scholarly journals Sigmoid Models for the Growth Curves in Medium-Growing Meat Type Chickens, Raised under Semi-Confined Conditions

2016 ◽  
Vol 16 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Monika Michalczuk ◽  
Krzysztof Damaziak ◽  
Antoni Goryl
Keyword(s):  
Standard Error ◽  
Logistic Model ◽  
Growth Curves ◽  
Gompertz Model ◽  
Richards Model ◽  
Comparison Of Results ◽  
The Mean ◽  
Two Peaks ◽  
Growth Deceleration ◽  
Meat Type

Abstract The study analyzed the growth of medium-growing chickens of the CCGP experimental line, using Gompertz, Logistic, and Richards models as well as body gain curves. The birds were reared until 9 wk of age. To fit BW values to the applied models, determination coefficients (R2,Ř2) and standard error of the mean (±SE) were calculated for 487 male and 493 female chickens. The comparison of results obtained demonstrated the Gompertz model to be the most precise equation to describe the growth of both sexes of CCGP chickens, though in all examined models the determination coefficients were approximating 99%. According to the Gompertz model, the chickens may reach the maximum BW at the age of 16 wk (5900 g - males and 4000 g - females), whereas the maximum daily BW gain - on day 47 (69.0 g) in males and on day 41 (50.0 g) in females. Values achieved in the Logistic model were the most diverging from the values obtained with other models, whereas the Richards model may be successfully applied to estimate BW of chickens. Females were reaching the maximum BW gains earlier, but the curve of their BW gain was proceeding with two peaks (at ca. 4 wk - 313.09 g/wk and at 6 wk - 327.59 g/wk), which was probably due to partial growth deceleration as a result of allowing the birds to use free ranges on day 14. In the case of males, the maximum BW gain (727.35 g/wk) was reached at 6.2 wk.

scholarly journals Temporal progress of southern rust in maize under different environmental conditions

2003 ◽  
Vol 28 (3) ◽  
pp. 273-278 ◽  
Author(s):  
Cláudia V. Godoy ◽  
Lílian Amorim ◽  
Armando Bergamin Filho ◽  
Herbert P. Silva ◽  
Willian J. Silva ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Disease Severity ◽  
Logistic Model ◽  
Inflection Point ◽  
Gompertz Model ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve ◽  
Puccinia Polysora ◽  
The Mean

The progress of the severity of southern rust in maize (Zea mays) caused by Puccinia polysora was quantified in staggered plantings in different geographical areas in Brazil, from October to May, over two years (1995-1996 and 1996-1997). The logistic model, fitted to the data, better described the disease progress curves than the Gompertz model. Four components of the disease progress curves (maximum disease severity; area under the disease progress curve, AUDPC; area under the disease progress curve around the inflection point, AUDPCi; and epidemic rate) were used to compare the epidemics in different areas and at different times of planting. The AUDPC, AUDPCi, and the epidemic rate were analyzed in relation to the weather (temperature, relative humidity, hours of relative humidity >90%, and rainfall) and recorded during the trials. Disease severity reached levels greater than 30% in Piracicaba and Guaíra in the plantings between December and January. Lower values of AUDPC occurred in later plantings at both locations. The epidemic rate was positively correlated (P < 0.05) with the mean daily temperatures and negatively correlated with hours of relative humidity >90%. The AUDPC was not correlated with any weather variable. The AUDPCi was negatively related to both variables connected to humidity, but not to rain. Long periods (mostly >13 h day-1) of relative humidity >90% (that corresponded to leaf wetness) occurred in Castro. Severity of southern rust in maize has always been low in Castro, thus the negative correlations between disease and the two humidity variables.

Weight and feather growth of nestling tree swallows

1982 ◽  
Vol 60 (5) ◽  
pp. 1080-1090 ◽  
Author(s):  
Reto Zach ◽  
Keith R. Mayoh
Keyword(s):  
Brood Size ◽  
Logistic Model ◽  
Growth Curves ◽  
Gompertz Model ◽  
Weather Conditions ◽  
Growth Rate Constant ◽  
Tree Swallows ◽  
Primary Feather ◽  
Weight Growth ◽  
Feather Growth

