146:1, 2012 ESVP/ECVP Proceedings 2011 73

OSTEOCHONDROSIS IN FIGHTING BULLSU. D�avila*, L. Maniscalco y, M. A. Sierra*,

B. Biolatti y and A. M�endez**Department of Anatomy and Comparative Pathology, University of C�ordoba

and yDepartment of Animal Pathology, University of Turin, ItalyIntroduction: Osteochondrosis (OCD) is characterized by failure ofendochondral ossification involving the articulareepiphyseal carti-lage complex. Articular pathologies are frequent in these bulls asthey are bred to be overweight. This disease has been linked to riskfactors including incorrect feeding, grazing on hard surfaces, heredi-tary factors, conformation defects and trauma.Materials and Methods: The study was carried out on 200 fightingbulls (3e4 years old) where the joint surfaces of the carpal and meta-carpal bones III and IV were analyzed radiographically and by scan-ning electron microscopy. Areas of interest for histopathologicalexamination were sampled and fixed in 10% neutral buffered forma-lin. Bone samples were decalcified in 11% hydrochloric acid. Tissueswere stained with haematoxylin and eosin and Fraser Lendrum stain.Results: In 80% of samples of joint cartilage there were significanthistopathological changes consistent with OCD. In all the affectedcases, the lesion was bilateral, appearing on the surface of the carti-lage corresponding to areas of friction within the joint.Conclusions: OCD in the fighting bull is characterized by abnor-malities in endochondral ossification of the cartilaginous complex ofthe articulareepiphyseal region. The aetiology most likely relates totrauma or biomechanical factors in cartilage that has been weakenedby nutritional or hormonal imbalance, vascular disruption and ge-netic factors.

SYSTEMIC SPREAD OF INFECTION IN TAIL-BITTEN PIGSH.-K. Sihvo*, O. Simola*, C. Munsterhjelm y and P. Syrj€a*

*University of Helsinki, Helsinki, Finland andySwedish University of Agricultural Sciences, Uppsala, Sweden

Introduction: Tail biting causes inflammation of the tail and is as-sociated with abscesses, especially in the lung and spine, of finishingpigs. Three routes of spread of infection from the tail have been pro-posed previously: venous, lymphatic and cerebrospinal. The aim ofthis study was to test those routes for systemic spread of infection intail biting.Materials and Methods: Thirty-five growing, tail-bitten pigs and21 age-matched, unbitten controls were subjected to necropsy exam-ination. Internal organs, tail and central nervous system were exam-ined microscopically and tissues with inflammatory lesions werecultured.Results: Venous route: chronic purulent or necrotizing interstitial orbronchopneumonia with (n5 7) or without (n5 2) abscesses was as-sociated with severe tail damage. Bacteriology revealed primary andsecondary pathogens (e.g. environmental bacteria). Pulmonary acti-nobacillosis, mild lymphocytic interstitial pneumonia and mild lym-phocytic infiltration of several organs were evenly present both inbitten and control animals. Lymphatic route: enlarged and mildly re-active lumbar lymph nodes were present in two pigs; both had a se-verely bitten tail. Cerebrospinal route: mild multifocal meningeallymphocytic infiltrates were present both in bitten and control pigs.Conclusions: Systemic spread of infection in growing, tail-bittenpigs occurs mainly via the venous route, targeting the lungs, and toa lesser extent via lymphatic spread. Tail biting seems also to predis-pose the pig to opportunist lung infections.

A CASE OF MULTICENTRIC B-CELL LYMPHOMAIN AN ALPACA

K. BelakDepartment of Pathology and Wildlife Diseases, National Veterinary Institute,

Uppsala, SwedenIntroduction: Alpacas have progressively gained popularity as com-panion animals in Sweden. Reports of neoplasia in New World cam-elids are uncommon and most reports are of neoplasia in llamas. Thiscase report describes the pathological features of a multicentric lym-phoma found in an alpaca.Materials and Methods: A 10-year-old male alpaca that had beenused for breeding purposes presented with a history of progressiveweight loss and markedly enlarged lymph nodes. Following humanedestruction a complete necropsy examination was performed.Selected tissues were fixed in 10% neutral buffered formalin, sec-tioned and processed routinely. Immunohistochemistry was per-formed on samples of lymph nodes with reagents specific for CD3and CD79a.Results: At gross examination, marked generalized lymph node en-largement was found with replacement of normal nodal architectureby homogeneous pale tan, firm tissue. The animal was emaciated.Histopathological examination revealed a neoplastic proliferation oflymphocytes, characterized by a dense packeting of round to slightlyelongated, pleomorphic mesenchymal cells in a fine fibrous stroma.Mitotic activity was relatively high. Immunohistochemical labellingwith anti-CD79a showed strong labelling of a large proportion of neo-plastic cells.Conclusions: Based on these features the tumour was diagnosed asa multicentric B-cell lymphoma.

APROSENCEPHALY AND OTOCEPHALY IN A LAMBWITHOUT OTX2 MUTATION

L. Brachth€auser*, S. Klumpp y, W. Hecht*,K. Kuchelmeister z, M. Reinacher* and C. Herden*

*Institut f€ur Veterin€ar-Pathologie, yKlinik f€ur Kleintiere,Justus-Liebig-Universit€at Giessen and zInstitut f€ur Neuropathologie,

Universit€atsklinikum Bonn, GermanyIntroduction: Aprosencephaly is a rare condition in veterinary andhuman medicine characterized by a complete absence of the telen-cephalon and diencephalon that can be associated with severe facialdysmorphism designated as otocephaly. Dysfunctional mutation lead-ing to otx2 gene heterozygosity is associated with this phenotype inmouse models.Materials and Methods: Morphological abnormalities of the skulland central nervous system (CNS) are described in a stillborn lambby computed tomography, magnetic resonance imaging and patho-logical examination. Cells of developed parts of the brain were char-acterized immunohistochemically and DNA was isolated for otx2 genesequencing.Results: Craniofacial alterations comprised a severely reduced anddysplastic splanchnocranium with pinnae fusing in the midventralpart of the brain (otocephaly). The microencephalic brain lackedthe entire forebrain (telencephalon and dienencephalon), while thecerebellum had a normally developed layered and mature cortex.No polymorphic sites were recognized within the otx2 gene, whichwas fully sequenced for the first time in Ovis aries.Conclusions: CNS malformations may have varied aetiologies inveterinary and human medicine. In this case of true aprosencephaly,no mutations of the otx2 gene were found. Thus, metabolic and oxy-genic disturbances might be possible teratogenic causes for this natu-rally occurring condition.