Nonlinear mixed effects models for comparing growth curves for Guzerá cattle

Abstract

The objective of the present work was to evaluate the accuracy of the fitted Gompertz and von Bertalanffy models for male and female Guzerá cattle, respectively. Four production regions in Northeast Brazil were included in the models as a fixed effect, and the animals were included as a random effect. In addition, the coefficients of the growth models in the production regions were compared. The accuracy of the fit equations was assessed with the Akaike information criterion, Bayesian information criterion, mean absolute deviation, mean squared error, and coefficient of determination. Confidence intervals were used for comparing the production regions. The Guzerá males in the Gado-Algodão and Serra Geral da Bahia production regions were statistically equal in asymptotic weight, and the animals in the Itapetinga-Valadares and Mata-Agreste regions had equivalent maturity rates. The Guzerá females in the Itapetinga-Valadares and Serra Geral da Bahia regions had the same asymptotic weight. The maturity rates in Itapetinga-Valadares were equal to those estimated for Mata-Agreste and Serra Geral da Bahia. The inclusion of the fixed effect of the production region and the random effect of the animals in the models improved the fit quality and increased the possibility of generating growth curves for each region.

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].…”

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

“…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. Determining the most suitable model in a group of herds is very important for the development of more effective selection strategies and the regulation of management practices (KORKMAZ et al, 2011;ALVES et al, 2020). In addition, it helps technicians and breeders through decisions related to Rev.…”