Análise da curva de crescimento de machos Hereford

Mazzini, Ana Rita de Assumpção; Muniz, Joel Augusto; Aquino, Luiz Henrique de; Silva, Fabyano Fonseca e

doi:10.1590/s1413-70542003000500019

Cited by 37 publications

(34 citation statements)

References 8 publications

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“…Large cattle, independently of breed, are usually heavier at birth than medium and small cattle (Long et al, 1975;Vargas et al, 1999). The average birth weight obtained was 33.7 kg, consistent with that reported for Hereford herds in the state of Rio Grande do Sul (Mazzini et al, 2003).…”

Section: Discussionsupporting

confidence: 86%

Development and reproductive performance of Hereford heifers of different frame sizes up to mating at 14-15 months of age

et al. 2018

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-Body development and reproductive performance of a hundred forty-two 14 to 15-month-old heifers, classified at weaning according to frame size as small, medium, and large, were evaluated. The parameters evaluated were: body weight, hip height, body condition score, weight gain, ovarian activity, and pregnancy rate. At weaning, body weight and hip height were significantly different among frame scores, (small -133.0 kg, 92.2 cm; medium -158.5 kg, 96.6 cm; and large -185.2 kg; 100.2 cm). After weaning, heifers grazed together on natural pastures during the autumn and on ryegrass (Lolium multiflorum La.) during the winter and spring. Frame score differences remained until the beginning of the breeding season (BS), starting on average at 14 months of age. Weight gain between weaning and the beginning of BS was not different among frame scores (0.740 kg/day, on average). Body weights at the beginning of the BS were significantly different, of 255.7 kg (53.3% of the mature weight) for small heifers, 285.0 kg (59.4%) for medium heifers, and 307.6 kg (64.1%) for large heifers. Ovarian activity at the beginning of the BS was not different among the three groups. The average weight gain values during the BS of 0.492, 0.472, and 0.421 kg/day for small, medium, and large heifers, respectively, were significantly different. Pregnancy rates were not different among groups (small, 71.4%; medium, 76.4%; and large, 76.5%). Frame score did not influence the reproductive performance of heifers, but the small and medium heifers conceived 29 and 20 days earlier, respectively, than the large heifers.

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Section: Discussionsupporting

confidence: 86%

Development and reproductive performance of Hereford heifers of different frame sizes up to mating at 14-15 months of age

et al. 2018

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“…os modelos não lineares geralmente fornecem melhor ajuste que os modelos lineares em estudos de crescimento, tendo ainda a vantagem de fornecer estimativas de parâmetros com interpretação biológica (MAZZINI et al, 2003;MENDES et al, 2008;FERNANDES et al, 2014). Os modelos não lineares gompertz e logístico foram ajustados com resultados satisfatórios para descrever o crescimento de frutos de coqueiro anão verde e de frutos de tamareira anã (TERRA et al, 2010).…”

Section: Introductionunclassified

Descrição Da Curva De Crescimento De Frutos Do Cajueiro Por Modelos Não Lineares

et al. 2016

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RESUMO -o objetivo do trabalho foi avaliar o ajuste dos modelos gompertz e logístico, com estrutura de erros independentes e autorregressivos, no desenvolvimento de frutos de caju, com base em medidas de comprimento e largura do fruto, tomados ao longo do tempo. a estimação dos parâmetros foi feita por meio de rotinas no software R, utilizando-se do método dos mínimos quadrados e o processo iterativo de gaussNewton. Os modelos foram comparados pelos critérios: coeficiente de determinação ajustado (R 2 aj ), desvio padrão residual (DPR), critério de informação Akaike (AIC) e critério bayesiano de Schwarz (BIC). Para os dois modelos, os dados apresentaram autocorrelação residual positiva, tanto para a variável comprimento como para a largura do fruto, descrita por processo autorregressivo de primeira ordem. em geral, por todos critérios de avaliação da qualidade de ajuste, os dados se ajustaram ao modelo logístico com uma estrutura autorregressiva da primeira ordem, havendo no entanto superestimação do tamanho do fruto nas últimas idades, tanto no crescimento em comprimento (cm) como em largura (cm). termos para indexação: Modelo de crescimento. Medidas biométricas. Regressão não linear. Cajú. DESCRIPTION OF THE GROWTH CURVE OF CASHEW FRUITS IN NONLINEAR MODELSABSTRACT -The objective of this study was to evaluate the adjustment of gompertz and logistic models, with independent and autoregressive error structure in cashew fruits growth, based on the length and width measurements of the fruit, taken through the time. The estimation of the parameters was done in R software routines using the method of minimal squares and the interactive process of gauss-newton. the models were compared by the following criteria: the adjusted coefficient of determination, residual standard deviation, Akaike information criterion and Schwarz Bayesian criterion. For both models, the data showed positive residual autocorrelation for both variables: length and width of the fruit, described in autoregressive process of order one. in general, both models adjusted to the data, however there was an overestimation of the fruit size at the late stages. the logistic model was the most adequate to describe the cashew fruit growth in length and width.

