Tierärztliche Fakultät - Digitale Hochschulschriften der LMU - Teil 01/07 Archiv

Functional anatomical investigations on the interphalangeal joints of the forelimb in the horse. The proximal and distal interphalangeal joints are of particular importance in sporting horses, as degenerative diseases or fractures lead to a loss in performance. It was the objective of this study to investigate several biomechanical properties of the coffin and pastern joints. Forty three specimens of 30 male and female horses of different breeds and sizes were examined. Their age ranged between 3 months and 30 years. Using computertomographic osteoabsorptiometry (CT-OAM), the distribution of the subchondral bone density was determined topographically in three-dimensional reconstructions of the distal and proximal interphalangeal joints. The specimens were divided into 6 age groups. Following exarticulation the joints were evaluated for chondral lesions. These were documented by using a template of the respective articular surface and were summed up graphically in order to demonstrate the most common locations for chondral damage. The size of the articular surfaces was determined in order to investigate a relationship between the subchondral bone density and the size of the joints. Five specimens (coffin joint and pastern joint) were examined with regard to split lines in the articular cartilage. The articular cartilage was pierced at regular intervals (2 mm) at 90° angles with needles that had previously been dipped into ink. The subchondral plate of four specimens (proximal and distal interphalangeal joint), after maceration and demineralisation, was investigated with regard to subchondral split lines in the same way as described above. The CT-OAM shows a relatively low subchondral bone density in the first age group (horses up to 9 months). In the following age groups the bone density generally increased, varying with the age of the horse. The maximum bone density is found in the palmar areas of the coffin joint and the pastern joint. As far as the coffin joint is concerned, this is due to weight bearing and the tension of the deep digital flexor tendon, which causes a compressive loading of the navicular bone. The latter is pressed against the distal articular area of the middle phalanx. In the proximal interphalangeal joint, the suspensory apparatus, in addition to weight bearing, has an enhancing effect on the subchondral bone density. The subchondral bone density is significantly higher on the distal articular surface of the proximal phalanx than on the distal articular surface of the middle phalanx. One of the reasons being that the trochlea of the metacarpophalangeal bone is about 20% smaller than the trochlea of the proximal interphalangeal bone. This means that the same weight has to be carried by a smaller area; thus increasing the relative load of the articular surface and resulting in a higher subchondral bone density. The orientation of the cartilaginous and subchondral split lines is quite similar. In the proximal interphalangeal joint the split line pattern has a clear sagittal preference. In principle this applies to the coffin joint, too. In the distal articular surface of the middle phalanx, however, split lines are oriented in a transverse direction at the palmar aspect of the trochlea. This indicates transverse strain of the trochlea in this area. The orientation of the cartilaginous and subchondral split lines is interpreted as an expression of functional adaptation to tensile stress. Cartilage lesions are seen in areas with a high subchondral bone density as well as in areas with a relatively low subchondral bone density. The lesions in areas with a high subchondral bone density are caused by permanent high mechanical loading. In contrast lesions in areas with a relatively low subchondral bone density are attributed to peak loads of a short duration. The investigations on the subchondral bone density could significantly deepen the understanding of the biomechanical properties of the interphalangeal joints. Long-term strain could be visualised by the study of the split lines. This gives evidence of a physiological incongruence of the interphalangeal joints. It is, however, necessary to investigate the contact surfaces and contact pressures in vitro in order to evaluate the articular surfaces with regard to physiological incongruence.

