Immune response in pigs to Aujeszky's disease viruses defective in glycoprotein g1 or gX.

Two Aujeszky's disease virus glycoprotein genes, gX and g1, have been used to produce deletion mutants which have then been developed into vaccines. These deletions then allow differentiation between pigs infected with wild type virus and those given the vaccine. It is not clear whether the glycoproteins encoded for by these genes are needed to induce a full protective immune response, in which case deletion mutants would suffer from lack of potency. To test this, commercially available Aujeszky's virus vaccines which lacked either gX or g1 were compared and isogenic constructs were made which differed only in the absence or presence of gX and, or, g1. These constructs and vaccines were used to vaccinate the natural host of Aujeszky's disease, the pig, and potency was measured using challenge with wild type virus. In all cases vaccines which lacked g1 performed significantly less well than those in which g1 was present, whereas deletions of gX had no significant effect on vaccine performance.     

Possibilities and limits of immunodiagnosis of strongyle infections in horses

In an investigation period over 8 months the natural course of infection was studied by means of coproscopic and serological methods in 27 mares and 29 foals. The examination of the stool showed in mares, before the beginning of the grazing season, an infection rate of 100% with small and a rate of 7.4% with large strongyles (Str. vulgaris). Serologically the ELISA showed in foals only a distinct increase of antibody activity with the somatic antigen. The mares retained the high IgG-values of activity, which were already found at the beginning of the investigations. Even though the agglutination test can be applied for control of the effectiveness of therapy in a horse population, individual diagnostic possibilities remain limited. This is due to the reduced sensitivity and specificity of the IgG(T)-concentration under natural conditions of infection. The double-antibody-sandwich-ELISA technique has shown to be basically feasible as a test for antigens from small strongyles. Somatic antigen could most sensitively be demonstrated by antibodies to ES-antigen, ES-antigen, however, by antibodies against somatic antigens.     

One-step purification of the major rainbow trout immunoglobulin

Salmonid immunoglobulin purification has been hampered by time-consuming, labour-intensive, conventional chromatographic procedures. In this report we describe the use of immunoaffinity chromatography for the purification of immunoglobulins from trout serum in a single step. An anti-heavy chain monoclonal antibody (1G7) which reacts with more than 85% of total trout immunoglobulins was used to purify the trout immunoglobulin. The purity achieved was higher than 95%, and the immunoglobulins recovered were fully immunogenic. This method served equally well in isolating immunoglobulins from the sera of other salmonids (coho salmon and chinook salmon). The procedure should be useful in the standardization of salmonid immunoglobulin reagents.     

Canine distemper viral antigens and antibodies in dogs with rheumatoid arthritis

Dogs with canine rheumatoid arthritis had significantly elevated levels of antibodies to canine distemper virus. This increase was particularly seen in the synovial fluids, compared with paired sera, and was not found in dogs with infective arthropathies, osteoarthritis or in osteoarthritis secondary to rupture of the cranial cruciate ligament. Analysis of the immune complexes precipitated from synovial fluids showed immunoglobulins in all types of arthropathy. Western blotting analyses showed reactivity with anti-distemper antisera in immune complexes from dogs with rheumatoid arthritis, but not in immune complexes from dogs with other joint diseases. These results suggest that there are increased immune responses to distemper in canine arthritis and that these may be due to the presence of this paramyxovirus in affected joints. The implications for the role of a possible infectious agent in rheumatoid arthritis in the dog are considerable.     

Inability to predict the adult sexual performance of bulls by prepuberal sexual behaviors

The objective of this investigation was to determine the extent to which the sexual performance of adult bulls (18 to 24 mo of age) can be predicted by prepuberal sexual behaviors. Tests were administered to 121 polled Hereford bulls to determine whether adult sexual performance (especially serving capacity or ejaculation rate) was related to 1) whether or not the subjects mounted estrous females at 6 mo of age, 2) the age at which the bulls attained their first ejaculation, 3) the frequency of sexual behaviors exhibited in heterosexual interactions and 4) the frequency of male-male mounting exhibited in all-male groups. None of the above measures reliably predicted adult serving capacity. Prepuberal interest in mounting other males and estrous females and the age at which ejaculatory competence was attained bore little relationship to serving capacity at 18 to 24 mo. Individual differences in rate of ejaculation were consistent from one age to another only after the bulls had reached 18 mo. We concluded that the sexual behaviors of prepuberal beef bulls were of limited usefulness in predicting adult sexual performance.     

