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Notes: The postnatal development of the epithelium of the ruminal papillae was described in lambs during their first few weeks of life. Papillae from the ventral sac were collected from 4 one-week-old lambs and from 4 one-month-old lambs. The stages of epithelial differentiation, which were developmental, were discussed in relation to their transepithelial metabolic exchange.

Notes: There are a number of differences between the claws of the front and hind limbs in cattle concerning macroscopic shape, chemical and physical properties of claw horn and epidemiological data. Front claws have superior data in almost every respect. Virtually no information is available on the mechanical stability of the suspensory apparatus of the third phalanx.It was the objective of this study to develop a method to measure the maximum strength (N/mm2) of the suspensory apparatus of the bovine distal phalanx. This apparatus includes all layers of tissue such as bone, corium, corioepidermal junction and wall horn. The feet of 13 clinically healthy beef bulls were collected from the local abattoir. Testing was performed in three locations of the wall segment (dorsal, abaxial, axial) in a material testing machine. The corium and the corioepidermal junction were set under increasing tension until failure occurred. Maximum stress was recorded.The values ranged between 2.47–3.13 N/mm2 (dorsal), 4.08–4.87 N/mm2 (abaxial) and 2.27–2.66 N/mm2 (axial). No differences could be validated statistically between front and hind claws and between lateral and medial claws respectively. Abaxial ultimate stress values were significantly higher than dorsal and axial ones. Between the two a statistical difference could not be validated. Most of the specimens (57.1%) were torn apart at the corioepidermal junction, almost a quarter of the samples (27.6%) were to a degree disrupted at the corioepidermal junction and to a certain extent in the deeper layers of the corium. A few samples showed disruption within the horn (11.5%) or at the attachment of the third phalanx (3.8%).Biomechanical features of the experimental set-up are discussed. The biological significance of these findings is that the body weight and the additional dynamic loading is predominantly taken over by the abaxial part of the claw, while the dorsal and axial aspects are less loaded.

Notes: The aim of this work was to investigate the postnatal development of the feline spinal cord. Our study showed that the main period of growth leading to the cervical and lumbar enlargements begins after birth and is completed at the age of 5–6 months. Comparing the relationship between the length of the spinal cord and the vertebral column, we found that in contrast to the adult cat, in the newborn cat, length, area and volume of segments show similar values along the spinal cord. This also applied to the length of the vertebrae.Due to a heterogeneous growth, not all segments of the spinal cord end up situated cranial to their corresponding vertebrae. As a consequence, the end of the conus medullaris is still located within the sacral canal in animals older than 2 months. These findings strongly propose that injections into the vertebral canal of the cat have to be performed caudal to the sacral vertebrae.

Notes: An electronmicroscopic study of the seminiferous epithelium of the bovine is described Particular attention is given to the presence of intercellular bridges between development cells. These bridges are described, and a hypothesis is formulated regarding their probable role in the synchrony of cellular development in meiosis

Notes: In experimental ophthalmology avian models play an important role in the investigation of the pathophysiology of glaucomas. One major problem in establishing new experimental designs is a deficiency in basic anatomical data of the avian eye bulb. The aim of this study was to give a detailed description of the vascularization of the ciliary body and the iridocorneal angle in the avian eye. The vascular anatomy of the avian eye was studied in 50 birds of different species and orders (Phasianiformes, Accipitriformes, Columbiformes) by light microscopy as well as by stereomicroscopy and scanning electron microscopy (SEM) of corrosion cast specimen. The comparison of the different species revealed that independently of the bird order the vessels were orientated in a similar way, thus enabling to establish a schematic diagram. There is a redundancy in the arterial blood supply of the ciliary body and iridocorneal angle, which is supplied by the circulus arteriosus iridis and the circulus arteriosus. For the first time we were able to create a corrosion cast of the complete avian sinus venosus sclerae by injection of a liquid plastic (Reckli®, Chemiewerkstatt GmbH, Herne, Germany) in the venous system. The sinus venosus sclerae is characterized by a double-ring like structure. It drains into several vv. ciliares anteriores reaching the circulus venosus sclerae. A clearer understanding of the vascularization of the anterior eye segment, in particular of the sinus venosus sclerae, provides a step forward in experimental ophthalmology, especially regarding glaucoma research based on an avian model.