In der vorliegenden Arbeit wurde erstmals der antioxidative Status von neugeborenen Hundewelpen bestimmt. Zusätzlich wurde untersucht, ob die Zufütterung von Lactoferrin bzw. Enterococcus faecium einen Einfluss auf den antioxidativen Status der Tiere ausübt. Dazu wurden 42 neonatale Beagle-Welpen am 3. Tag nach der Geburt von den Muttertieren getrennt und in zwei unabhängigen Fütterungsversuchen von Hand aufgezogen (Lactoferrin-Versuch und Ec. faecium-Versuch). Der antioxidative Status wurde als TEAC an Tag 3, 7, 14, 28, 56, 70, 84 und 98 im Blut der Welpen gemessen. Zusätzlich wurden die Plasmakonzentrationen des antioxidativ wirksamen Vitamin E bestimmt. Als Vergleich zur mutterlosen Aufzucht dienten 11 neugeborene Beagle-Welpen, die bei ihren Mutterhündinnen aufwuchsen. An Tag 1, 3, 7 und 14 wurden bei ihnen neben der TEAC die Vitamine E und C im Blut gemessen. Außerdem wurde freies Eisen, die latente Eisenbindungskapazität sowie Gesamteisen bestimmt und die totale Eisenbindungskapazität und Transferrinsättigung berechnet. Nach der Geburt kam es bei den neugeborenen Hundewelpen durch erhöhten oxidativen Stress zu einer deutlichen Verminderung des antioxidativen Status im Blut. Dabei konnte kein Einfluss der Lactoferrin- bzw. Ec. faecium-Supplementierung festgestellt werden. Es wurde kein Zusammenhang zwischen dem erniedrigten antioxidativen Status und einem vermehrten Auftreten von Neugeborenenerkrankungen oder einer erhöhten Welpensterblichkeit offensichtlich.

The existence of a melatonin rhythm in the domestic pig with respect to the light intensity has been discussed controversally. These controversial results are caused in part by inappropriate RIA methods. Until now, there are no published results describing non-immunological identification of melatonin in the domestic pig. Therefore, the main-objective of this study was to establish a HPLC method for the determination of melatonin in plasma and saliva samples of domestic pigs and to examine the correlation of the melatonin concentration of these two specimens. A further aim of this study was the possible replacement of blood sampling which requires the restraint of the animal by minimally invasive saliva sampling. The study was conducted on 12 domestic crossbred pigs aged 14 weeks (6 gilts, 6 barrows), which were housed in single pens under standardized conditions and under an equatorial lightregime (LD 12:12). Photophase light intensities were set in two groups with 250 lux and 470 lux, scotophase light intensities were below 1,0 lux. Blood and saliva samples were collected over a period of 24 hours on two non-successive days with sampling intervalls of 3 hours. Following chloroform extraction, samples were analyzed by a HPLC system. Identification and quantification of melatonin were achieved by comparing the retention times with those of authentical standards containing a known melatonin concentration. Results of this study showed that the HPLC method is appropriate for the determination of melatonin concentrations of both plasma and saliva samples and comprises a remarkably high sensitivity, which allows a reliable measurement of melatonin concentrations even in photophase samples. Results revealed identical concentrations of both photophase and scotophase melatonin concentrations at a light intensity of 250 lux, indicating a lack of suppression of pineal melatonin secretion during photophase. This indicates that differences in hormone concentrations driven by day/night-changeovers were not sufficient for pigs to differenciate between day and night at a light intensity of 250 lux. Results also showed significantly lower photophase melatonin concentrations at a light intensity of 470 lux, compared to 250 lux. This indicates a stronger light-induced melatonin supression, not being able to synchronize melatonin secretion to the lightregimen completely and therefore may have been assessed as insufficient by the animals. Furthermore, results showed clear differences in the melatonin profiles of castrated male and intact female pigs. There was no correlation of salivary and plasma melatonin concentrations. Therefore blood samples cannot be replaced by minimal-invasive saliva samples. Further studies should be done to investigate the light intensity, which entrains the synchronisation of the melatonin profile to the lightregime. This could be done by using this highly sensitive HPLC method to assess the photic demands of domestic pigs kept in indoor piggeries. Particular attention should be given to the consequences of a potential effect of a stress-load on the animals and its stimulating effects on the synthesis of melatonin, as well as potential sex differences.