Six models were tested for weight and feather growth of nestling tree swallows (Iridoprocne bicolor). The logistic model, with an asymptotic weight A of 22.4 g and a growth-rate constant K of 0.51 day−1, was most appropriate for weight growth. Observed curves for individual birds were of diverse shape and some lacked weight recession. Growth of primary feather 9 and rectrix feather 6 followed the Gompertz model, with A and K values of 80.9 and 49.6 mm, and 0.21 and 0.20 day−1, respectively. Fitting of the models to feather length was complicated because growth curves for individual birds did not coincide in time, and fledging occurred before completion of growth. Long nestling times were associated with slow weight and feather growth, and A and K were consistently negatively correlated. The variation of A, K, and nestling time among broods ranged from 49.2 to 95.1%, and brood size could not account for much of the observed variability. Presumably, various nest-box variables and weather conditions as related to the age of nestlings are important. Primary and rectrix growth were similar and closely linked but apparently unrelated to weight growth. Growth of feather vanes was closely linked to feather growth. Birds that failed to fledge had depressed weight, feather, and vane growth. Weight growth and recession seem to be particularly well suited for investigating natural and man-made environmental stresses.

Growth curves of ostriches (Struthio camelus) from Oudtshoorn in South Africa

1995 ◽  
Vol 61 (1) ◽  
pp. 161-164 ◽  
Author(s):  
S. C. Cilliers ◽  
J. J. du Preez ◽  
J. S. Maritz ◽  
J. P. Hayes
Keyword(s):  
Growth Parameters ◽  
Growth Curves ◽  
Live Weight ◽  
Gompertz Model ◽  
Parameter Estimates ◽  
Mean Values ◽  
Struthio Camelus ◽  
Body Weights ◽  
Males And Females ◽  
The Mean

AbstractGrowth results of 43 ostrich males and females were used to compile growth parameters of a flock that is representative of Oudtshoorn birds, using the Gompertz model. Growth results comprised 19 recordings of body weight for each individual commencing from 1-day-old to day 520. Individual fits of data to the growth model were exceptionally good, resulting in low CV values of 0·02 and 0·03 for the mean values of all estimates of mature live weight for male and females respectively. The estimated mean mature body weights for the flock were 119·2 kg for males and 122·3 kg for females. Rates of maturing were 9100 and 8500 for males and females respectively which corresponded to ages of 180·83 and 199·2 days at which maximum gain in weight were achieved. None of these parameter estimates differed significantly between sexes. Results in the present study suggested substantial adjustments to growth parameters for Oudtshoorn ostriches published by du Preez, Jarvis, Capatos and de Kock, 1992.

scholarly journals Growth curves in meat-type and laying quail: a Bayesian perspective

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2743
Author(s):  
Robson Marcelo Rossi ◽  
Daiane De Oliveira Grieser ◽  
Vagner De Almeida Conselvan ◽  
Simara Márcia Marcato
Keyword(s):  
Body Weight ◽  
Bayesian Approach ◽  
Goodness Of Fit ◽  
Nonlinear Models ◽  
Growth Curves ◽  
Gompertz Model ◽  
Body Growth ◽  
Coturnix Coturnix ◽  
Body Weight Data ◽  
Meat Type

The aim of this study was to assess the goodness of fit for nonlinear models, using the best model to describe body growth curves, comparing the parameters obtained for gender and one meat-type (Coturnix coturnix coturnix) and two laying (Coturnix coturnix japonica) quail strains, as well as nesting via MCMC (Markov chain Monte Carlo processes) methods under a Bayesian approach. A total of 1,350 one-day-old mixed quail were used: 400 of meat-type, 450 of yellow laying, and 500 of red laying strains distributed in a completely randomized design with three treatments (each treatment corresponded to one strain) and five replications. The experimental period consisted of 1 to 42 days of age. At 21 days of age, quail sexing was performed by means of sexual dimorphism, being individually identified at one day of age with numbered rings, allowing determining growth curves by gender. Birds were reared in a conventional system, fed ad libitum with diets formulated to meet nutritional requirements. Body weight was determined weekly and assessed using nonlinear models: Logistic, Brody, Von Bertalanffy, and Gompertz, whose parameters were estimated under a Bayesian approach via MCMC algorithm by means of BRugs package from the software R. DIC (Deviance Information Criterion) criterion was used to select the best nonlinear model, i.e. the lower the DIC value is, the better the model goodness of fit to the data. Gompertz model was better adjusted to the data regardless the gender or strain. Meat-type quail had the highest asymptotic weights and the highest age at which growth rate was maximum, followed by red and yellow strains. All nestings presented significant differences (p < 0.05) between gender for contrasted parameters. Meat-type, yellow, and red females presented values significantly (p < 0.05) higher for asymptotic weight (370, 203, and 215 g, respectively) when compared to males (274, 131, and 143 g, respectively), which were earlier in body growth. Gompertz model was better adjusted to body weight data of quail regardless the gender or strain and the Bayesian approach allowed obtaining accurate estimations. Meat-type strain presented the highest body asymptotic weight, followed by red and yellow laying strains. Females presented higher asymptotic weight than that found for males of their respective strains but were later in growth.

