Veterinary Services

A full-term male Luing calf from a large suckler herd was presented as a stillbirth, the tenth in the group of 150 cows.  Necropsy at Edinburgh revealed fully inflated lungs but no colostrum in the stomach and no evidence that the calf had stood. No infectious agent was identified.  Histopathology of myocardium and skeletal muscle revealed acute myofibre degeneration with loss of striation, eosinophilic fibres and tissue oedema.  These findings were consistent with acute degenerative myopathy suggestive of vitamin E deficiency.

Another suckler herd in the Borders experienced diarrhoea and ill thrift problems and a high number of losses at calving.  A female Limousin-cross calf, bought-in at two- weeks-old, was presented for postmortem examination.  The main finding was multiple areas of pale streaking in the muscles of the limbs and the thoracic wall.  The kidneys were also pale and enlarged.  Analysis of a blood sample collected before euthanasia revealed high creatinine (536 umol/l, reference range <165) and creatinine kinase (69,580 iu/l, reference range <50), suggesting both renal failure and a myopathy.  Vitamin E concentrations were low in both blood (0.5 umol/l, reference range 3-18) and liver (1.12 umol/kg fresh tissue, reference range > 5). Nutritional cardiomyopathy and renal failure secondary to myoglobinuria were diagnosed.

Toxic conditions

Two cows died on rented land on which broiler litter was spread in February.  The second cow was submitted for postmortem examination at Dumfries. The cow had been weak and recumbent for 48 hours before death.   No significant lesions were noted. Clostridium botulinum type D toxin was detected in the faeces confirming a diagnosis of botulism.  The Food Standards Agency was informed.

Parasitic diseases

40 suckler cows were turned onto a hill in Dumfries and Galloway. They were treated with imidocarb before moving as it was a known Babesia area.  Despite this treatment, five cows died and three were sent for postmortem examination.  Many ticks were present in the groin, axilla and udder of one cow.  It was jaundiced with a packed cell volume of 0.02 l/l (reference range 0.26-0.38) and haemoglobinuria.  Large numbers of Babesia divergens organisms were seen within red blood cells on a Giemsa stained smear.  The SAC VS suggested that either exposure to infected ticks had occurred after the effect of the imidocarb had worn off or that the challenge had been severe.

Generalised and systemic conditions

Mucosal disease was diagnosed on three occasions by Dumfries during the month.  In one case the carcase of a three-month-old Limousin cross calf was submitted for postmortem examination. This calf was one of 90 born to purchased heifers.  Some were already pregnant and others were mated after their arrival on the farm.  They were kept on separate premises from the rest of the herd.  There were no problems at calving but many calves had required repeated treatments for pneumonia since they were three weeks old.  The submitted calf had continued to deteriorate.  Mild pneumonic changes were found but the most significant lesions were present in the gastrointestinal tract. Necrotic foci one to two mm in diameter affected the mucosa of the rumen and small and large intestines.  The changes were most severe in the caecum (figure 1 - see attached top right-hand side) with one area appearing devitalised with a localised peritonitis.  Ulceration of the abomasal folds was also present and the calf tested positive for bovine virus diarrhoea (BVD) antigen.

Alimentary tract disorders

Samples of blood and faeces were submitted to Ayr from a six-year-old Holstein-Friesian cow. It was bought as a replacement heifer but was now in poor body condition and scouring. Johne's disease was confirmed by microscopy and serology. Fluke eggs were detected in the submitted faecal sample. They appeared paler in colour than liver fluke eggs and the possibility of rumen fluke was considered. At postmortem examination large numbers of pale pink, fleshy flukes (Paramphistomes)  measuring approximately five to seven mm were found in the rumen and reticulum (figure 2 - see attached top right-hand side). In addition the mucosa of the small intestine was very inflamed, thickened and corrugated. Histopathology confirmed the diagnosis of Johne’s disease, but there was no evidence of any pathology associated with the rumen flukes.

Rumen fluke eggs were also detected in a faecal sample submitted from an old cow described as thin and recumbent in Wigtownshire.  No Fasciola hepatica eggs were found although there was also a nematode worm egg count of 500 eggs per gram.

Enteric colibacillosis due to infection with K99 Escherichia coli was diagnosed in a two-day-old Holstein bull calf submitted for postmortem examination at Aberdeen. Numerous motile protozoa were observed in a faeces sample submitted from another older live affected calf. The farm reported an ongoing scour problem in calves up to a month of age. A farm visit was carried out to collect fresh faeces samples for further investigation of the scour problem and to assess the clinical significance of the motile protozoa observed. Motile protozoa were observed in two of the samples. Rotavirus was detected in five of the nine samples collected. No other enteropathogens were detected. The scour problem was attributed to infection with rotavirus and it was concluded that the motile protozoa were an incidental finding not of clinical significance.

Respiratory tract diseases

Bacterial pneumonia was commonly diagnosed in calves at grass this month, with three cases having an associated pericarditis. On one of the affected farms, three calves had died from a group of 45. On postmortem examination oedema of the ventral neck was evident and there was excess fluid present in some joints. The pericardium was dramatically thickened and the pericardial sac was filled with fibrinous pus, compressing the heart (figure 3 - see attached top right-hand side). The lung tissue adjacent to the heart was consolidated and adhered to the thoracic wall, and the liver had a “nutmeg” appearance. A heavy growth of Pasteurella multocida was recovered from lung tissue and bronchial lymph node. Escherichia coli was recovered from the heart, pericardium, kidney and joint swabs. Histopathology confirmed a severe acute suppurative bronchopneumonia and a fibrous to fibrino-suppurative pericarditis. Centrilobular hepatic necrosis and haemorrhage consistent with severe passive congestion was evident.

Nervous system disorders

 
Antibody to louping-ill virus was detected in a blood sample from a two-year-old Limousin heifer. On clinical examination she was hyperaesthetic, ataxic and salivating excessively.  IgM antibody was predominant, indicative of recent infection.

Musculo-skeletal conditions

A two-year-old Belgian blue bull was euthanased and submitted for postmortem examination at Dumfries one month after purchase.  The bull was kept isolated on straw for ten days before being turned out with the cows.  He became lame on both hind legs within 24 hours of turn out and deteriorated despite various antibiotic treatments.  The bull was very reluctant to move and stood so that there was less than one metre between the fore and hind feet.  There was swelling at the coronary band of both medial hind claws.  Both claws were affected by white line disease. There was severe under-running of the soles, tracking of pus to the coronary band, septic arthritis of the pedal joint and pedal bone osteomyelitis (figure 4 - see attached top right-hand side). There was no evidence of laminitis.  The pelvis was examined and the distance between the ventral acetabular rims measured only 16cm.  The SAC VS proposed that this narrow pelvis, combined with extreme muscling, lead to uneven distribution of weight on the hind limbs.