Veterinary Services

The prolonged period of snow and freezing temperatures experienced over much of Scotland during January created problems for many farmers in providing adequate feeding to out-wintered stock. 

Two Scottish blackface hoggs were submitted to Ayr for postmortem examination. They were from a group being fed silage during the period of snow. Considerable losses were reported to have occurred in the group over a period of two months. The submitted carcases were in poor bodily condition. Dermatitis with skin necrosis and thickening above the coronet in both hind-limbs of one animal was thought by SAC C VS to be due to frost-bite.  Hepatic necrosis and haemorrhage consistent with chronic fasciolosis was evident in both animals, but Fasciola hepatica eggs were not demonstrated in faeces samples. Neuropathology carried out on the brain of one carcase revealed mild to moderate multifocal rarefaction and vacuolation of the white matter. These changes were considered to be due to severe metabolic stress. Liver fluke control and the relevant sections of the welfare code for wintering animals were discussed with the owner to prevent further losses.

Toxic conditions 

A yearling Scottish blackface lamb was submitted to Aberdeen for examination after seven from a batch of 100 were found recumbent. The group was being fed pit silage during a period of heavy snow, but also had access to some rough grazing. Rhododendron species leaves were found within the rumen.  This type of poisoning is usually only encountered when a lack of grazing or adequate alternative feeding causes sheep to seek out other sources of feed and eat otherwise unpalatable plants.

Parasitic diseases

Dumfries described an unusual case of Strongyloides worm infection.  A group of 15 bluefaced Leicester and four beltex ram lambs were housed on a local holding at the beginning of December.  Some animals developed a scour which resolved after the concentrate ration was changed.  However, the Leicester rams continued to lose condition and some three weeks after housing the group were given a combination levamisole and triclabendazole drench.  The two worst affected Leicester rams continued to waste and died in January.  Both carcases were emaciated and in each the large intestine was distended with dry, pelleted faeces.  In addition, there was a generalised lymphomegaly.  One carcase showed mild lung consolidation, while in the second there was a pleural effusion and ascites.  Cytology of the pleural fluid revealed it to be a mildly suppurative exudate containing eosinophils suggesting parasitic involvement.  Further histopathology of other tissues identified an eosinophilic enteritis affecting the small intestine.  On examination of rectal contents 4,400 and 8,500 Strongyloides species eggs per gram were counted.  Strongyloides worm infections are considered to be significant only in very young lambs and calves, in which they can cause diarrhoea.  SAC C VS suggested that in this case the parasite larvae penetrated the skin of the bluefaced Leicester animals following housing.  Larval migration through the lungs would account for the pleural exudate, with adult worms establishing themselves in the small intestine to produce an enteritis.

The exceptionally high incidence of fasciolosis continued into January with six outbreaks of acute liver fluke disease and 40 cases of chronic disease recorded.  Subacute fasciolosis was confirmed in an eight-month-old Zwartble lamb submitted to Aberdeen. Ill thrift, anaemia and three deaths were reported in a group of 19 lambs purchased three months previously. On necropsy the liver was found to contain large numbers of immature flukes and faeces samples from other lambs in the group were positive for Fasciola hepatica eggs.

Severe, chronic fasciolosis was diagnosed in a ten-month-old Suffolk lamb submitted to Edinburgh.  At necropsy the lamb was very thin and the abdomen was distended by more than 20 litres of clear, yellow fluid. The liver appeared to be loosely wrapped in multiple layers of fibrin and was small, pale, distorted and firm.  The surface of the liver was irregular with scattered foci of haemorrhage.  The main bile duct was distended and packed with numerous adult flukes and many more were present in the gall bladder.  SAC C VS proposed that the ascites was the result of fluid exudation from the distorted, fibrosed liver (hepatic hypertension) rather than hypoproteinaemia, biliary obstruction or infection.

Reproductive tract conditions

Foetopathy due to Listeria monocytogenes was diagnosed in a flock of beltex and beltex cross ewes in Perthshire.  Four abortions occurred in the 500 ewe silage-fed flock in the two weeks prior to lambing.  When abortion material was submitted for examination there was evidence of a non-purulent placentitis, extensive pulmonary petechiation and of multiple pinpoint white lesions in the foetal liver.  A heavy pure growth of Listeria monocytogenes was recovered from foetal stomach contents of the aborted lambs.