Veterinary Services

Hypocupraemia was confirmed at Aberdeen following the examination of blood samples from a group of ill thriven six-week-old lambs.  Three of the animals sampled had plasma copper concentrations below the limit of detection of the assay.

Toxic conditions

Four deaths occurred over a period of five days in a group of 20 rams on an Ayrshire holding after they were fed a cattle concentrate ration.  On necropsy, jaundice and marked renal and hepatic changes suggested copper poisoning, and this diagnosis was later confirmed by analysis of liver tissues.

Parasitic diseases

SAC VS advised Scottish veterinary practices that significant outbreaks of nematodirosis were likely from the middle of May.  The first outbreaks were duly recorded in lambs during the last week of the month, on farms in Ayrshire and Argyllshire.  By the end of May, 45 incidents of disease were recorded by the eight Scottish centres, compared to 14 over the same period in 2007.  Nematodirus battus worms were recovered from lambs submitted for necropsy to Dumfries from two separate farms.  In one instance the lambs were treated with moxidectin three weeks earlier, although this product has no persistent effect against Nematodirus species.  Nematodirosis was also diagnosed in a seven-week-old lamb from a farm in Ross-shire, where four lambs out of a group of 100 died one day. On a farm near Edinburgh the owner of a 150 ewe flock reported ill thrift and the loss of between 60 and 70 lambs when he submitted a five-week-old cross bred ram lamb that weighed only 4.8 kg.  A small intestinal wash yielded 3,000 N. battus worms.

Lesions of acute and chronic fasciolosis were evident in hoggs and a ewe submitted for postmortem examination from a lowground flock in Inverclyde.  Despite treatment, a mortality rate of approximately five per cent was reported by the farmer. Flukicide resistance was suspected and appropriate advice given. Chronic fasciolosis was diagnosed on three Ayrshire farms.  One owner reported around 30 deaths in a group of 220 lowground ewes despite flukicide treatments in November and February.  An investigation was initiated, as lack of efficacy of two different flukicides was suspected.  The SAC VS advised treatment with a third product along with post-treatment faecal sampling to clarify the situation regarding product efficacy. 

Generalised and systemic conditions

Outbreaks of clostridial disease were common during the month. In all cases inadequate or no vaccination against this group of bacterial disease had been carried out. Thurso reported one case of black disease (necrotic hepatitis due to Clostridium novyi type B) secondary to acute fasciolosis in an unvaccinated ewe. Clostridium perfringens type D disease (pulpy kidney) was diagnosed in 18 Scottish flocks.  In Ayrshire a thriving three-week-old Texel lamb that died suddenly, was necropsied.  Postmortem findings were pathognomonic and epsilon clostridial toxin was detected in a filtrate of ileal contents.  The ewes were not vaccinated against clostridial disease prior to lambing.  The disease was also diagnosed on necropsy of a three week-old Charollais lamb from Ross-Shire. This was the fourth lamb to die suddenly after turnout.  In this case the ewes were unvaccinated, although the lambs received a single dose of multivalent clostridial vaccine shortly after birth.  Advice was given on the correct use of such clostridial vaccines.

The owner of a large flock of mule ewes in Angus reported losses among lambs during the first week of life.  When two casualties were submitted for examination, necropsy revealed abscesses in the lung, myocardium and both kidneys in one animal and multiple abscessation of the liver in the second (figure 4 - see top right-hand side).  Subsequent bacteriology identified Staphylococcus aureus as the cause of infection in the first lamb and Fusobacterium necrophorum in the second.

Alimentary tract disorders

Clostridium perfringens type B disease (lamb dysentery) was confirmed in two 14-day-old lambs from an unvaccinated organic flock in Aberdeenshire.  Clostridium perfringens was isolated in profuse growth from small intestinal contents and both beta and epsilon toxins were detected by ELISA.  Lamb dysentery was also identified on four farms in the Thurso area, where routine vaccination of pregnant ewes had ceased. 

The owner of a Texel flock in Perthshire reported the loss of a second good lamb from a batch of 120, over a period of 24 hours.  The carcase showed marked bloating and when the abdomen was opened there was clear evidence of intestinal haemorrhage syndrome or red gut.  This condition is classically associated with the consumption of large quantities of readily fermentable grass or legumes.  However, in this case a gut wash revealed the presence of a huge number of tapeworms, weighing more than 300g (figure 5 - see top right-hand side), but no evidence of significant infection with nematode worms.  The presence of tapeworms within the gut is not generally believed to be a significant cause of disease in sheep.  However, the weight of infection in this case lead to speculation that the presence of such a heavy burden had some effect on the lamb’s normal gut function.

Reproductive tract conditions

Between January and May 2008 the owners of 401 flocks submitted material to their local SAC centre to investigate ovine abortion outbreaks.  This compared to 547 flocks over the same period in 2007, representing a decrease of more than a quarter.  While this may reflect economic conditions, there are also reasons to believe that widespread vaccination against the two main causes of abortion may be leading to an overall reduction in losses. In most years, 12 or more pathogens are diagnosed as the cause of abortion.  This season the two most common causes in Scottish flocks remained Chlamydophila abortus and toxoplasmosis (figure 6 - see top right-hand side). These accounted for more than half of the diagnosed sheep abortion outbreaks in 2008.

Other causes of abortion included the bacterial organisms Campylobacter, Listeria and Salmonella, which together accounted for 20 per cent of diagnoses.   The "Other" category, which was associated with more than 25 per cent of diagnosed outbreaks, is composed of a number of pathogens encountered more sporadically.  In 2008 this group included viral infections such as border disease and bacteria such as Bacillus licheniformis, Yersinia pseudotuberculosis, Pasteurella multocida and verotoxin positive strains of Escherichia. coli.

Congenital goitre was identified on postmortem examination of a stillborn Scottish blackface lamb submitted to Edinburgh.  While the lamb weighed 3.97kg, the thyroid was 220g and subsequent histology confirmed hyperplasia of the gland.  This was the fourth lamb to be born with this condition on one particular area of the hill.

Musculo-Skeletal conditions

Streptococcus dysgalactiae subspecies dysgalactiae was responsible for deaths and severe polyarthritis in 20 to 30 lambs from each of three flocks in Argyll, Ayrshire and Stirlingshire.  On one farm stiffness and swollen joints were evident in lambs at around ten days of age.  Similar clinical signs had been noted by the farmer in previous years.

Nervous system disorders

An outbreak of conjunctivitis in lambs was observed on a farm in Inverness-shire. The condition did not respond well to antibiotic treatment and subsequently Mycoplasma conjunctivae was identified from conjunctival swabs by PCR.

Skin diseases

Many biting lice (Damalinia ovis) were detected in a skin scraping submitted from an Ayrshire flock suspected of having sheep scab.