Selection of nonlinear mixed models for growth curves of dairy buffaloes (Bubalus bubalis)

Abstract

The determination of livestock growth patterns is important for meat or milk production systems, and nonlinear models are used to summarize and interpret the information. The aim of this study was to more accurately estimate growth curve parameters in buffalo cows by evaluating and selecting nonlinear mixed models that employ different types of residuals and include or not contemporary groups (CG) as a covariate. Weight records from 720 animals obtained over a period of 60 months were used. The growth curves were fit using nonlinear mixed-effects models. The Bertalanffy, Gompertz and Logistic models were evaluated. Modelling residuals using four structures (constant, combined, exponential and proportional) and the inclusion or not of CG in the models were also evaluated. The Akaike information criterion (AIC) and Bayesian information criterion (BIC) were used to select the model. In addition to estimating the parameters of the nonlinear growth models and their correlations, the instantaneous growth rate and inflection point were obtained. The Bertalanffy model with a combined residual structure and CG exhibited the lowest AIC and BIC values. Asymptotic weight (A) estimates ranged from 621.8 to 742.1 kg, and the maturity rate (k) ranged from 0.068 to 0.115 kg/month. The correlation between A and k ranged from −0.32 to −0.82 among the models evaluated. The selection criteria indicated that the Bertalanffy model was the most suitable for growth curve analysis in buffaloes.

Nonlinear Mixed-Effect Models to Describe Growth Curves of Pepper Fruits in Eight Cultivars Including Group Effects

“…This methodology efficiency corroborated with some works that obtained good results, such as applications for eucalyptus spp. trees [32], pepper [7], Guzerá cattle [10], dairy buffaloes [11], dairy goats [33], heifers [34] and larch [16]. This shows the effectiveness of the methodology in different contexts.…”

“…Several researchers have used NLME modeling in different contexts, including the development of animal growth curves, as can be seen in Alves et al [10] for Guzerá cattle and in Araujo Neto et al [11] for dairy buffaloes. In addition to applications in the animal field, this methodology has been recurrently applied in the silvicultural area, such as in the development of height-diameter models [12][13][14][15][16], crown-base-height models [17] and diameter model [18].…”

Linear and Nonlinear Mixed Models to Determine the Growth Curves of Weaned Piglets and the Effect of Sex on Growth

“…During the last few years, mixed models have been widely used to model the growth of domestic animals [43][44][45]. Although there is little difference between the fit of fixed effects models and mixed models, the predictive capacity of mixed models for new observations is better [22,42].…”

Fit and genetic parameters of the growth curve of Polled Nellore cattle

“…Growth is a complex process of cell proliferation that involves interactions between genetics, nutrition, and other environmental influences (POSADA et al, 2014), and understanding this process is important for optimizing management and feeding practices as well as for the genetic improvement of species (DO and MIAR, 2020). In view of this, over the years, several non-linear models have been used to describe the growth curve of beef cattle (DUAN et al, 2021) and other species (ARAÚJO et al, 2020;MENCHETTI et al, 2020;RIBEIRO et al, 2021). However, there is no consensus on which model is the most suitable for estimating growth curves, since adequacy is particular to each population and each population or breed has a specific growth pattern.…”