Veterinary Services

As highlighted in the January SAC C VS Disease Surveillance Report, SAC offered discounted blood tests to producers to provide an early warning of metabolic disease.  Shepherds were encouraged to submit blood samples from ten pregnant ewes, five from twin-bearing ewes and five from animals carrying triplets.  These blood samples were tested for serum beta-hydroxybutyrate (BOHB) and urea in order to provide an indication of energy status and of short term protein intake.  In an early submission under this arrangement Edinburgh detected elevated serum BOHB in three sampled animals, with levels ranging from 2.2 to 4.9 mmol/l (reference range <1.2 mmol/l).

Toxic conditions 

Six sheep from a group of 16 that escaped from their pasture three days previously were found dead.  Necropsy revealed pulmonary oedema and fibrous plant material, including lancet shaped waxy leaves with light coloured edges in their rumens. Tissue histopathology findings suggested a toxaemia and neuropathology confirmed mild encephalitis.  The leaves were subsequently identified as being those of Pieris japonica (Lily of the valley bush), a commonly grown ornamental shrub.  The leaves contain grayanotoxin, an alkaloid with digitalis-like cardiotoxic effects and is highly toxic to animals and humans. 
 
Reproductive tract conditions

The predominant abortion diagnosis in February was toxoplasmosis, with nine outbreaks identified in flocks around Scotland.  Frequently the history was that shepherds were aware of the risks to their flocks but were unable to source the appropriate vaccine prior to tupping.  A further six outbreaks of abortion associated with Chlamydophila abortus were also confirmed.

Musculo-Skeletal conditions

Aberdeen confirmed infection with Streptococcus dysgalactiae subsp. dysgalactiae in a neonatal lamb with joint ill.  Last year the flock owner reported 50-60 similar cases.  In previous years SACCVS has diagnosed as many as 30 outbreaks of this condition in Scottish flocks.  As well as being widely present within the environment, Strep. dysgalactiae is carried within the lower reproductive tract and on the teats of clinically normal ewes.  Lambs may therefore acquire the organism during parturition or when attempting to find a teat.  Antibiotic treatment of established cases is usually unsuccessful.  SACCVS recommends that an adequate intake of colostrum, good environmental hygiene, disinfection of the navel with tincture of iodine, the use of clean instruments when docking and castrating, and cleanliness at tagging are all important control measures.

Nervous system disorders

Listerial encephalitis was diagnosed on six occasions this month. In one case a pure growth of Listeria monocytogenes was isolated on direct culture of brain stem tissue taken from a mule gimmer that was seen to be frothing at the mouth and staggering prior to death. In a second case, bacteriology was unrewarding following the postmortem examination of a two-year-old ewe that died after showing neurological signs.  However, neuropathology identified typical foci of inflammatory cells with adjacent perivascular cuffing.  These changes are consistent with listerial encephalitis.