The influence of stocking density on behaviour, health, and production in commercial fattening turkeys - a review.

1. This paper reviews literature on the effects of stocking density on behaviour, health, and production in intensively housed fattening turkeys.2. Worldwide, there are various regulations and recommendations on the maximum stocking density. While stocking density can be determined based on the space covered by the body, a more appropriate method considers space requirements for natural behaviour. Turkeys are less likely disturbed at low stocking density as seen by increased sitting, lying, and preening behaviours compared to animals housed at high stocking density. Furthermore, lower stocking density together with smaller group size, species-appropriate light conditions and suitable structuring of barn housing are repeatedly mentioned as good strategies to prevent injurious pecking.3. Increased stocking density - in terms of weight and animal number per floor area - is related to increased litter moisture, which can have negative impact on animal health. High stocking density can also lead to poor body mass gain and increased mortality, which are not only indicators of impaired welfare but also of economic interest.4. Based on the available scientific literature and economic aspects with regard to the above criteria, a maximum stocking density for turkeys appears to be 36-a maximum of 40 kg live weight per m2 of usable floor space. However, the number of animals per square space should also be limited to avoid increased litter moisture and reduced health.

Investigation of the prevalence and severity of foot pad dermatitis at the slaughterhouse in fattening turkeys reared in organic production systems in Germany.

The present study shows the prevalence and severity of foot pad dermatitis (FPD) in turkeys reared in organic production systems assessed at slaughterhouses in Germany. The investigations of altogether 1,860 turkeys of the strains Kelly Broad Breasted Bronze (Kelly BBB; 540 toms, 540 hens) and British United Turkeys (B.U.T.) 6 and the Test Product 7 (TP 7; 780 hens) showed that 97.7% of the examined turkeys were diagnosed with different degrees of FPD. Only 4.6% of the toms and 1.3% of the hens had feet without lesions. Most frequent were necrotic lesions measuring up to 2 cm in diameter (64.3% of all turkeys). Extensive necrotic lesions of the foot pads (toms: 29.8%; hens: 12.4%) and necrosis of superficial scales (toms: 11.3%; hens: 7.6%) were less frequent. Plantar abscesses were rare findings (1.9%). In general, the feet of the Kelly BBB hens were more affected by foot pad lesions than those of the Kelly BBB toms. There were significant differences between the investigated flocks concerning the occurrence of foot pad lesions. The aim in rearing turkeys must be the reduction of FPD.

Current approaches to avoid the culling of day-old male chicks in the layer industry, with special reference to spectroscopic methods.

The negative correlation between fattening and laying performance prevents breeding improvement in both laying performance and meat yield. Therefore, specialized chicken lines have been bred in order to achieve either an efficient production of high-quality eggs or high growth rates. As a result, day-old male chicks are culled in the layer hatchery, which poses animal welfare and ethical problems. Breeding companies, scientific groups, and hatcheries are attempting to resolve this issue, with a common aim to find feasible alternatives for the routine killing of male layer chicks. Some approaches aim to influence the sex ratio, while others target at the economically feasible use of the male layer offspring, such as the fattening of "laying hen brothers" or crossbreedings of layers and broilers to create "dual-purpose chickens." Another approach is the sex determination prior to hatch. One of the prerequisites of in ovo sex determination is a practicable method that can be used in industry. The analysis needs to be rapid, cost-efficient, and highly precise; in addition, negative impacts on hatching rate, animal health, and/or performance parameters should be limited. Furthermore, sex determination should be performed before the sensory nervous system's response of the chick embryo to certain or potentially harmful stimuli is developed, which according to current knowledge is before the d 7 of incubation.

[Veterinary treatment of pigeon flocks]. / Tierärztliche Betreuung von Taubenbeständen.

