Age Determination in the Dingo and Crossbreeds.

Growth curves were derived for captive known-age dingoes, Canis familiaris dingo, and their crosses with similarly sized domestic dogs, C. f. familiaris. Regular body measurements including weight and dried eye-lens weights were used. Age calibration curves and confidence limits were then produced to enable age estimation of animals of unknown birth date. Head length was the better predictor of age up to about 120 days, and eye-lens weight to about 500 days. The only difference in growth patterns in dingoes and crossbreeds from central and southern Australia was between sexes.

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Growth of Grey Kangaroos and the Reliability of Age Determination from Body Measurements II.* The Western Grey Kangaroos, Macropus fuliginosus fuliginosus, M. f. melanops and M. f. ocydromus

Wildlife Research ◽

10.1071/wr9820203 ◽

1982 ◽

Vol 9 (2) ◽

pp. 203 ◽

Cited By ~ 18

Author(s):

WE Poole ◽

SM Carpenter ◽

JT Wood

Keyword(s):

Growth Curve ◽

Young Animal ◽

Age Determination ◽

Growth Curves ◽

Birth Date ◽

First Year ◽

Body Measurements ◽

Grey Kangaroo ◽

Pass Through

Seven body measurements were taken at regular intervals throughout life from both male and female western grey kangaroos of known birth date. For each sex of three subspecies and for each body measurement a growth curve was fitted, and confidence intervals calculated for determining the age of new animals. As with eastern grey kangaroos, a phase change in the growth curve was apparent at the time when the young vacate the pouch. Join points in the curve for each subspecies of western grey kangaroos were estimated empirically, as three-quarters through the interval between first emergence and final vacation of the pouch by a young animal. The growth curves were represented by a four-parameter non-linear model consisting of two hyperbolas constrained to pass through the common point. Tables presented contrast the ages at which percentile growth values are attained for each subspecies, and also provide examples of the determination of age from body measurements for both males and females, at monthly intervals during their first year. As found for the eastern grey kangaroo, head length proved to be the most reliable criterion, and all measurements of animals older than 2 years were unreliable for age determination.

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Growth of Grey Kangaroos and the Reliablility of Age Determination from Body Measurements III. Interspecific Comparisions between Eastern and Western Grey Kangaroos, Macropus giganteus and M. fuliginosus

Wildlife Research ◽

10.1071/wr9840011 ◽

1984 ◽

Vol 11 (1) ◽

pp. 11 ◽

Cited By ~ 6

Author(s):

WE Poole ◽

SM Carpenter ◽

JT Wood

Keyword(s):

Growth Models ◽

Age Determination ◽

Growth Patterns ◽

Adult Size ◽

Body Measurements ◽

Foot Length ◽

The Common ◽

Rates Of Growth ◽

Body Parameters

Seven body measurements were taken at regular intervals throughout life from both male and female eastern and western grey kangaroos. Evaluation of the reliability of criteria for determination of age and some aspects of the growth models for the two species were presented in earlier papers in this series. In this paper the common patterns and relationships between species in the growth characteristics of their body parameters are described and analysed. Comparison is made between species and sexes of rates of growth and size attained both within the pouch and following vacation of the pouch. Head, arm, leg and foot length were important discriminators, particularly when contrasted in various ways to summarize different body proportions. The insular form M.f. fuliginosus readily separated from the mainland forms, and M.f. ocydromus showed some differences which were related to its longer pouch life. Hybrid animals showed growth patterns intermediate to those of their parents. Sexual dimorphism in patterns ofgrowth was not detected during pouch life but was exhibited by all species after the young vacated the pouch and grew towards their full adult size.

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Reproduction of the whiptail wallaby, Macropus parryi Bennett (Marsupialia : Macropodidae), in captivity with age estimation of the pouch-young

Wildlife Research ◽

10.1071/wr97128 ◽

1998 ◽

Vol 25 (6) ◽

pp. 635 ◽

Cited By ~ 1

Author(s):

P. M. Johnson

Keyword(s):

Age Estimation ◽

Sexual Maturity ◽

Post Partum ◽

Age Determination ◽

Oestrous Cycle ◽

Gestation Period ◽

Body Measurements ◽

In Captivity ◽

The Mean

Reproduction of the whiptail wallaby, Macropus parryi, was studied in captivity. The mean length of the oestrous cycle was 41.8 days while the mean length of the gestation period was 38.0 days. M. parryi bred throughout the year and post-partum oestrus was not recorded although mating did occur during the pouch life when the pouch-young was 118–168 days of age. The length of the pouch-life was 256–267 days and weaning occurred 104–215 days after emergence from the pouch. Sexual maturity for females occurred at 509–647 days of age. An age-determination table was produced and found useful for predicting age of pouch-young using body measurements.