Delayed ovulation in dairy cattle – a field study The aim of the present study was, to analyze the incidence of delayed ovulation in dairy cattle and to evaluate its influence on the conception rate. The examinations were carried out on 304 animals (293 cows and 11 heifers) of the breeds Swiss Brown (65%), Holstein (26%) and Simmental (9%). The animals were kept on 49 different farms in the area of the Artificial Insemination Center Rinderunion Baden-Württemberg e.V. (RBW). After the artificial insemination, the internal and external symptoms of estrus were documented in a protocoll, followed by an ultrasound check of the genital tract. During the check the number of follicles on the ovaries were counted, and after measuring the follicles’ diameter the average diameter was calculated. Twenty-four hours later all animals were checked again by ultrasound and checked for a possible ovulation. If no ovulation was observed, the animals were checked again 7–14 days later for the presence of a corpus luteum. The first check of the group was done on more than half of the animals (53%) after the first artificial insemination. The total percentage of animals with delayed ovulation was 46.1%. The pregnancy rate of the group of animals with spontaneous ovulation was 48.8% versus 34.2% from the group with delayed ovulation (difference p>0,05; Chi-Square analysis). The best pregnancy rate of the group of animals with spontaneous ovulation was achieved during the first and second artificial insemination (50.0% and 53.3%). The intervall in days between the date of the delivery and the date of the first insemination had no significant influence on the incidence of delayed ovulation. Likewise no influence of the number of inseminations (1, 2, 3, etc) could be observed. The percentage of animals with delayed ovulation was lowest in the 3rd lactation (33.3%) and highest in the group with 5 lactations and more (54.0%). 63 About half of the animals (143; 49.6%) were inseminated between 11 and 20 hrs. after observation of the estrus onset. A quarter of the animals were inseminated just 21-30 hrs. after the observation of the estrus and by the analysis of the delayed ovulation it was not possible to find a significant difference between the groups. The intensity of the estrus had no relation to the incidence of delayed ovulation. The conception rate from 161 animals with spontaneous ovulation was not related to the time of insemination. The group that was inseminated in the first 10 hrs. after the observation of estrus had a tendency to show the best results. A second insemination (double insemination) was done on 46 of the animals that showed a delayed ovulation. The pregnancy rate of this group was 37.0% and not significantly different from the group with delayed ovulation and single insemination. The results of this study demonstrate that the delayed ovulation is a frequent phenomenon which cause a decrease in the conception rate.

Phenotypic and genotypic characterization of the ENU-induced mutant mouse line HST001 for use in nephrological research A dominant mutation was established in the line HST001 within the Munich ENU mouse mutagenesis project. On the genetic background of the inbred strain C3H heterozygous mutant mice showed a pathological increase of the plasma urea concentration. The phenotypic characterization of the mutant line included the measurement of body and organ weights, food intake and a broad spectrum of clinical chemical and hematological parameters as well as histological investigations of inner organs. For those examinations heterozygous mutant mice were mated to C3H mice and the offspring were divided in the two groups of mutant and wildtype littermates according to the concentration of plasma urea. The mutation showed complete phenotypic penetrance in all generations examined. In addition the genomic localization of the causative mutation was determined by linkage analysis. At the age of 4 weeks the body weight of the mutant mice and the wildtype mice showed no difference. After 6 weeks the mutant mice grew more slowly leading to a significantly lower body weight compared to the wildtype littermates. At the age of 26 weeks the body weight of mutant mice was about 20% reduced as compared to controls. Mutants also showed a reduction of the nose-rump-length and the body fat content. Regarding the relative organ weights the mutant mice showed significantly higher values for the spleen and the brain. The clinical-chemical and hematological parameters were determined in the animals at the age of 12, 18 and 24 weeks. The mutant mice had significantly higher plasma concentrations of urea and total protein as well as a higher activity of the alkaline phosphatase. Beside that they showed lower plasma concentrations of triglycerides and glucose and a lower activity of amylase than the wildtype mice. The mutants showed increasing plasma urea levels whereas the levels decreased in the controls. At the age of 24 weeks the mutants showed levels, which were two-fold higher than those of the controls. The histopathological investigation of the kidneys did not reveal any alterations, which could to explain the pathological increase of the plasma urea concentration in the mutant mice. However urea secretion via the kidneys was impaired, since the mutants showed significantly lower urine urea levels compared to the wildtype mice. The investigation of the hematological parameters resulted in the occurrence of altered values in the 18 und 24 weeks old mice. The mutant mice showed reduced numbers 91 of erythrocytes as well as decreased values for hemoglobin concentration, mean corpuscular volume and hematocrit. The hitherto existing results of the linkage analysis of the mutation in the genome using polymorphic microsatellite markers showed that the mutation maps to chromosome 7. This result has to be confirmed and specified by using additional markers and a larger number of animals.

