Veterinary Services

The predominant diagnosis for sheep was helminth disease based on the submission of faecal samples and carcases from affected flocks for examination.  In addition large numbers of pooled faecal samples were received for parasite monitoring in groups of lambs. 

Fifty eight outbreaks of nematodirosis were recorded by SAC C VS during June. This compared with 41 cases reported over the same period in 2009.  In one Ayrshire flock deaths occurred amongst eight-week-old lambs, despite treatment with a benzimidazole anthelmintic.  In this case uraemia was also evident and concurrent nephrosis was suspected, but autolysis prevented histopathological confirmation.  Nematodirus battus was also associated with seven deaths in a similar age group of lambs on another Ayrshire farm. Affected animals were reported to be lethargic, scouring and anorexic. As well as evidence of N. battus worms, large numbers of coccidial oocysts were also demonstrated in the caecal contents of an affected lamb.  Evidence of nematodirosis was detected on examination of submitted faecal samples.  On one occasion a sample submitted from scouring lambs to Thurso contained 148,000 Nematodirus battus and 6,500 strongyle eggs per gram.

Acute and chronic fasciolosis were associated with deaths in flocks in Ayrshire and Argyll. In one Ayrshire flock lesions of acute and chronic fasciolosis were evident at post-mortem examination in a Lleyn ewe that was treated with a flukicide pre-lambing.  Chronic fasciolosis and coccidiosis were diagnosed in an Argyllshire island hill flock.  Losses of ewes were reported to have occurred during the winter followed by signs of “bottle-jaw”, after the January flukicide treatment was missed. 

Alimentary tract disorders

Intestinal torsion (red gut) was found to be the cause of death when the carcase of a two-month-old Rissington cross Lleyn ewe lamb was submitted to Aberdeen.  The lamb had been weaned from artificial milk onto pellets some four days previously.

Intestinal obstruction was found on postmortem examination of an 11-week-old, Suffolk-cross ewe lamb.  There was a compacted pellet of hair and ingesta wedged in the proximal colon at the point where the diameter of the lumen diminishes.  The caudal third of the small intestine, caecum and proximal colon were distended by fluid content, while the distal colon was empty.  There was also evidence of secondary peritonitis. 

A two-year-old Golden Guernsey goat was diagnosed with Johne’s disease based on the presence of acid/alcohol fast bodies typical of Mycobacterium avium paratuberculosis in a faecal smear.

Respiratory tract conditions

Pneumonia due to infection with Mannheimia haemolytica was diagnosed in a two-month-old lamb from an Aberdeenshire unit. This was the second confirmation of pneumonic pasteurellosis in the flock. In the interim the lambs had been gathered for blanket treatment with antibiotic.  In both lambs there was evidence of coccidiosis, and speciation confirmed the presence of a significant proportion of pathogenic species of Eimeria.  Furthermore a large number of N. battus worms were observed in a small intestinal wash from the second lamb.

Ovine pulmonary adenocarcinoma (OPA) with secondary Mannheimia haemolytica pneumonia was confirmed in a ten-month-old Dorset cross ewe lamb from an Aberdeenshire flock, which records cases of OPA annually.  The same diagnosis was made in the case of a yearling Scottish blackface ram from an Ayrshire farm.  The affected animal had shown clinical signs of pneumonia wand a watery fluid nasal discharge.

A gimmer was submitted for necropsy to Thurso with a history of general malaise.  Gross findings included the presence of large numbers of Dictyocaulus filaria worms within the trachea and areas of consolidation in the ventral lungs.  Histopathology of the affected lung confirmed a severe verminous pneumonia.

Cardiovascular diseases

Five]centres reported cases of acquired ovine heart disease this month.  At Dumfries a mule ewe was submitted after being found dead unexpectedly.   At postmortem examination there was an increased volume of pericardial fluid containing a fibrin clot.  Severe endocarditis lesions were found on both atrioventricular (AV) valves, but particularly marked on the right side. The liver had a nutmeg appearance and the lungs were oedematous consistent with congestive heart failure.  Streptococcus bovis was cultured from the carcase in a septicaemic distribution.

Postmortem examination of a three-month-old thin male Suffolk-cross lamb in Aberdeen revealed the right atrium and auricle to be dilated and thin walled.  Again, a vegetative lesion was present on the right AV valve and changes were noted in the lungs and liver consistent with heart failure.  In this case Pseudomonas aeruginosa was recovered from the viscera.

A six-week-old Texel cross lamb was ill thriven for a period before death.  A large abscess was found within the wall of the right atrium and smaller abscesses in the lungs, kidney and ventricular walls.  Several joints were affected by septic arthritis.  Staphylococcus aureus was isolated from the lesions raising the possibility of an underlying tick pyaemia.

Congenital heart disease was also reported this month when the necropsy of a two-month-old Texel cross lamb at Edinburgh revealed a patent foramen ovale, secondary left ventricular dilatation and circulatory failure.  This lamb was found in a dyspnoeic state a few hours after turnout and died shortly after.

Mammary diseases

Milk samples were received from two flocks experiencing outbreaks of mastitis.  S. aureus was isolated on one occasion and Bibersteinia (Pasteurella) trehalosi on the other.  In each case it was speculated that the poor grass availability and consequent reduced milk yields may have contributed to the problem, as hungry lambs caused teat damage through over-zealous sucking.