A curva de Brody foi selecionada como a melhor, porque possui menos parâmetros. A curva de Gompertz teve a tendência de subestimar pesos e alturas. Los modelos de Gompertz y von Bertalanffy han sido confrontados por Silliman La expresión clásica de la curva de von Bertalanffy es de la siguiente forma. curva (Ü de absorción espectral — spectraI-absorption curve curva (Ü de cumulative frequency curve curva (Ü de Gompertz — Gompertz curve curva (Ü de.

Author: Muzshura Goltikree
Country: Ecuador
Language: English (Spanish)
Genre: Finance
Published (Last): 10 October 2004
Pages: 241
PDF File Size: 2.23 Mb
ePub File Size: 13.17 Mb
ISBN: 802-7-71001-495-8
Downloads: 14010
Price: Free* [*Free Regsitration Required]
Uploader: Kerr

Comparison of several models to fit the growth curves of Kivircik and Daglic male lambs.

Gompertz function

Turkish Journal of Veterinary Animal Sciencev. Genetic and phenotypic aspects of the growth curve characteristics in Mehraban Iranian fat-tailed sheep. Small Ruminant Researchv. Growth and mature weight of Mehraban Iranian fat-tailed sheep. Revista Brasileira de Zootecniav.

A comparison of nonlinear models for describing weight—age relationships in cattle. Journal of Animal Sciencev. Morphmetric evaluation of Mangalarga Marchador horses: Genetic and environmental aspects of the growth curve parameters in beef cows. A multiple range and multiple F tests. Analysis of growth curves and strategies for altering their shapes. A growth study of beef cattle. Canadian Journal of Animal Sciencev.

Statistical theory with engineering applications.

Breed and sex differences in growth curves for two breeds of dog guides. Cautionary note about R 2. The American Statisticianv. A description of the growth of sheep and its genetic analysis.

Animal Sciencev. Variance analysis for biometric measures of the Pantaneiro Horse Archivos de Zootecniav. A mathematical equation for animal growth from embryo to adult. Animal Productionv.

Applied linear regression models. Pesquisa Agropecuaria Brasileirav. The effect of a feature of regression disturbance on the efficiency of fitting growth gompfrtz. Factor gompeertz of body measurements in Arabian horses.

Growth rate consists of baseline and systematic deviation components in Thoroughbreds. Determination of the best nonlinear function in order to estimate growth in Morkaraman and Awassi lambs Small Ruminant Researchv.


A flexible sigmoid function of determinate growth. Annals of Botanyv. Analysis of growth equations. Forest Sciencev. Growth analysis on the process of grain filling in rice.

Gompertz function – Wikipedia

Acta Agronomica Sinicav. Hanoverian, Brazilian Showjumper, English Thoroughbred and Crossbred horses reared by the Brazilian Army were weighed and measured from six months of age to adult.

In total 4, measurements on 1, horses were available. The Richards Curve did not converge for weight or height of any of the genetic groups or sexes. The logistic curve crva not converge for any of the weight traits while the Gompertz also did not converge for height in several groups.

Results for the Weibull and Brody curves were similar in all cases so where possible the Brody curve was selected as the best curve as it had less parameters.

The Gompertz curve tended to underestimate mature weights and height. Estimates for both weight and yompertz were in general higher in males than for females. The k parameters, which indicate maturity, were of similar magnitude for the Brody, Gompertz and Weibull curves, for both height and weight within breed.

This parameter indicated that there is little difference in maturation rates between males and females. Resultados para as curvas de Weibull e Brody foram similares em todos os casos.

Brody, Gompertz, Logistic, Richards, Weibull. Many data points taken over time are reduced to a few parameters. An ideal equation is one which adequately predicts the overall shape of a growth curve and, in addition, can be extended or modified to give greater flexibility and precision MOORE, Selection of fast or slow growing animals can be carried out using these functions, especially animals which are more mature at an earlier age BROWN et al.

Non linear functions with exponential components are most commonly used to describe this type of growth, as these summarize a large volume of data. These functions are easy gojpertz interpret biologically and easily compared between different production systems SILVA et al. The other parameters are cruva constants which help to determine curve shape.


The objective of this study was to select a non-linear function which best describes growth of curvz reared by the Brazilian Army. The study has dams and 15 stallions.

Both mares and stallions were from the proper herd or on loan from other studs. Weaning was at six months of age. Stallions also received alfalfa hay daily Medicago sativa ad libitum. Data were also collected from Military Organizations distributed in all of Brazilian national territory, except Amazon, where the animals are sent after 24 months of age.

The horses may be stabled or semi-stabled, depending on the station. The horses may be transferred between stations, depending on necessity, or because they are used by a particular officer who uses the horse in competition.

Data was collected by veterinarians in each station. Data was available on 4, weight and shoulder height measurements on 1, Hanoverian, Brazilian Showjumper, English Thoroughbred and Crossbred horses, measured from six months of age to adult.

Curves Weight and height were analysed as a function of time using Gompertz, Brody, Logistic, Weibull and Richards curves. The Richards curve describes changes in size Y weight or height in relation to age tand is represented by the equation: The interpretations of the parameters are as follows: The parameter m assumes the following values for the other curves in the Richards family: The Gompertz curve is a limiting case of the generalised logistic as t becomes very small or very large, whose equation is: The Weibull curve is: The mean square of the residual was calculated for each function.