Veterinary treatment of pigeon flocks requires specific knowledge on the management of the various pigeon flocks as well as of common diseases in these birds and important diagnostic and therapeutic measures. In this context, it is important to differentiate between racing pigeons, thoroughbreds and pigeons kept for meat production, that is, between food-supplying and companion animals. The following article provides an overview of the species-specific characteristics of Columba livia f. domestica and frequently occurring diseases as well as common therapeutic and prophylactic measures.

[Pathologic-anatomic and morphometric examinations on the heart in feral cockatoos]. / Pathologisch-anatomische und morphometrische Untersuchungen am Herzen von wildlebenden Kakadus.

OBJECTIVE: To evaluate the heart of free-living psittacine birds macroscopically and morphologically, and to compare the results to findings published for psittacine birds living in captivity to obtain information on the influence of bird keeping in a human environment on the psittacine heart. MATERIAL AND METHODS: In total, 84 wild-living cockatoos were examined, including 50 sulphur-crested cockatoos (Cacatua galerita), 31 galahs (Eolophus roseicapilla) and three long-billed corellas (Cacatua tenuirostris). The birds were euthanized because of a local cockatoo control program in Australia, and were examined pathologically within 8 hours of euthanasia. A macroscopic necropsy was performed, and the heart was assessed morphologically. Furthermore, a histological organ screening was conducted. RESULTS: The birds demonstrated good body condition and excellent muscle condition. Except for some paleness of the heart muscle, none of the animals showed any pathological alteration of the heart or large vessels. The mean heart mass was 8.7 g for the sulphur-crested cockatoos, 5.3 g for the galahs and 8.6 g for the long-billed corellas. Independent of the species examined, a highly significant correlation was found between the heart and body masses (r = 0.91; p < 0.001), which was also confirmed as significant within the sulphur-crested cockatoo (r = 0.59; p < 0.001) and galah groups (r = 0.52; p = 0.003). This correlation can be used to calculate the expected heart mass based on the body mass, using the formula: heart mass (g) = 2.9 + 0.01 x body mass (g). In comparison to reports on Australian parakeets, the relative thickness of the heart muscle wall of the left ventricle found in this study was greater. CONCLUSION: In comparison to psittacine birds kept in captivity, wild-living cockatoos have good body condition and rarely suffer from macroscopically detectable diseases of the heart or large vessels. The cardiac fitness level is superior in comparison to that found in healthy appearing psittacine birds kept in captivity. CLINICAL RELEVANCE: The results can serve as a basis for the assessment of the heart in psittacine birds, because in contrast to earlier reports, the heart of healthy psittacine birds not previously exposed to any human influence could be assessed.

Aerobic cloacal and pharyngeal bacterial flora in six species of free-living birds.

AIMS: The purpose of this study was to investigate the culturable aerobic pharyngeal and cloacal bacterial flora of free-living birds, to determine the physiological bacterial microbiota, to identify possible interactions between feeding behaviour and the composition of the pharyngeal and cloacal microflora and to investigate the occurrence of pathogenic bacteria. METHODS AND RESULTS: Cloacal and pharyngeal swabs of 167 free-living birds, including water rails (Rallus aquaticus), spotted crakes (Porzana porzana), mute swans (Cygnus olor), barn swallows (Hirundo rustica), reed warblers (Acrocephalus scirpaceus) and black cormorants (Phalacrocorax carbo) from Germany, were cultured to determine the prevalence of aerobic bacteria. Statistical analysis of bacterial findings and feeding behaviour was performed. A widespread soil and water bacteria were isolated, which are expected to be present in the habitat and food. However, some potentially avian- and human-pathogenic bacteria, such as Aeromonas hydrophila, Elizabethkingia meningoseptica, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, were also recovered. CONCLUSIONS: Free-living birds of the examined species harbour several environmental bacteria, which could be facultative pathogenic. SIGNIFICANCE AND IMPACT OF THE STUDY: Prevalence of bacteria in healthy free-living birds of the species included in this survey is influenced by environmental and alimentary factors.

