Post-prandial serum bile acid concentrations and ammonia tolerance in Maltese dogs with and without hepatic vascular anomalies

SUMMARY: Post-prandial serum bile acid concentrations were measured in 200 Maltese dogs in an attempt to identify those with subclinical portosystemic shunts. Five of these were later shown to have hepatic pathology or abnormal liver function. In the other 195 Maltese bile acid concentrations ranged from 1 to 362 μmol.L^-1 (mean ± SD, 70 ±50 μmol.L^-1; median, 65.0 μmol.L^-1). Of these, 79% were above the reference range (0 to 31 μmol.L^-1) established from 23 mixed-breed control dogs. It was therefore not possible to determine the prevalence of subclinical portosystemic shunts on the basis of bile acid determinations.
Further investigation of liver function was performed to investigate why bile acid concentrations were increased in these dogs. Rectal ammonia tolerance tests were normal in 102 of 106 Maltese tested and liver samples (11 dogs) and plasma biochemistry profiles (9 dogs) demonstrated no significant hepatic disease or dysfunction.
Of 2 Maltese with hyperammonaemia after administration of ammonium chloride, one had a large congenital portosystemic shunt that was confirmed at surgery. In the other there were no macroscopic portosystemic communications, but a liver biopsy showed histological changes consistent with microscopic portovascular dysplasia.
Total serum bile acid concentrations were consistently lower when assessed by highperformance liquid chromatography than by an enzymatic spectrophotometric method. This discrepancy was substantially larger in Maltese than in control dogs, suggesting the presence of an additional reacting substance in the serum of Maltese dogs.     

Glomerulopathy in dogs with congenital portosystemic shunts

Kidney specimens from 12 dogs with congenital portosystemic shunts were examined histologically. Glomerulopathy of variable severity was present in the kidney sections of all 12. Marked irregular thickening of the glomerular capillary wall was the most prominent pathological change, the renal interstitium being largely unaffected. The severity of lesions was not correlated with the age of dogs at the time of necropsy. An immunoperoxidase technique failed to demonstrate significant IgA or IgG deposition in affected glomeruli. Proteinuria was generally mild or absent despite significant glomerular lesions, except in dogs with concurrent urinary tract infection.     

The development of a recombinant Babesia vaccine.

Crude extracts of Babesia bovis parasites were shown to induce levels of protection in susceptible cattle equivalent to that resulting from natural infection. The crude material was systematically fractionated and tested in numerous sequential vaccination/challenge experiments in adult cattle. Antigens in protective fractions were then purified by affinity chromatography with monoclonal antibodies. Three highly protective (more than 95% reduction in parasitaemias) antigens were thus identified. None of these antigens was immunodominant; a number of immunodominant antigens were identified and all were immunosuppressive and/or non-protective. The three protective antigens were cloned and expressed as either beta-galactosidase or glutathione-S-transferase (GST) fusion proteins. Two of these, GST-12D3 and GST-11C5, when used in combination were almost as protective as has been previously shown for the commercially available live attenuated vaccine. A short fragment of a third antigen (21B4) has also been shown to be protective. In two of the antigens, repetitive segments have been shown to be non-protective while the third antigen (12D3) does not contain repetitive domains. Homologues of these antigens exist in other Babesia species and it is anticipated that these may be candidate antigens for protective vaccines against those species.     

Effect of Modified Eros Centre on Some Reproductive Parameters of the Sow

The effect of a modified eros centre on weaning to oestrus interval, follicle size, ovulation and farrowing rate and total born litter size was investigated. In modified eros centre 94.4% and in group housing 79.1% of the sows (p < 0.01) expressed oestrus within 10 days post‐weaning. Weaning to oestrus interval was shorter (p < 0.001) for sows kept in modified eros centre. The interval from onset of oestrus to the time of ovulation was longer for sows in group housing (p=0.05). The time of ovulation was negatively correlated (r=?0.50) with the interval from weaning to oestrus (p=0.005). The time of ovulation after onset of oestrus was significantly (p < 0.05) shorter for sows expressing oestrus within 2–4 days of weaning, compared with the animals that expressed oestrus between days 5 and 6 post‐weaning and was shortest for sows expressing oestrus after day 6 post‐weaning. Farrowing rate was not affected by a modified eros centre. Litter size tended to be smaller in group‐housed weaned sows (p=0.10). The timing of last artificial insemination relative to time of ovulation did not affect litter size (p > 0.10). The implication of these results is that a modified eros centre may improve some of the post‐weaning oestrous parameters of the sow.     

