scholarly journals TIME RELATIONS OF GROWTH

1927 ◽  
Vol 10 (5) ◽  
pp. 637-658 ◽  
Author(s):  
Samuel Brody
Keyword(s):  
Body Weight ◽  
Growth Curve ◽  
Growth Curves ◽  
The Body ◽  
Time Rate ◽  
Instantaneous Rate ◽  
Rate Of Growth ◽  
Constant Percentage

Growth curves consist, in all cases, of two major segments. The first major segment is, in the case of higher animals and plants, made up in turn of several (probably five) shorter segments during each of which growth takes place at a constant percentage rate. The transitions between the successive stages are abrupt, the abruptness being of the order of metamorphosis in cold blooded animals. It has been made clear in the first paper of this series that the time rate of growth following the major inflection declines at a constant percentage rate. The junction between the two major segments occurs at puberty in animals and flowering in plants. The two major segments are not symmetrical about the major inflection. The slope of the segment following the inflection is always less than the slope of the segment preceding the inflection. The major inflection does not occur in the center of the growth curve. The instantaneous rate of growth at the beginning of growth is of the order of 100–200 per cent per day (i.e. the body weight is doubled in from 7 to 17 hours). It may be mentioned that 2 months after conception the rate of growth in man is only 8 per cent per day. This is contrary to all the published statements. Thus, Minot concluded that growth begins at 1000 per cent per day; Jackson concluded that in man, growth during the 1st month takes place at 57.5 million per cent per month; during the 2nd month 990 per cent per month; during the 3rd month 390 per cent per month (8 per cent per day is only 240 per cent per month). The reason for the discrepancy between the values derived, by the method adopted by the writer, and the values given in the literature is explained by Fig. 1.

Effects of some factors on growth of lambs and the determination of growth curve models

2018 ◽  
Author(s):  
Ayhan Yilmaz ◽  
Ferda Karakus ◽  
Mehmet Bingöl ◽  
Baris Kaki ◽  
Gazel Ser
Keyword(s):  
Body Weight ◽  
Growth Curve ◽  
Growth Models ◽  
Age Groups ◽  
Growth Curves ◽  
The Body ◽  
Least Square ◽  
Coefficient Of Determination ◽  
Male And Female ◽  
Growth Curve Models

he aims were to identify the body weight of the several age groups in Norduz lambs and its correlations between these traits were to determine the best non-linear growth curve models for the growth performance of the Norduz sheep breed. A total of 91 male and female of Norduz lambs were evaluated under extensive system conditions. The least square means for weights at birth and at 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195 and 210 days of age periods were 4.51±0.56, 9.28±0.25, 11.14±0.29, 14.99±0.37, 18.21±0.43, 22.54±0.54, 22.33±0.25, 23.59±0.54, 25.58±0.55, 28.07±0.58, 29.45±0.60, 29.98±0.84, 32.44±0.61, 32.03±0.59 and 31.45±0.57 kg, respectively. There were differences in favor of lambs of four-year old dams at 15 days of age and also lambs born single at 90 days of age for the body weight. The effect of weight of dam at birth, 30, 45, 60 days of age was significant (P less than 0.05-P less than 0.01) and the birth weight in lambs importantly effected the weights at 15, 30, and 45 days of age. All correlations between the body weights of several age periods were significant as statistical (P less than 0.01). As for the growth models, distinguished models were compared using the coefficient of determination and mean square error for both sexes. As a result, we concluded that von Bertalanffy model were the best model in comparison with the other models for biological growth curves in Norduz male and female lambs.

Factors governing the shape of the growth curve of body weight and the age at slaughter of Suffolk × Welsh lambs

1966 ◽  
Vol 8 (3) ◽  
pp. 435-444 ◽  
Author(s):  
J. S. Broadbent ◽  
J. H. Watson
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Growth Curve ◽  
Compensatory Growth ◽  
Marked Effect ◽  
Growth Curves ◽  
Live Weight ◽  
Linear Component ◽  
Slaughter Weight ◽  
Birth Type

Curves of growth in live-weight, from birth to 16 weeks of age, of 362 Suffolk × Welsh lambs were analysed for the effect of sex, birth type, sire and test centre environment and related to variation in age at slaughter.The relative pre-natal disadvantages of twin lambs resulted in their curves of growth differing from those of single-born animals, particularly in males. Test centre environment exerted a marked effect in such cases. At one centre, male twins showed marked compensatory growth.Differences in growth existed between the 14 sire progeny groups. As the linear component of the growth curves decreased, the quadratic values became increasingly negative. Deceleration of growth was most marked in slowest growing progeny groups and this was accentuated by a poor test centre environment.These factors combined to influence age at slaughter, which was also related to birth weight of the lamb. Lambs at the best test centre reached slaughter weight 10 and 16 days earlier than lambs at the two remaining centres. Sires produced differences in age at slaughter of 10 to 14 days, within centres.

