Veterinary Services

Two deaths occurred over a period of two days in a group of four-month-old pedigree lambs on a Renfrewshire farm.  Although at grass, these animals were also receiving a concentrate mix containing oats and barley.  The ruminal pH of two submitted casualty lambs was 4.2 and 5.4 respectively.  This was likely to have been lower immediately after death as the lambs had been dead for around forty-eight hours prior to necropsy.  A diagnosis of acidosis secondary to carbohydrate overload was reached.

The carcase of a female goat was submitted to Perth with a history of death following a short period of recumbency and scouring.  On necropsy there was generalised congestion of the body tissues.  The rumen was filled with fibrous digesta and a significant quantity of whole grain, while the small and large intestinal contents were fluid in nature, blood-tinged and contained what appeared to be strands of mucosa.   The pH of the rumen contents was approximately 4.0 and no other significant lesions were recorded on further examination.  Subsequent bacteriology and histopathology of the brain failed to identify an infectious cause for these findings, and again a diagnosis of ruminal acidosis secondary to carbohydrate overload was reached.

Parasitic diseases

Chronic fasciolosis was diagnosed in a Scottish blackface flock on an Argyllshire island, despite flukicide treatment.  The same disease was suspected in another Argyllshire island flock in which ewes were showing submandibular oedema.   Elevated liver enzyme activity suggested hepatocellular and hepatobiliary damage due to F. hepatica, but no faecal samples were submitted for examination.  The same diagnosis was suspected to be the cause of wasting of two Texel shearling rams on the basis of markedly elevated serum liver enzyme levels and hypoalbuminaemia, but again faeces samples were not submitted for confirmation.

Generalised and systemic conditions

Enterotoxaemia due to Clostridium perfringens Type D (pulpy kidney disease) was diagnosed in a four-month-old cross ewe lamb from an Ayrshire flock.  Three lambs died after a short illness and the animal presented for postmortem examination was bloated prior to death.  Animals in the affected group were in good condition, unvaccinated, had recently been moved on to foggage and were receiving high protein creep feed.  Postmortem examination of a casualty lamb revealed abdominal tympany and evidence of gassy ruminal bloat, resulting in rupture of the abdominal muscles and ruminal wall.  The kidneys were soft and autolysed.   Ruminal pH indicated a degree of ruminal acidosis and both alpha and epsilon clostridial toxin were demonstrated in bowel filtrate, indicative of enterotoxaemia due to Clostridium perfringens Type D (pulpy kidney disease).  Vaccination of the group with a multivalent clostridial vaccine was recommended.

Alimentary tract disorders

A drenching gun injury was the suspected cause of death in a three-month-old lamb from an Inverness-shire holding. At necropsy there was evidence of a large necrotic region extending from the larynx down the neck along the fascial plane of the muscles.  The affected tissue was found to contain a yellow material thought to be anthelmintic.

A ewe was submitted to Inverness for postmortem examination following a rapid loss of body condition over a period of a few weeks. The ewe was otherwise bright and alert with no other clinical signs. The carcase was emaciated and wet and there was a marked thickening of the ileal and jejunal mucosa (Figure 3 - see top righ-hand side). Intestinal scrapes identified acid/alcohol fast bodies typical of Mycobacterium avium paratuberculosis which confirmed a diagnosis of Johne’s disease.

Respiratory tract conditions

Pneumonic pasteurellosis was diagnosed at Aberdeen in a nine-week-old easycare lamb. Mannheimia haemolytica was isolated from the lungs. Nematodirosis and pneumonic pasteurellosis were confirmed in previously submitted lambs, but deaths reportedly continued despite treatment with ivermectin and a long acting antibiotic.

Two previously healthy lambs died at different times while their group was being gathered to be vaccinated.  Both lambs were seen to slow down, become recumbent and then die within five minutes of the apparent onset of illness. Postmortem examination of the two affected lambs revealed enlarged carcase lymph nodes and bilateral fibrinous pneumonia with pleural adhesions.  Mannheimia haemolytica and Arcanobacterium pyogenes were isolated from lung lesions.  Histopathology confirmed fibrino-suppurative bronchopneumonia in both cases with no evidence of underlying viral involvement.

A crossbred ewe was submitted to Dumfries from a farm where a number of lamb deaths had recently occurred due to pneumonia.  At necropsy the pluck felt heavy and firm nodular lesions of up to 4 cm diameter were found within the lungs (Figure 4 - see top right-hand side).  In addition, large numbers of fluke were present in the liver and there was a severe mastitis affecting one half of the udder.  Mannheimia haemolytica was subsequently isolated from both the lungs and mammary gland.  Although an underlying ovine pulmonary adenocarcinoma (jaagsiekte) condition was suspected, lung histopathology indicated only changes consistent with pneumonic pasteurellosis.

Musculo-Skeletal conditions

A four-week-old ram lamb examined postmortem at Dumfries was one of a batch of lambs with joint ill, which failed to respond to antibiotic treatment.  In addition to septic arthritis affecting both carpal joints, a spinal abscess was also identified.  Pleurisy and a pleural abscess with adjacent abscesses in the lung were found.  A pure growth of Streptococcus pleuranimalium was isolated from both carpal joints.  This was an unusual isolate and it is unknown whether it was the initiating cause or an incidental finding following antibiotic treatment.

Nervous system disorders

Louping ill was diagnosed on neuropathological examination of the brain of a two-year-old crossbred gimmer submitted to Aberdeen.  Approximately ten deaths were reported in sheep away-grazed on hill land, with affected animals appearing to tremble before dying after a short period.  The sheep were reported to have been treated with alphacypermethrin six weeks previously.

Skin diseases

 
Corynebacterium pseudotuberculosis, the cause of caseous lymphadenitis (CLA), was isolated in heavy, pure growth from an abscess below the ear of a four-month-old, Suffolk ram lamb from a flock in the Edinburgh area.   It is unusual to diagnose CLA in such young animals.  In Aberdeen a more typical case was recorded when C. pseudotuberculosis was isolated from a skin sample from a 17-month-old Suffolk ewe with a swelling at the angle of the jaw.