Isoenzyme studies on Theileria (Protozoa,Sporozoa). Enzyme activity associated with the erythrocytic stage

Summary

Bovine blood containing piroplasms of Theileria parva, as well as non‐injected blood, was lysed and subjected to iso‐electric focussing.

Staining for 13 different enzymes revealed parasite‐associated bands of glucose phosphate isomerase (GPI) activity, not of any of the other enzymes. There were no variations between individual donor animals in the host cell GPI bands and these bands did not interfere with the recognition of the parasite‐associated bands, so that purification of the piroplasms was unnecessary. Blood from cattle infected with T. mutans also gave parasite‐associated bands of GPI, but no such bands were seen in zymograms of blood from cattle infected with a Theileria sp. from Japan. Depending on the level of parasitaemia, up to four parasite‐associated bands were found in one strain of T. parva and up to three in two other strains. Among the disadvantages of using piroplasm material for the study of isoenzymes of T. parva is the fact that animals often die before their parasitaemia is sufficiently high, and that some strains never give rise to a high parasitaemia.     

Auditory brainstem responses in the normal beagle

Summary

The latencies of the peaks in brainstem responses and the threshold response were determined in 18 healthy beagles.

In the first series of measurements the dogs were sedated and the stimulus was delivered via an in‐the‐ear transducer. The latencies, the threshold levels, and the influence of the stimulus repetition rate on the latencies were measured. Using a miniature electret microphone in the outer ear canal near the tympanic membrane, it was found that at a level setting corresponding to 0 dB human level (HL) the major peak in damped oscillation during condensation reached a sound pressure level (SPL) of about 27 dB and the secondary rarefaction peak reached 24 dB SPL.

In the second series of measurements the dogs were not sedated and the stimulus was delivered via a headphone.

The wave forms, the mean latencies for peaks I to V as a function of the stimulus level, and the threshold of each wave are presented from both series. In the first series the latency values at 80 dB HL (107 dB SPL) were 1.21, 1.97, 2.67, 3.12 and 3.61 ms for peaks I, II, III, IV and V, respectively. The thresholds for peaks I to V were 47.5 ± 9.5, 47.5 ± 11.5, 41.3 ± 13.0, 63.3 ± 17.4 and 28.0 ± 9.7 dB HL, respectively. The difference in peak latency between the first and the second series was 0.065 ms. This difference corresponded to the difference in length of the acoustic pathways.

Analysis of variance was used to determine whether the successive peaks in the response followed at a constant time interval, i.e., whether a shift in the first peak with a change in the stimulus level was followed by the same shift in subsequent peaks. The analysis showed a significant (P < 0.001) interaction between the inter‐peak latency differences and the effect of stimulus level. This inter‐peak latency depended on stimulus level, although the effect was small.

The use of the in‐the‐ear transducer and sedation resulted in a far more efficient procedure than the use of the headphone without sedation.     

Aluminium intoxication in a dog

Summary

A two‐year‐old male Barsoi dog was presented after a two‐week period of muscle twitching and convulsions during exercise, which worsened to a state of tetraparesis and coma. Removal of a gastric foreign body, containing aluminium, resolved the presenting signs. Parallel with this clinical recovery the elevated serum levels of aluminium decreased to values of two normal control dogs, suggesting that the neurological signs were due to A1 intoxication.     

Myocardial damage in cats that died after anaesthesia

Summary

The necropsy findings of 85 cats that died up to six weeks after administration of injectable anaesthetics are described The most obvious findings in these cats were degeneration and necrosis of heart muscle fibres followed and related to time after the administration of the anaesthetics, by infiltration of predominantly mononuclear cells and by an increase in collagenous connective tissue. The lesions were most obvious on the inner side of the myocardium, indicating that hypoxic injury occurred during anaesthesia. The possible mechanism of the damage to the heart and its role in the pathogenesis of cardiomyopathy in the cat is discussed.     

The bovine pituitary‐adrenocortical axis and milk yield

Summary

A review is given of the available literature concerning the relationship between the bovine pituitary‐adrenocortical axis and milk yield in dairy cattle. A severe drop in milk yield (more than 50%) can be induced by a single or repeated intramuscular injection of at least 200 IU ACTH or by a single intramuscular injection of 14.6 mg dexamethasone. Sixty minutes after an intravenous injection, both 200 IU ACTH and 100 mg cortisol are equivalent to a plasma cortisol concentration of at least 31 ng/ml. Thus the decrease in milk yield after an intramuscular injection of more than 200 IU ACTH can hardly be induced by cortisol only. The fact that bovine plasma hardly binds any dexamethasone, in sharp contrast with bovine mammary epithelial tissue, is a possible explanation of the special part which dexamethasone plays in milk yield.     

