Veterinary Services

Aberdeen confirmed rumen acidosis in two nine-month-old lambs submitted from the 20 that died in a group of 228 lambs.  The group had had limited access to feed from troughs since the onset of snow at the beginning of December, but were recently moved to a feeder and overeating was suspected.  The rumen pH in both lambs was 4.0 (Reference Rangel >6.5).

Toxic conditions 

 
Three Texel ewes died on a holding in Dumfries-shire. One carcase was submitted for necropsy and the findings of jaundice and black kidneys were typical of copper poisoning.  This was confirmed by tissue biochemistry when liver copper content was 37,200umol/kg DM (reference range 314-7,850umol/kg DM) and kidney copper 3,170umol/kg DM (reference range <787umol/kg DM).  These results were sufficiently high to trigger a report to the Food Standards Agency Scotland.  The ewes were not at the time receiving any supplementary feed, but were administered copper needles in October 2010.  Such routine treatment had been in place for many years, and before the introduction of Texel animals to the holding, after soil analysis had indicated low copper and high molybdenum levels. 

Respiratory tract conditions

Lungworm larvae were detected in faecal samples received from Scottish blackface ram lambs that were housed for three weeks and had developed a cough when being handled or moved.  Anthelmintic treatment was advised based on this result and a Strongyle egg count of 2,250epg.  The possibility of a concurrent Mycoplasma infection was not ruled out.

Necropsy of a six-year-old Texel-cross ewe at Edinburgh revealed ovine pulmonary adenocarcinoma (OPA) and secondary Mannheimia haemolytica pneumonia.  OPA was believed to have been eradicated from the affected farm five years previously.  This was the fifth older ewe to have died in the previous four months.

Reproductive tract conditions

Unusually, abortion due to infection with Salmonella species was the most common diagnosis in early-lambing flocks in January.  Salmonella Montevideo infection was diagnosed by Aberdeen in a pedigree Suffolk flock of 160 ewes.  Some 20 ewes were reported to have produced large dead lambs, although there was no associated history of systemic illness in the ewes.  Further investigation indicated that no breeding females were added the flock and there was no contact with other sheep.

At Edinburgh six sets of abortion material were submitted over two days from one farm.  Thirteen ewes had aborted over two weeks and were dull, but not seriously unwell.  Salmonella Montevideo was isolated from five of the six submissions.

Nervous system disorders

There were seven diagnosed outbreaks of listerial encephalitis this month, compared to three cases during January 2010.  At Aberdeen listeriosis was confirmed on two units.  In one of these outbreaks two deaths were reported in a group of 240 mule ewes that were fed big bale silage.  The submitted ewe had a history of recumbency with terminal muscle tremors.  Histopathological examination confirmed the presence of a non-suppurative meningitis and severe encephalitis consistent with a diagnosis of listeriosis.   The same condition was also confirmed in two lambs, submitted from another hill farm in Aberdeenshire, with clinical signs of a head tilt, fitting and paddling prior to death. The lambs had also been fed silage and the flock owner reported a similar problem in 2010.

On another unit, neuropathology confirmed a diagnosis of listeriosis in a mule ewe hogg from a group that was only fed grass. This was the second animal from the group to be found with neurological signs.  Further investigation revealed that haylage was provided in the severe weather in December and the feeders were not emptied.   SAC C VS considered this was the likely source of spoiled feed material, which had then led to infection.

Cerebrocortical necrosis was confirmed on neuro-histopathology in a female pigmy goat.  It was submitted for postmortem examination following the sudden onset of severe neurological signs.  Treatment with anti-inflammatory medication had failed to produce any improvement and the goat was euthanased after 24 hours.  Gross examination revealed a slight increase in CSF and the left side of the brain was slightly swollen.  The brain did not fluoresce under UV light prior to fixation and the histopathological lesions of CCN were not as extensive as those usually seen in sheep.  Thiamine supplementation of the other goats in the group was advised.

Skin diseases

With the passage of the Sheep Scab (Scotland) Order 2010 in December, the suspicion and diagnosis of Psoroptes ovis infections became notifiable once again to    the Divisional Veterinary Manager of the local Animal Health Office.  SAC C VS confirmed and reported 11 outbreaks of scab during January 2011, up from six over the same period last year.