title: Comparison on accuracy of different nonlinear models in predicting growth of Podolica bulls.
abstract: Animal growth does not follow a linear pattern, being explained mathematically by functions that have parameters with biological meaning. These parameters are used to estimate the expected weight of animals at specific ages. Several nonlinear models have been used to describe growth. This study was carried out to estimate the parameters of logistic, Gompertz, Richards and von Bertalanffy growth curve models in a sample of Podolica young bulls to determine the goodness of fit. Animals were weighed every 3 months from birth to 810 days of age. The results indicate that all the growth models used were easily fitted to the observed data with Gompertz and logistic functions presenting less computational difficulty in terms of number of iterations to achieve convergence. Moreover, logistic and Richards equations provided the best overall fit being useful to describe the growth of Podolica bulls. Considering that the literature lacks information on growth curves in Podolica breed, the study of a mathematical model for growth describing the developmental pattern of a specific population within a peculiar environment is a useful tool to improve Podolica breed production.
authors.affiliation: Department DETO - Section of Veterinary Science and Animal Production, University of Bari 'Aldo Moro', Valenzano, BA, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Selvaggi
authors.affiliation: Department DETO - Section of Veterinary Science and Animal Production, University of Bari 'Aldo Moro', Valenzano, BA, Italy.
authors.forename: Vito
authors.initials: V
authors.lastname: Laudadio
authors.affiliation: Department of Agro-Environmental and Territorial Sciences, University of Bari 'Aldo Moro', Bari, Italy.
authors.forename: Angela Gabriella
authors.initials: AG
authors.lastname: D'Alessandro
authors.affiliation: Department DETO - Section of Veterinary Science and Animal Production, University of Bari 'Aldo Moro', Valenzano, BA, Italy.
authors.forename: Cataldo
authors.initials: C
authors.lastname: Dario
authors.affiliation: Department DETO - Section of Veterinary Science and Animal Production, University of Bari 'Aldo Moro', Valenzano, BA, Italy.
authors.forename: Vincenzo
authors.identifier: http://orcid.org/0000-0003-0089-4393
authors.initials: V
authors.lastname: Tufarelli
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D002417:Cattle / Q000254:growth & development*; D004777:Environment; D005544:Forecasting; D007558:Italy; D008297:Male; D017711:Nonlinear Dynamics
keywords: Podolica breed; growth curve; nonlinear models