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“…Já para o parâmetro A, verificase que as funções de Brody e Bertalanffy apresentaram valores muito próximos. A função Logística subestimou esse parâmetro, concordando com os resultados de Ludwig et al (1981), Tedeschi et al (2000) e Mazzini et al (2003), com valores finais e iniciais baixos. Conseqüentemente, Tabela 3 -Estimativa dos parâmetros A, B e K das funções de Brody, Gompertz, von Bertalanffy e Logística, para a relação comprimento de cabeça / comprimento padrão (CCAB/CP) e para as características morfométricas da piracanjuba.…”

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Curvas de crescimento morfométrico de piracanjuba (Brycon orbignyanus)

Gomiero¹,

Freitas

Santos³

et al. 2009

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RESUMOConduziu-se um experimento no setor de piscicultura da Universidade Federal de Lavras -M.G., com o objetivo de estabelecer curvas de crescimento morfométrico em função do peso corporal para a piracanjuba (Brycon orbignyanus). Alevinos de piracanjuba foram cultivados em viveiros de terra e alimentados com ração comercial até atingirem peso aproximado de 1 kg. Durante o período experimental realizaram-se amostragens aleatórias, onde foram avaliadas as medidas morfométricas comprimento da cabeça (CCAB), comprimento padrão (CP), altura (AND) e largura (LND) tomada no 1°raio da nadadeira dorsal e as razões morfométricas (CCAB/CP, AND/CP, LND/CP, AND/LND) utilizando-se as funções de Brody, von Bertalanffy, Gompertz e Logística. As funções estudadas apresentaram bom ajuste para todas as medidas morfométricas e para a razão CCAB/CP. As funções de Brody, von Bertalanffy e Gompertz apresentaram qualidades de ajuste semelhantes e superiores à função Logística para as medidas morfométricas. Para a razão CCAB/CP a função Logística apresentou-se superior às demais. A taxa de crescimento da CCAB e LND foi superior às do CP e AND, indicando um crescimento mais rápido da cabeça e largura do que do comprimento padrão e altura. Conclui-se que todos os modelos estudados apresentaram bom ajuste, sendo o de Brody e o de von Bertalanffy os que descrevem melhor o crescimento morfométrico da piracanjuba. Termos para indexação:Modelos não-lineares, morfometria, piracanjuba. ABSTRACTAn experiment was carried out at the fish farming sector of the Universidade Federal de Lavras -M.G., with the objective of establishing morphometric growth curves as a function of the body weight of piracanjuba (Brycon orbignyanus). Fingerlings of piracanjuba were cultivated in earthen ponds and fed a commercial diet (ad libitum) until they reached weight of about 1 kg. During the experimental period, samplings were randomly selected to take morphometric measures of the head length (CCAB), standard length (CP), height (AND), and breadth (LND), taken at the first ray of the dorsal fin. Measures and the morphometric ratios CCAB/ CP, AND/CP, LND/CP, AND/LND were evaluated by Brody, von Bertalanffy, Gompertz and Logistic functions. All models showed a good fit for morphometric measures and the CCAB/CP ratio. Brody, von Bertalanffy and Gompertz functions presented similar fit qualities when studying morphometric measures while the Logistic function provided poor fit. However, the Logistic function presented better fit quality for the CCAB/CP ratio than the other functions. Growth rate of the variables CCAB and LND was higher than CP and AND, indicating a faster growth of head and breadth in relation to standard length and height. All models studied presented good fit, but the Brody and von Bertalanffy functions better described the morphometric growth of the fish.

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Análise da curva de crescimento de machos Hereford

Cited by 37 publications

References 8 publications

Development and reproductive performance of Hereford heifers of different frame sizes up to mating at 14-15 months of age

Development and reproductive performance of Hereford heifers of different frame sizes up to mating at 14-15 months of age

Descrição Da Curva De Crescimento De Frutos Do Cajueiro Por Modelos Não Lineares

Curvas de crescimento morfométrico de piracanjuba (Brycon orbignyanus)

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