Notes: Introduction:  Elbow dysplasia is one of the most important orthopaedic diseases of the canine elbow joint. The medial coronoid process (MCP) and the anconeal process (AP) are involved with a high incidence.Aims:  The aim of this study was to clarify whether these processes are especially loaded resulting in osteoarthrosis.Material and Methods:  Elbow joints were examined from dogs of various breeds, with a body weight over 20 kg and an age ranging from 1 to 12 years. Only joints without damage to the articular cartilage have been included in this investigation. Articular surfaces have been evaluated macroscopically, subchondral bone density (long-term loading) and split-lines (long-term tensile loading) have been determined.Results:  In the humeral fossa olecrani, there was a distinct impression on the inner side of the lateral compared to the medial epicondyle. In the ulna, the MCP was much greater than the lateral coronoid indicating that the medial process has to support the humeral condyle to a higher extent. Subchondral split lines with a transverse orientation in the fossa olecrani gave evidence of long-term transverse tensile loading in this area. Split lines on the MCP were oriented radially as if the lateral edge was bent downwards. Subchondral bone density in the fossa olecrani was higher towards the lateral epicondyle in comparison to the medial. Furthermore, there was a bone density maximum on the medial part of the humeral condyle opposite of the MCP with its very high density.Discussion:  Gait analyses showed that there is a transverse, medially oriented force of up to 4% bodyweight acting on the paw during midstance. As the carpus is stable when slightly hyperextended during midstance loading there is a long lever arm from the ground up to an assumed rotation centre in the depth of the trochlear notch. The medially directed ground reaction force slightly rotates the forearm inwards causing a bending moment about the elbow joint, which leads to an increased pressure of the AP and the MCP. This bending in addition to sagittal loading is the reason for the high susceptibility of the MCP and AP.

Notes: Introduction:  On one hand, the distal phalanx in cattle is suspended by the wall segment of the dermis, on the other hand it is supported in the palmar/plantar region by the bulb with its specialized subcutaneous tissue. Recent results of various studies suggest that changes in tissue composition of the bulb and slackening of the suspension can lead to an unphysiological position of the distal phalanx within the horn capsule. This leads to an altered distribution of pressure and mechanically influences the dermal blood supply. In the worst case these changes may lead to sole ulcer.Aims:  The aim of this study was to develop a method to allow measuring the minimal distance between the surface of the distal phalanx and the inner surface of the horn capsule under various loading.Material and Methods:  The right front and the left hindclaws have been taken from seven healthy beef bulls (German Simmentals, average body weight 580 ± 25 kg) from the local abattoir. After functional claw trimming the feet have been scanned in a computed tomograph (veterinary surgical clinics) in unloaded and the loaded state [distribution of body weight: 55% (front legs): 45 % (hind legs)]. Each distal phalanx and claw capsule have been reconstructed in both datasets via threshholding (‘marching-cube-algorithm’). The minimal distance between both objects has been measured by the ‘nearest-neighbour-algorithm’.Results:  No significant differences could be observed between front and hind claws and lateral and medial claws respectively. In the unloaded state there was a distance of 4–6 mm in the dorsal, abaxial and axial aspect of the distal phalanx, which almost remained constant in the loaded state. On the solear surface values increased from 3 mm at the tip of the coffin bone to 7–8 mm at the flexor tubercle where significant distance changes (approx. 3 mm) could be observed.Discussion:  A tilting movement of the distal phalanx becomes obvious with loading. Thus, especially the region of transition between the soft and the hard bulb experiences heavy compressive stress. This coincides topographically with the incidence of sole ulcers.

Notes: Introduction:  In many breeds osteoarthrosis of the hip joint is the most typical orthopaedic disease. Numerous studies concerning etiology, pathogenesis and therapy of this disease still consider an exact congruity to be the basis of a physiological joint function. No data, however, are available as far as the distribution of load in the articular surfaces is concerned.Aims:  It was the aim of this investigation to describe the biomechanical features of the canine hip joint as exactly as possible with respect to long-term and momentary loading.Material and Methods:  Hip joints from 43 dogs (bodyweight 〉20 kg) with an average age of 6 years were investigated. The subchondral bone density was determined with the method of CT-osteoabsorptiometry. With help of cartilaginous and osseus split lines the preferential orientation of the collagen fibres could be determined. In an in vitro experimental setup the contact areas and the contact pressure distribution within the joint have been measured.Results:  In the acetabulum, maxima of subchondral bone density were distributed tricentrically: cranially, dorsally and caudally. In the femoral head, only the area close to the attachment of the ligament was highly mineralized. Cartilagineous and osseous split lines within the acetabulum gave evidence of a long-term tensile stress. In contrast to these findings, there was no clear preferential orientation in the caput ossis femoris. With load increasing initially isolated contact areas extended and became confluent at a loading force of 75% body weight. Values of maximal joint pressure (maximal joint reaction force applied: 400% bodyweight) reached 8–10 MPa.Discussion:  The findings clearly show that the articular surfaces of the hip joint are loaded inhomogeneously. For the first time, it was possible to demonstrate that the healthy canine hip joint is physiologically incongruent. Furthermore, areas of cartilage degeneration within the joint surface coincide with regions that are loaded to a higher extent a priori. From the biomechanical point of view it is recommended that all kinds of acetabular fractures – even those affecting the caudal third of the acetabulum – should be surgically repaired in an adequate way.