Veterinary Services

Nutritional and metabolic disorders
An ill-thriven Ryeland ewe was submitted to Aberdeen Disease Surveillance Centre (DSC) for post mortem examination. Necropsy and subsequent biochemical tests revealed chronic enteropathy, selenium deficiency and a liver copper overload that had resulted in hepatic encephalopathy. Although there was no gross evidence of a copper-induced haemolytic crisis, the liver copper concentration exceeded the threshold of 500 mg/kg, necessitating notification to the Food Standards Agency (FSA) as required by Chapter 53 of the Food Safety Act. Investigations into this case are ongoing.

Many of the Cheviot cross Meatlinc hoggs in a group from an Inverness-shire flock were reported to have poor fleece, to be weak and to become recumbent when gathered. A male hogg was submitted for examination and clinical examination confirmed poor body and wool condition as well as evidence of lachrymation. On post mortem the animal's liver was found to be slightly pale and greasy, and the liver vitamin B12 level was measured at less than 0.07ug/g WM (reference range >0.19ug/g WM), confirming ovine white liver disease. In addition liver selenium was also found to be low at 0.4mg/kg DM (reference range 0.9-3.5mg.kg DM).

Toxic conditions
Copper poisoning was confirmed at the Edinburgh Centre in one of a group of Beltex gimmer hoggs. Intensive feeding of concentrates, the stress of transportation and a breed predisposition were considered to be contributory factors in this case.

Parasitic diseases
Acute fasciolosis was diagnosed in a flock of 160 Cheviot ewes on the Isle of Skye, in which five sudden deaths had been recorded over an eight-day period despite the ewes having been drenched with oxyclozanide some two weeks earlier. Post mortem examination of a ewe and a hogg revealed haemorrhagic tracts throughout the liver parenchyma and in one case the liver capsule had ruptured. The flukes recovered from the livers of the examined sheep measured between 9-20mm, while fluke eggs were detected in the faeces of two of the other dead animals.

Acute fasciolosis was also diagnosed on post mortem examination of three ewes at the Edinburgh Centre. A total of seven deaths had occurred in a flock of 700 ewes over a period of two weeks. The ewes had grazed fields known to have previously had fluke-infected cattle. The ewes had been drenched with the anthelmintic albendazole throughout the summer and the same drug had been used at the higher dose to treat for fluke. All three ewes appeared to be in good body condition but necropsy of the first ewe revealed hepatomegaly, with necrotic, haemorrhagic tracts and peritonitis. The second carcass was jaundiced and again the liver was pale and enlarged, with rupture of the capsule and haemorrhage into the abdominal cavity. Immature flukes of around 12mm in length were present within the liver parenchyma. The third ewe had a friable liver, with cavities and necrosis. One of the ewes also had evidence of parasitic gastroenteritis, suggesting the use of anthelmintic had been ineffective against both the immature fluke as would be expected and gastrointestinal helminths.

Generalised and systemic conditions
Lymphoblastic leukaemia was confirmed in a three-year-old Texel cross ewe with a history of dramatic weight loss, vague dullness and anorexia over the preceding three months. Subsequent post mortem examination confirmed multicentric lymphosarcoma with leukaemic spillage. Lymphoblastic tumour cells were present in mesenteric lymph nodes, kidney and skeletal muscle. The case appeared to be a sporadic one with no other sheep affected in the flock.

Alimentary tract disorders
A five-year-old Scottish Blackface ewe was submitted alive from an upland Berwickshire flock of 900 ewes. This animal had a history of weight loss over the preceding two months and had recently started to scour. The shepherd reported that he had frequently encountered chronic ill thrift amongst the older ewes of the flock during the 20 years he had worked on this farm. As an example he stated that over the course of the previous year, 12 ewes had been affected in this way and had either died or been culled as a result. Gross post mortem examination confirmed very poor bodily condition and marked thickening and orange discolouration of the ileal mucosa. A diagnosis of paratuberculosis (Johne's disease) was duly confirmed when acid-fast organisms were seen in large numbers on a mucosal scrape stained by the Ziehl Neelson method. Further investigation of future cases of ill-thrift in the flock was advised. Johne's disease was also confirmed this month in flocks from the Perth and Thurso areas.

Widespread scouring and two deaths were reported amongst a group of 260 ewe lambs, at grass on a Borders farm. Mucosal haemorrhage and thickening, affecting much of the caecum and colon was evident on post mortem examination of an affected lamb. A gut wash and total worm count identified 1,600 Haemonchus contortus, 7,700 Nematodirus battus and numerous tapeworms, while bacteriology yielded Yersinia pseudotuberculosis. Subsequent histopathology confirmed yersiniosis superimposed upon low-grade parasitic gastroenteritis.

Respiratory tract conditions
Ovine pulmonary adenocarcinoma (OPA,jaagsiekte), with secondary bacterial pneumonia due to Mannheimia haemolytica, was found to be the cause of death in a 12-month-old Soay lamb from an Aberdeenshire flock. Clinical signs of OPA most commonly affect sheep over two years of age, although as in this case, it can sometimes affect younger animals.

A ewe hogg submitted to the Thurso Centre for post mortem examination after dying suddenly, had lesions of parasitic bronchitis with large numbers of Dictyocaulus filaria lungworms present in the bronchial tree. A month earlier the same farm had reported the death of a recently purchased Suffolk ram, which also showed a massive lungworm infestation. Although none of the other 200 ewe hoggs in the batch showed clinical signs of infection, a prophylactic group treatment of anthelmintic was administered as a precaution.

Renal diseases
Following the diagnosis of urolithiasis within a group of housed ram lambs in the Edinburgh area, a feed sample was submitted for mineral analysis. The sample was found to contain phosphorus and magnesium at levels above those recommended for an intensive tup ration. In addition, the recommendation on the label was to feed the concentrate at no more than 70% of the total diet, with roughage material making up the other 30%. The feeding system in use on the farm was ad lib access to both the concentrate ration and to rough forage - meaning that relative intakes were difficult to monitor and control. It was therefore suggested that this ration was unsuitable for ad lib feeding, even with the provision of forage material. The inclusion of ammonium chloride in the diet as a urine acidifier was also considered.

Skin diseases
As a result of continuing local awareness and concern over caseous lymphadenitis (CLA), the Inverness Centre continued to receive a number of submissions from sheep with abscesses on the head and neck.

Arcanobacterium pyogenes was isolated from two cases including an abscess on the jaw line of a newly acquired Beltex gimmer.

Arcanobacterium pluroanimalium was isolated from a facial abscess in a hogg and Streptococcus dysgalactiae subspecies dysgalactiae was cultured from an abscess on the jaw of a Texel gimmer, which had also been recently purchased.

Psoroptes ovis mites were detected in a wool sample from a group of hoggs in Morayshire in which about 20 out of 90 were pruritic, confirming sheep scab.