Veterinary Services

Toxic conditions

Edinburgh confirmed lead poisoning as the cause of sudden death in a recently calved three-year-old Limousin-cross suckler cow and nervous signs in two others. Acute systemic disease was suspected initially on the necropsy but no significant organisms were isolated and no Clostridium perfringens toxins were detected. Histological examination of a range of tissues from the necropsy revealed congestion and terminal degeneration but no inclusion bodies typical of lead poisoning or other specific changes. The kidney lead concentration was 34.5 ppm (reference range < 20.00) confirming lead poisoning. Analysis of a blood sample from the third cow revealed a lead concentration of 1.94 umol/l (reference range 0-1.21). The clinically affected cows recovered following treatment. A battery was eventually found in the field. The Food Standards Agency was informed because of the potential contamination of the food chain.

Generalised and systemic conditions

Necropsy of a seven-day-old Holstein calf (one of a group of six) from a dairy unit in Fife revealed multiple small abscesses throughout the liver and frank pus in the renal pelvis. The synovial fluid in both fore and hindlimb joints was cloudy and histopathological examination of the brain showed a severe diffuse meningitis. Listeria monocytogenes was isolated from liver, spleen, kidney and synovial fluid. The dam of this calf was fed mouldy baled silage in the calving pen. The SAC suspected that the L. monocytogenes bacteraemia was due to an ascending umbilical infection immediately after birth.

Alimentary tract disorders

Mucosal disease was confirmed in a 15-month-old stabiliser bull. Necrotic ileitis (figure 1 - see top right-hand side) and ulceration of the mucosa of the caecum and colon were apparent at necropsy and BVD virus was isolated from the spleen. The farmer purchased a group of four bulls from a single source three months previously and all had died.

Calf mortalities on a Lanarkshire, dairy farm were investigated. Foot and mouth disease movement restrictions prevented the sale of animals and due to a shortage of individual pens, the calves were grouped together from a day of age and bedded on shavings that were piled up rather than replaced. Both calves received were in poor body condition. One had large amounts of roughage in the rumen and erosions and ulcerations in the abomasum. An ulcer had perforated and resulted in peritonitis. The other calf had ulceration of the distal oesophagus and enteritis, with no milk or roughage present in the stomachs. Histopathology suggested a subacute, ongoing viral infection. Splenic lymphoid depletion was also evident suggesting BVD infection, although virus isolation proved negative. The SAC postulated that husbandry problems played a major role in the poor condition of these calves but that acute BVD infection may be present.

Mycotic rumenitis with subsequent systemic mycotic invasion was diagnosed in a recently purchased, 23-month-old bullock. It was the third animal to die in a group being fed bread, vegetables and silage. Two other animals in the group showed signs of respiratory disease. Necropsy revealed peritonitis arising from ruptures of the rumen. The peritoneal surface of the rumen appeared stretched and torn while the rumen wall showed extensive mycotic infiltration, inflammation, oedema and some haemorrhage on histopathology. Fungal elements were present in lymphatics and capillaries causing thromboemboli. The liver had multifocal areas of mycotic hepatitis, while in the lung there were mycotic thromboemboli in some arterioles. The findings were consistent with mycotic rumenitis and subsequent dissemination of fungal elements to liver and lung via the circulatory system causing systemic mycotic invasion. On-going vigilance in assessing the quality of feed being supplied to the cattle was recommended.

Two outbreaks of alimentary tract disease were investigated in dairy youngstock at grass in Dumfries and Galloway. In one case, the group of four-month-old calves was described as pot bellied with scour and secondary pneumonia. Viscera was received and lesions consistent with yersiniosis and parasitic gastroenteritis were observed on histopathology of the intestines. Yersinia may have been secondary to intestinal damage due to parasitism.

A second dairy with an ill thrift problem submitted the carcases of two six-month-old Holstein calves. The remaining forty animals in the group were thin and scoured. Calf diphtheria also affected several calves. Since turnout the calves had been treated with anthelmintics and for coccidiosis. Their dams were BVD vaccinated. Both carcases had necrotic ulceration affecting the hard palate and oesophagus in addition to mild pleurisy and a severe scour. The rumen pH was around 5.8 suggesting acidosis and poor rumen function. Despite worm egg and coccidial oocyst counts being negative histopathology revealed damage due to chronic coccidiosis and parasitic gastroenteritis. The oesophageal lesions suggested viral involvement although no viruses were isolated in cell culture.

Reproductive tract conditions

Streptococcus pluranimalium was cultured from the stomach contents of an aborted foetus from a mature, dairy cow. Congested with occasional small peri-vascular haemorrhages the white matter of the brain was found on histopathology. A severe and extensive predominantly suppurative broncho-pneumonia was present in the atelectic lung which was severely congested. The inter-cotyledonary membrane of the placenta contained polymorphonuclear neutrophils and the peri-portal (centri-acinar) areas of the liver contained a mild mononuclear inflammatory cell infiltrate. These findings were consistent with an infectious disease, probably bacterial and centred on the placenta. Streptococcus pluranimalium is described as a cause of bovine mastitis but this is the fourth time that SAC has isolated it in pure growth from the stomach content of an aborted bovine foetus.

Dumfries diagnosed two concurrent diseases in a foetus submitted after two of five Belted Galloway cows aborted shortly before term. The herd of 120 commercial cattle kept separately was unaffected. The foetus had a slightly domed head and it was reported that the first foetus also had an unusually shaped head. BVD virus was isolated from the foetal thyroid but histopathology of foetal tissues revealed vacuolation within neurones and hepatocytes consistent with an additional diagnosis of mannosidosis. This autosomal recessive, lysosomal storage disease was previously recognised in Belted Galloways. In this case the bull was used before without any problems.

Musculo-skeletal conditions

A farm was visited to examine calves with polydactyly. During spring 2006 and 2007 a new Belgian Blue bull was run with cows that had failed to get in calf over the winter. In 2006 two calves were born with three toes while in 2007, five of the thirty calves sired by the bull were affected (figure 2 - see top right-hand side). Only front feet were affected and the severity of the condition varied, with the calves doing better indoors than when turned out. The metacarpal phalangeal joints could not be flexed in some cases. All of the affected calves were bulls, except for one. The dams were Holstein cows, aged from three to eight years and sired by different bulls. Polydactyly is reported in the Simmental breed where a polygenic transmission is proposed. It is also recorded in the Holstein and Hereford breeds. In the latter, a recessive, sex linked factor is blamed. The bull was sold in this case.