October 2009 RVL Monthly Report
Hoose pneumonia was a frequent diagnosis in a number of laboratories, particularly in Sligo and Kilkenny in October. Affected animals ranged in age from seven to 18 months. Diffuse pulmonary oedema, patent hoose and emphysema were consistent features of these cases. In the case of an 18 month old heifer presented to Sligo, all cohort replacement heifers were coughing. Intensive use of prophylactic anthlemintics in the first grazing season was thought to have impaired acquired immunity. Parastic gastroenteritis was diagnosed by Kilkenny and Limerick in a number of six month old calves at grass. Ill thrift, chronic diarrohea and high strongyle egg counts were features of these cases. Cork identified Paramphistomidae (rumen fluke) eggs in dung samples from dairy cows. The consistency of the faeces and the condition of the cows warranted treatment. Rumen fluke were considered of limited veterinary significance but seem to be emerging in significance. After ingestion of encysted metacercariae, excystment occurs in the duodenum and young flukes attach and feed there for about six weeks before migrating forward to the forestomachs where they mature. Clinical signs seen are caused by the duodenal phase of the life cycle.
Athlone detected BVD in the spleens of a 5 month old calf and a 10 month old heifer which were both dehydrated and scouring. Bovine coronavirus (BoCo) was isolated in nasal smears submitted to Kilkenny and Sligo from coughing 3 to 4 weeks old calves. Corona virus is being isolated more frequently from coughing calves of this age.
Pneumonia was found in two four month old poor thriving calves submitted to Athlone for necropsy. The first calf had a significant strongyle worm burden, while the second had coccidiosis and salmonellosis. Peritonitis, persistent BVD infection and chronic parasitism were diagnosed in the three calves. Kilkenny cultured Haemophilus somnus (1) and Pasturella multocida (3) from the pneumonic lungs of emaciated calves in a herd where 30 of 42 calves had died. These cases emphasis the many facets of ill thrift.
Kilkenny cultured Salmonella dublin from the faeces of cows with pyrexia and severe diarrhoea in a number of herds. In the previous two weeks two cows had died in one of these herds. S. dublin was also cultured by Kilkenny from a cow with reduced milk yield, inappetant, with dysentery but was otherwise normal. S. dublin was also a frequent isolate from aborted bovine foetuses submitted to Kilkenny. Other abortofacients encountered during the month in the various laboratories included Neospora caninum, Bacillus licheniformis and Streptococcus uberis. Kilkenny found that many cases of mummified foetus had maternal serology positive for Neospora. Mummification is a common feature of Neospora abortion.
Sligo diagnosed Black disease in a cow, while Athlone encountered two cases, the first in a year and half old heifer and the second in a three and a half year old cow. Migratory fluke tracts were evident in the heifer. Sligo diagnosed four cases of Blackleg during the month.
Sligo reported acute peritonitis in a six month old calf as a result of a large umbilical abscess, with extensive adhesions between ventral rumen and the abdominal wall. Sligo and Kilkenny diagnosed traumatic reticulo-peritonitis in two eight year old cows. Inappetance, reduced milk yield and weight loss were all features of their histories. Diffuse purulent septic peritonitis associated with chronic perforation of the reticular wall by a 12cm piece of sharp wire was noted in the Sligo case. In the Kilkenny case the reticulum was adhesed to a liver abscess and there was a pericardial effusion. Kilkenny found a liver abscess protruding into the caudal vena cava, microabscesses and haemorrage in the lungs of a four year old cow with a history of epistaxis (see photo 1). Micro-abscessation of the left ventricular wall and the interventricular septum was found by Athlone in a four year old heifer which died suddenly. A dissecting aortic aneurysm was discovered in a well grown five month old Charolais heifer presented to Athlone. This resulted in haemorrhage into the right thoracic cavity, mediastinum and extending cranially halfway up the neck in the peritracheal connective tissue. There was also chronic pericarditis.
