Veterinary Services

Nutritional and metabolic disorders

A Perthshire hill farmer was feeding 50 housed Simmental cross cows and 9 late born calves ad-lib straw in feed trailers and once a day was pouring an unspecified quantity (thought to be approximately 400 litres) of pot ale syrup on top of the straw.  When the pot ale syrup ran out straw alone was fed for approximately four days when a couple of bales of silage was scattered onto the top of the straw. 

Over the following 2 weeks six cows died and a further six cows were found to be depressed with drooping ears, swollen abdomens, ruminal stasis, and diarrhoea.  Three cows were submitted to the Perth Centre for post mortem examination all showing similar pathology. The cows were dehydrated with a massively swollen abdomen. The rumen was distended with a large volume of well-masticated ingesta. The abomasum was also distended with ingested straw, which was not well masticated together with water. Reticulum, omasum and cranial rumen contained large volumes of dry, impacted ingesta. All the internal linings (mucosal) of all parts of the forestomachs were grossly normal. However, there was an extensive peritonitis involving the outer (serosal) surfaces of the cranial rumen and reticulum, liver and abdominal surface of diaphragm. Despite extensive searching no foreign body could be found in any case.

The cows which died, had all stopped ruminating before death, but this had not affected their appetite and continued to eat the straw and drink. All of the cows affected were in the older age bracket the three examined post mortem being nine, ten and twelve years old.

It is known that impaction can occur when cattle are fed poor quality roughage. It is most common in pregnant beef cattle that increase their intake of low-quality roughage during extremely cold weather in an attempt to meet increased energy needs. The cause is considered to be the consumption of excess roughage low in both digestible protein and energy. The condition can develop slowly but death may be acute as a result of associated peritonitis and shock.

The farmer was advised as a remedial measure to feed silage rather than  straw and to feed a high protein supplement such as dark grains or rape meal with sugar beet pulp as an additional energy source.

On a recent visit to the farm in question the cows were being fed ad-lib pot ale and ad-lib silage. When the silage was not fed this was replaced with approximately one kilogram per head of a mixture of soya meal, rapeseed meal and sugar beet pulp. Since the change in diet deaths had ceased and  no more cows had developed ruminal stasis. Hypomagnesaemia was diagnosed in a three-month-old Charolais cross calf from a herd in Inverness-shire. The housed calves had been separated  for castration when one animal started to fit as it was being moved through the pen. It was treated immediately with magnesium and recovered. A pre-treatment serum sample had a magnesium level of 0.3 mmol/l (reference range 0.8-1.0 mmol/l).

Parasitic conditions

Chronic liver fluke problems were commonly diagnosed particularly in the far north and south-west of Scotland.  The Thurso Centre reported cases in cattle aged six months to 15 years.  The main presenting sign was scour and in two cases submandibular oedema (bottle jaw).  Many of the affected animals had been at grass until December and treatment at housing was planned.  However, in one out-wintered herd chronic fasciolosis was treated in October with a good response.  In January monitoring revealed that the animals had been re-infected requiring further treatment.  There were also reports from farmers that higher numbers of  livers were condemned due to fluke in December and January than in previous years and some farms were experiencing the problem for the first time.

Numerous cases of ill-thrift in adult cattle were investigated in January. In one typical case a 33-month-old beef cow was submitted for necropsy at the Ayr Centre with a history of wasting after housing, the second young cow to die in this way.   Necropsy revealed a “pipestem liver” with adhesions of the omentum to the liver, fibrous change in the liver parenchyma and a small burden of adult flukes.   The mucosa of the distal two-thirds of the small intestine was thickened and corrugated.   Histopathology of the intestine revealed lesions consistent with parasitic enteritis rather than Johne’s disease.   The animals had been dosed with an anthelmintic and a flukicide effective against adult fluke only at housing, which had removed most of the parasites present but substantial damage to the intestine and liver remained and a burden of immature flukes, which continued  to develop into adults.

Coccidiosis was another common diagnosis this month in younger calves.  In one typical example the disease was diagnosed in two groups of young calves by the Thurso Centre and in one case a three-week-old calf had in excess of 500,000 coccidial oocysts per gram of faeces (opg) suggesting severe challenge from birth.  Most animals aged four to eight weeks in these groups were showing signs of the condition and some were depressed.  All the affected calves were beef suckler animals housed on slats, bedded in straw with a creep feed.

An eight-week-old calf from a herd in Ross-shire was examined post-mortem, one of  two calves from a group of twelve, which had died after showing signs of diarrhoea with blood streaks. Another two in the group were affected but were responding to antibiotic and fluid therapy. The coccidial oocyst count of the calf submitted was 270,300 epg.
Histopathology revealed severe subacute enteritis with crypt necrosis and coccidial organisms confirming the diagnosis of coccidiosis.

