Tissue and (or) chemical body composition was determined in 18 Svalbard reindeer, aged [Formula: see text] months prepartum to [Formula: see text] years, and in mainland Norway reindeer, aged [Formula: see text] months prepartum to [Formula: see text] years. At the end of the growing season, the fat content in the ingesta-free body was very high (27–40%) in Svalbard reindeer. Two mainland yearling males had 4.5% body fat as compared with 27.8% in a Svalbard male yearling. At the end of winter the weight decrease of Svalbard reindeer was close to 50%. The loss of ash, protein, water, and fat from the body was estimated at 16.8, 30.9, 34.3, and 76.3%, respectively. Animals that had starved to death showed an additional weight loss of 8% and a nearly complete loss of fat. Liver content of Fe increased from 97 mg/kg in late summer to 3463 mg/kg in late winter and 5075 mg/kg in animals that had starved to death. There were significant linear relationships between the percent water and percent fat in the ingesta-free body and between the weight of the fat-free and ingesta-free body and the weight of its components, namely water, protein, and ash.

Suboptimal performance of bone densitometer, operator and/or subject may cause artifacts of consequence both for individual patient management and research. The prevalence and effects of such artifacts are largely unknown in densitometry. A cross-sectional population-based study was carried out of artifacts in forearm bone densitometry with single X-ray Absorptiometry (SXA) of the nondominant hand (distal and ultradistal site). After the screening, all scans were reviewed for artifact detection and reanalysis. The effect on the bone mineral density (BMD) result was found by comparing artifactual scans with a reanalyzed version or with normal repeat scans. All women aged 50-74 years, all men aged 55-74 years and 5-10% samples of other age groups aged >/=25 years attending the fourth Tromso health study were invited to have bone densitometry. The response rate from the background population was 80% (n = 7948). Fourteen percent of subjects had a movement artifact at either the distal or ultradistal site. The individual BMD variation was twice as large in scans with a movement artifact (0.94%) compared with normal scans (0.58%) (p = 0.0027). The radial endplate was inaccurately detected in 74% of the scans. Reanalysis of these scans led to a mean 3.8% decrease in the BMD value and an increase in the prevalence of osteoporosis of 10%. Artifacts were thus common, and their effects were clinically relevant in forearm bone densitometry. Artifacts and their effects need to be characterized in other bone densitometry settings also.

Seasonal changes in serum levels of growth hormone, cortisol and thyroxine in calves and adult Spitzbergen reindeer (Rangifer tarandus platyrynchus) were measured and compared to those previously found in Norwegian reindeer (R.t. tarandus). Cortisol did not differ significantly between summer and winter, or between the subspecies. Growth hormone and thyroxine exhibited highly significant seasonal changes and subspecific differences: winter levels of growth hormone were much higher than summer levels in the Spitzbergen reindeer, while Norwegian reindeer differed very little from season to season. Both Spitzbergen and Norwegian reindeer had markedly reduced thyroxine levels during winter, but the values from the former were much lower than those from the latter. In summer, however, the levels were equal. The high levels of growth hormone and low levels of thyroxine in the Spitzbergen reindeer during winter are indicative of high lipolytic activity and a reduced metabolic rate, respectively.

No abstract

1981. Body growth and carcass composition of lean reindeer (Rangifer tarandus tarandus L.) from birth to sexual maturity. Can. J. Zool. 59: 1040-1044.Body growth and carcass composition were measured in lean reindeer during the juvenile growth period between birth and 3 years of age. Mean carcass weight in these lean reindeer was 56 2 4% of body weight and the deposition of body muscle and bone mass was linearly correlated with body weight after the 1st month of age. The weight of the brain relative to body weight and carcass weight declined, while the relative changes in heart, liver, kidneys, parotid glands, and tissues of the gastrointestinal tract were small after the neonatal period. The extractable fat content in carcasses increased from 4.4 to 11.4% of wet weight or approximately 100 g fat at birth and 3.5 kg fat in adult reindeer. Fat-free dry matter represented a constant percentage (18-20%) of wet carcass weight independent of body weight after the neonatal period, while a significant inverse relationship between carcass fat and body water was found. RINGBERG, T. M., R. G. WHITE, D. F. HOLLEMAN et J. R. LIJICK. 1981. Body growth and carcass composition of lean reindeer (Rangifer tarandus tarandus L.) from birth to sexual maturity. Can. J. Zool. 59: 1040-1044.La croissance totale et la composition de la carcasse ont fait I'objet d'une analyse chez le renne maigre durant la $node de croissance, de la naissance jusqu'a 1'Lge de 3 ans. La masse moyenne de la carcasse chez ces rennes reprtsente 56 4% de la masse totale et l'addition de muscles et d'os suit une relation lintaire avec la rnasse totale aprks le le mois de vie. La masse du cerveau par rapport aux masses du corps et de la carcasse subit un dtclin, alors que les changements relatifs du coeur, du foie, des reins, des parotides et des tissus du systkme gastrointestinal sont faibles aprks la ptriode nkonatale. Le contenu en graisses extraites des carcasses augmente de 4,4 A 11,4% de la masse a l'ktat frais, ou d'environ 100 g de graisses a la naissance, a 3,s kg chez l'adulte. La matikre 3 c h e sans les graisses reprtsente un pourcentage constant (18-20%) de la masse de la carcasse a l'ktat frais, quelle que soit cette masse aprks la ptriode nkonatale; il y a, par contre, une relation inverse entre le contenu lipidique de la carcasse et le contenu hydrique du corps.[Traduit par le journal] IntroductionMaterials and methods Reindeer and caribou (Rangifer tarandus L.) populate the northernmost habitat of the cervidae family and show alterations in body weight and skeletal growth rate synchronous with the marked seasonal changes in their environmental conditions (Kelsall 1968; Dauphin6 1976;Thomas and Broughton 1978). Assessment of the purely age-related growth rate in these animals tends to be complicated by these alterations in body weight. Such data are important when the impact of environmental factors upon body condition is evaluated, and as background data for studies on seasonal changes in the metabolic and endocrinological status of these anim...