Simple hierarchical and general nonlinear growth modeling in sheep

Abstract

Differential equations and advanced statistical models have been used to predict growth phenomena. In the present study, general nonlinear growth functions such as von Bertalanffy, Gompertz, logistic, and Brody, along with hierarchical modeling were applied to investigate the phenotypic growth pattern of Iranian Lori-Bakhtiari sheep. Growth data from 1410 Lori-Bakhtiari lambs were used in the present study. The results showed that the Brody function outperformed the other three nonlinear growth functions. In addition, including hierarchical growth modeling results allowed the adoption of many random effect structures, suggesting that hierarchical growth modeling has a useful role in growth data modeling. This method provides an estimation of growth parameters based on individual animals, improving individual growth selection. The results suggest this approach for growth modeling. Combining the strength of individual growth modeling with general growth modeling, e.g., von Bertalanffy, Gompertz, logistic, and Brody would be deeply appealing in the future. In this regard, dealing with sheep growth phenomenon using pure mathematical models, i.e. grey system theory models that could be new powerful prediction tools for breeders and experts, has not been done yet. However, running the analysis on large datasets will require significantly higher computational power than is ordinarily available.

Curva De Crecimiento Y Tasas De Crecimiento Absoluto Y Relativo De Cabritos Locales en El Norte De México

“…La curva de crecimiento fue similar y coincidió con ambos modelos, y desde el inicio de la prueba se observó un crecimiento gradual y sostenido (Figura 1). El valor obtenido del parámetro A (peso maduro) en el presente estudio, tanto del modelo Gompertz (62.5) como del Logístico (58.3) es mayor al que se ha encontrado en otros caprinos locales, como en Túnez (Najari et al, 2007) Las diferencias en los resultados de estos estudios en lo referente a los parámetros A y k se pueden atribuir a factores como: modelo utilizado, genotipo del animal, ambiente agroclimático, manejo de los animales (con énfasis en la alimentación), y selección (Özdemir and Dellal, 2009;Ghaderi-Zefrehei et al (2018), aunque otro factor puede ser la longitud del periodo de la prueba. EL resultado del parámetro b no se discute debido a que no tiene una interpretación biológica (Ariff et al, 2010;Adenaike et al, 2017).…”

Comparison non-linear growth models to reflect body weight and body measurements of pre-weaning Kejobong goat

“…Moreover, Gompertz and Logistic models are the most common used model to describe growth traits which have 3 parameters, which are asymptotic mature body weight/body size (a); integration constant (b) and growth rate constant (k). The variance of estimated parameter value for a, b, and k when fitted in the different growth models to the same growth data, indicating that the applied model sharply affects the estimated model parameters [8]. Gompertz models was reported the best model for modeling growth of goat including Alphine goat [9]; Beetal goats [10]; Colored mohair goats [11]; Raeini Cashmere goat [12].…”

Discrete-Time Gompertz Model for Adana Breed Pigeons

“…Various number of parameterizations and reparameterizations of GM can be found in the literature [11]. The use of mathematical population growth models in various fields has become a very useful research area in recent years [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. In these research published in the literature, nonlinear mathematical growth models were used, in which more than one parameter should be estimated.…”