Fitting milk production curves through nonlinear mixed models
| Autor: | Raúl Macchiavelli, Mónica Belén Piccardi, Mónica Balzarini, Gabriel A. Bó, Ariel Capitaine Funes |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Population level Information Criteria Expected value Models Biological COMPARISON CRITERIA 03 medical and health sciences Lactation Statistics medicine Production (economics) Animals LACTATION CURVES Nonlinear mixed effects model Mathematics 0402 animal and dairy science 04 agricultural and veterinary sciences General Medicine Producción Animal y Lechería Random effects model Milk production 040201 dairy & animal science Dairying Parity 030104 developmental biology medicine.anatomical_structure Nonlinear Dynamics CIENCIAS AGRÍCOLAS ESTIMATION Animal Science and Zoology Cattle Female Seasons RANDOM EFFECT Otras Producción Animal y Lechería Food Science |
| Popis: | The aim of this work was to fit and compare three non-linear models (Wood, Milkbot and diphasic) to model lactation curves from two approaches: with and without cow random effect. Knowing the behaviour of lactation curves is critical for decision-making in a dairy farm. Knowledge of the model of milk production progress along each lactation is necessary not only at the mean population level (dairy farm), but also at individual level (cow-lactation). The fits were made in a group of high production and reproduction dairy farms; in first and third lactations in cool seasons. A total of 2167 complete lactations were involved, of which 984 were first-lactations and the remaining ones, third lactations (19 382 milk yield tests). PROC NLMIXED in SAS was used to make the fits and estimate the model parameters. The diphasic model resulted to be computationally complex and barely practical. Regarding the classical Wood and MilkBot models, although the information criteria suggest the selection of MilkBot, the differences in the estimation of production indicators did not show a significant improvement. The Wood model was found to be a good option for fitting the expected value of lactation curves. Furthermore, the three models fitted better when the subject (cow) random effect was considered, which is related to magnitude of production. The random effect improved the predictive potential of the models, but it did not have a significant effect on the production indicators derived from the lactation curves, such as milk yield and days in milk to peak. Fil: Piccardi, Mónica Belén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Desarrollo Rural. Area de Estadística y Biometría; Argentina Fil: Macchiavelli, Raúl. Universidad de Puerto Rico; Puerto Rico Fil: Funes, Ariel Capitaine. DAIRYTECH; Argentina Fil: Bó, Gabriel A.. Universidad Nacional de Villa María; Argentina. Instituto de Reproducción Animal Córdoba; Argentina Fil: Balzarini, Monica Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Desarrollo Rural. Area de Estadística y Biometría; Argentina |
| Databáze: | OpenAIRE |
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