Veterinary Services

Generalised and systemic conditions

A seven-year-old Holstein cow died suddenly two months after calving twins. She had suffered from milk fever but was milking well. Necropsy at the Dumfries centre revealed a 20 cm circular swelling on her ventral abdomen. On incision noxious gas was released and the subcutaneous muscle over a 40 cm diameter area was black. The milk vein ran through the centre of this area and clotted blood lay under the skin. The abdominal muscle was positive for Clostridium novyi by Fluorescent Antibody Test (FAT) and Clostridium novyi was also cultured from the liver. A presumptive diagnosis of Malignant Oedema was made, thought to be secondary to the administration of calcium into the milk vein.

Respiratory tract conditions

At the Edinburgh centre, the lungs from three adult dairy cows were submitted for examination. The group had started to show signs of respiratory disease at grass four to five weeks previously. In all cases the tracheal mucosa showed numerous petechial haemorrhages and the trachea contained copious amounts of froth and fluid, with blood clots. The bronchi and terminal bronchioles contained moderate numbers of adult lungworms. The lungs showed severe overinflation, interlobular emphysema, congestion and oedema and there was severe suppurative pneumonia affecting cranial and middle lobes in all cases. The caudal lobes were affected with consolidative changes at the periphery and within the lung mass. FAT’s on non-suppurative consolidated tissues for Respiratory Syncitial Virus (RSV) and Parainfluenza 3 virus (PI3) were all negative. Pasteurella multocida was isolated from one of the plucks. Histopathology of all three sets of lung tissue show a combination of acute and chronic lesions of bacterial-type bronchopneumonia coupled with extensive parasitic-type pneumonia. Alveolar smooth muscle hyperplasia was evident indicating more long-standing lungworm exposure.

Alimentary tract conditions

A dairy farm in Dumfriesshire had a serious calf scour problem where at least half of the calves developed scour and died at around two to three weeks of age. Treatment with fluids and antibiotics had little effect. Cows were vaccinated against rotavirus, coronavirus and E coli K99 and calves were treated prophylactically with halofuginone in the first week of life. The findings after postmortem examination of four calves varied and included rotavirus, cryptosporidia confirmed by histopathology of the intestine and hypogammaglobulinaemia. After continuing problems two affected calves were euthanased for examination. There were no gross changes in the intestines and the Zinc Sulphate Turbidity (ZST) levels indicated adequate colostrum absorbtion and immune protection. On histopathology the villi in the lower small intestine were fused and collapsed. The crypts were elongated and the Peyer’s patches depleted. Numerous gram-negative bacteria were attached to and associated with the enterocytes in the crypts and villi. A diagnosis of diarrhoea due to attaching and effacing E. coli was made. A pure growth of E coli was isolated from one case, which was identified as E coli O26 by PCR. This strain has been described as a cause of attaching and effacing lesions in calves.

It was concluded that as the pathology affected the cypts as well as the villi this limited the ability of the mucosa to regenerate and predisposed calves to the more common enteric infections described above. This villous and crypt pathology had been seen on histopathological examination of the earlier calves and explained the failure to respond to treatment.

Diseases of the circulatory system

Babesiosis was confirmed in a three-year-old Limousin cow on a farm near Inverness. Three deaths were reported in a group of 30 animals. Affected animals presented with red urine. Large numbers of piroplasms resembling Babesia divergens were seen in blood smears.

Nervous system disorders

A two-year old bullock was submitted to the Edinburgh centre with a history of illness for two days while at grass progressing to recumbency with laboured breathing and flickering eyes prior to death. The lungs were congested and oedematous with stable foam in the airways. There was anterioventral collapse with fine fibrous adhesions between the lung lobes. Rough, red fibrous plaques were present over the parietal pleura, pericardial sac and epicardium. The bile ducts were thick and fibrous and two liver fluke (1.3-1.5cm long) were found. There appeared to be a slight excess of cloudy cerebrospinal fluid (CSF). Laboratory testing revealed normal lead levels and brain cultures were sterile. Histology of the lung revealed that the pleural plaques were areas of intensely congested, chronic fibrous pleurisy. Histology of the brain revealed a severe suppurative meningitis occasionally extending to the underlying neural tissue. Meningeal inflammation over the cerebellum was the most prominent feature and there was local, focal malacia of cortical grey matter suggesting secondary brain swelling. These findings are consistent with a bacterial infection and confirmed the meningitis suspected grossly.

Reproductive tract conditions

A twelve year old Bison bull had been fighting with another bull five days prior to death. Since fighting it had been looking stiff and uncomfortable. There were flesh wounds affecting the thorax, rump and neck. Three days after fighting the bull was seen to be passing a white mucous discharge from the anus. At postmortem examination at the Inverness centre there was a rib fracture and there were gore wounds, one of which had penetrated the skin, passed dorsally through the intercostal muscles for 15 cm before penetrating the thoracic pleura. The scrotum was swollen and contained strangulated small intestines, which were intensely congested and the loops were adhesedrent to each other. The bull was cryptorchid with the right testicle being present in the inguinal canal. It is possible that the scrotal hernia developed as a result of damage following the fight (there was no evidence of bruising in this area) or the intestine may have passed through the hernia which caused the bull to appear weak and was then challenged by the other bull. There was no evidence of any other underlying disease process that may have initiated the fighting.

Toxic conditions

Examination of liver and kidney at the Aberdeen centre confirmed copper toxicity in a three-year-old cow, which died following access to copper sulphate in a footbath. The liver copper levels did not exceed the threshold for reporting to the Food Standards Agency. A single animal was affected.