Ability of induced corpora lutea to maintain pregnancy in beef cows

Experiments were conducted in beef cows without a primary CL, in which pregnancy had been maintained with exogenous progestogen. In preliminary trials, replacement CL induced ipsilateral to the embryo and after, rather than before, d 36 of pregnancy, maintained more pregnancies after withdrawal of exogenous progestogen (13/13 vs 2/6; P < 0.05). In Exp. 1, in cows with replacement CL induced by treatment with hCG on d 28 of pregnancy, treatment with flunixin meglumine on d 31 through 37 did not increase maintenance of pregnancy. Experiment 2 was conducted to evaluate directly the effects of concentrations of PGF2alpha and estradiol-17beta during d 31 through 35 of pregnancy on maintenance of pregnancy by replacement CL induced between d 28 and 31. In cows that maintained pregnancy while progestogen was provided, maintenance of pregnancy after withdrawal of exogenous progestogen tended to be greater with high (5/5) than with low (2/6; P < 0.10) concentrations of PGF2alpha and greater with low (6/7) than with high (2/6; P = 0.10) concentrations of estradiol-17beta. Secretion of progesterone by replacement CL was greater (P < 0.05) in cows with high than in those with low concentrations of PGF2, during d 31 through 35. Prostaglandin F2alpha may facilitate attachment of the bovine embryo (d 30 to 40) in a manner similar to that reported for implantation in other species. Cows that did not form CL in response to hCG on d 28 to 31 responded well when retreated after d 36. Again, maintenance of pregnancy was greater when replacement CL were induced after (9/9) rather than before d 36 (8/16; P < 0.05).     

Parasites of domestic and wild animals in South Africa. XXXVIII. Ixodid ticks collected from 23 wild carnivore species

Ixodid ticks were collected from 104 wild carnivores belonging to 23 species in various nature reserves and on several farms in all nine provinces of South Africa. Seven feral cats in a nature reserve were also examined. Twenty-four tick species belonging to seven genera were recovered and identified. Amongst these ticks we consider the adults of Haemaphysalis leachi, Haemaphysalis spinulosa, Haemaphysalis zumpti, Ixodes rubicundus, Rhipicentor nuttalli, Rhipicephalus simus and Rhipicephalus turanicus to be true parasites of wild carnivores. Although numerous adult Rhipicephalus appendiculatus and Rhipicephalus zambeziensis were collected from some lions these were either sick or old animals. The immature stages of seven species regularly utilized wild carnivores as hosts on an opportunistic basis.     

The distribution of tsetse (Diptera: Glossinidae) and bovine trypanosomosis in the Matutuine District, Maputo Province, Mozambique

A tsetse and bovine trypanosomosis survey was conducted during 1998 and 1999 in the Matutuine District of Maputo Province (Mozambique). A total of 59 Glossina brevipalpis and 17 Glossina austeni were captured throughout the district. Survey results suggest that Glossina brevipalpis is mainly concentrated in dense vegetation along the Maputo River and in the wetlands east of the river. G. austeni, on the other hand, was captured mainly in dense thickets in drier areas. Both tsetse species are suspected to be vectors of bovine trypanosomosis. Bovine trypanosomosis (75,5% Trypanosoma congolense) was diagnosed in 53 animals (13,9%) from seven sampling sites distributed throughout the district. The prevalence of cattle with anti-trypanosomal antibodies was high (29,9%).The incidence of trypanosomal infections in sentinel cattle was also high. The widespread distribution of bovine trypanosomosis and the high prevalence of infection are likely to have a significant impact on cattle production and, hence, the cattle restocking exercise in the district.     

Effect of triple therapy on eradication of canine gastric helicobacters and gastric disease

Nine helicobacter-positive pet dogs with upper gastrointestinal signs were studied to evaluate the effect of a triple therapy, normally applied to humans for the eradication of gastric helicobacters, on clinical signs and gastric histology, as well as the recurrence of helicobacters after eradication in an extended follow-up in four dogs. Endoscopy was performed at entry to the study and repeated after eradication therapies and additional treatments. If the triple therapy (amoxycillin, metronidazole and bismuth subcitrate) failed, tetracycline and omeprazole were prescribed. Additional therapies were instituted if clinical signs persisted after eradication therapies. Helicobacter status was verified from gastric biopsy specimens by the urease test and histological examination, and in a few dogs also by brush cytology. Triple therapy eradicated gastric helicobacters in 7/9 dogs; gastric helicobacters were also eradicated in one dog treated with tetracycline and omeprazole. Eradication of helicobacters resulted in significant improvement, but not total resolution, of clinical signs. Subsequent additional therapies resulted in further alleviation of clinical signs. Neither triple therapy nor additional therapies had a significant effect on gastric histological changes. Gastric helicobacters recurred in 4/4 dogs within three years of the eradication treatment. Because canine gastric helicobacters alone were not definitively shown to induce clinical signs, routine eradication therapy seems not to be warranted at present.     

