Studies of bovine Mycoplasma mastitis. 3. Testing of biochemical properties of Mycoplasma strains isolated from 3 stocks

Thirty-two isolates of altered milk samples taken from cows with mastitis on three industrialised dairy cattle units were biochemically tested following five passes through no-inhibitor media, assessment of filtratability through 450-nm-membrane filter, and clone assay. Something between five and ten clones of each of the strains involved were tested for their growth properties both at 22 degrees C and in no-serum media, sensitivity to digitonin and capability of aesculin hydrolysis. TTC reduction (triphenyltetrazolium-chloride), as well as for decomposition of glucose, arginine, and urea. The properties found were characteristic of M. bovis, A. laidlawii, and A. axanthum, and of the family of mycoplasmataceaea in the strains of one of the stocks.     

The role of elastase in the differentiation of Bacteroides nodosus infections in sheep and cattle

Eighty-seven Bacteroides nodosus isolates were examined for elastase production by clearing of elastin particles in TAS agar medium. These included 54 ovine virulent isolates, 28 ovine benign isolates and five bovine isolates. In addition 22 ovine virulent, 16 ovine benign and two bovine isolates were examined for decline in proteolytic activity over a 13-day period in the degrading proteinase test using hide power-azure as substrate. There was a remarkable correlation between elastase production, relative stability of proteolytic activity in the hide powder-azure test and virulence of B nodosus. Ovine virulent isolates invariably produced elastase whereas ovine benign isolates and bovine isolates were elastase negative. Bovine isolates produced only mild lesions in the feet of challenged sheep.     

Effect of staining and freezing media on sortability of stallion spermatozoa and their post-thaw viability after sex-sorting and cryopreservation

Sex‐sorted, frozen–thawed stallion spermatozoa remain out of reach of commercial horse breeders because of the low efficiency of the sex‐sorting process and unacceptable fertility rates after insemination. Two experiments were designed to test the effects of alternative staining and freezing media to improve the viability of sex‐sorted frozen–thawed stallion spermatozoa. Experiment 1 compared two freezing media, INRA 82^® and a modified lactose‐ethylenediaminetetraacetic acid (EDTA), for the cryopreservation of sex‐sorted stallion spermatozoa. No significant differences between the two freezing media could be identified, suggesting that both cryodiluents would be suitable for incorporation into a sex‐preselection protocol for stallion spermatozoa. Experiment 2 compared Kenney’s modified Tyrode’s (KMT) and Sperm TALP (Sp‐TALP) as the staining and incubation medium for stallion spermatozoa prior to sex‐sorting. A significant increase in the percentage of acrosome‐reacted spermatozoa occurred after staining and incubation in the clarified Sp‐TALP compared with KMT. As no improvements in sorting rates were achieved using Sp‐TALP, it was concluded that stallion sorting protocols could include KMT as the staining and incubation medium while either INRA 82^® or lactose‐EDTA could be employed as a cryodiluents.     

Extending ideas about animal welfare assessment to include 'quality of life' and related concepts

Ideas within the animal welfare science arena have evolved continuously throughout the last 30 years, and will continue to do so. This paper outlines some of these developments. These included reformulation of the five freedoms concept into the five domains of potential welfare compromise. This accommodated weaknesses in the former by distinguishing between the physical/functional and the mental factors that contribute to an animal's welfare state. This development reflected a rising scientific acceptance that the mental experiences of animals were legitimate foci for study and highlighted that what the animal itself experiences represents its welfare status. Initially, most concepts of animal welfare emphasised predominantly negative subjective experiences, such as thirst, hunger and pain, and negative affective states or feelings including anxiety, fear and boredom, but today positive experiences or emotions such as satiety, vitality, reward, contentment, curiosity and playfulness are also considered to be important. During the same period, the focus shifted from evaluating the impacts of individual mental subjective experiences or emotions towards seeking a more comprehensive, multifactorial understanding. The five domains concept was specifically designed to achieve this. Subsequent notions about quality of life (QoL) had the same objective, and emphasised the importance of positive experiences. However, some approaches to QoL assessment relied heavily on empathetic speculation about what animals may experience subjectively and this raised concerns about inappropriate anthropomorphic projections. Such pitfalls may be minimised when informed personnel rigorously apply objectively based methodologies to QoL assessments limited to a short time frame. It is clear that both formal and somewhat less formal QoL assessments of this type are already used to guide decision-making about the ongoing care and therapeutic management of animals on a daily basis. However, application of the recently introduced concepts of 'a life not worth living', 'a life worth avoiding', 'a life worth living' and 'a good life' is problematical, because extending the assessment time scale to the whole of life is attended by a number of as yet unresolved difficulties. Accordingly, their value in the practical management of animals is limited so that, at present, reliance on the minimum standards and recommendations for best practice outlined in codes of practice or welfare will continue to be necessary and worthwhile. Nevertheless, these concepts have value in providing a contextual theme that strongly focuses attention on the promotion of a lifelong QoL with an overall balance that is positive.     