Growth modeling of dairy heifers in Québec based on random regression

2012 ◽  
Vol 92 (1) ◽  
pp. 33-47 ◽  
Author(s):  
R. I. Cue ◽  
D. Pietersma ◽  
D. Lefebvre ◽  
R. Lacroix ◽  
K. Wade ◽  
...  
Keyword(s):  
Body Weight ◽  
Growth Curve ◽  
Growth Modeling ◽  
The Body ◽  
Random Regression ◽  
Individual Growth ◽  
Residual Variance ◽  
Brown Swiss ◽  
Dairy Heifers ◽  
Height Data

Cue, R. I., Pietersma, D., Lefebvre, D., Lacroix, R., Wade, K., Pellerin, D., de Passillé, A-M. and Rushen, J. 2012. Growth modeling of dairy heifers in Québec based on random regression. Can. J. Anim. Sci. 92: 33–47. A total of 144 006 weight (calculated from tape girth measurements) and height data records from Québec dairy heifers were analyzed using random regression to estimate growth curve parameters of Ayrshires, Brown Swiss and Holstein animals to permit prediction of individual heifer growth from 0 to 32 mo. There were, on average, 5.15 records per heifer (minimum 3 records, maximum 25 records). The body weight data were analyzed using linear and quadratic fixed and random regressions, with a power-of-the-mean (POM) function to model the residual variance. The POM was 1.2 for Holstein and Ayrshire and slightly less than 1 for Brown Swiss. Estimated body weight at 24 mo was 507, 564, 624 kg, for Ayrshires, Brown Swiss and Holstein, respectively. The height data were analyzed with a Brody, monomolecular non-linear growth curve model. Mature height was estimated to be 148 cm in both Holstein and Ayrshires, and 150 cm in Brown Swiss. Random regression models were shown to be able to predict individual growth, and can be incorporated in decision-support tools to help producers reducing the average age at first calving.

BODY TEMPERATURE AFFECTS THE SHAPE OF AVIAN GROWTH CURVES

1993 ◽  
Vol 01 (04) ◽  
pp. 363-374 ◽  
Author(s):  
C. ZONNEVELD ◽  
S.A.L.M. KOOIJMAN
Keyword(s):  
Body Temperature ◽  
Growth Curve ◽  
Time Course ◽  
Growth Curves ◽  
The Body ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Gradual Development ◽  
Mathematical Equations ◽  
Von Bertalanffy Growth Equation

Growth of birds is described by a variety of mathematical equations. These equations generally lack a biological motivation. As a result, it remains unclear why growth in different species should be described by different equations. In this article, we argue that the gradual development of endothermy affects the growth of birds. Hence, differences in the growth curve may result from differences in the thermal ontogeny. We assume that birds would grow according to the von Bertalanffy growth equation, if their temperature were constant. Using the deviations from this growth curve, we reconstruct the time course of the temperature of growing birds. This reconstruction well describes data on the ontogeny of the body temperature in birds.

Growth-Rates of the Bandicoot Isoodon-Macrourus and the Brushtail Possum Trichosurus-Vulpecula

1993 ◽  
Vol 41 (2) ◽  
pp. 141 ◽  
Author(s):  
RT Gemmell ◽  
JK Hendrikz
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Growth Curve ◽  
Growth Rates ◽  
Post Partum ◽  
Quadratic Equation ◽  
The Body ◽  
Brushtail Possum ◽  
Trichosurus Vulpecula ◽  
Iterative Analysis

Although the bandicoot Isoodon macrourus and the brushtail possum Trichosurus vulpecula give birth to similar-size young, about 200 mg, the pouch young of the bandicoot grow more quickly than those of the possum. The bandicoot is weaned at 59 days when the body weight is between 90 and 250 g. A young possum weighs about 20 g at Day 60 and between 780 and 1031 g when weaned at Day 170-180 post partum. The body weight of both species has been described previously as a continuous curve expressed by a quadratic equation. In this study, instead of assuming the growth curve to be continuous, the growth curve has been expressed as two components. The growth rates of both species were similar from birth until Day 12 post partum; the bandicoot then had a faster growth rate. The results from iterative analysis indicated a change in growth rate at Day 30 (data for Days 31 and 32 were missing) and Day 96 post partum for the bandicoot and possum, respectively. Thus, both marsupials showed a change in growth rate as hair appeared, eyes opened and the young first left the pouch.

