Veterinary Services

Generalised and systemic conditions

The owner of a 150-cow dairy herd in the Scottish Borders reported the loss of four young calves over a period of a month. The affected animals were said to have shown signs of neurological disease in the first two or three days of life, and to have died rapidly thereafter, despite treatment with antibiotic. When the carcass of a three-day-old Belgian Blue cross calf was submitted for examination it showed signs suggestive of septicaemia/toxaemia, with generalised congestion, fibrinous perihepatitis and the appearance of widespread renal haemorrhages. The meningeal blood vessels were also acutely congested. A zinc sulphate turbidity test on blood from the calf indicated that it had received an adequate quantity of maternal colostrum. Bacteriology yielded Klebsiella ornithinolytica from a range of viscera. Subsequent neuropathology revealed the presence of several large areas of acute malacia where cells showing apoptotic change were evident, some of which were surrounded by inflammatory cells. This was considered to be consistent with an acute localised vascular problem, such as that caused by septic thrombi following septicaemia due to Klebsiella ornithinolytica.

Alimentary tract diseases

A ten-year-old spring-calving cow from a herd of out-wintered suckler cattle on a Roxburghshire farm, being fed a diet of straw, plus a mineral supplement was found recumbent and hypothermic in a field. The recumbent cow failed to respond to treatment with calcium and magnesium, and was euthanased on humane grounds the following day. The owner reported that a second heifer from the same herd had developed similar signs and died one week earlier. Necropsy of the cow revealed subcutaneous oedema and loss of all body fat. A single central incisor was missing, but the teeth were otherwise sound. Internally, the rumen was grossly distended and impacted with dry fibrous material, which was composed mainly of straw. No other significant lesions were detected in the distal intestine, where the contents were very limited in quantity. The most common predisposing factor in rumen impaction is believed to be a ration high in fibre, but lacking adequate rumen degradable protein. The ration in this case was consistent with such an underlying aetiology.

Respiratory tract diseases

Two bronchoalveolar lavage (BAL) samples and one nasopharyngeal swab were received at the Perth Centre from vaccinated, pyrexic, housed calves with a nasal discharge. IBR was detected by fluorescent antibody test (FAT) from the above samples. IBR virus which grew equally well at 37oC and 40oC identifying it as a wild-type virus was isolated from one of the BAL samples.

Two sudden deaths were reported to the Aberdeen Centre in a group of feeding heifers housed since early November on a well-managed beef unit. Post mortem examination of the lungs from the second animal affected revealed uniform deep purple consolidation of the apical and cardiac lung lobes and anteroventral areas of the diaphragmatic lobes of the lungs, with oedema and congestion. Pneumonia of bacterial aetiology was suspected but bacterial culture proved negative and histopathological examination suggested an acute allergic response to an inhaled or ingested allergen with no evidence of bacterial or viral involvement. Further submissions were encouraged but to date the unit has not encountered further problems.

Diseases of the circulatory system

A 400kg, eight-month-old Aberdeen Angus bull calf from a Selkirkshire farm was submitted to the St Boswells Centre for post mortem examination. The affected housed animal had received antibiotic and anti-inflammatory treatment for some two weeks, for what was believed to be pneumonia and pericarditis. Post mortem examination of the carcass confirmed the presence of marked pulmonary oedema, but no evidence of active pneumonia. The heart was greatly enlarged, and the myocardium appeared both soft and pale. No gross valvular lesions were apparent, but a small area of necrotic degeneration was noted in the pericardium. The other main finding was dramatic hepatomegaly, with evidence of a "nutmeg" pattern of hepatic degeneration. A diagnosis of congestive heart failure was made and subsequent histopathology confirmed widespread subacute to acute degenerative cardiomyopathy of a nutritional type, as well as changes in the lungs, liver and other tissues consistent with heart failure. Nutritional cardiomyopathy is an unusual diagnosis in an animal of this age, with no history of recent turnout or nutritional stress, and subsequent tissue biochemistry failed to indicate deficiencies in either vitamin E or selenium at the time of death. A diagnosis of heart failure, secondary to a cardiomyopathy of unknown aetiology, was therefore recorded.

Parasitic conditions

Fasciolosis was a common diagnosis in January. In the Inverness region fasciolosis was diagnosed in a herd in which fifteen Limousin cross cows from a group of 46 had lost condition and some were scouring.

In a small herd on the Isle of Skye, a three year old Limousin cross heifer, with weight loss and scour, aborted at the eighth month of gestation. The dam of the heifer in question had been diagnosed with paratuberculosis (Johnes disease) but, no evidence of Johnes disease was evident in this animal. Liver fluke eggs were detected in a faecal sample from the affected heifer.

Reproductive tract conditions

Numerous foeti were examined at the Dumfries Centre, including those pertaining to ongoing investigations of abortion problems on two farms.

Abortion due to Neospora caninum was confirmed from two foeti from one large dairy farm, with an ongoing abortion problem affecting five percent of the herd. Foetal fluids proved seronegative for Neospora caninum suggesting exposure to the agent prior to the development of foetal immunity. However, characteristic histopathological lesions were noted in the brain of both cases and the diagnosis was confirmed by immunohistochemistry.

Abortion associated with bovine virus diarrhoea virus (BVDV) and Bacillus licheniformis infection was diagnosed from two foeti from a newly established suckler herd. In both cases BVDV was isolated from the thyroid gland and Bacillus licheniformis was isolated in septicaemic distribution with characteristic histopathological changes noted in one case. In the other case gross congenital deformities were noted including a domed head and cerebellar hypoplasia. A BVDV vaccination program had not been completed prior to the cows being served in this case.