Angiofibroma of the nasal cavity in 13 dogs

This case series describes a rare entity, nasal angiofibroma, in 13 dogs that were presented to the University of Wisconsin, School of Veterinary Medicine from 1988 to 2000. All dogs in this case series presented with clinical signs and radiographic changes that were strongly suggestive of a locally invasive neoplasm. However, histopathology completed on transnostral core biopsy samples revealed benign appearing vascular proliferation with secondary lymphosuppurative inflammation was established despite cytologic criteria of malignancy present in five dogs. On the basis of the outcomes in this case series, nasal angiofibroma should be considered a differential for dogs presenting with clinical signs consistent with a malignant nasal tumour.     

An instructional model for training competence in solving clinical problems

We examined the design of a course that aims to ease the transition from pre-clinical learning into clinical work. This course is based on the premise that many of the difficulties with which students are confronted in this transition result from a lack of experience in applying knowledge in real practice situations. It is focused on the development of competence in solving clinical problems; uses an instructional model with alternating clinical practicals, demonstrations, and tutorials; and extends throughout the last pre-clinical year. We used a "proof-of-concept" approach to establish whether the core principles of the course design are feasible with regard to achieving the intended results. With the learning functions and processes as a frame of reference, retrospective analysis of the course's design features shows that this design matches the conditions from theories of the development of competence in solving clinical problems and instructional design. Three areas of uncertainty in the design are identified: the quality of the cases (information, openness), effective teaching (student and teacher roles), and adjustment to the development of competence (progress, coherence).     

Infection of central nervous system endothelial cells by cell-associated EHV-1

Infection with equine herpesvirus-1 (EHV-1) causes respiratory disease, late-term abortions and equine herpesvirus myeloencephalitis (EHM). Our understanding of EHM pathogenesis is limited except for the knowledge that EHV-1 infected, circulating peripheral blood mononuclear cells (PBMC) transport virus to the central nervous system vasculature causing endothelial cell infection leading to development of EHM. Our objective was to develop a model of CNS endothelial cell infection using EHV-1 infected, autologous PBMC. PBMCs, carotid artery and brain endothelial cells (EC) from 14 horses were harvested and grown to confluency. PBMC or ConA-stimulated PBMCs (ConA-PBMCs) were infected with EHV-1, and sedimented directly onto EC monolayers ('contact'), or placed in inserts on a porous membrane above the EC monolayer ('no contact'). Cells were cultured in medium with or without EHV-1 virus neutralizing antibody. Viral infection of ECs was detected by cytopathic effect. Both brain and carotid artery ECs became infected when cultured with EHV-1 infected PBMCs or ConA-PBMCs, either in direct contact or no contact: infection was higher in carotid artery than in brain ECs, and when using ConA-PBMCs compared to PBMCs. Virus neutralizing antibody eliminated infection of ECs in the no contact model only. This was consistent with cell-to-cell spread of EHV-1 infection from leucocytes to ECs, demonstrating the importance of this mode of infection in the presence of antibody, and the utility of this model for study of cellular interactions in EHV-1 infection of ECs.