman, M. and Nish, P. and Malau-Aduli, A.E.O. (2007) Predictive characteristics of lactation models for pasture-based Holstein-Friesian dairy cows. In: Dairy Science 2007, 18-20 September, Melbourne." name="eprints.citation" />
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<meta content="Mathematical functions to describe a series of milk test day records have the advantage of minimizing random variation, while simultaneously summarizing the lactation profile. Five empirical functions and two mechanistic models were used to model herd and individual milk yield profiles of multiparous Holstein-Friesian cows on 113, 290 milk yield records (8438 lactations) collected from 1994-2005. The models tested were the incomplete gamma (IG), a modified gamma (MG), an exponential (EXP), a polynomial regression (PR), a mixed log (ML), the bi-compartmental (BC), and Dijkstra (DJ) functions, the latter two being mechanistic models. Each model was fitted using the non-linear (NLIN) function of SAS. Model accuracy was evaluated based on residual mean square (RMS), the magnitude and distribution of residuals, and the correlation between the observed and predicted values. All the models, except MG, did equally well in portraying the lactation profile. Parameter estimates were significant (P<0.05), with large serial correlations indicating biased predictions, especially during mid-lactation. Correlations of residuals and observed herd average lactations ranged between -0.13 (MG) to 0.19 (IG), while that between observed and predicted was between 0.76 and 0.99 for the same models. Lactation curves of individual cow milk yields were more varied, exhibited the tendency for a second peak which were not accurately modeled. Mechanistic models performed best with herd data, the PR model fitted overall best, while the MG model fitted the profile least accurately in this study. " name="DC.description" />
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<h1 class="ep_tm_pagetitle">Predictive characteristics of lactation models for pasture-based Holstein-Friesian dairy cows</h1>
<p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Adediran, S.A.</span> and <span class="person_name">Roche, J.R.</span> and <span class="person_name">Donaghy, D.J.</span> and <span class="person_name">Rawnsley, R.</span> and <span class="person_name">Freeman, M.</span> and <span class="person_name">Nish, P.</span> and <span class="person_name">Malau-Aduli, A.E.O.</span> (2007) <xhtml:em>Predictive characteristics of lactation models for pasture-based Holstein-Friesian dairy cows.</xhtml:em> In: Dairy Science 2007, 18-20 September, Melbourne.</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_3990' );" onmouseout="EPJS_HidePreview( event, 'doc_preview_3990' );" href="http://eprints.utas.edu.au/2965/3/Malau-Aduli_2007DairySciSympMelbourne.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" border="0" class="ep_doc_icon" /></a><div class="ep_preview" id="doc_preview_3990"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/2965/thumbnails/3/preview.png" border="0" class="ep_preview_image" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/2965/3/Malau-Aduli_2007DairySciSympMelbourne.pdf"><span class="ep_document_citation">PDF</span></a> - Requires a PDF viewer<br />182Kb</td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://www.mcmconferences.com/dairy/index.html">http://www.mcmconferences.com/dairy/index.html</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Mathematical functions to describe a series of milk test day records have the advantage of minimizing random variation, while simultaneously summarizing the lactation profile. Five empirical functions and two mechanistic models were used to model herd and individual milk yield profiles of multiparous Holstein-Friesian cows on 113, 290 milk yield records (8438 lactations) collected from 1994-2005. The models tested were the incomplete gamma (IG), a modified gamma (MG), an exponential (EXP), a polynomial regression (PR), a mixed log (ML), the bi-compartmental (BC), and Dijkstra (DJ) functions, the latter two being mechanistic models. Each model was fitted using the non-linear (NLIN) function of SAS. Model accuracy was evaluated based on residual mean square (RMS), the magnitude and distribution of residuals, and the correlation between the observed and predicted values. All the models, except MG, did equally well in portraying the lactation profile. Parameter estimates were significant (P<0.05), with large serial correlations indicating biased predictions, especially during mid-lactation. Correlations of residuals and observed herd average lactations ranged between -0.13 (MG) to 0.19 (IG), while that between observed and predicted was between 0.76 and 0.99 for the same models. Lactation curves of individual cow milk yields were more varied, exhibited the tendency for a second peak which were not accurately modeled. Mechanistic models performed best with herd data, the PR model fitted overall best, while the MG model fitted the profile least accurately in this study. </p></div><table style="margin-bottom: 1em" border="0" cellpadding="3" class="not_ep_block"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Conference or Workshop Item (Paper)</td></tr><tr><th valign="top" class="ep_row">Additional Information:</th><td valign="top" class="ep_row">In: DF Chapman, DA Clark, KL Macmillan, DP Nation (Editors). Dairy Science 2007, Meeting the Challenges for Pasture-
Based Dairying’, Proceedings of the 3rd Australasian Dairy Science Symposium, The University of Melbourne, Victoria,
Australia, 3:423-430 (2007)</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">model, lactation profile</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/270207.html">270000 Biological Sciences > 270200 Genetics > 270207 Quantitative Genetics</a><br /><a href="http://eprints.utas.edu.au/view/subjects/300401.html">300000 Agricultural, Veterinary and Environmental Sciences > 300400 Animal Production > 300401 Animal Breeding</a></td></tr><tr><th valign="top" class="ep_row">Collections:</th><td valign="top" class="ep_row">UNSPECIFIED</td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">2965</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Dr Aduli E.O. Malau-Aduli</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">24 Jan 2008 11:10</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">24 Jan 2008 11:58</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=2965;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=2965">item control page</a></p>
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