scholarly journals ORGAN WORK AND ORGAN WEIGHT

1939 ◽  
Vol 69 (3) ◽  
pp. 467-483 ◽  
Author(s):  
Florence Walter ◽  
T. Addis
Keyword(s):  
Body Weight ◽  
Organ Weight ◽  
The Body ◽  
Heart Weight ◽  
Albino Rats ◽  
Liver Protein ◽  
Kidney Weight ◽  
Albino Rat ◽  
Liver Size ◽  
Rate Of Growth

1. The ratios between the rates of growth of the body and of the heart, kidneys, and liver are approximately uniform between 40 gm. body weight and the body weight at maturity in the albino rat. The male and female hearts grow at 0.75 times the rate of growth of the body, the male kidneys at 0.717 times, the female kidneys at 0.648 times, and the liver at 0.838 times the rate of growth of the body as a whole. 2. Formulas for the prediction of organ weight from body weight were derived from the data on 1591 albino rats kept under constant conditions. 3. A series of experiments in which dietetic and metabolic variables were introduced into otherwise constant conditions showed that the heart weight was not affected by diet, and that both kidney weight and weight of liver protein (used as a measure of effective liver size) varied in the direction of change in the protein content of the diet. Decrease in rate of metabolism induced by thyroidectomy and increase in metabolism following the administration of thyroxin led to a corresponding fall and rise of heart, kidney, and liver protein weight. These results were confirmed in experiments on fasted rats with the exception that under these conditions thyroidectomy did not appreciably decrease liver protein weight relatively to fasted controls. Increase in organ metabolism due to dinitrophenol had no effect on organ weight. 4. When experimental changes alter the composition of the body with respect to fat or water, the comparison of experimental and control organ weights in terms of any one function of body weight is fallacious. 5. Conditions that change kidney weight usually change liver protein weight in the same direction and roughly to the same degree. The possible meaning of two exceptions to this rule is discussed. 6. The observations made are regarded as supporting the hypothesis that, after weaning, change in the weight of the heart, kidney, and liver protein is determined mainly by change in the amount of work done by these organs.

Body composition of British and zebu × British cattle in northern Australia 1. Breed and growth rate effects on yield of carcass, dressed carcass composition and offal composition

1984 ◽  
Vol 39 (2) ◽  
pp. 177-193 ◽  
Author(s):  
R. M. Seebeck
Keyword(s):  
Growth Rate ◽  
Body Composition ◽  
Body Weight ◽  
Abdominal Fat ◽  
Lower Proportion ◽  
Carcass Composition ◽  
The Body ◽  
Carcass Yield ◽  
Rate Of Growth ◽  
Rate Effects

ABSTRACTComparative slaughter was used to assess the body composition of Shorthorn-Hereford (SH), Africander cross (A×), Brahman cross (B×), and late castrated Brahman cross (B×(late)) steers of the F, generation with respect to their yield of carcass, gross carcass composition and offal composition. Animals were slaughtered at pre-determined weights of 315, 355, 399, 449 and 505 kg.The B× animals had the highest carcass yield (expressed either as dressed carcass weight at the same fasted body weight or at the same empty body weight), while the A×, B×(late) and SH animals had similar carcass yield. Within a breed, rate of growth affected carcass yield, with faster growing animals having the lower carcass yield, particularly with respect to fasted body weight.The breeds were different in carcass composition but this was dependent on both size and growth rate. Brahman cross animals had a lower proportion of bone than A× and SH animals, particularly at the higher body weights. Faster growing animals tended to contain more muscle and bone and less fat, with the exception of the SH animals.The breeds were also significantly different in the composition of the offal components. A× were notable for high head weights and low tail weights, B× having high blood weights and low total gut tissue weights, and Bx(late) having high hide weights and low abdominal fat weights.Rate of growth had some effect on offal composition, the general trend being that the faster growing animals were characterized by a lower proportion of heart, blood and pancreas. However there was also evidence that the rate of growth differentially affected the offal composition with respect to breeds. This effect mainly arose because the faster growing B×(late) animals had lower weights of abdominal fat. Within the other breeds, the opposite trend was observed.