Diagnostic features, confirmation and disease progression in 28 cases of lethal acrodermatitis of bull terriers

Lethal acrodermatitis (LAD) is a genetically determined metabolic disease of bull terriers first described in the USA in the 1980s. In this study, the largest so far reported, 28 bull terriers born in the UK were diagnosed as suffering from LAD, and the clinical findings and the progression of the disease with time are described. The main characteristics of LAD are stunting, splayed digits, eating difficulties, skin disease of the face and feet, and increased susceptibility to microbial infections. In older dogs, paronychia, nail disease and hyperkeratosis of the footpads develops, becoming severe in dogs over six months of age. A diagnosis of LAD can be strongly suspected in any bull terrier showing a combination of the aforementioned signs from an early age. Dermatohistopathological demonstration of marked parakeratotic hyperkeratosis is strongly supportive of the diagnosis of LAD and, in association with the typical clinical findings, is sufficient to confirm a diagnosis. Although many of the clinical signs and the pathology of this condition suggest zinc deficiency, the measurement of blood zinc levels as a diagnostic aid is of limited value.     

Use of a circular external skeletal fixator for stifle arthrodesis in a dog

Arthrodesis of the right stifle was performed in a 21 kg German shepherd dog that had sustained a comminuted fracture of the lateral femoral condyle as a result of a gunshot wound. The arthrodesis was stabilised with a circular external skeletal fixator. A simplified technique to facilitate creation of the osteotomies of the femur and tibia, and positioning of the stifle at the desired angle, is described. Compression of the subchondral bone surfaces of the distal femur and proximal tibia was achieved using tensioned coiled transarticular Kirschner wires. Arthrodesis of the stifle was confirmed radiographically 21 weeks following surgery, and the fixator was removed. After union of the arthrodesis and removal of the fixator, the dog was fully weightbearing when standing or walking, and intermittently weightbearing or non-weightbearing at faster gaits.     

Ameliorative effects of sodium bentonite on phagocytosis and Newcastle disease antibody formation in broiler chickens during aflatoxicosis

The ameliorative effect of graded levels of dietary sodium bentonite (0.2, 0.4 and 0.6 per cent wt/wt of feed) on in vitro-impaired phagocytosis and suppressed immune response to Newcastle disease vaccine during aflatoxicosis (AF) in broiler chicks was investigated. Both percentage and mean of phagocytic activities were decreased significantly (P < 0.05) in chicks fed 2.5 mg aflatoxin per kg feed. The addition of sodium bentonite was significantly effective in ameliorating the negative effect of AF on the percentage and mean of phagocytosis. The presence of AF alone in the diet depressed the immune response of chicks as measured by haemagglutination inhibition (HI) test. Sodium bentonite was also effective in ameliorating the suppressive effect of AF on the HI -titre in chicks vaccinated against Newcastle disease. The best results obtained when sodium bentonite was added at the rate of 0.4 per cent wt/wt of feed to the AF-containing diets.     

Regulation of atrial fibrillation in horses with oral quinidine sulfate. Discussion of the disease picture in a typical case

Atrial fibrillation is a disorder of cardiac rhythmicity, and its importance in the horse depends on the underlying cause and the function of the horse. Before the decision is taken to start treatment, it has first to be ascertained whether treatment is worthwhile and whether the horse is an appropriate candidate for treatment. This article gives a short overview of current opinion on the cause and treatment of atrial fibrillation in the horse. The most used treatment at the moment, oral chinidine sulphate, is discussed. The hemodynamic consequences of atrial fibrillation and the response of a patient to treatment with chinidine sulphate are also discussed.     

Scrapie surveillance in Great Britain: results of an abattoir survey, 1997/98

A randomised sample of 2,809 apparently healthy sheep, 55 per cent of them less than 15 months of age, which were slaughtered for human consumption at abattoirs in Great Britain in 1997/98, was taken to establish the prevalence of scrapie infection. The medulla oblongata of each sheep was examined histopathologically at the level of the obex, and fresh brain tissue was examined for scrapie-associated fibrils (SAF) to establish whether there was evidence of scrapie. In addition, histological sections of the medulla from 500 of the sheep were immunostained with an antiserum to PrP, and the same technique was also applied to any animal found positive or inconclusive by the histological or SAF examinations. Any sheep which was positive by any of these diagnostic methods was also examined by Western immunoblotting, for the detection of the disease-specific protein PrP(Sc). A total of 2,798 sheep (99.6 per cent) were negative by all the methods applied. Ten animals were SAF-positive but negative by all the other methods, and in one animal there was immunohistochemical staining which could not be interpreted unequivocally as disease-specific. A mathematical model was used to estimate the prevalence of scrapie infection in the national slaughtered sheep population which would be consistent with these results. By this model, the absence of unequivocally substantiated cases of scrapie in the sample was consistent with a prevalence of infection in the slaughter population of up to 11 per cent.