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March 2011 RVL Monthly Report

Bovine

Diarrhoea in young calves was a frequent finding in March, and low ZST levels consistent with poor colostrum intake were often found in such cases. Kilkenny saw many cases of neonatal enteritis and diagnosed rotavirus, coronavirus, Cryptosporidium and coccidia, both singly and combined. In the case of one ten-day-old calf with diarrhoea, Kilkenny detected rotavirus, Cryptosporidium, and Salmonella Dublin. Dublin examined a neonatal calf which was one of four from the same group which had died over a ten day period. Diarrhoea was evident on necropsy while Campylobacter sp., rotavirus and Cryptosporidium spp. were detected in faeces. Multifactorial diarrhoea was diagnosed. Cryptosporidium spp. was also detected in the faeces of a ten-day-old calf submitted to Athlone with severe enteritis and dehydration. Indeed Dublin reported that among the several cases of calf enteritis it encountered in March, Cryptosporidium and rotavirus were the most commonly detected pathogens on post mortem examination. Athlone necropsied a pair of one-week-old calves from a single outbreak of neonatal scour and detected rotavirus in one, but found both rotavirus and Cryptosporidium spp. in the second. Sligo reported that scour was the most common cause of mortality among its neonatal calf submissions.

Athlone saw a number of cases of pasteurellosis/mannheimosis in calves in March. Pasteurella multocida was isolated by Athlone from the consolidated lungs of an eight-week-old calf with a history of pining. In the case of a two-day-old calf with a history of poor suck and recumbency, a suppurative omphalitis and peritonitis was found on necropsy and Mannheima haemolytica was isolated from several organs. In a separate case, mannheimosis was confirmed in a one-day-old calf with diffuse fibrinous pleurisy and pneumonia. The ZST result indicated an inadequate passive transfer of colostral antibody. Kilkenny reported several separate cases of colisepticaemia in neonatal calves. Findings included navel infection, joint ill, peritonitis, pneumonia and meningitis. Limerick also reported a frequent finding of septicaemia in calves; among pathogens detected were Mannheima haemolytica, E. coli and Salmonella Dublin. 

Other findings in calves in March included a severe haemorrhagic emphysematous abomasitis diagnosed in a one-day-old calf submitted to Athlone. Clostridium spp. was isolated from the abomasums. The calf was concurrently infected with Bovine Viral Diarrhoea Virus (BVDV). Kilkenny diagnosed two unconnected cases of perforating abomasal ulceration, while Athlone diagnosed a perforating jejunal ulcer with fibrinosuppurative peritonitis in a one-week-old calf. Kilkenny saw three suspect Bovine Neonatal Pancytopaenia (BNP) cases in March. All were two-week-old calves and had haemorrhaged into tissues. One of the three was found to have thrombocytopaenia, neutropaenia and anaemia upon analysis of an antemortem blood sample. Sligo also reported one suspect case of BNP in March. Dublin saw a case of BNP in a 17-day-old Friesian Holstein calf which was found dead. Haemorrhage into the intestine was evident on necropsy while the trilineage hypoplasia evident on histological examination of bone marrow from the calf was characteristic of BNP.

Congenital defects in young calves seen in March included two cases of ventricular septal defects submitted to Limerick; one was an eight-day-old calf with a history of sudden death,  and the second was an eight-week-old calf found moribund in its pen. Sligo reported four cases of atresia coli in calves, while Athlone identified atresia jejuni in two Friesian-Holstein calves each from a separate herd.

Salmonellosis was a common diagnosis in cattle of all ages in March. Kilkenny confirmed Salmonella Dublin septicaemia in a six-day-old calf that had congestion and oedema of the lungs, there was a history of pneumonia in other calves on the farm. Dublin confirmed salmonellosis in a two-week-old calf submitted for post mortem with a history of sudden death. Salmonella Dublin was isolated from several tissues. Kilkenny necropsied a one-month-old calf which originated from a group where four other calves had died. Histological examination of tissues revealed suppurative meningitis and typhoid nodules in the liver, while Salmonella Dublin was isolated from tissues. Athlone isolated Salmonella Dublin from the carcass of a two-month-old calf found on necropsy to have interstitial pneumonia and meningitis. Dublin isolated Salmonella Dublin from a joint fluid sample taken from a calf with swollen joints; a number of other calves in the herd were similarly affected. Kilkenny isolated Salmonella Dublin from the faeces of a cow with a history of pyrexia and diarrhoea beginning five days after calving.

Findings in older calves and yearlings included a yearling heifer submitted to Athlone which had a history of lameness and stiffness. Post mortem examination revealed endocarditis of the bicuspid valve and a purulent embolic pneumonia. Streptococcus dysgalactiae subsp.  equisimilis was isolated from the cardiac lesion. Athlone also investigated the sudden death of a yearling bull with a history of hindlimb lameness. Necropsy of this animal revealed copious quantities of blood in the abomasum and upper small intestine which was associated with multifocal abomasal ulcers, while examination of the femoral heads revealed pathological change consistent with Osteochondrosis Dessicans (OCD) which would have caused the lameness. Dublin necropsied a 12-month-old bullock which had been ill for a month, and was unresponsive to therapy. Ulceration of interdigital space, dental pad, nares and oesophageal mucosa were found, while PCR testing of tissues proved positive for BVDV. Sligo necropsied a yearling bullock which originated from a group of housed animals which had suffered an outbreak of respiratory disease. Pathological changes encountered included a severe diffuse necrohaemorrhagic bronchopneumonia and a purulent foul smelling necrotic bronchitis (Figure 1).  PCR testing of lesions confirmed a diagnosis of Infectious Bovine Rhinotracheitis (IBR). Limerick investigated the death of a yearling bullock with a history of flaccid paralysis ante mortem. An on-farm investigation revealed that a number of animals on the farm were displaying clinical symptoms consistent with botulism. A nine-month-old bullock submitted to Athlone with a history of “pining” for four days ante mortem was found to have a large volume of fluid and grain in the forestomachs, a rumen pH of 4.8 was indicative of ruminal acidosis. Cork investigated a case of posterior ataxia of sudden onset in a 14-month- old heifer; necropsy revealed vertebral compression of thoracic spinal chord. 