Growth curve models for commercial pullets under severe heat stress condition

2009 ◽  
Vol 2009 ◽  
pp. 234-234
Author(s):  
J Fayazi ◽  
M R Ghorbani ◽  
M Nazari ◽  
J Momeni ◽  
A Jaferian ◽  
...  
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Heat Stress ◽  
Growth Curve ◽  
Egg Production ◽  
Harmful Effect ◽  
The Body ◽  
Basic Knowledge ◽  
Growing Period ◽  
Severe Heat Stress

The objectives of our study were to propose a growth curve and to develop a mathematical model to describe the body weight of pullet experiencing severe heat stress (42°C). Poultry producers who raise their own replacement pullets can control their pullet’s growth, condition and development. Many of the problems which occur during the early part of lay can be traced back to insufficient or improper type of body weight attained during the various stages of the growing period. In order to avoid these problems, the body weight of pullets must be controlled. Rearing conditions for pullets vary depending on environmental pressures and can affect growth rate. Without the basic knowledge of the flock grow-out, it is virtually impossible to understand and possibly solve problems which may later occur during the laying period. It must be kept in mind that once egg production begins, it is too late to solve problems resulting from growing period. The two most important criteria of pullet quality are uniformity within the flock and proper body weight at a specific age. Almost anything that adversely affects a pullet will usually be reflected in lower body weights and poorer flock uniformity. High ambient temperatures can be devastating to commercial pullet growth rate; coupled with high humidity they can have an even more harmful effect on proper and recommended body weight. Heat stress interferes with the poultry comfort and suppresses performance efficiency. In order to verify the effect of heat stress on pullet growth rate, many curve modelled, fitted and verified to proposed best one.

scholarly journals Evaluation of Growth Curve Models for Body Weight in American Mink

Animals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 22
Author(s):  
Duy Ngoc Do ◽  
Younes Miar
Keyword(s):  
Body Weight ◽  
Growth Curve ◽  
Model Comparison ◽  
American Mink ◽  
Growth Curves ◽  
Information Criterion ◽  
Selection Response ◽  
Growth Curve Models ◽  
Body Weights ◽  
Males And Females

Modelling the growth curves of animals is important for optimizing the management and efficiency of animal production; however, little is known about the growth curves in American mink (Neovison vison). The study evaluated the performances of four three-parameter (Logistic, Gompertz, von Bertalanffy, and Brody), four four-parameter (Richards, Weibull, Bridges, and Janoscheck) and two polynomial models for describing the growth curves in mink. Body weights were collected from the third week of life to the week 31 in 738 black mink (373 males and 365 females). Models were fitted using the nls and nlsLM functions in stats and minpack.lm packages in R software, respectively. The Akaike’s information criterion (AIC) and Bayesian information criterion (BIC) were used for model comparison. Based on these criteria, Logistic and Richards were the best models for males and females, respectively. Four-parameter models had better performance compared to the other models except for Logistic model. The estimated maximum weight and mature growth rate varied among the models and differed between males and females. The results indicated that males and females had different growth curves as males grew faster and reached to the maximum body weight later compared to females. Further studies on genetic parameters and selection response for growth curve parameters are required for development of selection programs based on the shape of growth curves in mink.

scholarly journals PECULIARITIES OF THE PHYSICAL DEVELOPMENT OF URBAN AND RURAL SCHOOLCHILDREN OF THE IRKUTSK REGION

2018 ◽  
Vol 97 (10) ◽  
pp. 957-961 ◽  
Author(s):  
Inna V. Mylnikova ◽  
N. V. Efimova ◽  
E. A. Tkachuk
Keyword(s):  
Body Weight ◽  
Body Length ◽  
Age Groups ◽  
Large Body ◽  
Growth Curves ◽  
Physical Development ◽  
The Body ◽  
Irkutsk Region ◽  
Development Processes ◽  
Total Body

Introduction. Physical development is one of the informative indices characterizing the health of the child population and reflecting the adverse effects of various environmental factors. Aim. To carry out a comparative assessment of physical development indices both in urban and rural schoolchildren in the Irkutsk region. Material and methods. The total body dimensions were studied. Results. Urban schoolchildren differ from rural peers in large body length indices (p = 0.000) and smaller values of the circumference of the chest (p = 0.002). The body weight of urban and rural boys had similar values, except for the age groups 9 (p=0,000), 12 (p=0,000) and 16 years (p=0,005). Rural schoolgirls outpaced urban peers by their body weight (р=0,016). Some differences from general patterns characteristic for the given period of ontogenesis are revealed: in rural schoolchildren, three crosses of growth curves are established. Correlation ratio of body length indices with other total sizes showed schoolchildren to have signs of desynchronization of physical development processes in different age periods. Discussion. The materials of the study indicate the processes of formation of total body size of rural and urban schoolchildren to differ. An assessment of the correlation ratios of body length parameters with other total sizes showed schoolchildren in different age periods to show signs of desynchronization of physical development processes.

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