The ontogenetic allometry of body morphology and chemical composition in dairy goat wethers
We studied the ontogenetic growth of goat wethers (castrated male goats) of the Saanen and Swiss Alpine breeds based on a large range of intraspecific body mass (BM). The body parts and the chemical constituents of the empty body were described by the allometric function by using BM and the empty bo...
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Elsevier
2018-01-01
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Online Access: | http://www.sciencedirect.com/science/article/pii/S1751731117001884 |
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author | R.A.M. Vieira N.M. Rohem Júnior R.S. Gomes T.S. Oliveira L.C.R. Bendia F.H.V. Azevedo D.L. Barbosa L.S. Glória M.T. Rodrigues |
author_facet | R.A.M. Vieira N.M. Rohem Júnior R.S. Gomes T.S. Oliveira L.C.R. Bendia F.H.V. Azevedo D.L. Barbosa L.S. Glória M.T. Rodrigues |
author_sort | R.A.M. Vieira |
collection | DOAJ |
description | We studied the ontogenetic growth of goat wethers (castrated male goats) of the Saanen and Swiss Alpine breeds based on a large range of intraspecific body mass (BM). The body parts and the chemical constituents of the empty body were described by the allometric function by using BM and the empty body mass (EBM) as the predictors for morphological traits and chemical composition, respectively. We fitted the allometric scaling function by applying the SAS NLMIXED procedure, but to evaluate assumptions regarding variances in morphological and compositional traits, we combined the scaling function with homoscedastic (MOD1), and the heteroscedastic exponential (MOD2) and power-of-the-mean (MOD3) variance functions. We also predicted the ontogenetic growth by using the traditional log-log transformation and back-transformed results into the arithmetic scale (MOD4). We obtained predictions from MOD4 in the arithmetic scale by a two-step process, and evaluated MOD1, MOD2 and MOD3 by a model selection framework, and compared MOD4 with MOD1, MOD2 and MOD3 based on goodness-of-fit measures. Based on information criteria for model selection, heterogeneous variance functions were more likely to describe 10 over 36 traits with a low level of model selection uncertainty. One trait was predicted by averaging the MOD1 and MOD2 variance functions; and nine traits were better described by averaging the MOD2 and MOD3 variance functions. The predictions for other 16 traits were averaged from MOD1, MOD2 and MOD3. However, MOD4 better described 11 traits according to the goodness-of-fit measures. Depending on the variable being analyzed, the body parts and the chemical amounts exhibited the three types of allometric behavior with respect to BM and EBM, that is, positive, negative and isometric ontogenetic growth. Reference BMs, that is, 20, 27, 35 and 45 kg, were used to compute the net protein and energy requirements based on the first derivative of the scaling function, and the results were presented in reference to the EBM and EBM0.75. Both the net protein and energy requirements scaled to EBM0.75 increased from 20 to 45 kg of BM. |
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spelling | doaj.art-8f86684bb55a4ecd8619e4965729b3882022-12-21T20:10:46ZengElsevierAnimal1751-73112018-01-01123538553The ontogenetic allometry of body morphology and chemical composition in dairy goat wethersR.A.M. Vieira0N.M. Rohem Júnior1R.S. Gomes2T.S. Oliveira3L.C.R. Bendia4F.H.V. Azevedo5D.L. Barbosa6L.S. Glória7M.T. Rodrigues8Laboratório de Zootecnia, Centro de Ciências e Tecnologias Agropecuárias (CCTA), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ, CEP 28013-602, BrazilAnimal Science Graduate Program, CCTA/UENF, Campos dos Goytacazes, RJ, CEP 28013-602, BrazilAnimal Science Graduate Program, CCTA/UENF, Campos dos Goytacazes, RJ, CEP 28013-602, BrazilAnimal Science Graduate Program, CCTA/UENF, Campos dos Goytacazes, RJ, CEP 28013-602, BrazilAnimal Science Graduate Program, CCTA/UENF, Campos dos Goytacazes, RJ, CEP 28013-602, BrazilAnimal Science Graduate Program, CCTA/UENF, Campos dos Goytacazes, RJ, CEP 28013-602, BrazilAnimal Science Graduate Program, CCTA/UENF, Campos dos Goytacazes, RJ, CEP 28013-602, BrazilLaboratório de Zootecnia, Centro de Ciências e Tecnologias Agropecuárias (CCTA), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ, CEP 28013-602, BrazilDepartamento de Zootecnia, Centro de Ciências Agrárias, Universidade Federal de Viçosa, Viçosa, MG, CEP 36570-000, BrazilWe studied the ontogenetic growth of goat wethers (castrated male goats) of the Saanen and Swiss Alpine breeds based on a large range of intraspecific body mass (BM). The body parts and the chemical constituents of the empty body were described by the allometric function by using BM and the empty body mass (EBM) as the predictors for morphological traits and chemical composition, respectively. We fitted the allometric scaling function by applying the SAS NLMIXED procedure, but to evaluate assumptions regarding variances in morphological and compositional traits, we combined the scaling function with homoscedastic (MOD1), and the heteroscedastic exponential (MOD2) and power-of-the-mean (MOD3) variance functions. We also predicted the ontogenetic growth by using the traditional log-log transformation and back-transformed results into the arithmetic scale (MOD4). We obtained predictions from MOD4 in the arithmetic scale by a two-step process, and evaluated MOD1, MOD2 and MOD3 by a model selection framework, and compared MOD4 with MOD1, MOD2 and MOD3 based on goodness-of-fit measures. Based on information criteria for model selection, heterogeneous variance functions were more likely to describe 10 over 36 traits with a low level of model selection uncertainty. One trait was predicted by averaging the MOD1 and MOD2 variance functions; and nine traits were better described by averaging the MOD2 and MOD3 variance functions. The predictions for other 16 traits were averaged from MOD1, MOD2 and MOD3. However, MOD4 better described 11 traits according to the goodness-of-fit measures. Depending on the variable being analyzed, the body parts and the chemical amounts exhibited the three types of allometric behavior with respect to BM and EBM, that is, positive, negative and isometric ontogenetic growth. Reference BMs, that is, 20, 27, 35 and 45 kg, were used to compute the net protein and energy requirements based on the first derivative of the scaling function, and the results were presented in reference to the EBM and EBM0.75. Both the net protein and energy requirements scaled to EBM0.75 increased from 20 to 45 kg of BM.http://www.sciencedirect.com/science/article/pii/S1751731117001884bivariate allometrymodel averagingheteroscedasticitySaanenSwiss Alpine |
spellingShingle | R.A.M. Vieira N.M. Rohem Júnior R.S. Gomes T.S. Oliveira L.C.R. Bendia F.H.V. Azevedo D.L. Barbosa L.S. Glória M.T. Rodrigues The ontogenetic allometry of body morphology and chemical composition in dairy goat wethers Animal bivariate allometry model averaging heteroscedasticity Saanen Swiss Alpine |
title | The ontogenetic allometry of body morphology and chemical composition in dairy goat wethers |
title_full | The ontogenetic allometry of body morphology and chemical composition in dairy goat wethers |
title_fullStr | The ontogenetic allometry of body morphology and chemical composition in dairy goat wethers |
title_full_unstemmed | The ontogenetic allometry of body morphology and chemical composition in dairy goat wethers |
title_short | The ontogenetic allometry of body morphology and chemical composition in dairy goat wethers |
title_sort | ontogenetic allometry of body morphology and chemical composition in dairy goat wethers |
topic | bivariate allometry model averaging heteroscedasticity Saanen Swiss Alpine |
url | http://www.sciencedirect.com/science/article/pii/S1751731117001884 |
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