scholarly journals Growth curves in meat-type and laying quail: a Bayesian perspective

2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2743 ◽  
Author(s):  
Robson Marcelo Rossi ◽  
Daiane De Oliveira Grieser ◽  
Vagner De Almeida Conselvan ◽  
Simara Márcia Marcato
Keyword(s):  
Body Weight ◽  
Bayesian Approach ◽  
Goodness Of Fit ◽  
Nonlinear Models ◽  
Growth Curves ◽  
Gompertz Model ◽  
Body Growth ◽  
Coturnix Coturnix ◽  
Body Weight Data ◽  
Meat Type

The aim of this study was to assess the goodness of fit for nonlinear models, using the best model to describe body growth curves, comparing the parameters obtained for gender and one meat-type (Coturnix coturnix coturnix) and two laying (Coturnix coturnix japonica) quail strains, as well as nesting via MCMC (Markov chain Monte Carlo processes) methods under a Bayesian approach. A total of 1,350 one-day-old mixed quail were used: 400 of meat-type, 450 of yellow laying, and 500 of red laying strains distributed in a completely randomized design with three treatments (each treatment corresponded to one strain) and five replications. The experimental period consisted of 1 to 42 days of age. At 21 days of age, quail sexing was performed by means of sexual dimorphism, being individually identified at one day of age with numbered rings, allowing determining growth curves by gender. Birds were reared in a conventional system, fed ad libitum with diets formulated to meet nutritional requirements. Body weight was determined weekly and assessed using nonlinear models: Logistic, Brody, Von Bertalanffy, and Gompertz, whose parameters were estimated under a Bayesian approach via MCMC algorithm by means of BRugs package from the software R. DIC (Deviance Information Criterion) criterion was used to select the best nonlinear model, i.e. the lower the DIC value is, the better the model goodness of fit to the data. Gompertz model was better adjusted to the data regardless the gender or strain. Meat-type quail had the highest asymptotic weights and the highest age at which growth rate was maximum, followed by red and yellow strains. All nestings presented significant differences (p < 0.05) between gender for contrasted parameters. Meat-type, yellow, and red females presented values significantly (p < 0.05) higher for asymptotic weight (370, 203, and 215 g, respectively) when compared to males (274, 131, and 143 g, respectively), which were earlier in body growth. Gompertz model was better adjusted to body weight data of quail regardless the gender or strain and the Bayesian approach allowed obtaining accurate estimations. Meat-type strain presented the highest body asymptotic weight, followed by red and yellow laying strains. Females presented higher asymptotic weight than that found for males of their respective strains but were later in growth.

Forecasting and Analyzing Internet Users of China with Lotka–Volterra Model

2017 ◽  
Vol 34 (01) ◽  
pp. 1740006 ◽  
Author(s):  
Xiaoxia Fu ◽  
Ping Zhang ◽  
Juzhi Zhang
Keyword(s):  
Prediction Accuracy ◽  
Logistic Model ◽  
Gompertz Model ◽  
Absolute Error ◽  
Volterra Model ◽  
Percentage Error ◽  
The Internet ◽  
Internet Users ◽  
The Mean ◽  
The Relationship

In the background of big data era, the ability to accurately forecast the number of the Internet users has considerable implications for evaluating the growing trend of a newly-developed business. In this paper, we use four models, the Gompertz model, the Logistic model, the Bass model, and the Lotka–Volterra model, to forecast the Internet population in China with the historical data during 2007 to 2014. We compare the prediction accuracy of the four models using the criterions such as the mean absolute percentage error (MAPE), the mean absolute error (MAE) and the root mean square error (RMSE). We find that the Lotka–Volterra model has the highest prediction accuracy. Moreover, we use the Lotka–Volterra model to investigate the relationship between the rural Internet users and the urban Internet users in China. The estimation results show that the relationship is commensalism.

scholarly journals Modelling Growth Curves In Kampung Super Garut Chicken Fed With Pasak Bumi Meal (Euricoma longifolia Jack)

2019 ◽  
Vol 19 (1) ◽  
pp. 69
Author(s):  
Abdul Kholik
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Standard Error ◽  
Body Weight Gain ◽  
Growth Curves ◽  
Gompertz Model ◽  
Mathematic Model ◽  
Growth Curve Model ◽  
Curve Model ◽  
Scatter Plots

