Veterinary Services

Toxic conditions

A two-year-old, Texel ram was submitted to the Edinburgh Centre for post mortem examination. It was seen to have a swollen head some two days previously, but this condition had improved once the ram was housed. A blood sample was taken at that time and analysis of liver enzymes indicated elevated GGT at 400 iu/l (reference range 27-31 iu/l) and AST of 1920 iu/l (20-60 iu/l). The ram subsequently died, despite treatment with corticosteroids and antibiotic. At necropsy the carcass was markedly jaundiced, the liver friable and the kidneys and urine dark. Copper toxicity was suspected and confirmed on the basis of a kidney copper value of 5,020 umol/kg DM (reference range <780 umol/kg DM). Other rams in the group were said to be clinically unaffected.

Copper poisoning was also diagnosed in a gimmer and ewe from a Beltex flock in Inverness-shire. This flock had received feed known to contain excess copper during the winter. Despite the feed being removed, cases of copper poisoning have subsequently occurred, the majority at lambing time. The liver copper levels on this occasion were 13,100 umol/kg DM in the ewe and 14,900 umol/kg DM in the gimmer (reference range 314-7850 umol/kg DM).

Parasitic diseases

Following the exceptionally high rainfall during the summer and autumn of 2004, concerns had been expressed that the incidence of fasciolosis might significantly increase during the winter and spring. This has indeed been the case, although the increase has been somewhat less than many feared. In the first four months of this year, 88 outbreaks of chronic liver fluke disease and six of acute fluke disease have been reported in Scotland. Recorded outbreaks over the equivalent period last year were 53 and two respectively. In one typical case liver fluke disease was diagnosed in Cheviot gimmers from a flock in Sutherland. This group of 160 gimmers had suffered a general loss in condition over the winter and at the time of faecal sampling the best animals showed a body condition score of only 1.5. Some of the gimmers also showed evidence of parasitic gastroenteritis (PGE) on faecal examination. Chronic fasciolosis and PGE were diagnosed in a six-year-old Bluefaced Leicester ewe from a small flock in the Western Isles. Liver fluke eggs were also detected in the faeces of ewes from a flock of Cheviots in Ross-shire, reported to be suffering a "downer ewe" problem.

Chronic fasciolosis was diagnosed post mortem in a two-year-old Scottish Blackface ram from the Edinburgh area. The ram had been imported from Ireland in October 2004, when it was quarantined for two weeks before being mixed with the flock. No treatments were given during this quarantine period. The ram had a history of chronic weight loss and ill thrift, and had failed to respond to treatment with antibiotics. At necropsy the carcass was pale and oedematous, with effusions into the body cavities and no internal fat reserves. The liver was pale, with multiple tracks over the roughened surface. The bile ducts were full of mature flukes. There was no history of fasciolosis on the farm in question, and based on the chronic nature of the lesions and size of the fluke it was proposed that the ram had been infected prior to purchase.

Alimentary tract disorders

The Edinburgh Centre reported deaths due to lamb dysentery in two different flocks. Both are operated under organic principles and the routine vaccination of lambing ewes is not currently practised. In one outbreak ten neonatal lambs died in the 50-ewe Scottish Blackface flock. At necropsy of the lambs sections of small intestine were found to be ulcerated and haemorrhagic. Both beta and epsilon toxins of Clostridium perfringens were detected in gut contents, confirming the diagnosis of type B enterotoxaemia (lamb dysentery).

Reproductive tract conditions

Salmonella indiana was associated with ewe deaths and abortions in a 600 ewe commercial flock in the Edinburgh area. A total of six ewes were reported to have become dull, before going on to abort their lambs and die. These losses affected ewes of all ages, but were confined to a single lambing shed. A four-year-old crossbred ewe and abortion material from two other sick ewes was submitted for examination. In the adult carcass, emphysematous foeti were found within a thickened oedematous uterus. The aborted foetuses were markedly autolysed and emphysematous, and the placenta in one case showed necrosis of the cotyledons. Subsequent bacteriology led to the isolation of Salmonella indiana from the reproductive tract of the ewe and from both sets of abortion material.

Acid-fast bodies similar in morphology to Brucella spp, were identified on smears from the foetal stomach contents of an aborted twin lamb, from an EAE-accredited flock in Sutherland. Interestingly none of these organisms were seen on smears made from the other twin or from the placenta, which had no significant abnormalities. There was no evidence of Brucella organisms on culture of the submission. Advice was sought from the State Veterinary Service, but no further investigations were initiated.

Fusobacterium necrophorum was isolated in profuse growth from the foetal stomach contents of twin aborted foetuses and from the associated placenta. The same organism was also isolated from the foetal stomach contents of an aborted lamb from a different flock.

Musculo-Skeletal conditions

A report of widespread lameness came from the owner of a group of 800, one-month-old Suffolk-cross lambs on a Berwickshire farm. Several lambs in each field were affected in one or more leg, with visibly swollen joints apparent in many cases. A further 12 lambs had either died or been euthanased, due to chronic lameness. When one live and one dead lamb were submitted for necropsy they were seen to be in poor bodily condition. The live lamb was found to have a purulent arthritis, affecting a stifle and a hock joint. The dead lamb also had polyarthritis, as well as a spinal abscess and valvular endocarditis. Bacteriology led to the isolation of Streptococcus dysgalactiae subsp. dysgalactiae in pure culture from all lesions.

This was one of 13 outbreaks of polyarthritis due to Strep. dysgalactiae recorded in neonatal lambs in Scotland during March and April which represents a marked increase in this condition from the two cases reported over the same period last year and the three outbreaks recorded in 2003. In many cases outbreaks occurred in flocks where hygiene in the lambing shed appeared satisfactory, and where navel treatment and the prophylactic use of antibiotic was already practised. It is clear that this emerging problem has a significant economic and welfare impact. Further research is now required in order that suitable control policies might be designed.

Nervous system disorders

Border disease was diagnosed from neuropathological examination of two, ten-day-old Scottish Blackface lambs from a large Perthshire hill flock. Pregnant ewes from the flock were grazed in December with a group of suckler heifers, and two of those heifers have since been diagnosed with mucosal disease. Investigation of possible links between the disease in the cattle and sheep is currently being carried out.

Skin diseases

Orf was considered to have contributed to the starvation and death of a three-week-old, Suffolk-cross lamb submitted for post mortem examination at the Edinburgh Centre, one of five lambs of this age to have died. Although reported as a sudden death, the lamb was thin and dehydrated, and intestinal contents were very limited. Two one centimetre diameter, granular, nodular lesions were present within the mouth, one at the commissure of the lips and one on the gum adjacent to the incisor teeth. Orf virus DNA was detected in both mouth lesions.

Damalinia ovis lice were detected in wool samples submitted from pruritic animals in Scottish Blackface flocks from Perthshire and Inverness-shire. In the latter case the same condition had been diagnosed two months previously. Around 50 animals from the flock of 400 remained pruritic despite treatment.