[Efficacy of doxycycline for treatment of chlamydiosis in flocks of racing and fancy pigeons]. / Wirksamkeit von Doxycyclin bei Chlamydiosen in Taubenbeständen.

OBJECTIVE: Evaluation of the clinical efficacy of doxycycline application via drinking water in the treatment of chlamydiosis in infected, clinically ill flocks of racing and fancy pigeons (Columba livia f. domestica) under field conditions. MATERIAL AND METHODS: In the scope of a field study, 13 pigeon flocks with clinically manifest ornithosis were treated over a period of 25 days with a novel doxycycline formulation via drinking water. Infection with Chlamydia psittaci had been confirmed beforehand by molecular-biological investigation of organ material from dissected pigeons in each flock. Therapeutic success was evaluated by PCR-analysis of triple swabs from 10 animals of each flock on day 25 of treatment and 7 days after completion of the therapy, as well as by repeated individual and daily herd examination. RESULTS: The causative agent Chlamydia psittaci together with additionally documented atypical chlamydia species in six of the 13 flocks could thereby no longer be detected. Furthermore, a resolution of clinical symptoms was achieved in each of the treated pigeon flocks. CONCLUSION: Application of doxycycline in the described therapy regimen proved successful for the treatment of ornithosis. In addition, excellent acceptance and tolerance of the deployed formulation could be confirmed in praxis.

[Radiographic findings in raptors affected with a mycosis of the respiratory tract]. / Röntgenzeichen bei an Mykose des Respirationstrakts erkrankten Greifvögeln.

OBJECTIVE: Summary of typical radiographic signs in birds of prey with aspergillosis compared to signs previously established in parrots. MATERIALS AND METHODS: Evaluation of radiographs of 110 falcons (Falco spp.) with aspergillosis confirmed by endoscopy. RESULTS: Compared to parrots primarily subtle radiographic signs were detected in falcons (especially inhomogeneously increased radiodensities of the airsacs/lungs). Two typical signs for diseased falcons consisted of the poor delineation of the cardiac silhouette and the line-shaped increased radiodensity of the caudal lung border. Radiographic diagnosis of the lung is limited due to the strong flight musculature. CONCLUSION: The varying results between avian species can be explained by the different radiographic anatomy, husbandry conditions and x-ray technique (digital versus analog). CLINICAL RELEVANCE: A pet bird-experienced practitioner should be aware of specific radiographic signs in birds of prey suspected of having aspergillosis.

[Examinations on the pharmacokinetics and compatibility of enalapril in racing pigeons]. / Untersuchungen zur Pharmakokinetik und Verträglichkeit von Enalapril bei Brieftauben.

OBJECTIVE: It was the aim of this study to examine the compatibility and the pharmacokinetics of the angiotensin converting enzyme inhibitor enalapril after oral application in racing pigeons and Amazons, and to contribute to a safe dosage regime of this drug in birds. MATERIAL AND METHODS: For the examination of drug compatibility, three groups of pigeons (n = 8 each) received enalapril into the crop at a dose of 5 or 10 mg/kg body weight, or placebo, respectively. Health status, and water and food consumption were monitored regularly, and clinical, hematological and blood-chemical parameters were determined. To determine a suitable starting dosage, birds were treated with enalapril at a dose of 2.5 mg/kg (first trial) and 1.25 mg/kg (second trial), and blood samples were collected at defined time points. Using high performance liquid chromatography (HPLC), the enalapril concentration in the plasma samples was determined. RESULTS: Drug application did not cause any significant drug-related difference between the groups. Nearly all measured parameters were found to be within normal physiological ranges. Only for hematocrit was a slight but significant increase found for the group treated with 5 mg/kg enalapril. In pigeons, after application of 2.5 mg/kg enalapril, the maximum plasma concentration was found in the first sample taken (388.2 ± 174.1 mg/kg). The application of 1.25 mg/kg resulted in a maximum concentration of 116.1 ± 70.2 ng/ml after 30 minutes in pigeons. In the Amazon birds, the maximum value was found after 1 hour (first sampling) of 43.3 ±6.0 ng/ml. In all examinations, the enalapril concentration was <15 ng/ml after 8 hours. The terminal half-life was 2.68 hours for pigeons and 2.36 hours for Amazons. CONCLUSION: The results underline the good compatibility of enalapril after oral administration in healthy pigeons. A starting dosage of 1.25 mg/kg enalapril given twice daily can be recommended. CLINICAL RELEVANCE: The study provides basic data (compatibility and pharmacokinetics) for the application of enalapril in birds such as the racing pigeon.