Ligation of the caudal mesenteric artery during resection and anastomosis of the colorectal junction for annular adenocarcinoma in two dogs

An 8-year-old terrier cross and a 10-year-old German Shorthaired Pointer presented to the University Veterinary Centre, Sydney, for investigation of long-standing tenesmus and dyschezia. Both patients had an annular adenocarcinoma at the colorectal junction. Exploratory laparotomy was performed and the affected large intestinal segment was removed by resection and anastomosis. In both dogs, the caudal mesenteric artery was intimately associated with the mass, necessitating its ligation and transection. Postoperatively, there was no evidence of anastomosis breakdown in either case and both animals recovered well from surgery. The dogs were euthanased 8 and 10 months, respectively, after surgery because of clinical signs relating to metastatic disease.     

Malignant Sertoli Cell Tumour in a Young Simmenthal Bull – Clinical and Pathological Observations

Tumours are rare in the bovine testicle. A case of malignant Sertoli cell tumour in a 29‐month‐old Simmenthal bull that was hospitalized with a history of severe unilateral scrotal swelling is reported. On inspection and palpation, the scrotal sac was found enlarged with fluctuant content in the right side. The right testicle was enlarged, hard and indolent. Also the right plexus pampiniformis and funiculus spermaticus were enlarged. Sonograms revealed severe changes in the right testicle with a loss of homogeneity and multiple hyperechogenic areas. After slaughter, the scrotum with testicles were removed and evaluated pathologically. On section, the right testicle contained areas of necrosis, haemorrhage, and mineralization. Histology showed Sertoli cells in tubular structures surrounded by dense fibrous stroma replacing normal testicular tissue. Both lymphatic and blood vessels were infiltrated by neoplastic cells. Immunohistochemically, the neoplastic cells stained positive for vimentin and negative for cytokeratin and S‐100. Based on the pathological observations a diagnosis of right‐sided malignant Sertoli cell tumour with vascular invasion and hydrocele was established.     

Sperm Supply and Egg fertilization in the Ostrich (Struthio camelus)

We used egg break‐out and spermatozoa trapped in the perivitelline layer of eggs to test the hypothesis that sperm supply and egg fertilization rate are high in the ostrich. Egg fertilization status was determined at break‐out by the appearance of the germinal disc (GD) and then the perivitelline layer overlying the GD region was collected to count sperm (Sperm_OPVL) under fluorescence following staining with 4′,6′‐diamidino‐2‐phenyindole (DAPI). The study was carried out on commercial ostrich farms over two laying seasons. In the first year, 229 eggs from nine randomly chosen ostrich pens comprising pairs, trios (two females, one male) and larger groups were collected for 1 week of every month of laying. Eggs contained 253 ± 18 Sperm_OPVL/mm² of the GD (mean ± SEM; range 0–1330). Egg fertilization rate averaged 89.4 ± 3.4% and varied from 78.6 to 98.2% between pens. Month had no effect on sperm supply or egg fertilization status. Eggs from paired birds (sex ratio 1 : 1) had less sperm in the GD than the eggs from pens with a higher sex ratio. In the second year, 150 eggs from seven pens, each containing only one male and either one, two or three females, were studied for 2 weeks at the beginning (winter), middle (spring) and end (summer) of laying. Eggs contained 364 ± 45 Sperm_OPVL/mm² of the GD (range 0–2880). Season had no effect on sperm supply or egg fertilization. The number of Sperm_OPVL varied between pens, assumed to be due to variation between individual males. The number of Sperm_OPVL increased as the sex ratio increased only when very high‐ranking males were excluded from the analysis. Egg fertilization rate was 94.4 ± 3.1% but varied from 64.0 to 100% between pens. Egg fertilization was not affected by season or sex ratio. Low fertilization rates were observed in two pens and appeared related to the lack of synchrony between timing of laying and sperm production in the first, and lack of mating in the second pen. We conclude that ostrich flocks generally have high rates of egg fertilization and any infertility is associated with lack of sperm supply.