Veterinary Services

The carcase of a three-year-old greyface ewe was submitted to Dumfries. Three ewes had died and a further six were ill, following the introduction of a barley based ration the previous week.   The rumen pH at necropsy was 3.9, confirming a diagnosis of acidosis.

Toxic conditions

 
A group of Scottish blackface ewes strayed into a village through a damaged fence.  Later several were found collapsed.  They were treated with calcium, vitamin B1 and antibiotics.  One animal that failed to respond to treatment was euthanased and submitted for necropsy. The rumen contained large numbers of plant leaves, shoots and buds.  These were identified as those of a Pieris species (Figure 2 - see top right-hand side).  Members of this genus are popular garden shrubs related to rhododendrons, and are toxic to sheep.

Parasitic diseases

Diagnoses of liver fluke disease continued at historically high levels. Five outbreaks of acute fasciolosis and 33 outbreaks of chronic fasciolosis were diagnosed by SAC. 
A nine-month-old lamb was found in lateral recumbency one week after flukicide treatment.  After euthanasia, end stage liver disease due to fasciolosis was seen at necropsy. The treatment appeared successful in removing the fluke burden but neuro-histopathology confirmed spongy changes in the brain, consistent with hepatic encephalopathy.

Two ewes were submitted for postmortem examination from a farm with a history of thin, anaemic sheep.  Several ewes aborted and there were several deaths.  Both carcases were emaciated and anaemic. Increased volumes of pericardial, pleural and abdominal fluid suggested hypoproteinaemia.  Huge numbers of flukes measuring between 10 and 21 mm were present within the livers and gall bladders of the affected ewes.  The owner stated that the group were treated with triclabendazole on three occasions between September and late December and with closantel in November.   The SAC is investigating the possibility of flukicide resistance.

Chronic fasciolosis and pneumonia due to Mannheimia haemolytica were also evident in a four-year-old ewe in an Ayrshire flock. It was from a group of 40 to 50 lean ewes, despite flukicide treatment in January.  Approximately 15 ewes died over a month in the outbreak.

Alimentary tract disorders

Blood samples were received from a farm with an annual problem of thin ewes.  Ovine pulmonary adenocarcinoma (OPA) and Johne’s disease were diagnosed previously.  Of the 92 samples collected from thin ewes, 14 were positive for Johne’s disease by ELISA. A further four animals produced titres in the suspicious range for the assay. 

Reproductive tract conditions

Toxoplasmosis was diagnosed in two flocks in Lanarkshire and Argyll.  In one affected flock of 320 unvaccinated lowground ewes, more than thirty abortions and stillbirths were recorded over a period of two weeks. Other live but weak lambs were born. In the absence of placental material, the diagnosis was based on the  demonstration of antibodies in an affected foetus.  In the other affected flock focal necrotic lesions were evident in placental cotyledons. The diagnosis was confirmed by foetal serology in a twin lamb whose sibling survived.

The value of submitting abortion material from several affected ewes was demonstrated when multiple infectious causes of abortion were identified in a flock by Edinburgh.  In addition to abortion due to Chlamydophila abortus, another foetus showed Bacillus licheniformis infection. The organism was isolated from the stomach and histopathology demonstrated a diffuse suppurative placentitis.  Another foetus submitted from the same holding tested positive for antibodies to Toxoplasma gondii.

A housed batch of Texel ewes experienced numerous abortions, whilst the outdoor group on the same farm was unaffected.  Escherichia coli was isolated in pure growth from foetal stomach contents in several submissions. Histopathology provided evidence of pulmonary inflammation and bacterial placentitis.  The isolate tested negative on a standard PCR assay for toxigenic strains of this organism.

Two live blue-faced Leicester rams were presented to Ayr alive. They both showed paraphimosis and ulcerative and necrotic balanitis affecting the tip of the penis.  Four other rams had clinical signs, but improved after antibacterial therapy.  At necropsy fibrinous pericarditis was also evident in the older ram and lung abscessation associated with an acute necrotising bronchopneumonia in the younger ram.  A mixed bacterial growth including Corynebacterium jeikeium was recovered from the penile lesions and Bibersteinia trehalosi from lung abscesses.  In addition ovine herpesvirus DNA (OvHV-2) was detected in blood and tissues from one of the rams.  Further on-farm investigation revealed two more rams with raw ulcerative lesions at the tip of the penis and vulval erosions or necrosis in two of 50 ewes examined. Although OvHV-2 DNA was not detected in these affected animals, five out of seven in-contact rams had OvHV-2 DNA detected in blood samples by PCR. The significance of this finding is unclear, although a case has been described where OvHV-2 DNA was demonstrated in the blood of ewes and tups with similar lesions (Pritchard and others 2008, Veterinary Record 163, 86-89).

Renal diseases

The third tup to die since 44 were housed in November was submitted to Dumfries.  The group were fed a ewe/lamb rough mix and the animal in question had its vermiform process removed ten days earlier due to urolithiasis.   After an initial clinical improvement following this procedure the ram deteriorated and was later found dead.  At necropsy the bladder had ruptured, resulting in free urine in the abdomen leading to peritonitis.  The urethral mucosa was inflamed and blocked from three cm proximal to the glans penis with a thick matrix of blood and crystals.  These crystals were not typical of struvite on microscopy. Analysis proved them to be 40 percent oxalate, 15 percent calcium, 15 percent phosphate, one percent magnesium and 0.5 percent ammonium.  Analysis of the rough mix confirmed a satisfactory ratio of calcium to phosphate and the source of the oxalate remained unclear.  However there have been no further problems since a change onto a ram specific ration.