Causes of morbidity and mortality in free-living birds in an urban environment in Germany.

Free-living birds are often presented to veterinarians at rehabilitation centers as well as in private practice. Information about disease processes and causes of death of indigenous free-living birds can aid the clinician in establishing proper treatment and in the assessment of potential zoonotic risks. For the present study, pathogens as causes of morbidity and mortality were determined by performing a complete necropsy on free-living birds presented to the Clinic for Birds and Reptiles of the University of Leipzig (Germany) that died shortly after admission or were euthanized due to an unfavorable prognosis. Over a 2-year period, 251 birds representing 13 families (Accipitridae, Apodidae, Columbidae, Corvidae, Falconidae, Fringillidae, Hirundinidae, Paridae, Passeridae, Picidae, Strigidae, Sturnidae and Turdidae) were examined. Trauma (62%), including several bite injuries inducing bacterial septicemia caused by Pasteurella multocida, was the most common cause of morbidity. Parasitic disease (18%) was mainly caused by Trichomonas gallinae, Eucoleus dispar and Syngamus trachea. Metabolic disease (13%), including fibrous osteodystrophy, was almost exclusively limited to juvenile specimens. Different Enterobacteriaceae including E. coli, Salmonella Typhimurium DT040 as well as Mycobacterium avium ssp. avium were identified as causal agents of primary bacterial disease (5%). Primary bacterial infection as cause of death or disease was of major importance in nestlings. Viral infections, mycoses and intoxication had minor significance as causes of morbidity.

Prevalence and severity of foot pad alterations in German turkey poults during the early rearing phase.

In the previously performed field study from 2007 to 2009, it became evident that foot pad alterations were already commonly found in turkeys at the age of 6 wk. At this early age, 45% of the clinically examined birds were diagnosed with epithelial necrosis. Therefore, it became important to specifically analyze the situation during the early rearing phase. The present study reflects the prevalence and severity of foot pad alterations of turkey poults up to the age of 35 d (5 wk), starting as early as the age of 3 d. From 24 turkey farms throughout Germany, in general 5,531 turkeys [3,131 male and 2,400 female] of the British United Turkeys 6 strain from 46 flocks, were examined to that effect. Prevalence and severity increased within the duration of stay in the stable, and the prevalence was higher (P < 0.001) during the second visit between d 22 to 35 (factor: 0.94). Therefore, 27.3% (d 3 to 5; male/female: 39.1/25.0%) and 63.3% (d 22 to 35: 61.3/65.7%) of the examined poults had alterations of the foot pads, such as hyperkeratosis (d 3 to 5: 20.4/14.2%; d 22 to 35: 17.6/17.1%), high-grade hyperkeratosis with adhesive dirt (d 3 to 5: 8.7/10.7%; d 22 to 35: 29.2/39.3%), and epithelial necrosis (d 3 to 5: 0.1/0.1%; d 22 to 35: 14.6/9.3%). Female poults showed a higher risk (P < 0.001) of developing food pad alterations (factor: 0.76) than male poults. Male poults developed a higher percentage of epithelial necrosis than hens shortly before relocation. A higher stocking density during the very early rearing phase (d 3 to 5) led to a worse foot pad health status (P < 0.001). Because even mild alterations in the foot pad condition can be indicators for suboptimal design of the rearing environment and are to be seen as a pre-state for severe cases of foot pad dermatitis, it is important to set the main focus on the early rearing phase.

