Veterinary Services

Generalised and systemic conditions

A yearling Charolais cross bullock was presented alive to the Dumfries Disease Surveillance Centre (DSC) with a three-day history of pyrexia (rectal temperature 105º F). The animal was dull and quiet although still on its feet. It had an oculonasal discharge with crusting of the nose, conjunctivitis and corneal oedema. The peripheral lymph nodes were palpably enlarged and the rumen fill was very poor. Multiple one-millimetre ulcers covered the dental pad, hard palate, lips and gum margins. A single ulcer was seen on the right hind coronary band. On postmortem, the spleen was enlarged, the intestines congested and the faeces mucoid. Serology for Malignant Catarrhal Fever was positive. Sheep had lambed in the adjacent field but the animal had only been purchased one month previously. Deer were also present on the farm.

A five to six-week-old Limousin cross calf, which had been scouring prior to death, was submitted to the Perth DSC for postmortem. The 76 kg calf was in good condition and the perineum was stained. Approximately 70-80 % of the lung tissue was a deep purple colour with consolidation and pus in the apical lobes. The intestines were very pale with fluid contents only. The thyroid gland was grossly enlarged weighing 90.6 g.

The worm egg count and coccidial oocyst count were both negative. Pasteurella multocida was isolated from the lungs with no significant isolates from the intestines.

Histology indicated an acute bacterial pneumonia with secondary changes in the liver. The changes in the thyroid suggested colloid goitre, (a previous iodine deficiency that has now resolved). The farm in question had problems with low iodine problems in the past. Thyroid iodine levels were well above the minimum reference range in this case despite the very large thyroid gland.

Respiratory tract conditions

There were an unusually high number of cases of sudden death associated with Respiratory Syncitial Virus (RSV) infection in young cattle at grass presented to the Thurso DSC. Commonly the animals were one to twelve weeks old and had been apparently clinically normal prior to death. Diagnosis was made by fluorescent antibody test (FAT) examination of lung tissue. In two of these cases there was an associated Pasteurellosis.

A five-year-old Aberdeen Angus cross cow was brought onto better grazing for calving. She was noted to be "slow" and was found dead the next day. Postmortem examination at the Dumfries DSC revealed severe emphysema and lung congestion. FAT for RSV was negative and nothing significant was isolated on bacteriology. Histopathology showed marked interlobular septal oedema, intra alveolar oedema and congestion of the alveolar capillaries. These changes were consistent with allergic type lung disease but the cause was unknown.

Reproductive tract conditions

A three-year-old Aberdeen Angus cow, which had been straining to pass urine was necropsied by the private veterinary surgeon. Multiple nodules were present within the vaginal wall extending into the cervix. A section of the mass was submitted for histopathology. This indicated a poorly differentiated, malignant tumour. A uterine carcinoma was suspected from the appearance of the cells but these tumours usually metastasise early and widely before the primary tumour is identified. A leiomyosarcoma was considered more likely because they are much slower to metastasise. Both would be unusual in a young animal.

Musculoskeletal conditions

At the Thurso centre, the poor quality supplementary feeding being used in May and June resulted in a higher number than usual of cases of White Muscle Disease in newborn calves. Liver Selenium and vitamin E levels in some of the cases were virtually undetectable.

Another herd in Ross-shire reported that the calves were lethargic, slow to suck and had poor sucking ability. Three one-week-old calves were found to have vitamin E levels of 0.3, 0.4 and 0.4umol/l (reference range 3.0-18.0umol/l).

Nervous conditions

A fifteen-month-old Limousin heifer was submitted for postmortem. 15 cases had been euthanased by the farmer over a six-month period with similar clinical signs. There was a history of using poultry litter as fertilizer for the pasture. Several heifers were noted to be incoordinated and would stop and lie down. The 350 kg heifer, which remained recumbent was in very good condition with sunken eyes, although no evidence of scour. The tracheal mucosa was congested with a thick mucoid lining. Lungs were congested. A much reduced grass like ingesta was present in the rumen with abomasum and intestines virtually devoid of contents. No other gross pathology was recorded. Vitreous Calcium and Magnesium levels did not indicate deficiencies. No histological changes were noted in the brain and although this is not diagnostic for botulism a lack of brain pathology is consistent with known cases. Botulism does not produce any specific histopathological changes. The changes present in other organs could be explained by paralysis of the diaphragm, hypoxia and respiratory failure as is seen in botulism but are in no way diagnostic. No other specific cause of death was apparent and a presumptive diagnosis of botulism was made on the basis of history, clinical signs and pathology. The clinical cases stopped after the cattle were removed from the affected pasture. The food standards agency Scotland was informed on the case and measures taken to protect the food chain.

Toxic conditions

A four-month-old Belgian Blue heifer appeared to be ataxic two weeks after turn out. Teeth grinding and ruminal stasis was noted. The animal was euthanased after developing convulsions and following a postmortem at the Dumfries centre the kidney lead content was measured at 51.5ppm (NR < 20ppm). A second stirk was blind and head pressing. Its blood lead level was 5.49umol/l (NR <1.21umol/l). The Food Standards Agency (FSA) was informed. The source was an old painted door, which was being used to cover a water tank.

Copper toxicity was confirmed in a six-month-old Jersey heifer, which died after a short clinical history of depression and anorexia. At postmortem examination at the Aberdeen DSC there was severe generalised jaundice, and, as the liver copper concentration exceeded 500 mg/kg wet weight, the FSA was notified. Initially a home mix was implicated. It was suspected that minerals had been inadvertently included at twice the recommended rate. However a second death due to copper poisoning was confirmed in a slightly younger calf, which had not been exposed to the home mix. Investigations into the source are ongoing including analysis of a proprietary concentrate feed and assessment of copper concentration of liver samples from euthanased male calves to monitor the liver copper status of the dry cows.