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Age, growth, maturity, longevity and natural mortality of the shortfin mako shark (Isurus oxyrinchus) in New Zealand waters

Marine and Freshwater Research ◽

10.1071/mf05077 ◽

2006 ◽

Vol 57 (2) ◽

pp. 143 ◽

Cited By ~ 60

Author(s):

S. D. H. Bishop ◽

M. P. Francis ◽

C. Duffy ◽

J. C. Montgomery

Keyword(s):

Fork Length ◽

Growth Curves ◽

Growth Patterns ◽

Birth Date ◽

First Year ◽

Natural Mortality ◽

Relative Growth ◽

Mako Shark ◽

Shortfin Mako ◽

Males And Females

Shortfin mako sharks were aged by counting growth bands in sectioned vertebrae (n = 256), and assuming annual band-pair deposition. No systematic ageing bias was present and count precision was high. 0+ juveniles were identified from length–frequency plots and assigned ages based on a theoretical birth date of 1 October and their date of capture. A Schnute generalised growth model fitted to the combined vertebral and 0+ data described the growth patterns best. Shortfin makos grow very rapidly initially, increasing by ~39 cm fork length in their first year. Thereafter, males and females grow at similar but slower rates until about age 7 years, after which the relative growth of males declines. Longevity estimates were 29 and 28 years for males and females respectively. Natural mortality (M) is probably in the range of 0.10–0.15. Median ages at maturity were 7–9 years for males and 19–21 years for females. Comparisons of growth curves reported here and elsewhere suggest no regional differences in growth rates. The shortfin mako is a late-maturing species with moderate longevity and low natural mortality. With these life history characteristics and an unknown stock size and structure worldwide, management should be of a precautionary nature.

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Identical twins and developmental stability

Animal Science ◽

10.1017/s0003356100034474 ◽

1962 ◽

Vol 4 (1) ◽

pp. 144-164 ◽

Cited By ~ 12

Author(s):

C. S. Taylor

Keyword(s):

Growth Curves ◽

Identical Twins ◽

Body Measurements ◽

Frequency Distributions ◽

Stability Of Development ◽

Mean Size ◽

Degree Of Maturity ◽

The Stability ◽

Average Size ◽

Slow Growing

1. The stability with which dairy cattle develop in body size up to 2 years of age was studied in 60 pairs of uniformly treated identical twins, i.e. an assessment was made of the influence of season, genotype, mean size of twin pair, age and degree of maturity on the level of within-pair variability.2. The frequency distributions of size differences shown by one-egg twins were in many cases decidedly leptokurtic.3. The similarity in size of the identical twins studied was only slightly, if at all, influenced by season. Within-pair variability under free outdoor grazing was certainly not any greater than under semi-controlled conditions indoors.4. The stability with which cattle grew appeared to depend on their genotype. Identical twins of the Shorthorn breed were somewhat more alike in size than were the twins of other breed-types; crossbreds were, on average, 50 % less stable than purebreds in average size () ; although crossbreds grew with somewhat greater stability ().5. Whatever their mean size, all pairs of identical twins of the same breed appeared to grow postnatally with more or less equal stability (). Small, slow growing pairs showed a greater disparity in average size ().6. Stability of development continually changed with age but not violently. Each body measurement appeared to have its own characteristic age trend. It is false to believe that variation automatically increases with increasing age. As they grew older, identical twins tended to become less alike in their later maturing body measurements whereas their early maturing body measurements tended to decline in variability. There was an overall trend with degree of maturity; variability steadily increased to a maximum and subsequently declined.7. It is suggested that environmentally induced instability of development may remain at a minimum level so long as growth curves are not seriously distorted from their exponential path to maturity.

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PATTERNS OF GROWTH IN HEIGHT AND WEIGHT FROM BIRTH TO EIGHTEEN YEARS OF AGE

PEDIATRICS ◽

10.1542/peds.24.5.904 ◽

1959 ◽

Vol 24 (5) ◽

pp. 904-921

Author(s):

Robert B. Reed ◽

Harold C. Stuart

Keyword(s):

Growth Curves ◽

Growth Patterns ◽

Individual Growth ◽

Growth Spurt ◽

Adolescent Growth Spurt ◽

Wide Range ◽

Basic Facts ◽

The Individual ◽

Rates Of Growth ◽

Mature Size

In this report is displayed the range of variation observed in the growth curves of height and weight in a series of 134 children observed from birth to 18 years. For purposes of simplification the individuals have been classified on the basis of their rates of growth during three successive 6-year intervals. Even in terms of this crude classification several basic facts about individual growth patterns of height and weight are apparent. The wide range of differences between individuals applies not only to facts about size at specific ages but also to the pattern of change followed from age period to age period. The rate of growth during early childhood, i.e. before 6 years of age, is associated with, but not specifically predictive of, size at maturity and timing of the adolescent growth spurt. Individuals with rapid growth before 6 years of age tend to have large mature size and early adolescent growth spurt. It will be the objective of future reports from this research project to determine the manner in which the individual differences in growth demonstrated and classified here are related to aspects of physical development, to environmental influences such as dietary intake and to the level of health of the child.