AbstractChicken growth will be showing a curve with certain mathematic model. The aim of this research was to predict growth curve model of kampung super garut chicken Fed With Pasak Bumi Meal (Euricoma longifolia Jack). This research used descriptive eksperimental method with 100, divided in five groups. Every groups fed with Pasak Bumi Meal in five categories is R0 (0%), R1 (0,025%), R2 (0,050%), R3 (0,075%) and R4 (0,100%). Chickens reared for 12 weeks, the collected data is body weight and body weight gain. Scatter plots data is used for estimated determination coefficient (R2), correlation coefficient (r), and standard error (SE). The results showed that; (1) addition of pasak bumi flour in ration at level 0,075% in ration resulted growth performance optimal; (2) The Gompertz model with the formula of  Y = 1965.2 exp (-3.7890e-0.1456t ) was the best model with coefficient determination (R2) of 99.94%, coefficient of correlation (r) of 99.97%, and standard error (SE) of 16.01%. (3) growth rate until 12 weeks ages still increase.

scholarly journals ANÁLISE DA CURVA DE CRESCIMENTO DA CIRCUNFERÊNCIA ESCROTAL DE TOUROS DA RAÇA CANCHIM E DO GRUPO GENÉTICO MA

2003 ◽  
Vol 8 (1) ◽  
Author(s):  
L. MARTÍN NIETO ◽  
L.O.C. SILVA ◽  
A.N. ROSA ◽  
A. GONDO
Keyword(s):  
Logistic Model ◽  
Linear Models ◽  
Growth Curves ◽  
Gompertz Model ◽  
Genetic Group ◽  
Scrotal Circumference

O objetivo deste trabalho foi ajustar diferentes curvas de crescimento para circunferência escrotal (CE) em função da idade, em touros da raça Canchim e do grupo genético MA mediante a utilização de modelos não lineares. Na análise foram empregadas 27.363 medidas da circunferência escrotal, provenientes de 5.520 touros da Raça Canchim e, 8.892 medidas de circunferência escrotal oriundas de 1.450 touros do grupo genético MA. Os resultados obtidos demonstram que o modelo Gompertz foi o que melhor descreveu o crescimento da CE nos touros da raça Canchim e o Logístico foi o mais adequado para descrever o crescimento da CE no grupo genético MA. O modelo Brody apresentou pouca utilidade no ajustamento da CE em função da idade. Growth curves of Scrotal circunference in Canchim and MA bulls Abstract The objective of this study was to adjust different growth curves of scrotal circumference (SC) by age. The data consisted of records on Canchim bulls and bulls of the MA genetic group wich were fit by no linear models. Were considered 27.363 measures on 5.520 Canchim bulls and 8.892 measures on 1.450 bulls of the MA genetic group. The results showed that the Gompertz model was the best to describe the growth of SC in the Canchim bulls and the Logistic model was the most appropriate to describe the growth of SC in the MA genetic group. The Brody model presented little usefulness in the adjustment of SC by age.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Genotoxicity Screening of Leachates from Solid Industrial Wastes Evaluated with the Allium Test

1997 ◽  
Vol 25 (3) ◽  
pp. 311-321 ◽  
Author(s):  
Peter G. Odeigah ◽  
Jide Ijimakinwa ◽  
Bimbo Lawal ◽  
Rebecca Oyeniyi
Keyword(s):  
Steel Slag ◽  
Settling Tank ◽  
Growth Curves ◽  
Solid Wastes ◽  
Industrial Wastes ◽  
Allium Test ◽  
Chemical Company ◽  
The Mean ◽  
Paint Sludge ◽  
Toxic Industrial Waste

Six solid wastes from the metal industry, from the chemical industry and from the production of pesticides were investigated for their toxic and genotoxic properties by using the Allium test. To simulate environmental conditions and better assess their environmental impact, the solid wastes were leached with water, and the water-extractable micropollutants were lyophilised before screening. The mean root lengths of onions exposed to different concentrations of the leachates were measured, and EC50 values were determined from the growth curves. The EC50 values of the wastes were ranked, in the order: organochlorine pesticide waste, settling tank sludge from a chemical company, paint sludge, lead slag, steel slag and aluminium slag. The leachates were also mitodepressive, and caused significant increases in the frequency of chromosome aberrations. These results demonstrate that the Allium test is a useful screening test for the evaluation and ranking of toxic industrial waste.

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