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The transverse tensile strength of a naturally fallen red deer antler (Cervus Elaphus) was determined through indirect Brazilian tests using dry disc-shape specimens at quasi-static and high strain rates. Dynamic Brazilian tests were performed in a compression Split-Hopkinson Pressure Bar. Quasi-static tensile and indirect Brazilian tests were also performed along the osteon growth direction for comparison. The quasi-static transverse tensile strength ranged 31.5-44.5 MPa. The strength increased to 83 MPa on the average in the dynamic Brazilian tests, proving a rate sensitive transverse strength. The quasi-static tensile strength in the osteon growth direction was however found comparably higher, 192 MPa. A Weibull analysis indicated a higher tensile ductility in the osteon growth direction than in the transverse to the osteon growth direction. The microscopic analysis of the quasi-static Brazilian test specimens (tensile strain along the osteon growth direction) revealed a micro-cracking mechanism operating by the crack deflection/twisting at the lacunae in the concentric lamellae region and at the interface between concentric lamellae and interstitial lamellae. On the other side, the specimens in the transverse direction fractured in a more brittle manner by the separation/delamination of the concentric lamellae and pulling of the interstitial lamellae. The detected increase in the transverse strength in the high strain rate tests was further ascribed to the pull and fracture of the visco-plastic collagen fibers in the interstitial lamellae. This was also confirmed microscopically; the dynamically tested specimens exhibited flatter fracture surfaces.

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BACKGROUND: Antlers are lined by soft velvet tissue during antler growth. Later, the velvet is shed before rut onset. There are no detailed histological descriptions of the growing velvet, nor whether the velvet changes according to stag age. Our aims were to: 1) describe the basic histology of pampas deer antler velvet from adult and yearling males; and 2) determine the influence of age and time of antler growth on velvet's tissues morphometry. MATERIALS AND METHODS: Samples were collected from 10 stags allocated in two groups, either adult (3-5 years old, n = 5) or yearling males (2 years old, n = 5). The day of antler cast was recorded for each animal. In spring, the stags were anaesthetised and velvet samples were collected from the third tine's distal end. Samples were described qualitatively and a restricted morphometrical analysis of the antler velvet was performed. RESULTS: The number of keratinocyte layers and the thicknesses of: total epidermis, corneum, intermediate and basale epidermal strata, total dermis, superficial and deep dermis were determined. Age and days after antler casting positively influenced in conjunction epidermal thickness (p = 0.037), and tended to influence both stratum intermedium (p = 0.076) and stratum corneum (p = 0.1) thicknesses. Age influenced stratum corneum thickness (p = 0.04). The pampas deer antler velvet lacked both sweat glands and arrector pili muscles. CONCLUSIONS: The deep dermis was densely irrigated but displayed abundant and well developed collagen bundles. Both total epidermal and stratum corneum thicknesses related positively to the age of the animals but were not to the time since antler cast.

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The objective of this study was to investigate asymmetry in antlers of Caspian Red Deer or maral (Cervus elaphus sibiricus) from two different genetic origins and maintained under similar conditions. Eighteen male Caspian Red Deer aged 24 months were studied. Nine animals belonged to the local Kazakh population and nine were directly imported Russian deer. The following data were obtained for right and left antlers: wet weight, stem length and circle and 1st, 2nd and 3rd shoot lengths. To obtain the values of antler asymmetries we used the absolute differences between the value of each trait on left and right sides. According to values of asymmetries obtained, the two populations neither showed differences from each other nor exhibited consistent directional trends in mean measures. Therefore, it could be concluded that Russian marals have adapted well to environmental conditions, presenting no different levels of environmental stress in relation to local Kazakh ones.

El objetivo de este estudio fue investigar la asimetría en las astas del Ciervo Rojo del Mar Caspio o Maral (Cervus elaphus sibiricus) en dos rebaños de origen genético diferente y mantenidos bajo condiciones similares. Se estudiaron 18 ciervos rojos del mar Caspio (machos) de 24 meses de edad. Nueve de los 18 animales pertenecían a la población nativa de Kazajistán y nueve fueron importados directamente desde Rusia. Se obtuvieron los siguientes datos para las astas derecha e izquierda: peso húmedo, longitud del tallo, circunferencia y primera, segunda y tercera longitud de los cuernos. Para obtener los valores de asimetrías de las astas se registraron las diferencias absolutas entre el valor de cada rasgo, izquierdo y derecho. De acuerdo a los valores obtenidos de las asimetrías, no se registraron diferencias entre ambas poblaciones, tampoco se observaron tendencias direccionales consistentes en el promedio de medidas. El ciervo rojo ruso se ha adaptado bien a las condiciones ambientales y no presentó niveles de estrés ambiental diferentes en relación con los animales nativos de Kazajistán.

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