In einem Langzeitversuch an adulten Fischer-Ratten wurden die Auswirkungen einer unzureichenden und einer marginalen Zinkversorgung auf den Knochenstoffwechsel untersucht. Den Zinkmangeltieren wurde mit Hilfe einer phytathaltigen, semisynthetischen Diät körpereigenes Zink entzogen. Dabei wurden die Ergebnisse mit paargefütterten Kontrolltieren verglichen. Das Ergebnis der Studie ist, dass Zinkmangel keine nennenswerten Auswirkungen auf den Knochenstoffwechsel hat.

The aim of the present study was to make a statement about selected blood ingredients for twelve pig breeds regarding the influence of the genotype. A possible race-dependence was proved for haematological parameters especially for erythrocytes, thrombocytes and leucocytes. Differences between the breeds were also found for electrolytes and the trace elements although a statement concerning breed-specifity was more difficult because some other environmental factors can have strong influence on these parameters as well. In part clear differences, which are caused by different physical characteristics and attributes of the animals such as muscle mass and susceptibility to stress, were established for substrates and enzymes. We were able to show that the pietrain pigs possess a remarkably higher concentration of some blood ingredients, in comparison with “German Landrace and Edelschwein“. To conclude, the results show, that there are marked differences in characteristics. We detected a varying influence of the genotype on the hematological and chemical blood parameters. The varying concentration of the blood parameters in the examined breeds seems to result from breed-specific metabolism and resistance to infections and environmental influence. The immune-histochemical search for accumulation of pathological prion protein with the antibody L42 in 48 brain tissue sections of both sows and boars was negativ. Nonetheless, it is possible to experimentally infect pigs with the infectious prion protein from cattle. This means that, in spite of the species-barrier, even though the infection was transmitted parenterally, pigs, along with many other animals, are susceptible to an infection with the bse-agent. There is a definite need for acquiring further knowledge on the exact onset of and events during infection and on the degree of contagiousness of transmissible spongiform encephalopathy not only in swine.

Neospora caninum - a causal agent of abortion in cows The present study gives an overview of the current knowledge of N. caninum, particularly concerning the incidence of abortions in cattle populations infected by this parasite. In 1988 the Toxoplasma-like protozoon found in dogs was named N. caninum. In more than 40 countries N. caninum has been diagnosed since that time and about 17 different species were found to host infections by N. caninum. There are reports about 26 isolates. A different species, N. hughesi, was found to infect horses. Three different isolates of this species were described. There are conflicting reports about the exact phylogenetic classification of N. caninum. Especially the taxonomical relationship between Neospora, Toxoplasma and Hammondia is still being discussed controversely. It is generally accepted that N. caninum belongs to the phylum of Apicomplexa, the class of Sporozoa, the subclass of Coccidia, the order of Eucoccidia and the suborder of Eimeriina. During its life cycle N. caninum passes through various phases like sporogony, schizogony and gamogony. Definitive and intermediate hosts are needed for parasite`s development. To date not every detail of the parasite`s life has been investigated. Numerous investigations took place up until 1998 when it became obvious that the dog is a definitive host of N. caninum. Currently there is no evidence that other canids may also function as definitive hosts. It is difficult to distinguish oocysts of N. caninum from those of other eimerian species. N. caninum is transmitted either vertically from a cow to its fetus by tachyzoites or horizontally by ingesting oocysts, tachyzoites or bradyzoites. Reduced fertility and abortions are severe problems caused by neosporosis in cattle populations. Abortions can occur sporadically, endemically or epidemically. Concerning the season in which abortions take place a connection to climatic conditions favouring the survival of oocysts in the environment was suggested. But nevertheless N. caninum induced abortions can happen during the whole of the year. After the infection of a cow by N. caninum its first pregnancy probably results in abortion. During the following pregnancies the fetus of the same cow is likely to become infected, too, but abortion is unprobable. The resulting calf is infected chronically and also gives birth to infected offsprings. Only in exceptional circumstances may abortion occur again during the second or third pregnancy of the same cow. Sometimes stillbirths or malformations occur. The individual immune system of a cow chronically infected by N. caninum plays an important role for the transmission of the fetus and for the probability of abortion. Serological diagnoses of infections by N. caninum have to be confirmed by histopathological examinations to ensure that symptoms observed were really caused by this parasite. But former investigations demonstrate that the confirmation of diagnosis is difficult, especially if tissues dispatched are in bad condition. Immunological studies have been initiated to learn more about the parasitic activities of N. caninum and the host-parasite interaction. There is a chance to develop a vaccine to avoid the transplacental transmission of the parasite. The next step is the prevention of the horizontal infection. In general prevention from infection is of great importance in herds with infertility and abortions. Feeding with contaminated food and water should be avoided. Furthermore placentas potentially infected and stillborn calves should be removed. Affected herds should be examined serologically and histopathologically. Economic losses caused by infections by N. caninum result from reduced fertility, reduced milk production, lower average daily weight gain as well as from abortion. But up to now the severity of economical losses can not be quantified exactly, because aborted fetuses are not examined routinely. There is no zoonotic potential of N. caninum. Allthough it was possible to infect monkeys with a high dose of tachyzoites, there has been no natural infection seen up to now. And no indicate of N. caninum infections in aborted human fetuses were fou

