Nonlinear models to describe the testicular size growth curve of Mangalarga Marchador stallions

2021 ◽  
pp. 103422
Author(s):  
Danielle Estanislau Coelho Silva ◽  
Jurandy Mauro Penitente-Filho ◽  
Domingos Lollobrigida Souza Neto ◽  
Bruna Waddington ◽  
Renan Reis de Oliveira ◽  
...  
Keyword(s):  
Growth Curve ◽  
Nonlinear Models ◽  
Size Growth ◽  
Testicular Size

scholarly journals Body growth and phenotypic variation of the carcasses of native duck lineages (Cairina moschata)

2018 ◽  
Vol 16 (3) ◽  
pp. e0405
Author(s):  
Eva C. J. Almeida ◽  
Paulo L. S. Carneiro ◽  
Ronaldo V. Farias Filho ◽  
Lorena A. Nunes ◽  
Carlos H. M. Malhado ◽  
...  
Keyword(s):  
Growth Curve ◽  
Phenotypic Variation ◽  
Nonlinear Models ◽  
Principal Component ◽  
Meat Production ◽  
Feeding Management ◽  
Genetic Groups ◽  
Absolute Growth ◽  
Best Fit ◽  
Production Characteristics

Natives ducks are birds that require little handling and are resistant to many diseases that affect chickens. Thus, they adapt to low-input farming conditions, which contributes to the food security of small farmers. Although they exhibit potential for growth, their production characteristics are relatively unknown, so they are underexploited. The objective of this study was to compare how nonlinear models fit the growth curve of two genetic groups of duck and to evaluate variation based on carcass characteristics. Two hundred and twenty four animals were weighed weekly, from birth to 90 days of age. We used nonlinear models (Brody, Richards, Gompertz, Von Bertalanff and Logistic) to describe growth curve. For the evaluation of phenotypic variation, we measured seven carcass traits from 81 ducks carried out by principal component analysis. The logistic model best fit the growth curve, and the absolute growth rates (AGR) for the Catolé duck showed that females reached their maximum AGR at approximately 30 days but did not reach their ideal commercial weight. The drumstick, thigh and liver yields accounted for 41.17% of the differences between the Catolé and Paysandu ducks. The slaughter of male Catolé ducks is recommended between 70 and 90 days because a drastic decrease in growth occurs after this time. For the slaughter of females, feeding management modifications and improvement in growth indices are recommended to increase the final weight and AGR. The carcass yields indicate potential for native duck meat production.

scholarly journals Nonlinear models in the height description of the Rhino sunflower cultivar

2022 ◽  
Vol 52 (3) ◽  
Author(s):  
Anderson Chuquel Mello ◽  
Marcos Toebe ◽  
Rafael Rodrigues de Souza ◽  
João Antônio Paraginski ◽  
Junior Carvalho Somavilla ◽  
...  
Keyword(s):  
Growth Curve ◽  
Critical Points ◽  
Nonlinear Models ◽  
Information Criterion ◽  
Coefficient Of Determination ◽  
Maximum Acceleration ◽  
Inflection Points ◽  
Best Fitting ◽  
Microsoft Office

ABSTRACT: Sunflower produces achenes and oil of good quality, besides serving for production of silage, forage and biodiesel. Growth modeling allows knowing the growth pattern of the crop and optimizing the management. The research characterized the growth of the Rhino sunflower cultivar using the Logistic and Gompertz models and to make considerations regarding management based on critical points. The data used come from three uniformity trials with the Rhino confectionery sunflower cultivar carried out in the experimental area of the Federal University of Santa Maria - Campus Frederico Westphalen in the 2019/2020 agricultural harvest. In the first, second and third trials 14, 12 and 10 weekly height evaluations were performed on 10 plants, respectively. The data were adjusted for the thermal time accumulated. The parameters were estimated by ordinary least square’s method using the Gauss-Newton algorithm. The fitting quality of the models to the data was measured by the adjusted coefficient of determination, Akaike information criterion, Bayesian information criterion, and through intrinsic and parametric nonlinearity. The inflection points (IP), maximum acceleration (MAP), maximum deceleration (MDP) and asymptotic deceleration (ADP) were determined. Statistical analyses were performed with Microsoft Office Excel® and R software. The models satisfactorily described the height growth curve of sunflower, providing parameters with practical interpretations. The Logistics model has the best fitting quality, being the most suitable for characterizing the growth curve. The estimated critical points provide important information for crop management. Weeds must be controlled until the MAP. Covered fertilizer applications must be carried out between the MAP and IP range. ADP is an indicator of maturity, after reaching this point, the plants can be harvested for the production of silage without loss of volume and quality.