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Mortality Estimation: Biased Results from Unbiased Ages

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f84-227 ◽

1984 ◽

Vol 41 (12) ◽

pp. 1843-1847 ◽

Cited By ~ 8

Author(s):

Jay Barlow

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

Age Estimation ◽

Age Determination ◽

Mortality Rates ◽

Age Classes ◽

Estimation Errors ◽

Mortality Estimation ◽

Age Estimates

Estimates of mortality rates from age distributions are biased by imprecision in age estimation, even if age estimates are unbiased. I have derived a method for predicting the magnitude of this bias from information on the precision of age determination. Monte Carlo simulations show that bias can be accurately predicted. The commonly used Chapman–Robson mortality estimator is shown to be robust to imprecision in age determination if all age-classes are included. Errors are likely, however, if one or more age-classes are excluded or if other mortality estimators are used. Biases can be corrected if the distribution of age-estimation errors is known.

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Radiographic pelvimetry in 0 to 24 month-old pacas (Agouti paca, Linnaeus, 1766)

Arquivo Brasileiro de Medicina Veterinária e Zootecnia ◽

10.1590/1678-4162-10060 ◽

2019 ◽

Vol 71 (4) ◽

pp. 1293-1298

Author(s):

N.F. Smargiassi ◽

I.C.C. Lippi ◽

R.G.S. Oliveira ◽

M.R.F. Machado ◽

T.H.C. Sasahara ◽

...

Keyword(s):

Age Determination ◽

Strong Tendency ◽

Birth Date ◽

Scientific Interest ◽

Closure Time ◽

Ossification Centers ◽

Constant Growth

ABSTRACT The pelvimetry consists of the metric determination of the pelvis dimensions and its use is directly related to the reproduction. The cartilage closure time of the ossification centers varies according to the bone, some closing already in the uterine life and others remaining present for many years. The objective was to evaluate, radiographically, the pelvic diameters by pelvimetry during the first 24 months of life in pacas, the second lagest Brazilian rodent and an animal that has shown big recent scientific interest, aiming the estimated age determination. Twelve pacas were used, which were monthly radiographed up from birth until 24 months old, with the animals anesthetized. The pacas are dolicopelvic animals and with pelvis presenting strong tendency to constant growth along the 12 first months of age, fact that can be useful in the approximated animals’ age determination that do not have precise birth date, for example.

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Validation of Age Estimation in the Harp Seal, Phoca groenlandica, Using Dentinal Annuli

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-165 ◽

1983 ◽

Vol 40 (9) ◽

pp. 1430-1441 ◽

Cited By ~ 65

Author(s):

W. D. Bowen ◽

D. E. Sergeant ◽

T. Øritsland

Keyword(s):

Outer Layer ◽

Age Estimation ◽

Transverse Section ◽

Age Determination ◽

Middle Layer ◽

Harp Seal ◽

Growth Layer ◽

Phoca Groenlandica ◽

Incremental Growth ◽

Absolute Age

We investigated the validity and accuracy of age estimation in harp seals, Phoca groenlandica, using a sample of 155 known-age teeth from seals age 3 mo to 10 yr. Under transmitted light, transverse sections of harp seal canine teeth showed distinct incremental growth layers (IGLs) in the dentine. The first growth-layer group (GLG), representing Ist-year growth, consists of two IGLs: an outer layer of opaque dentine, bounded by the neonatal line, and an inner layer of translucent dentine. Subsequent GLGs, each representing 1 yr of growth, generally consist of three IGLs: an outer layer of interglobular dentine deposited during the annual molt in April, a middle layer of opaque dentine formed during the northward spring migration (May–June), and an inner layer of translucent dentine formed from July to March. We show that dentinal GLGs can be used to estimate the absolute age of harp seals. The accuracy of the method decreases with age. Only 72.4% of estimates of 0-group seals were correct using only transverse sections. These errors were virtually eliminated (99.0% correct age determination) when the tooth root was examined. Based on a single examination of a transverse section, the probabilities of correctly estimating age are 0.983, 0.889, 0.817, and 0.553 at ages 1, 2, 3, and 4 + yr, respectively, when clearly inaccurate tag-tooth associations are omitted. The respective probabilities are only slightly higher when age is based on the average of five blind readings, being 1.0, 0.889, 0.833, and 0.625. Beyond age 3 yr, existing data are insufficient to estimate reliably the accuracy of age determined by counting GLGs.

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