Veterinary Services

Nutritional and metabolic conditions

A two-year-old Holstein heifer from a Dumfriesshire farm died one month pre-calving, after a 48 hour period of anorexia and lethargy leading to recumbency and death. Necropsy revealed jaundice and the liver was found to be swollen and pale, with a nutmeg appearance. The gall bladder was very distended and the spleen enlarged. Many adult liver flukes were present. Histopathology revealed severe hepatic lipidosis consistent with liver failure, secondary renal lipidosis and circulatory collapse. This degree of pathology is usually only seen in recently calved, very high yielding dairy cows and is considered unusual in a heifer.

Generalised and systemic conditions

Four of a group of 25 six-month-old Limousin bullocks died over 10 days. They were housed with their dams in early December. The right hind leg of the one animal submitted for postmortem at Dumfries was swollen from hock to hip, with emphysema present subcutaneously and in the muscle fascia. The medial thigh muscles were black and contained gas bubbles. The spleen was swollen and there was evidence of haemoglobinuria. The diagnosis of blackleg was confirmed with Clostridium chauvoei clearly demonstrated on a fluorescent antibody test (FAT).

Alimentary Tract Conditions

An abomasal lymphosarcoma was suspected on necropsy of a two-year-old Holstein calved heifer that had been rolled to treat a suspected left displaced abomasum. Over the subsequent two weeks the cow deteriorated, with signs of milk drop, anorexia and weight loss. At postmortem the abdomen was noticeably distended and the rumen, reticulum and abomasum were very well filled with ingesta. This was unexpected given the history of anorexia. No abomasal displacement was detected. The intestines were completely empty apart from a small amount of bile and mucus. Vagal indigestion was suspected although there was no evidence of adhesions affecting the reticulum. Histopathology revealed marked thickening and distortion of the abomasal mucosa by an intense, predominantly lymphocytic infiltration that appeared to form follicles. The findings were consistent with a provisional diagnosis of abomasal lymphosarcoma and the local Animal Health Office was informed under Enzootic Bovine Leucosis regulations.

A multifactorial disease incident was investigated by Dumfries. Two three-month-old Holstein calves were submitted for postmortem from a herd where calf scour had been a problem during the previous three months. The calves became ill at four to six weeks of age. The response to treatment was poor and the calves progressively lost condition. Both calves were pot bellied and faecal stained. There was evidence of pneumonia with antero-ventral lung consolidation from which Arcanobacterium pyogenes was isolated. The low rumen pH values (pH5.5 and 5.2) suggested ruminal acidosis. In addition, Salmonella Dublin was isolated in systemic distribution from one calf and they were both positive for bovine virus diarrhoea (BVD) antigen.

Respiratory tract diseases

Pasteurella multocida and Histophilus somni were isolated from broncho-alveolar lavage samples taken as part of an investigation of respiratory disease in six-month-old calves on an Aberdeenshire calf rearing unit. The unit reported 100 per cent morbidity in the group of 92 calves but no deaths. All calves sampled were pyrexic with clear nasal discharges.

Respiratory syncytial virus (RSV) was detected by FAT tests on sections of lung from a pluck submitted from a three-month-old calf on an Aberdeenshire unit that experienced an ongoing pneumonia problem. Histopathological examination confirmed the presence of an acute interstitial pneumonia typical of RSV infection, with secondary bacterial pneumonia. RSV was also diagnosed as a cause of pneumonia on three farms in Ayrshire this month. On one dairy farm there were five deaths over a period of five days. Both calves submitted for necropsy showed emphysematous bullae on the surface of the caudal lung lobes with consolidation of the antero-ventral lobes. RSV was detected by FAT on lung tissue from both calves. Pasteurella multocida was cultured from lung tissue from both calves and Histophilus somni was cultured from one.

An eight-month-old castrated beef cross calf submitted from a suckler herd in Ross-shire was one of a group of 84, all of which were treated for clinical signs of pneumonia during the immediate post weaning period. The calf was vaccinated against RSV, parainfluenza virus type 3 and Mannheimia haemolytica well before housing in October. Acute suppurative broncho-pneumonia was found on necropsy. Moderate growths of Histophilus somni and Pasteurella multocida were recovered from lung cultures and the FAT for bovine herpes virus type 1 was positive.

Reproductive tract disorders

An increase in the number of bovine abortion submissions was noted this month. Bacterial causes of abortion were most common: a predictable trend given the poor silage making conditions in 2007. Two aborted foetuses were submitted from a dairy farm in Ayrshire that recorded four abortions over the previous six weeks. Campylobacter fetus fetus was recovered from foetal tissues from both foetuses and histopathology showed a dramatic inflammation in the lungs consistent with bacterial infection of the placenta and foetus.

A beef suckler unit in Perthshire experienced unusually high levels of barren cows. A hired bull was used and venereal Campylobacteriosis was suspected. Two of the 13 vaginal washings carried out on barren animals were positive for Campylobacter fetus fetus.

Listeria monocytogenes was cultured from the viscera and stomach contents of a foetus. It was the second abortion in an 80-cow suckler herd in a month. Both abortions occurred at approximately seven months gestation. The cows were housed and fed silage. Histopathology of the lung showed a diffuse increase in interstitial cellularity, a finding consistent with an infectious process. Fungal abortion was diagnosed in a single abortion in a cow from a beef herd in the Scottish Borders. Aspergillus fumigatus was isolated from culture of the foetal stomach contents. Bacillus licheniformis abortion caused abortion in a cow from a pure-bred Luing herd in the Borders, the second to abort in five days. The foetus had severe fibrinous pericarditis and evidence of hepatopathy.

Nervous system disorders

Neuropathological examination confirmed lesions of cerebro-cortical necrosis in a nine-month–old Simmental cross bull that died following blindness progressing to lateral recumbency and opisthotonus. Two animals in a group of 50 were affected. The bulls were housed but their diet had changed. They were fed silage and barley until one week prior to the onset of clinical signs when the silage was replaced with hay.