2010 - 79 (5)

Paper in Dutch

Encephalitozoon cuniculi is a protozoan parasite that may cause nervous symptoms, kidney disease and eyelesions in rabbits. The main problem is to diagnose the parasite as the cause of the observed symptoms in the livinganimal.A simple, most frequently used method is serology. However, a positive serology result should not be regardedas a correct diagnosis, since many rabbits appear to possess antibodies without showing any symptoms of the disease.A negative serology result can usually be considered as truly negative. In practice, based on clinical signs and apositive serology result, a treatment is usually started. It consists of fenbendazole, 20 mg/kg orally sid, during 4weeks. The prognosis is guarded. Some rabbits recover completely. However, in many other rabbits the clinical signsare irreversible.

A 6-year-old, male striped skunk (Mephitis mephitis) weighing 5.9 kg was anesthetized for diagnosticimaging procedures and subsequently for a laminectomy at level L6/S1 as treatment of lumbosacral stenosis.On both occasions, anesthesia was induced by a face mask using 5% isoflurane in oxygen. After endotrachealintubation, anesthesia was maintained with isoflurane in oxygen. When necessary, intermittent positivepressure ventilation was instituted.For the surgical intervention, analgesia was provided with pre-operative carprofen, perioperativeintravenous infusion of fentanyl and postoperative buprenorphine. The constant rate infusion of fentanylprovided a sufficient level of analgesia and reduced the amount of isoflurane needed. Hypoxemia occurred atthe end of surgery and was successfully treated using a vital capacity manoeuvre. The recovery from bothanesthetic procedures was smooth and uneventful and the surgical intervention was successful. Three weeksafter surgery the skunk was able to move the pelvic limbs voluntarily.

A 9-year-old spayed female Flemish cattle dog was presented with a history of vaginal discharge and a slowlyprogressive bilateral symmetrical alopecia on the neck, shoulders and flanks, ventral abdomen and the perineal area.Clinical examination revealed pattern alopecia with the presence of macular melanosis on the ventral abdomen andin the perineal area. The dog also had a swollen vulva and gynecomasty. Abdominal ultrasonography revealed thepresence of two intact ovaria (with cystic follicles in the right ovarium) and a stump pyometra. Ovariectomy andstump removal were performed. Histopathological examination demonstrated that one polycystic ovary wascharacterized by multiple follicular cysts. The collection of all data led to the diagnosis of hyperestrogenism causedby a cystic ovary. This case demonstrates that even with a misleading history (spayed bitch) a correct interpretationof skin lesions can lead to the diagnosis of hyperstrogenism due to ovarian cysts.

The present paper describes a study in which the association between the shape of the lactation curve based ondaily milk yield recordings and the registration of the first post partum heat as detected by an automated heat detectionsystem was examined. In total, 689 animals from 2 herds were included in the study. On both farms, the daily milkproduction was automatically registered by the management system. This data was used to determine in which weekpost partum the peak lactation occurred. Then the shape of the lactation curve between the first week and the peakweek was calculated, which served as a good reflection of the rapidity with which the milk production starts up.Both herds were equipped with similar pedometers to detect cows in heat in a standardized and reasonably accurateway. The first heat was registered on average 52 days post partum. Factors significantly associated with the intervalbetween parturition and first estrus were parity and maximum milk yield. Older cows and cows with a higher peakproduction were detected in heat significantly later. The rapidity with which the lactation starts up (expressed as theshape of the lactation curve) and the calving season were not significantly associated with the interval betweenparturition and first estrus.

Quantitative microbial risk assessment (QMRA) is used to estimate the risk level of pathogens along thefood chain and to support management decisions for the reduction of food safety risks. The degree of credibilitythat can be attached to risk assessment results depends largely on the quality and quantity of the data, themodel structure and the assumptions made. Quality Assurance (QA) in QMRA is defined as the structurethat ensures that all the steps in the risk evaluation process are scientifically based so that the policy questionsbeing posed can be answered. Whereas sensitivity analysis and scenario analysis are generally applied inQMRA, formal methods for the evaluation of data quality, the critical evaluation of assumptions, structuredexpert elicitation, the checklist approach and peer review are rarely used in QMRA, even though they wouldimprove the transparency of the risk analysis process. An overview of QA methods for QMRA is presented.The degree of implementation of these methods should be proportionate to the stakes of the risk managementquestions and should be discussed in consultation between the risk assessors and the risk managers.

Paper in Dutch

Chinchillas are prone to develop a wide range of dental pathologies. The most common one is malocclusion,a condition in which the teeth are misaligned and/or incorrectly positioned in relation to one another.Odontomas, caries, tooth resorption, and periodontal and endodontic diseases have also been reported. Thisarticle presents an overview of the specific anatomy and the most common dental pathologies of chinchillas,including the various aspects of the clinical symptoms, diagnosis and treatment of these pathologies.

The equine practitioner is faced with a wide variety of dysrhythmias, of which some are physiological. Therecording of an exercise electrocardiogram (ECG) can help distinguish between physiological and pathologicaldysrhythmias, underlining the importance of exercise recordings.The evaluation of an ECG recording should be performed in a highly methodical manner in order to avoiderrors. Each P wave should be followed by a QRS complex, and each QRS complex should be preceded by aP wave.The classification of dysrhythmias according to their origin helps to understand the associated changes onthe ECG. In this respect, sinoatrial nodal (SA nodal), atrial myocardial, atrioventricular nodal (AV nodal) andventricular myocardial dysrhythmias can be distinguished.Artefacts on the ECG can lead to misinterpretations. Recording an ECG of good quality is a prerequisiteto prevent misinterpretations, but artefacts are almost impossible to avoid when recording during exercise.Changes in P or T waves during exercise also often lead to misinterpretations, however they have no clinicalsignificance.

Upon auscultation, cardiac dysrhythmias can be suspected, but electrocardiography is the ultimate diagnostictool. Electrocardiogram (ECG) recording used to be reserved to specialized centers, but nowadays relativelycheap and small recorders are available to the practitioner in the field. ECGs can therefore be recordedambulatory and during prolonged periods at rest or even during exercise. The know-how of a good quality recordingis mandatory for a correct diagnosis. The basic equipment consists of electrodes, a recorder and a wayto display the trace. Self-adhesive electrodes should be used, and positioned along the mean electrical axis ofthe heart. Small recording devices offer the advantage of allowing recordings during exercise.As the electrical impulse spreads through the heart, the ECG trace shows successively a P wave, a QRScomplex and a T wave. Ta waves are not always clearly visible in horses.The positioning of the electrodes may differ for ambulatory, exercise or long-term resting recordings.However, as long as the electrodes are positioned along the mean electrical axis, their exact position is not ofcrucial importance.