The physical state and plasma biochemical profile of young calves on arrival at a slaughter plant

AIM: To determine the welfare of calves arriving at a slaughter plant by assessing their physical state and plasma biochemical profile. METHODS: Calves (n=7,169) aged 4-10 days, were examined immediately after they were unloaded from trucks (n=20) and categorised on physical grounds as being in an 'unacceptable', 'marginal' or 'acceptable' state. 'Unacceptable' calves were lying down, unable to walk, extremely weak or seriously injured. 'Marginal' calves had a wet umbilicus, were hollow sided, apparently immature, or weak and slow and unsteady on their feet. 'Acceptable' calves were strong, walked freely, round-sided, bright and alert and had a dry umbilicus. After unloading, 27 'unacceptable', 306 'marginal' and 289 'acceptable' calves were weighed, examined clinically and a blood sample was taken from each. A second blood sample was taken from 118 of these calves, 12-15 hours later. The packed cell volume (PCV) and plasma concentrations of glucose, beta-hydroxybutyrate (BHB), total plasma proteins (TPP), gamma-glutamyl transferase (GGT), urea, creatine kinase (CK) and lactate were measured. RESULTS: Only 27 of the 7,169 calves examined (0.4%) were categorised as being in an 'unacceptable' state on arrival and these were euthanased shortly after unloading. Generally, the plasma biochemical profiles of the 'acceptable' calves were similar to those of 'marginal' animals. However the glucose concentration of 'marginal' calves was lower than that of 'acceptable' calves, suggesting that they had lower energy reserves. After 12-15 h in lairage, plasma glucose concentration decreased and the BHB concentration increased in both 'acceptable' and 'marginal' calves compared with concentrations measured on arrival. CONCLUSIONS: The percentage of calves presented for slaughter in an 'unacceptable' state was small (0.4%). However, 4% of calves were classified as 'marginal' and failed to meet all the requirements of the code of recommendations and minimum standards governing the welfare of young calves in New Zealand. The categorisation of calves by a physical assessment was supported by results of plasma biochemistry. As a result, plasma biochemical profiles are considered unnecessary for making decisions regarding the welfare status of calves arriving at a slaughter plant; an assessment of their physical state is sufficient.     

Conjunctival xanthoma in a blue and gold macaw (Ara ararauna)

A 17-year-old female blue and gold macaw ( Ara ararauna ) presented for evaluation of a discreet, conjunctival mass of the OD. No other abnormalities were found on ophthalmic or physical examination. A heterophilic leukocytosis was present on the complete blood count, and elevated aspartate aminotransferase activity, creatinine kinase activity and cholesterol were present on the plasma biochemistry panel. Surgical removal of the mass was complete and no recurrence has occurred by six months after excision. Reduction of dietary fats was recommended to reduce serum cholesterol levels and reduce the likelihood of future occurrence of xanthomas in this bird.     

Cardiorespiratory and anaesthetic effects of two continuous rate infusions of dexmedetomidine in alfaxalone anaesthetized dogs

Six Beagles were used in this prospective randomised crossover experimental study. Dexmedetomidine was administered at 0, 1 or 2 μg/kg IV for group C, LDA and HDA, respectively. Animals were induced and maintained with alfaxalone at 0.07 mg/kg/min with a CRI dexmedetomidine dose of 0, 0.5 or 1 μg/kg/h for group C, LDA and HDA, respectively. Cardiorespiratory variables, arterial blood gases and depth of anaesthesia were recorded. The recovery times and quality of recovery were scored. Group HDA produced a greater increase in the depth of anaesthesia than LDA. However, with both protocols, CI was halved compared to normal values in dogs. The use of oxygen before and during the anaesthetic maintenance is advisable, mainly if dexmedetomidine is going to be use as a pre-medicant and maintenance agent. The quality of recovery was better in groups receiving dexmedetomidine, without causing an increase in recovery time.