Influence of gender, breed and age on maturity characteristics of sheep.
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Fifty-one ewes, 50 wethers and 51 rams of Finn x whiteface or Suffolk x whiteface breeding were slaughtered at an average age of 271, 361, 459, 557 or 652 d to study changes in maturity characteristics with changes in age. When metacarpal epiphyseal cartilage (growth plates) ossifies with age, break joints on the distal end of the metacarpals fuse and the end of the bone then appears as a spool joint rather than as a break joint. This fusion occurs earlier chronologically in ewes than in rams or wethers. Most Finn x whiteface-cross ewes, which normally reach reproductive maturity earlier than Suffolk x whiteface-cross ewes, exhibited ossified metacarpal growth plates by 459 d of age; break joints of Suffolk x whiteface crosses were not fused until 557 d of age. Both breed groups of rams exhibited fused joints by 557 d of age, but only 3 of 10 wethers exhibited spool joints at 652 d of age. Microscopic examination showed that even in these three wethers the epiphyseal growth plate could still be detected. Yearling 2-yr-old classifications of sheep from teeth were not gender-dependent within the discrete age classes of this study. About half the sheep in each gender group were classified as yearlings at 459 d of age and about half in each group were classified as 2-yr-olds by 652 d of age. Stepwise multiple regression equations to estimate age of sheep in days were developed. Overall maturity, lean color and texture and rib bone maturity were the best carcass measures of maturity. Maturity scores for characteristics of the break joint did not enter any of the equations studied. When eye lens weight was included in equations with the best measures of carcass maturity, accuracy of estimates for age of sheep was improved. (+info)
Research in forensic odontology.
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Forensic odontology has established itself as an important and often indispensable science in medicolegal matters and in particular in identification of the dead. Much of its expertise is drawn from clinical experience based on basic research and advances in knowledge in dentistry in general. There has also been, particularly during the past two decades, an increasing body of research in specifically forensic dental matters and these studies form the subject of this review. Progress in this field, as in others, will depend upon development of training pathways and research facilities in our dental schools. (+info)
Differential growth and maturation in idiopathic growth-hormone-deficient children.
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This study describes and compares the growth and maturation of idiopathic growth hormone deficiency (IGHD) and evaluates the potential effects of growth hormone therapy. The sample includes 40 idiopathic growth-hormone-deficient children grouped according to duration of growth hormone replacement therapy. Somatic and craniofacial development, skeletal maturation and dental maturation were evaluated and compared. The results showed consistent delays in the maturity indices for IGHD children. Height age displayed the greatest delay (3 years) followed by skeletal age (2.2 years) and dental age (0.8 years). Overall craniofacial growth deficiencies were also demonstrated. Anterior cranial base and mandibular length were most affected; posterior cranial base length and facial heights were least affected. Analysis of covariance, controlling for the starting age of therapy, showed significant differences between children grouped according to duration of growth hormone therapy. Catch-up growth with hormonal therapy was established for height, facial height, skeletal age and posterior cranial base length. It was concluded that the various craniofacial skeletal components have different potentials for growth retardation with IGHD; catch-up growth following growth hormone replacement therapy was greatest for the components with the greatest initial (or baseline) growth potential. (+info)
Acceleration in dental development: fact or fiction.
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The aim of this investigation was to determine whether an actual acceleration in dental development has taken place over the last 30 years in a European population group, as is so readily observable in relation to body height. In this study, radiographs of 1038 healthy European children, 516 boys and 522 girls, were evaluated. The methodology and norms given by Nolla (1960) for both sexes were used and compared with the tooth developmental stages in our subjects. In girls, no difference to Nolla's norms could be detected. However, in boys, dental development has accelerated. This difference was most apparent in the 3- to 9-year-old age group and was statistically significant. Thus, over the last 30 years, a small acceleration in dental development has taken place in very young males. (+info)
An osteometrical study of the cranium and mandible of the lesser mouse deer (Chevrotain), Tragulus javanicus.
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The lesser mouse deer (Tragulus javanicus) is one of the most primitive ruminants. Skulls of lesser mouse deer were measured to evaluate their growth. The age was estimated from the eruption and attrition of molars on the mandible. A total of 95 specimens was divided into five age groups, and the growth pattern in each sex was established for some measurements. The relative growth coefficients were calculated for the head and body length and several parts of the cranium and mandible against the profile length. Sexual dimorphism could not be found on the skull in any age group except for measurements related to the upper canine. However, females showed a higher value in head and body length in the oldest group. This feature was consistent with an interpretation of mouse deer society as monogamous. Growth was more rapid in length than in width. Various statistical analyses showed that the visceral cranium related to masticatory facility was much better developed than the neurocranium. However, observations on the shape of the mandible ramus and of the premolars implied that the masticatory function was not suitable for taking roughage. This speculation agreed with previous reports on the feeding habits and digestive organs of the mouse deer. (+info)