Microbial and nutritional aspects of feeding fermented feed (poultry by‐products) to pigs

Summary

Broiler by‐products (heads, feet, and viscera) mixed with 4% dextrose were pasteurized for 4 min at 90°C core temperature, cooled to 20°C, and fermented with Lactobacillus plantarum as starter culture. These fermented poultry by‐products were fed to 12 individually housed fattening pigs as part (17.6% of the dry matter) of their fattening ration, the remainder composed of compound pig feed. Control pigs received a compound pig feed only. Both groups of pigs were fed restrictively on the basis of body weight. The technical results of the pigs fed the experimental diet showed a significantly improved feed:gain ratio (2.46 vs 2.57), a significantly higher carcass weight (86.1 vs 81.8 kg), a lower meat percentage (50.9 vs 52.5%) and an increased backfat thickness (21.5 vs 18.7%). The bacterial flora in the intestinal tract of the pigs fed the experimental diet differed significantly from the control animals. Decreased colony counts of mesophilic aerobic bacteria, Enterobacteriaceae, enterococci and lactobacilli were found in the rectal content and the prevalence of salmonella was lower.

It is suggested that the improved feed:gain ratio and the reduced bacterial activity of the measured groups of bacteria is a result of 1) the higher energy content of the diet, and(or) 2) an assumed enhanced digestibility of nutritional components in the diet, and(or) 3) the lower incidence of diarrhea in the pigs fed with fermented poultry by‐products. This resulted in a lower contamination level of enteropathogenic bacteria like, salmonella and Escherichia coli, in the gastro‐intestinal tract of the pigs fed fermented poultry by‐products.     

Veterinary practice and occupational health

Summary

The prevalence of allergy, lung function disorders, and bronchial hyperreactivity was studied in 102 Dutch veterinarians, subdivided into five professional groups (predominantly working with either swine, cattle, poultry, companion animals, or as a non‐practitioner). The mean age of the participants was 43 years; 6 participants were females. Twenty‐two per cent of the participants were overweight, and relatively more non‐practitioners than practitioners were overweight. Approximately 23% of the vets reported complaints of prolonged fatigue. The data suggest a relationship between complaints of prolonged fatigue and a more than average number of daily working hours. Only a small proportion of vets were sensitized against several allergens. There were no significant differences in prevalence of distinct lung function disorders or bronchial hyperreactivity between professional groups. It is hypothesized that the respiratory complaints (chronic coughing, chronic phlegm production, stuffed nose, sneezing) reported by the vets predominantly working in swine and/or poultry practice could be caused by irritation and/or inflammation of the first part of the trachea‐bronchial tree that has no measurable and permanent consequences for changes in lung function or increased bronchial hyperreactivity. The results of a skin test against allergens and determination of allergen‐specific IgE in blood indicated that the respiratory complaints were probably not related to allergy against the panel of allergens tested.     

Results of adrenalectomy in 36 dogs with hyperadrenocorticism caused by adrenocortical tumour

Summary

A total of 38 adrenocortical tumours were removed from 36 dogs with hyperadrenocorticism. The surgical approach was by way of a unilateral flank laparotomy (32 dogs; 14 left and 18 right), a bilateral flank laparotomy (3 dogs) or a midline celiotomy (1 dog).

Two dogs were euthanized during surgery because their tumours could not be resected. Eight dogs died from post‐operative complications. Pancreatic necrosis with peritonitis was the most common cause of death. Eight of the 26 dogs that survived had signs of recurrence of hyperadrenocorticism. Unsuppressible hyperadrenocorticism was found in four dogs; one dog had probably pre‐existent pituitary‐dependent hyperadrenocorticism, and adrenocortical function could not be re‐examined in the remaining three dogs.

Among the 37 tumours examined microscopically expansion of neoplastic tissue into blood vessels was found in 22 of them. Four adrenal glands with adrenocortical tumours also contained phaeochromocytomas. Necropsy was performed in eight dogs. Metastases were found in the lungs of two dogs and in the lungs and liver in one dog.

In combination with the data of previous reports, it is suggested that histological findings in surgery specimens are not good predictors for the clinical outcome.