Bayesian analysis for comparison of nonlinear regression model parameters: an application to ruminal degradability data

Rossi, Robson Marcelo; Martins, Elias Nunes; Guedes, Terezinha Aparecida; Jobim, Clóves Cabreira

doi:10.1590/s1516-35982010000200027

Cited by 6 publications

(9 citation statements)

References 8 publications

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“…The modeling follows the suggestion of a Bayesian approach (ROSSI et al, 2010;ROSSI, 2011), t is the incubation time in the rumen, in hours.…”

Section: Methodsmentioning

confidence: 99%

“…The modeling follows the suggestion of a Bayesian approach (ROSSI et al, 2010;ROSSI, 20 considered that the observations follow a Normal distribution, in other words, in which k * is the rate of solids passage in the rumen, which value was set at 2, 5 and 8% per hour.…”

Section: Methodsmentioning

confidence: 99%

“…The modeling follows the suggestion of a Bayesian approach (ROSSI et al, 2010;ROSSI, 2011), which considered that the observations follow a Normal distribution, in other words, To compare treatments, multiple comparisons were made between posteriori distribution of the averages of the parameters of interest. The treatments for which credibility intervals for the mean differences did not include zero were considered as different at the level of 5% significance.…”

Section: Methodsmentioning

confidence: 99%

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Aerobic stability, chemical composition and ruminal degradability of sugarcane silage with glycerin from biodiesel

et al. 2015

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The experiment was performed with the objective of studying the ensiled sugarcane silage with 0, 5, 10, 15 and 20% of glycerin in experimental PVC silos. The aerobic stability was assessed by measuring the pH and the temperature of the silage at 0, 24, 48, 72, 96 and 120h. The chemical composition, the levels of non-fiber carbohydrates (NFC) and the total digestible nutrients (TDN) were evaluated. The in vitro digestibility of dry matter (IVDDM) and the in vitro digestibility of the cell wall (IVDCW) in the silages were evaluated. In three fistulated cattle the in situ degradability of dry matter (DM) and the disappearance percentage of the neutral detergent fiber (NDF) in samples incubated at 0, 2, 6, 12, 24, 48, 72 and 96h were analyzed. The experimental design was completely randomized and the statistical analyzes were done using Bayesian inference. Increases were observed in DM, TDN, mineral matter, NFC and reductions in NDF, acid detergent fiber, crude protein and ether extract as the inclusion of glycerin was higher. IVDDM increased (P <0.05) in silage with 15 and 20% of glycerin in relation to those with 0, 5 and 10%. The IVDCW at levels of 10, 15 and 20% of glycerin was higher (P <0.05) compared to the other treatments. Increases were observed in the soluble portion (a), a reduction in the insoluble fraction (b), and an increase in the degradability fraction constant (c) of the silages with 5, 10, 15 and 20% of glycerin (P <0.05) compared to the control. Glycerin improved aerobic stability while maintaining a low pH and temperature during the observation period at levels of 15 and 20% of glycerin against the silage with 0, 5 and 10%. These results indicate glycerin as a promising additive for sugarcane silage, being able to enhance energy density and improve the aerobic stability of the ensiled matter when its inclusion is from 10 to 20%. Key words: Energy, glycerol, in vitro digestibility, non-fibrous carbohydrates, silage pH, temperature of silage ResumoObjetivou-se estudar a silagem de cana-de-açúcar ensilada com 0, 5, 10, 15 e 20% de glicerina em silos experimentais de PVC. Avaliou-se a estabilidade aeróbia medindo-se o pH e a temperatura da massa ensilada em 0, 24, 48, 72, 96 e 120h. Avaliaram-se a composição química, os teores de carboidratos não fibrosos (CNF) e nutrientes digestíveis totais (NDT). Avaliaram-se a digestibilidade in vitro da matéria seca (DIVMS) e da parede celular (DIVPC) das silagens. Em três bovinos fistulados avaliou-se a degradabilidade in situ da matéria seca (MS) e a porcentagem de desaparecimento da fibra em detergente neutro (FDN) em amostras incubadas em 0, 2, 6, 12, 24, 48, 72 e 96h. O delineamento experimental foi inteiramente casualisado e as análises estatísticas realizadas por meio de Inferência Bayesiana. Observaram-se aumentos na MS, NDT, matéria mineral, CNF e a redução de FDN, fibra em detergente ácido, proteína bruta e extrato etéreo à medida que a inclusão da glicerina foi maior. Houve aumento na DIVMS nas silagens com 15 e 20% de glicerina em relação à...

