Veterinary Services

Nutritional and metabolic disorders

Lambing sickness was suspected following the sudden deaths of four ewes in a group of 300 on an Aberdeenshire unit. Lambing was due to start in two weeks and several other affected ewes had reportedly responded to Ccalcium and Mmagnesium injection. The diagnosis was suspected but could not be confirmed in a ewe carcase submitted for post-mortem examination, but blood sampling of a representative group of ewes confirmed hypocalcaemia.

There was also evidence of hypocalcaemia in a flock of Swaledale ewes in Inverness-shire. A total of 14 ewes had died out of 660 during a period when there was a heavy cover of snow on the ground. During this time the concentrate ration had been increased from 0.5lb to 1.5lb per head. However, the ewes were in fat body condition and required to be driven to the troughs to eat. They were also reluctant to eat the supplied hay. When four carcases were examined, vitreous humour calcium levels were found to be 1.1mmol/l, 1.5mmol/l, 1.4mmol/l and 2.0mmol/l. Publications on this subject have suggested that a level below 1.45mmol/l is consistent with deficiency.

Toxic conditions

Copper poisoning was confirmed on the basis of tissue copper analysis in two hoggs that had been exposed to cattle feed. The owner of the Aberdeenshire unit reported 12-15 deaths in a batch of 38 of last year's lambs. The submitted carcases were severely jaundiced and tissue copper estimation confirmed the diagnosis. As the liver copper concentration exceeded the action level of 500 mg/kg wet weight, the Food Standards Agency were notified.

A Bluefaced Leicester ram from a flock in Ross-shire became recumbent and was submitted for post-mortem examination. The carcase showed generalised jaundice, with almost black kidneys and an orange-tinged liver. Plasma copper was found to be 34 umol/l DM (reference range 9.0-20.0 umol/l), liver copper 26,400 umol/kg DM (reference range 314-7850 umol/kg) and kidney copper 2210 umol/kg DM (reference range <787 umol/kg). A Beltex tup from the same group died the following day and was found to have liver copper of 27,100 umol/kg and kidney copper of 3,110 umol/kg. The group had been receiving copper supplemented feed.

Nine Bluefaced Leicester rams from a group of 15 were found dead, the day after a fall of snow in Dumfriesshire. The carcases of a shearling and a three-year-old ram were submitted for necropsy where rhododendron leaves were found to be present within the rumen and reticulum. In addition, there was evident pulmonary congestion and pleurisy in both animals, and the younger ram showed areas of pulmonary consolidation from which Pasteurella multocida was isolated. Aspiration pneumonia is a common sequelae to rhododendron poisoning. Examination of the field in which the rams died revealed that the heavy snowfall had weighed-down rhododendron branches in an adjacent field, bringing them within reach of the sheep.

Parasitic diseases

Ninety percent of a group of 44 hoggs were reported to be in very poor body condition. They had been diagnosed with sheep scab before prior to housing in January and had been treated with doramectin and triclabendazole at that time. When faeces samples were submitted to the Inverness Centre there was no evidence of Pparasitic gastroenteritis, but large numbers of liver fluke eggs were found to be present. In addition Psoroptes ovis mites were detected in skin scrapings submitted at the same time.

The first case of ovine Haemonchus contortus infection in Orkney was recorded this month in a three-year-old Bluefaced Leicester ram, brought on to the islands in October 2005. The cause of death was a pneumonia from which Pasteurella multocida was isolated, but the carcase showed signs of severe anaemia and numerous H. contortus worms were found within the abomasum. This animal had been treated with injectable avermectin and a combined fluke and worm preparation on arrival on Orkney, and with a levamisole product in January 2006. The exact source of the infection was not known.

Nematodirus battus infection was recorded in January-born lambs in Caithness and Orkney. One owner reported severe scouring lambs amongst a group that had been born inside in January and turned-out to permanent grass in February. When faeces samples were submitted from the affected lambs in March, they were found to contain between 250 to 2,500 Nematodirus eggs per gram.

