Veterinary Services

Nutritional and metabolic disorders

Fatty liver disease was diagnosed in a dull, anorexic five-year-old ewe.  At scanning the ewe had been shown to have twin foetuses and was due to lamb in less than seven days.  The serum betahydroxybutyrate level was found to be 8.1 mmol/l (reference range <1.2), serum non-esterified fatty acids (NEFA) 2,468 umol/l (reference range <600) and aspartate transferase (AST) 203 iu/l (reference range 20 - 60), while serum calcium was normal.  Similar biochemical changes were noted in a further four ewes from the same unit.

These animals were in excessively fat body condition and had either aborted or delivered stillborn full-term lambs.  Foeti and placentae were examined and no infectious cause of abortion was found.

A farm in Morayshire was used for overwintering a group of 200 Scottish Blackface hoggs.  Staff at the Inverness Centre were consulted when five lambs died and four others were seen to be dull, anorexic and in poor bodily condition.  Histopathology carried out on viscera submitted from one of the dead lambs revealed hepatic lipidosis, which appeared to be of metabolic aetiology.  A blood sample from another animal suggested that the liver pathology might have been due to ovine white liver disease, since the serum vitamin B12 level was subnormal at 114 pmol/l (reference range 295-737 pmol/l).  There was also evidence of  selenium deficiency, with red blood cell GSH-Px 31iu/ml RBC (reference range 42-200 iu/ml RBC). It was advised that more animals were blood sampled for trace element analysis to determine if the findings were representative of the group.

Toxic conditions 

Copper poisoning was diagnosed in a Beltex ewe that had been seen to be dull and was later found dead in a river. The gross findings were classic of a copper poisoning case, with a jaundiced carcass and black “gun-metal” kidneys. The kidney copper level was found to be 2,150 umol/kg DM (reference range 141 - 314 umol/kg DM) confirming the diagnosis.

Generalised and systemic conditions

A flock of 400 ewes in the Thurso area were housed in early January and fed a diet of very dry wrapped haylage.  Within two days, three ewes from different pens were found dead.  Post mortem examination revealed  septicaemia and Listeria monocytogenes was subsequently cultured from  viscera.  No further deaths occurred.

Alimentary tract disorders

Four Cheviot-cross hoggs from a group of 400 on an Inverness-shire farm died suddenly, while another 15 animals were reported to be unwell, with some recumbent and others showing evidence of blood at the nares. Post mortem examination of one of the dead lambs revealed poor body condition and evidence of anaemia.  A large abscess and associated tissue necrosis were discovered in the left retropharyngeal area.  Large blood clots were present in the rumen without evidence of  ruminal pathology, suggesting that the haemorrhage may have originated within the pharynx.  Fusobacterium necrophorum subspecies necrophorum was subsequently isolated from the abscess.  The group had received a dose of trace elements some two weeks previously and the possibility that a drenching gun injury may have initiated the condition could not be ruled out.

A three-year-old Scottish Mule ewe was submitted alive, but recumbent, for examination at the Edinburgh Centre.  The ewe, from a 320 ewe April-lambing flock had been in good body condition when the tups were introduced, but lost weight during December and was housed as a result.  Further deterioration occurred and by the time of post mortem examination body condition score was 0.5 (scale 0 – 5).  Ascites was  evident post mortem, the small intestinal contents were fluid and the ileum was thickened, although not corrugated or pigmented.  However,  smear examination of the ileal mucosa revealed many acid-alcohol fast organisms confirming the diagnosis of paratuberculosis (Johne's disease). There was also evidence of a significant gut nematode burden.

The pigmented form of Johne’s disease was also confirmed on necropsy of a four-year-old Scottish Blackface ewe.   The owner of this Ayrshire flock complained of four to five of 1,200 ewes per year being culled due to weight loss and scour.

Ten deaths were reported over a period of one week, in a Roxburghshire flock of 400 Scottish Blackface ewes.  When two adult ewes were examined  post mortem both showed severe abomasitis, with oedema of the abomasal wall and areas of intense inflammation over the mucosal surface.  Although an initial diagnosis of braxy (abomasitis due to Clostridium septicum) was made, subsequent culture of the affected tissues produced a pure growth of C. sordellii.

Nervous system disorders

Two 2-year-old Scottish Blackface rams with nervous signs were submitted to the Inverness Centre from a flock in Inverness-shire that had similar problems the previous year. The affected rams had been bought-in and were initially slightly lame before progressing to recumbency.  Both rams were in lateral recumbency and while one was dull, the other showed signs of paddling and nystagmus.  At post mortem examination the ram that had been paddling was found to have a purulent sinusitis and a pituitary abscess two centimetres in  diameter, from which Arcanobacterium pyogenes was recovered.  This individual was also found to have antibody to louping ill virus, although there was uncertainty over whether or not it had been vaccinated. Neuropathology carried out on the other ram indicated that pulpy kidney could not be ruled out. Further tests are underway on this animal to try to achieve a diagnosis.

Louping ill was diagnosed in a seven-month-old Scottish Blackface lamb submitted to the Perth Centre.  Fourteen of 300 lambs on the premises had died with a clinical presentation suggestive of the disease.  The flock was not vaccinated against the disease.

Outbreaks of listerial encephalitis were confirmed in the Aberdeen and Inverness areas. In the first outbreak nine deaths occurred in a group of 150 ten-month-old lambs on a diet of grass, haylage, barley, soya and beet pulp.  Clinical signs in affected animals included anorexia, circling and recumbency, with some animals responding to treatment with oxytetracycline.  In the second case four Cheviot hoggs died from a group of 260.  Again signs of circling were apparent in all four lambs, progressing to recumbency and death.  These hoggs were being fed turnips and silage. In both outbreaks the diagnosis was confirmed by the isolation of a profuse growth of Listeria monocytogenes from the brain, with typical neurological lesions being recorded on histopathology.

Renal diseases

A Texel-cross ram lamb died unexpectedly on a Berwickshire farm, the second sudden death  from a large group of housed lambs on a cereal-based diet. Post mortem examination  revealed that the terminal portion of the penis was necrotic and that the vermiform appendage was blocked with urinary calculi.  Internally the bladder was massively distended and  haemorrhage was apparent in the bladder wall. The resulting urinary pressure within the ureters had led to dilation of the renal pelvis in both kidneys.  A diagnosis of post-renal renal failure, secondary to urolithiasis was made.

Skin diseases

Examination of wool samples from a group of pruritic hoggs on an Inverness-shire farm revealed the presence of Damalinia ovis lice and Psoroptes ovis mites.  The Thurso Centre also diagnosed sheep scab on four occasions this month.  These included the identification of mites on sheep from neighbouring premises, suggesting that transmission may have occurred between flocks.

Caseous lymphadenitis was diagnosed in a ram from a flock in Ross-shire where the condition had been previously identified.  In two other cases where CLA was suspected, other pathogens were isolated from bacterial culture.  A newly developed swelling on the neck of a recently purchased Cheviot ram was found to contain only Arcanobacterium pyogenes, while the contents of a swelling on the face of a Suffolk ram produced a profuse growth of  Bacillus spp.