Veterinary Services

Toxic conditions

The owner of a flock in the Inverness area reported that six out of 400 ewe hoggs had been found in-extremis and showing signs of bruxism, abdominal pain and dyspnoea, while a further three animals were found dead. Postmortem examination of three carcases revealed a significant quantity of masticated tough, broad green leaves within their rumens. Rhododendron poisoning was diagnosed.

Parasitic diseases

Deaths due to subacute fasciolosis occurred on two farms in the Dumfries region during the last week of January. The first case involved a purchased one-year-old rouge ram lamb, which became the third to die on this unit. The lamb was noted to be thin and recumbent, although it had retained a reasonable appetite. Postmortem examination revealed that the carcase was severely anaemic, with subcutaneous oedema and large amounts of ascitic fluid. The liver was black and the surface obliterated by fluke migratory tracts. A large number of flukes measuring between 5 and 30 mm were present within the abdomen cavity and throughout the parenchyma of the liver. Evidence of a significant lungworm burden was also recorded. The tups, which were purchased in August 2006, had not been treated for worms or fluke since they arrived on the farm. In the second case, a ewe from the primitive castlemilk moorit breed died shortly after being handled. On postmortem examination the liver was found to be badly misshapen, with large numbers of immature fluke present throughout the parenchyma (see Figure 2 at top right-hand side).

Chronic fasciolosis was diagnosed on examination of faecal samples from five flocks in the island of North Uist. In two of these cases the samples had been collected two weeks after dosing with triclabendazole and small numbers of Fasciola hepatica eggs were found to be present. Since eggs may be detected in faeces for as long as three weeks after treatment has killed all adult fluke, the owner of these sheep was advised to submit further faeces samples at least seven days later in order to check the efficacy of the flukicide.

Thurso reported receiving faeces samples from two "rescued" goats showing signs of severe scour. Faecal worm egg counts were in excess of 20,000 per gram. Anthelmintic treatment was given and the animals improved slowly.

Generalised and systemic conditions

A total of 13 eight-month-old fully vaccinated cheviot lambs died suddenly over a six-day period on a holding in the Dumfries area. The lambs had been moved to better grass two weeks earlier. A carcase showed evidence of a moderate peritonitis. Although the abomasal folds were oedematous, the most marked intestinal changes were in the ileum and caecum, which were thickened and showed an inflamed serosa. Internally a ring of inflammation was also seen on the ileal mucosa and there was a marked typhlitis (see Figure 3 at top right-hand side). A FAT assay for Clostridium sordellii carried out on the caecum was positive, while Pasteurella trehalosi was cultured from several organs. Subsequent histopathology of the ileum demonstrated ulceration, distortion and hyperplasia of the mucosa. Gram staining revealed numerous large gram-positive bacteria within the necrotic, haemorrhagic mucosal tissues. The pathologist considered that these changes were indicative of a subacute lesion with attempts at mucosal repair. It was also postulated that pasteurellosis might have been secondary to the clostridial damage. Unfortunately no additional carcases were submitted for examination from this outbreak.

The Scottish Society for the Prevention of Cruelty to Animals (SSPCA) reported dead sheep in a field near Edinburgh. On inspection 45 to 50 emaciated carcases were found, with all appearing to be recent deaths. There was virtually no grass and only two creep feeders were present. Three live animals were euthanased and submitted for examination. Bodily condition was very poor. In each case there was evidence of only mild pulmonary and enteric parasitism, with the conclusion being that chronic malnutrition was the primary problem.

The owner of a flock in Angus reported the loss of three ewes from a group of 320. These had reportedly shown a short, vague illness and had died despite treatment with antibiotic. Examination of two carcases revealed good bodily condition with some evidence of recent scouring. Internally the main findings of significance were liquid small intestinal contents and a severe haemorrhagic typhlitis and colitis (see Figure 4 at top right-hand side). In each case the meninges also appeared congested and slightly cloudy. Subsequent bacterial cultures confirmed a pure growth of Listeria monocytogenes from the liver of one ewe and from the brain, liver and colon of the other.

Histopathology confirmed the presence of lesions consistent with a Listeria monocytogenes septicaemia and the same organism was felt to be the likely cause of the dramatic colitis.

Alimentary tract disorders

A five-year-old texel ewe from a small flock in Dumfriesshire reportedly lost condition over a few months and developed a scour before dying. Thickening of the intestine was evident and ZN-stained smears were positive for acid-fast bacteria confirming Johne’s disease. The whole ewe flock had been purchased as gimmers, which were thereafter managed as a single group. The owner was therefore advised of the likelihood that other ewes within the group might be incubating the disease.

Thurso diagnosed Johne’s disease at the postmortem examination of a three-year-old north country cheviot ewe with a history of weight loss and scouring. The owner reported that 15 others in this age group had died or been euthanased because of ill thrift or scouring. A check of the breeding records from the flock indicated that all the affected sheep were the offspring of one ram.

A four-year-old texel ewe from a flock in Ross-shire presented with progressive abdominal distension. Although the ewe was bright and alert there was obvious fluid distension of the abdomen resulting in dyspnoea. The abdomen contained approximately 40 litres of blood tinged fluid. There were multiple disseminated masses of varying size, ranging from pinhead to 2 cm, throughout the mesentery and on the parietal peritoneum. Similar lesions were seen on the visceral surfaces of the small and large intestines and on the diaphragm. Histopathological examination confirmed the diagnosis of adenocarcinoma with metastasis.

Reproductive tract conditions

Dumfries reported that three ewes aborted and one died from a group of 22 suffolk ewes on a local holding. Abortions had also been seen in a group of gimmers on the same unit. When twin foetuses were submitted for examination liver necrosis was noted and Escherichia fergusonii was isolated from the placenta and lambs in septicaemic distribution. This organism has previously been associated with abortions in ewes and abortions, scouring and mastitis in cows.

Musculo-Skeletal conditions

A three-year-old Scottish blackface ram was submitted to the Perth DSC with a history of slowly developing bilateral hind limb lameness. This had led to a developing ill thrift and recumbency. Marked firm swellings around both stifle joints and the right hock were found on postmortem examination. Dissection of these joints revealed inspissated pus and extensive granulation tissue. In addition there was a degeneration of the cartilage and gross fibrosis of the joint capsule, ligaments and associated soft tissues. A more acute purulent arthritis was noted on opening the left shoulder joint, where the excessive quantity of synovial fluid contained flecks of pus. Subsequent bacterial cultures confirmed the presence of Streptococcus dysgalactiae subsp. dysgalactiae in the affected joints. This organism is typically associated with outbreaks of septic arthritis in neonatal lambs, although cases affecting older sheep have also been reported from time to time.