scholarly journals Sigmoid growth curves, a new approach to study the dynamics of the epicotyl emergence of oak

2019 ◽  
Vol 61 (1) ◽  
pp. 30-41
Author(s):  
Joanna Ukalska ◽  
Szymon Jastrzębowski
Keyword(s):  
Growth Curve ◽  
Goodness Of Fit ◽  
Nonlinear Models ◽  
Germination Rate ◽  
Growth Curves ◽  
Model Parameters ◽  
Residual Variance ◽  
Nonlinear Behaviour ◽  
Pedunculate Oak ◽  
Growth Phenomenon

Abstract Three of the most frequently used sigmoidal growth curves from the Richards family are the logistic model, Gompertz model and Richards model. They are used in the analysis of organismal growth over time in many disciplines/studies and were proposed in many parameterisations. Choosing the right parameterisation is not easy. The correct parameterisation of the model should take into account such parameters that are useful to describe the analysed growth phenomenon and are biologically relevant without additional calculations. In addition, each parameter of the model only affects one shape characteristic of each growth curve, which makes it possible to determine standard errors and confidence intervals using statistical software. Growth curves in germination dynamics studies should provide information on topics such as the length of the lag in onset of germination, the maximum germination rate and, when it occurs, the time at which 50% of seeds will germinate and the final germination proportion. In this article, we present three parameterisations of the logistic, Gompertz and Richards models and indicate two parameterisations for each model, corresponding to the above-mentioned issues. Our proposition is parameterisation by taking into account the maximum absolute growth rate. Parameterisations indicated as useful for germination dynamics are characterised by the fact that each parameter has the same meaning in every model, so its estimates can be compared directly amongst the models. We also discussed the goodness-of-fit measures for nonlinear models and in particular measures of nonlinear behaviour of a model’s individual parameters as well as overall measures of nonlinearity. All described models were used to study the dynamics of the epicotyl emergence of pedunculate oak. After checking the close-to-linear behaviour of the studied model parameters and by taking into account the criteria of model selection (AICc of each growth curve and the residual variance [RV]), the best model describing the dynamics of epicotyl appearance of pedunculate oak was the Richards curve.

Evaluation of nonlinear models to define growth curve in Lohi sheep

2021 ◽  
Vol 205 ◽  
pp. 106564
Author(s):  
Numan Sharif ◽  
Asad Ali ◽  
Imran Mohsin ◽  
Nisar Ahmad
Keyword(s):  
Growth Curve ◽  
Nonlinear Models

scholarly journals Modeling the Growth of Forage Legumes

2020 ◽  
Vol 12 (5) ◽  
pp. 139
Author(s):  
Brunna R. Rezende ◽  
Michelane S. S. Lima ◽  
Hygor A. Santana ◽  
Wilhan V. dos Santos ◽  
Anderson R. da Silva
Keyword(s):  
Growth Curve ◽  
Goodness Of Fit ◽  
Nonlinear Models ◽  
Accumulation Rate ◽  
Growth Curves ◽  
Biomass Accumulation ◽  
Information Criterion ◽  
Dry Mass ◽  
Von Bertalanffy ◽  
Forage Legumes