[Echocardiography in Boid snakes: Demonstration and blood flow measurements]. / Echokardiographische Untersuchungen bei Boiden: Darstellung und Blutflussmessungen.

OBJECTIVE: Comparative echocardiography and blood flow measurements in different boid species. MATERIALS AND METHODS: 51 healthy snakes from seven different species were examined echocardiographically under standardized conditions. The heart and the great vessels were displayed using 2-D-ultrasonography. Pulsed-wave doppler technique measurements of the blood flow within the vessels were performed and results analyzed statistically. RESULTS: The examinations could be performed in non-sedated snakes in ventral recumbency. The best image quality was obtained using the ventrolateral coupling site. An examination scheme applicable to all examined snake species was established. Diversity in the anatomy of vessels could be detected in different snake species. A characteristic shape of the curve demonstrating the blood flow against time could be shown for the respective vessels. There were positive correlations between the size of the snakes and the absolute blood flow (total flow, systemic flow, pulmonary flow to body length: p<0.001; r=0.770; r=0.627; r=0.766; respectively to body mass: p<0.001; r=0.815; r=0.698; r=0.788), as well as negative correlations between the size of the animals and the blood flow relative to body mass (total flow, systemic flow, pulmonary flow to body length: p<0.001; r=-0.533; r=-0.512; r=-0.478; respectively total flow to body mass: p<0.001; r=-0.768). CONCLUSION AND CLINICAL RELEVANCE: When using standardized conditions, echocardiography in boid snakes is a useful diagnostic tool for the assessment of cardiac function. Reference values provided in this study serve as a basis for ultrasound examination in veterinary practice.

[Endocrinologic studies of male psittacine birds for the evaluation of their reproductive status]. / Endokrinologische Untersuchung männlicher Papageienvögel zur Beurteilung ihres Reproduktionsstatus.

OBJECTIVE: Evaluating methods of hormone measurement in different specimens of male parrots in order to assess their reproductive status and stress axis. MATERIAL AND METHODS: Cockatiels and rose-ringed parakeets were chosen as psittaciforme representatives and their endocrine profiles were examined. In various pre-experiments, suitable techniques for the determination of testosterone in plasma, saliva and faeces of male parrots were established. Before analysing the samples by enzyme immunoassay, blood and faeces were extracted using diethyl ether, while saliva could be tested without extraction. Based on the excretion of mainly conjugated testosterone metabolites, parrots' faecal samples were also hydrolysed with ß-glucuronidase/arylsulfatase before extraction. In addition, the levels of the stress hormone corticosterone were determined by radioimmunoassay in order to assess possible relationships between stress and the secretion of testosterone. RESULTS: The examined psittacine species displayed different seasonal secretion patterns for both testosterone and corticosterone. Cockatiels had maximum plasma testosterone levels in February, in contrast, rose-ringed parakeets showed highest concentrations in November. As a consequence of cumulative excretion, both species showed much higher faecal than plasma testosterone concentrations. In rose-ringed parakeets, the levels of corticosterone in plasma were exceptionally high compared to the cockatiels. CONCLUSION: According to this study, we have been able to establish suitable methods for testosterone analysis in blood and faeces of cockatiels and rose-ringed parakeets, supporting the assessment of their reproductive status. At present saliva does not appear to be an ideal medium for reliable hormone level measurement, thus further investigations are required concerning this subject. CLINICAL RELEVANCE: By means of process analysis, it will be possible to detect increasing testosterone levels and/or pathological alterations, which could be considered in breeding programmes.

Examinations on the prevalence of footpad lesions and breast skin lesions in B.U.T. Big 6 fattening turkeys in Germany. Part II: Prevalence of breast skin lesions (breast buttons and breast blisters).