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“…The modeling follows the suggestion of a Bayesian approach (ROSSI et al, 2010;ROSSI, 2011), t is the incubation time in the rumen, in hours.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Aerobic stability, chemical composition and ruminal degradability of sugarcane silage with glycerin from biodiesel

et al. 2015

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“…The modeling follows the Bayesian approach (ROSSI et al, 2010;ROSSI, 2011), it was considered that the observations follow Normal distribution, that is, For each parameter, 310,000 values were generated in a MCMC (Markov Chain Monte Carlo) process, considering a sampling period discard of 10,000 initial values. Thus, the final sample obtained in leaps at every 30 values, contains 10,000 generated values.…”

Section: Methodsmentioning

confidence: 99%

Nutritional composition and ruminal degradability of corn silage (Zea mays L.) with addition of glycerin in silage

et al. 2015

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The objective was to study the corn silage with addition of 0, 5, 10, 15 and 20% glycerin, ensiled in experimental silos of PVC. At the opening of the silos there were evaluated the chemical composition, in vitro digestibility of dry matter (IVDDM) and cell wall (IVDCW) and aerobic stability through measures of temperature and pH of silage at 0, 24, 48, 72, 96 and 120 hours. In situ degradability of dry matter, crude protein and neutral detergent fiber of silages were evaluated in fistulated cattle using samples incubated at 0, 2, 4, 6, 12, 24, 48 and 96 hours. The experimental design was completely randomized design and statistical analyzes were performed using Bayesian inference. Increases were observed in DM, mineral matter (MM), non-fibrous carbohydrates (NFC) and reductions for neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP) and ether extract (EE) as the inclusion of glycerin was higher. The content of total digestible nutrients (TDN) estimated in treatments with 5, 10, 15 and 20% glycerin, were superior to the control (P<0,05) range of 2.13, 8.95, 10.33 and 13.13% respectively. The temperature and pH of the silage with 10 and 15 and 20% glycerin remained lower than those levels (P<0.05) measured during silage and 20% glycerin showed high stability after 120hours. The IVDDM and IVDCW in corn silages with 15 and 20% were higher than the other (P<0,05). The effective degradability of DM fractions in passage rates of 2, 5 and 8% / h was better in silage with 15% and 20% glycerin. Glycerin has proved to be a great additive for corn silage being able to enrich the energy density, improving the degradability of DM and maintaining the aerobic stability of silage. Key words: Digestibility of dry matter, energy, aerobic stability, glycerol, pH, temperature ResumoObjetivou-se estudar a silagem de milho ensilada com 0, 5, 10, 15 e 20% de glicerina, em silos experimentais de PVC. Foi avaliada a estabilidade aeróbia por medidas de pH e temperatura da massa ensilada (TME) às 0, 24, 48, 72, 96 e 120h. Foi avaliada a composição química e a digestibilidade in vitro da matéria seca (DIVMS) e da parede celular (DIVPC). Em três bovinos fistulados avaliou-se a degradabilidade in situ da matéria seca (MS), e a porcentagem de desaparecimento da proteína bruta (PB) e da fibra em detergente neutro (FDN) incubadas em 0, 2, 6, 12, 24, 48, 72 e 96h. O delineamento experimental foi inteiramente casualisado e as análises estatísticas realizadas por Inferência Bayesiana. Foram observados aumentos de MS, CNF, matéria mineral e a redução de FDN, PB, fibra em detergente ácido e extrato etéreo à medida que se aumentou a inclusão da glicerina. O NDT estimado nas silagens com 5, 10, 15 e 20% de glicerina, foi superior ao controle (P<0,05) variando de 2,13; 8,95; 10,33 e 13,13%, respectivamente. O pH e a TME das silagens com 10, 15 e 20% de glicerina se mantiveram inferiores (P<0,05) aos com 0 e 5% de glicerina no período avaliado, destacando-se a silagem com 20% de glicerina com maior estabilidade até 120...

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“…As an alternative to the frequentist approach, the Bayesian methodology does not require the assumption of normality as a necessary condition and the inferences on the parameters are made on their posterior distribution. In this case, a model is supposed for each dataset and the parameters of each model are compared based on their posterior distributions (ROSSI et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Bayesian and Frequentist Approaches for Fitting the Gamma-Time-Dependent Model to Describe Neutral Detergent Fiber Degradation

et al. 2018

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The aim of the study was evaluate and compare the efficiency of Bayesian and frequentist approach to describe the rumen degradation of NDF. Simulated data was composed by four scenarios: regular restriction in the number of incubation times, random loss of incubation times, loss of specific parts of degradation curves, variation in the precision of the incubations procedures. Two real datasets was used, these real data encompassed the evaluation of NDF degradation of a tropical grass (Brachiaria decumbes). The model was fitted according their characteristics approach and compared by plots and assessors. The Bayesian and frequentist approach presented reliable estimates of degradation parameters for the majority of the data tested. Therefore, in specific cases with short random records number, the Bayesian approach showed greater bias of the estimates of incubation residue and estimates of degradation rate without a biological coherence of the parameters, compared to frequentist inference. In another words, the Bayesian approach fitted with prior diffuse, presented less flexible. Nevertheless, it is emphasized the importance of the background information before the modeling, mainly for the Bayesian approach, in order to define proper prior distributions. Future thorough studies about the influence of non-informative prior for the parameters are necessary.

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Bayesian analysis for comparison of nonlinear regression model parameters: an application to ruminal degradability data

Cited by 6 publications

References 8 publications

Aerobic stability, chemical composition and ruminal degradability of sugarcane silage with glycerin from biodiesel

Aerobic stability, chemical composition and ruminal degradability of sugarcane silage with glycerin from biodiesel

Nutritional composition and ruminal degradability of corn silage (Zea mays L.) with addition of glycerin in silage

Bayesian and Frequentist Approaches for Fitting the Gamma-Time-Dependent Model to Describe Neutral Detergent Fiber Degradation

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