Modeling the growth curve of agricultural crops is of paramount importance so that management tasks such as fertilization and irrigation can be carried out at the appropriate time, increasing the vegetal yield. With this purpose, nonlinear models are commonly employed. The objective of this work was to fit some of the main nonlinear models that best describe the growth curve of some of the main species of forage legumes, namely: Crotalaria juncea, Canavalia ensiformis, Cajanus cajan and Dolichos lablab L. A randomized block experiment was conducted in field conditions between November 2015 and February 2016 in southeastern Goiás, Brazil. The variables plant height, stem diameter, fresh and dry mass were measured after 15, 30, 45, 60 and 90 days from sowing. The following models were fitted: Gompertz, Logistic, Brody and von Bertalanffy. The following goodness-of-fit criteria were calculated: R2 (normal and adjusted), AIC (Akaike Information Criterion) and absolute mean error. The growth curves of morphological variables are easier to model than the biomass curves. The von Bertalanffy and Gompertz models presented in general the best fit. The species C. juncea has an expressive biomass accumulation rate.

scholarly journals Adjusting the growth curve of sugarcane varieties using nonlinear models

2020 ◽  
Vol 50 (3) ◽  
Author(s):  
Sérgio Alberto Jane ◽  
Felipe Augusto Fernandes ◽  
Edilson Marcelino Silva ◽  
Joel Augusto Muniz ◽  
Tales Jesus Fernandes ◽  
...  
Keyword(s):  
Growth Curve ◽  
Least Squares Method ◽  
Nonlinear Models ◽  
Height Growth ◽  
Coefficient Of Determination ◽  
Model Parameters ◽  
Suitable Model ◽  
Software Environment ◽  
Phenological Stages ◽  
Sugarcane Varieties

ABSTRACT: Assessing sugarcane (Saccharum spp.) stalk growth helps to adequately manage the phenological stages of the crop. The aim of this study was to describe the height-growth curve of four sugarcane varieties (RB92579, RB93509, RB931530 and SP79-1011), in irrigated plant-cane and ratoon cane plantations, using the Logistic and Gompertz nonlinear models, while considering all deviations from assumptions. The model parameters were estimated based on the least squares method using the Gauss-Newton algorithm. To select the most suitable model, nonlinear measures, adjusted coefficient of determination (R2 adj), residual standard deviation (RSD), and corrected Akaike information criterion (AICc) were used. Based on the best models, stalk height growth rates and crop phenological stages were determined using critical points. All tests were performed in the free software environment for statistical computing and graphics, R. In general, the Logistic and Gompertz models without AR(1) better described the plant-cane and ratoon cane stalk height, respectively. All varieties showed early growth, and the RB92579 variety presented higher rates in both cycles.

scholarly journals Growth curves of meat-producing mammals by von Bertalanffy’s model

2019 ◽  
Vol 54 ◽  
Author(s):  
Felipe Augusto Fernandes ◽  
Tales Jesus Fernandes ◽  
Adriele Aparecida Pereira ◽  
Sarah Laguna Conceição Meirelles ◽  
Adriano Carvalho Costa
Keyword(s):  
Growth Curve ◽  
Nonlinear Models ◽  
Growth Curves ◽  
Research Institutions ◽  
Direct Interpretation ◽  
Curvature Measurements

Abstract: The objective of this work was to evaluate how the parameterization and the application of different allometric values affect the obtention of the most adequate fit of von Bertalanffy’s model, in the description of the growth curve of meat-producing mammals (bovine, pigs, rabbits, and sheep). Among the nonlinear models, von Bertalanffy’s has been very often applied in several areas, with different parameterizations. This model has been commonly used with an allometric value of m = 2/3; however, for mammals, it is believed that this value can be m = 3/4. The analyzed data referring to the mass of meat-producing mammals according to their age were obtained from research institutions and from the literature. The results showed that von Bertalanffy’s model, with the allometric value of m = 3/4 and the used parameterization, provided better adjustments to quality evaluators. Besides, the model softened the overestimation of parameter a, giving a direct interpretation of parameter b, with the lowest values for curvature measurements, mainly for the parametric ones, and provided more reliable adjustments. Von Bertalanffy’s model can be used in the description of the growth curves of meat-producing mammals.

Sign in / Sign up

Export Citation Format

Share Document