This project involves the prevalence of breast skin alterations (breast buttons, blisters, purulent bursitis) in male and female fattened turkeys (British United Turkeys Big 6) from conventional intensive farming. In this case, 24 turkey farms across Germany and 11,860 turkeys (5,740 toms, 6,120 hens) were clinically examined, and 16,200 birds (8,400 hens, 7,800 toms) were evaluated on slaughter lines at 7 turkey abattoirs. Each turkey farm included examination of at least 3 consecutive fattening cycles. Especially in the meat examinations, breast skin alterations were a frequent discovery, particularly in the form of breast buttons. The turkey toms exhibited a prevalence of 27.15%, and the toms were affected significantly more frequently (P < 0.001) by these variations than the turkey hens (7.77%). It is possible that the higher BW of the male specimens leads to increased lying times and is therefore connected with more severe strain on the breast region. The increased fattening period of the turkey toms (slaughtering at wk 21 to 22 of life) vs. the female specimens (slaughtering at wk 15 to 17 of life) must be discussed as a cause. Breast blisters and bursitis sternalis were discovered with a prevalence of 7.36 and 1.24% in toms and more seldom in hens, at 0.30% and 0.15%. Large differences in prevalence were partially recognizable between individual farms as well as between the 3 fattening cycles on a farm. Breast buttons and breast blisters are pathological skin variations for which the etiology is multifactorial. Clear correlations between the prevalence of breast skin alterations and the manner of rearing the birds were not able to be determined. An improvement in this situation, which is considered very problematic from the perspective of bird protection and economics, may be achieved only via cooperation to achieve optimized rearing methods, management, and breeding practices.

Examinations on the prevalence of footpad lesions and breast skin lesions in British United Turkeys Big 6 fattening turkeys in Germany. Part I: prevalence of footpad lesions.

The present study demonstrates the prevalence of footpad lesions in turkeys and their level of expression in both live birds and in carcasses. In clinical investigations of 11,860 turkeys (5,740 males, 6,120 females) of the strain British United Turkeys Big 6, individuals of all the observed flocks showed alterations to the plantar skin. In general, the degree and severity of skin alterations were higher in the 16th week of life than in the 6th or 11th week of life. Epithelial necrosis, however, was already apparent in about 45% of individuals in the 6th week of life. At this point, deep lesions on the footpad surface were still rare findings. In the 11th week of life, such skin changes were apparent in 14.7% of males and 25.7% of hens. In general, the feet of male turkeys were less affected by footpad damage than those of females in the subsequent fattening period. In hens, the prevalence of lesions of the footpads at wk 16 of age was 60.0%, almost twice as high as in males of the same age group (33.8%). A comparison of the findings from the right and left feet showed that the state of the 2 extremities was correlated (Spearman correlation: r = 0.830). During the visual inspection of 16,200 slaughtered turkeys (7,800 males, 8,400 hens), almost all carcasses studied showed alterations to the footpad skin. Only 2.1% of males and 0.6% of females were without lesions. The most frequently observed lesions measured up to 2 cm in diameter (males: 59.2%; hens: 57.7%). Pronounced skin lesions of the footpad (males: 21.1%; females: 29.5%) and necrosis of the superficial epithelium (males: 17.5%; females: 12.1%) were less common. Foot abscesses were diagnosed only sporadically (males: 0.1%; females: 0.1%).

Prevalence of viral infections in captive collections of boid snakes in Germany.

Data on viral infections in apparently healthy snake collections in Germany were obtained with respect to husbandry conditions and health status. Samples from 100 boid snakes (from 14 collections) were examined microbiologically and for the presence of paramyxoviruses (PMVs) using RT-PCR. Blood was tested for the presence of antibodies against PMV, adenovirus and reovirus and for inclusion bodies indicative of inclusion body disease. Nine snakes tested positive for PMV, and inclusion bodies were detected in six snakes. Antibodies against PMV were found in one snake, and two snakes had antibodies against an adenovirus. A significant correlation was found between the origin of the snake and the presence of PMV, and between the presence of remarkable microbiological findings and husbandry conditions.