The aim of the present study was to formulate a standardised ultrasonographic examination procedure of the carpal region in cattle. Aided by an experimental filling of the joint pouches, those transducer positions were identified, at which the presence of an added filling can be detected best. The gained insights were then applied to clinical cases. Examinations were made with the real-time ultrasound unit Sonoline Prima (Fa. Siemens), equipped with a 5/7,5-MHz multi-frequency linear transducer. Initially, 8 isolated cadaver specimens were used to update and enlarge the topographic anatomical knowledge, and to recognize the typical ultrasonographic appearance. For the standardised examination procedure, the carpus was divided in 4 horizontal and in 8 vertical planes, which can be discovered by means of prominent bone structures on both young and adult cattle. The resulting 32 planes were scanned horizontally and vertically each, beginning proximally and moving the transducer distally one step at a time. Only the musculus abductor pollicis longus had to be examined in an oblique direction. The examination procedure was applied to 11 carpal joints of healthy cattle of all ages and sexes. The carpal flexor and extensor tendons, partially their tendon sheaths, the medial and lateral collateral ligament, the ligamentum accessoriometacarpeum and the bone surfaces of the carpus could be imaged without greater problems with the exception of the musculus abductor pollicis longus. The ultrasonographic imaging of the larger vessels and the median nerve, running over the palmar and medial aspects of the carpus, required some practice and did not succeed in every case. The antebrachiocarpal joint space, the intercarpal and carpometacarpal joint spaces could be clearly defined as interruptions of the echogenic bone surfaces, whereas the joint pouches could only be detected around the dorsal and the lateral aspects; Their joint capsules could not be identified. The topography of each ultrasonographic picture was explained in detail by means of drawn illustrations and it was compared to frozen anatomical sections. By doing so, a good correlation of structures in ultrasonographic pictures and anatomic parts could be performed. The experimental filling of the joints showed that the filled joint pouches of the carpus could be illustrated most easily close to the puncture sites of joints described in the literature. This worked out best when holding the transducer in a vertical position. Furthermore, 24 cattle with diseases of the carpal region, i.e. arthritis, bursitis, tendinitis, and tendovaginitis, could be examined. In conclusion, the following can be stated. The ultrasonographic pictures, illustrations, and frozen anatomical sections that were produced in this work for the different planes, describe nearly all structures of the carpus. On the grounds of these reference images an ultrasonographic examination of both healthy and diseased carpal joints can be performed a lot easier.

The aim of this study was to attain knowledge about ostrich behaviour in captivity and to conclude from that to appropriate animal husbandry under German farming conditions. Special concern was given to the use of the stables and the influence of different climate parameters. Recommendations for the optimisation of an appropriate husbandry of ostriches should be formulated.

Es wurde die Einheilung einer mit Plasma-Immersions-Ionen-Implantation beschichteten Autokompressionsklammer aus Nitinol im Seitenvergleich mit einer unbehandelten Klammer an sieben Beagle-Hunden überprüft. Aufgrund der Autokompressionsklammer war ein gleichzeitiger Vergleich der Heilung mit bzw. ohne Kompression möglich. Die Einheilzeit betrug drei Wochen. Die Ergebnisse wurden fluoreszenzmikroskopisch und mit konventioneller Histologie überprüft.