Photo 1:Blood clots and abscesses in the lung substance arising from septic emboli from a liver abscess that eroded the wall of the posterior vena cava. (Photo: Donal Toolan)
Kikenny found a distinct bloat line on the oesophageal mucosa of a six month old bloated calf. It was fed concentrates as normal but was found dead a few hours later. Ruminal acidosis was diagnosed by Athlone in two cohort 20-month-old heifers which were found dead. The pH of the rumen liquors were 3.6 and 3.3 respectively. There was a strong fermenting smell from the distended rumens.
Cork diagnosed copper toxicity in a three month old calf. There was generalized icterus, gun-metal coloured kidneys and haemoglobinuria. It transpired the calf received twice the recommended dose of an injectable copper supplement. No definitive copper source was found for a cow with copper toxicity diagnosed by Limerick. Two cows on the farm of origin showed jaundice and haemoglobinuria.
Both acute and chronic fluke infestation was regularly diagnosed in carcass and faecal submissions to the various veterinary laboratories during October. The wet year no doubt has contributed to the increased prevalence. Anecdotally, reduced flukicide treatment may also be a factor. Black disease in association with migratory fluke damage was diagnosed by Athlone in a hogget. Kilkenny found severe acute fluke lesions accompanied by high strongyle burdens in organic lambs, where four comrades had died over two days. A number of poor thriving lambs from several flocks were presented to Sligo. These lambs tended to be recently purchased, undersized and in poor body condition. Large strongyle egg burdens and Pasteurella pneumonia were consistent features of these cases.
(Figure 1 Fluke results for October 2005 to 2009)
Copper toxicity was diagnosed in young rams submitted to Sligo and Limerick. Both rams had orange livers, while the Limerick ram also had evidence of fluke damage and a history of jaundice, haemoglobinuria and depression (see photo 2).
Photo 2: The liver of a ram showing lesions of fascioliasis and jaundice. (Photo: Alan Johnson)
Poisoning due to Boxwood (Hebe odora) was diagnosed by Sligo in a three month old ram. Gross post mortem revealed marked pulmonary oedema. Hedge clippings had been thrown in to the field the lamb was grazing. The clippings ingested were confirmed to be poisonous by the Botanic Gardens.
Athlone diagnosed coccidiosis in three hens from a flock where 65 hens had died over a short period. Histopathology revealed mild to severe haemorrhagic enteritis with large numbers of coccidia. Limerick also diagnosed coccidiosis in a 3-month old peacock, with a history of pining and swelling around the eyes. Capillaria eggs and coccidial oocysts were identified by Kilkenny in a faeces submitted from a pining domestic pigeon.
Three turkeys submitted to Dublin were found to be seropositive for avian rhinotracheitis virus in a flock that had lost 17 birds. A strain of Arcanobacterium with 89% similarity to A. haemolyticum was isolated from one of the turkeys. Dublin diagnosed Mycoplasma gallisepticum infection in a three-month-old turkey from a small flock with a high prevalence of periorbital sinusitis, respiratory signs and poor performance. Post mortem examination also revealed pericarditis and air-sacculitis (see photo 3).
Photo 3: Bilateral periorbital sinusitis in a turkey associated with Mycoplasma gallisepticum infection. (Photo: William Byrne)
A recumbent 19 year old donkey submitted to Sligo was found to have significant thickenings on peritoneal and pleural walls, as well as a pericardial effusion and haemorragic enteritis. The thickenings were confirmed as lipoma on histopathology. Sligo found a colonic obstruction in a 16 year old pony, with severely worn and missing molar teeth. The obstruction was caused by impacted poorly chewed silage. Gastric dilation and rupture was diagnosed by Limerick in a 6-month old recently purchased filly foal, with a history of colic.
Cork diagnosed rabbit haemorrhagic disease in two rabbits from the one premises. Kilkenny isolated Bordetella bronchiseptica from the lung of a 22 month old chinchilla with a history of nasal discharge, inappetance and respiratory signs.
A pair of emaciated hares was submitted to Kilkenny, the first had Pasteurella multocida septicaemia and the second a necrotic liver lesion. A second pair had haemorrhagic enteritis due to coccidiosis. Another hare had extensive adhesions between the ribs and the lungs but no significant isolate was found.