Generalised and systemic conditions

Histophilus somni infection was suspected in a ten-month-old feeding heifer, which was euthanased followed a short clinical history when it was found collapsed and described as 'sleepy'. A single animal in a group of 50 heifers was affected. Post mortem examination revealed evidence of chronic necrotic laryngitis resulting in partial occlusion of the larynx and septicaemia with multiple renal infarcts, and neuropathological examination showed extensive suppurative thrombo-embolic meningoencephalitis (t.e.m.e)., pathology usually associated  with “sleeper syndrome” due to H. somni. The organism was not recovered from bacterial culture probably due to previous antibiotic treatment.

A two-month-old suckler calf died after an illness of seven days duration and was examined at the Inverness Centre. The calf had been dull, salivating, stiff and lame on its left foreleg. It had a black scour, was pyrexic (107F) and had a heart murmur. Latterly a large ulcer developed on its tongue. The left fore lameness was due to a large interdigital ulcer. Although there was a large ulcer on the dorsum of the tongue there were no lesions on the gums or hard palate. The ruminal mucosa was thickened and oedematous and there were haemorrhages present. The abomasum had ulcers and submucosal haemorrhages and there were ulcers and large haemorrhages scattered along the length of the small intestine. There was also a severe lobar pneumonia. No organisms were isolated from lung or systemic cultures but the calf had received antibiotic therapy. The animal proved antibody negative for bovine virus viarrhoea (BVD) virus and no BVD virus was isolated. Histopathology of the small intestine demonstrated the presence of mucosal collapse and necrosis. Even though BVD virus was not isolated the findings were suggestive of mucosal disease. However in previous screens of the young-stock in this herd there had been no evidence of BVD virus and although a bull was hired and used in the herd, without being tested, subsequent screening of  calves has failed to reveal any evidence of a breakdown due to BVD virus.

As the calving season started, cases of hypogammaglobulinaemia were diagnosed more frequently.  A two-day old, Charolais-cross calf from a herd in Ross-shire collapsed and then died the following day. The zinc sulphate turbidity (ZST)  level was 4 units (reference range >14 units). Profuse growths of Streptococcus bovis and Streptococcus pluroanimalium were isolated from systemic cultures and from the intestinal contents confirming that this was a case of hypogammaglobulinaemia and septicaemia.

Respiratory tract diseases

Pneumonia cases were again common this month.   Many of the cases examined post mortem had been vaccinated with multivalent respiratory vaccines and treated with antibiotics prior to death.  Initial investigations by bacterial culture and fluorescent antibody testing (FAT) commonly failed to identify the cause and histopathology of lung tissue produced a diagnosis.
In one example case from a Berwickshire farm, a five-month-old housed calf with respiratory signs was treated with antibiotic, but died the following day. On post mortem examination consolidation of some 40% of the lung tissue was apparent particularly in the anterior lobes where alveolar emphysema was also noted, while multiple large emphysematous bullae were noted in the diaphragmatic lobes.Although impression smears taken from the affected lung proved negative for respiratory syncytial virus (RSV) by fluorescent antibody testing (FAT), subsequent histopathology indicated lesions consistent with a viral-type pneumonia.  This, taken along with the characteristic gross findings, was regarded as sufficient to allow a presumptive diagnosis of RSV pneumonia.      

An investigation was conducted by the Inverness Centre into an outbreak of pneumonia in four-month-old suckled calves, which had been vaccinated against RSV and Mannheimia haemolytica. Two calves had died and approximately 20 of the 70 in the group had required treatment. Guarded nasal swabs from five animals proved negative by FAT for bovine herpes virus 1 (BHV1), RSV and parainfluenza virus type 3 (PI3). Pasteurella multocida was isolated from one of the swabs and Histophilus somni from another. One calf was submitted for post-mortem  examination and again FAT  for respiratory viruses proved negative and lung cultures were sterile, however the calf had received antibiotic therapy. On histopathology of the lung there was evidence of acute viral pneumonia with underlying chronic damage and a secondary, fairly mild, acute bacterial pneumonia. Investigations, including paired serology for respiratory viruses, are continuing.

A Borders farmer reported coughing and nasal discharge in a group of 20 housed, unvaccinated Aberdeen Angus cross calves, aged eight to nine months.  Samples obtained by bronchio-alveolar lavage (BAL) from four animals with pyrexia and increased lung sounds subsequently proved positive on FAT for RSV. Pasteurella multocida was also isolated on bacterial culture from two of the four samples.

Renal diseases

A four-year-old suckler cow submitted for post mortem examination showed severe bilateral pyelonephritis from which Corynebacterium renale was isolated on culture.