Spermatozoa characteristics in six psittacine species using light microscopy.

Even though breeding of companion birds has increased continuously for years, the fecundity assessment of birds has hardly been acknowledged. Knowledge of the structure of spermatozoa is crucial for evaluation of the basic reproductive biology of any species as well as for phylogenetic research and cladistic analyses of internal relationships. Spermatozoa of six different psittacine species (Nymphicus hollandicus, Myiopsitta monachus, Agapornis roseicollis, Melopsittacus undulatus, Tanygnathus lucionensis, Guarouba guarouba) were examined using light microscopy. Head length (nucleus including acrosome), head width, midpiece length and tail length were measured and documented. Significant differences were obvious among almost all of the species for almost all four parameters. However, in all the six species a significant moderate correlation between spermatozoa midpiece lengths and tail lengths (r=0.535, p

Computed tomography for the diagnosis and treatment monitoring of bacterial pneumonia in Indian pythons (Python molurus).

Eight Indian pythons (Python molurus) with clinical and microbiological evidence of pneumonia were examined by computed tomography (ct) before and after treatment. The results were assessed subjectively and measurements were taken following a standard protocol. Changes in the lung tissue of all the pythons were diagnosed, and the extent of the disease could be assessed. ct examinations after treatment showed an improvement in the six pythons whose clinical condition had improved, but in the other two pythons they demonstrated the severity of the disease. The subjective assessments were superior to the evaluation of measurements of attenuation in regions of interest. However, the average and the maximum attenuation provided additional information on the extent of the disease. Except for one python with only mild clinical signs, the attenuation after successful treatment was still higher than in healthy pythons.

Blindness as a sign of proventricular dilatation disease in a grey parrot (Psittacus erithacus erithacus).

An approximately eight-year-old female grey parrot (Psittacus erithacus erithacus) was presented with a two months history of blindness. The radiographic examination showed a dilatation of the proventriculus, ventriculus and gut. Ophthalmoscopy and electroretinography revealed degeneration of the retina. A proventricular dilatation disease was suspected. The bird was euthanased because of deteriorating condition and poor prognosis. The pathological examination showed an atrophy of the ventricular muscles and lymphoplasmacytic infiltrates of the myenteric plexus of the proventriculus, ventriculus and gut as well as moderate lymphoplasmacytic infiltrates of the cerebrum with moderate neuronophagia. Lymphoplasmacytic infiltrates in the retina, indicating proventricular dilatation disease, and subsequent retinal degeneration were found. A potential common aetiology for proventricular dilatation disease and blindness is discussed.

[3D-X-ray microcomputer tomography and optical coherence tomography as methods for the localization of the blastoderm in the newly laid unincubated chicken egg]. / 3D-Röntgen-Mikrocomputertomographie und Optische Kohärenztomographie als Methoden zur Lagebestimmung des Blastoderms im unbebrüteten Hühnerei.

The routine culling of the male offspring of hybrid layer type chickens is met with increasing public disapproval for both ethical and legal reasons. Until now practice-oriented methods for reliable sex diagnosis prior to hatch could not be developed. Molecular genetical analysis of blastodermic cells can be used for sex determination in unincubated eggs; however, knowledge of the precise localization of the germinal disc is crucial for the extraction of a carefully directed cell biopsy. In principle, 3D-X-ray micro computed tomography (3D-CT) has been proven a suitable method to localize the germinal disk in the unincubated egg without damaging the egg shell. No negative effects on embryogenesis and hatching rate of irradiated hatching eggs were established. The pictorial representation of the germinal disk using optical coherence tomography (OCT) failed in the unopened egg. The egg shell formed an impenetrable barrier for the currently available measuring method which utilized near infrared (NIR) wavelength regions. After opening the egg shell, the germinal disk could be visualized without any difficulties. In conclusion, technical possibilities for localization of the germinal disk in the unincubated egg already exist, but regarding technical parameters, the procedures have to be adapted to the specific purpose.