Generalised and systemic conditions

A 15-year-old Jacob ewe was euthanased after intermittent pyrexia and a history of anorexia of a month's duration. The submandibular, prescapular, mesenteric and popliteal lymph nodes were found to be enlarged and uniformly white. Histopathology confirmed the presence of lymphoma, with infiltration of the kidneys, liver, spleen and ileum.

Alimentary tract disorders

Two diagnoses of Johne's disease were identified in animals from a Dumfries-shire farm with a history of ewes wasting and developing scour before death. Both were confirmed on positive ZN-stained smears from the ileum.

Respiratory tract conditions

A four-year-old cross ewe weighing 94kg was submitted to the Dumfries Centre for necropsy. She was the fourth to die in a group of ewes due to start lambing within the next two weeks. She was seen eating cake at 9am, in sternal recumbency at 12pm and dead at 3pm, despite treatment with calcium and for twin lamb disease. Examination revealed pleurisy from which Mannheimia haemolytica was isolated.

Pasteurellosis due to M. haemolytica was diagnosed in a 7-10 day-old Texel ewe lamb from a flock in Inverness-shire. Due to poor weather the lambs were being kept inside for longer than usual, and about five lambs out of 30 had died suddenly. The flock is not routinely vaccinated against pasteurellosis.

A two-year-old North Country Cheviot ram was submitted to the Edinburgh Centre with a history of death following a short period of dyspnoea and no response to treatment with dexamethasone and enrofloxacin. Post-mortem examination revealed bilateral laryngeal chondritis, with fistula development into soft tissues on one side. Pasteurella trehalosi was isolated from lung, laryngeal tissues and local lymph nodes. It was concluded that the ram died from systemic pasteurellosis, arising from dissemination of bacteria from the laryngeal lesions.

Reproductive tract conditions

A flock of 70 mMule ewes in Skye had experienced five abortions. Campylobacter fetus subsp fetus was isolated from one foetus that was submitted for investigation.

A flock in Inverness-shire had four abortions in the flock of 130 ewes. A pure growth of Campylobacter sputorum subsp. bubulus was isolated from the foetal stomach contents of one lamb and from the placenta of its twin. This organism is frequently isolated in culture from sheath washes in bulls and is normally considered to be non-pathogenic. Histopathology of the placenta, showed evidence of a placentitis with a mononuclear cell infiltration suggestive of bacterial infection.

Abortion due to Listeria monocytogenes has been diagnosed in four flocks in the Edinburgh area on culture of fetal stomach contents. There was no association with silage feeding in any of the outbreaks. In one case the lambing flock was fed haylage and ewes suffered mild malaise following abortion. There were multiple petechial haemorrhages over the lungs in several of the foetuses examined and one foetus had raised white foci on the surface of the liver, as has been described in the literature in abortions due to L. monocytogenes.

Musculo-Skeletal conditions

A total of eight young lambs were submitted from a unit that reported lambs found off their legs and an increase in neonatal mortality. Bacterial polyarthritis due to infection with Streptococcus dysgalactiae was confirmed in four of the lambs and there was evidence of omphalophlebitis in two others.

Renal diseases

Urolithiasis was confirmed in a castrated male lamb in good body condition. The Aberdeenshire unit reported 18 deaths in a group of 800 hoggs over the previous three weeks. There was a large aggregate of white crystalline material just proximal to the vermiform appendage. Post-mortem examination also suggested inadequate dietary fibre and a review of management factors, such as water availability and provision of dietary fibre was recommended.

Skin diseases

A recently purchased two-year-old Texel gimmer in a small flock in Ross-shire had a hard mass with a sinus tract on the right mandible. A profuse growth of a Corynebacterium species was isolated in culture. It was not possible to identify the organism further, although the organism did not show the characteristics of C. pseudotuberculosis and a serum sample tested in the CLA ELISA produced a negative titre.