Purulent bronchitis  

Figure 1: Purulent bronchitis in a yearling with infectious bovine rhinotracheitis (IBR). Photo: Colm O Muireagáin.

Injury to adult cows due to gestation or calving problems was seen on a number of occasions by Dublin. In one such case, Dublin diagnosed peritonitis due to a uterine tear associated with parturition in a recently calved dairy cow that had become recumbent and had been treated initially for hypocalcaemia. In a separate case, Dublin necropsied a 15-year-old pregnant cow which had a history of weight loss, recumbency and unilateral abdominal swelling ante mortem. Necropsy revealed herniation of intestines into a distended space between the layers of the abdominal muscles where adhesions had formed. It was considered that the mechanical pressure of the heavily gravid uterus which contained a full term bull calf combined with the advanced age of the cow contributed to hernia development in this particular cow.  Traumatic reticulo-pericarditis also known as “Hardware disease” was diagnosed in Kilkenny in the case of a 15-month-old bovine which was found to have an 8 cm piece of wire embedded in the reticulum (Figure 2). A similar diagnosis was made by Cork in the case of a cow which had a chronic suppurative pericarditis and reticuloperitonitis which was caused by a wire 3 cm in length. Limerick dealt with a number of poisonings of adult cattle in March. In one such instance, Limerick diagnosed lead poisoning in a pair of two-year-old bovines from the same herd.  The diagnosis was confirmed by lead assay of kidney. In a separate case, yew leaves were found in the rumen contents of a pair of bovines from the same herd (Figure 3), these animals both had a history of sudden death. Infectious disease affecting adult bovine included an outbreak of Malignant Cataharral Fever investigated by Sligo. The diagnosis was confirmed by PCR testing of tissues from an affected cow submitted for necropsy. Athlone diagnosed chronic fasciolosis in a two-year-old heifer which was recumbent for two to three days ante mortem, having calved three weeks earlier.      

Traumatic reticulopericarditis  

Figure 2: Traumatic reticulopericarditis in a 15-month-old bovine. Photo: Donal Toolan.

Yew leaves in rumen  

Figure 3: Yew leaves in the rumen contents of a bovine with a history of sudden death. Photo: Ian Hogan.

Bovine abortion

Athlone isolated Listeria monocytogenes from the stomach contents of a bovine foetus aborted at approximately seven months of gestation. Sligo reported that abortifacients isolated from foetuses included Bacillus licheniformis, Arcanobacterium pyogenes, Salmonella Dublin and Staphylococcus aureus.

Ovine

Athlone dealt with a number of cases of clostridial disease in lambs in March. In one such case a two day old lamb was submitted for necropsy with a “watery” belly. Focal segmental haemorrhagic enteropathy was found on post mortem. Large numbers of gram-positive bacilli with subterminal spores (Clostridia spp.) were found, and based on the gross and microscopic findings a diagnosis of Lamb Dysentry was made. Athlone also dealt with two separate cases of pulpy kidney, in one outbreak, four one-day-old lambs which were found dead were submitted for post mortem examination. In a separate case pulpy kidney disease was diagnosed in a six-week-old lamb and in both cases similar lesions such as the presence of chicken fat clots in the pericardial sac were found.  Dublin saw a case of peritonitis in a neonatal lamb. Arcanobacterium pyogenes was isolated from affected tissue, several fractured ribs with purulent material at the fracture sites were also found. A diagnosis of traumatic dystocia with chondral fracturing and secondary infection was made. Athlone investigated a number of separate outbreaks of coccidiosis in lambs - the ages of lambs affected ranged from three weeks to ten weeks. Kilkenny diagnosed a case of listerial septicaemia in a week-old lamb while Athlone diagnosed E. coli K99 diarrhoea in a two-day-old lamb.

Cork diagnosed Ovine Pulmonary Adenomatosis (Jaagsiekte) in a sheep with chronic respiratory disease, based on histology (Figure 4), while Athlone diagnosed Listeriosis in a four-year-old ewe which had been unsteady on her feet after lambing. Histological findings of suppurative encephalitis were confirmatory of disease.  Sligo recorded a number of cases of hoggets which had developed metritis and subsequent peritonitis and septicaemia associated with dystocia.  Sligo also reported several cases of “Twin Lamb Disease”. Common post mortem findings in these cases included small contracted rumens, fatty livers while heavy worm burdens. Fasciolosis and poor dentition were often concurrent findings. Sligo and Cork dealt with cases of copper poisoning in sheep. Both cases had similar histories with sheep being fed ration supplemented with copper, while post mortem changes were those of generalised icterus and dark blue kidneys.

Ovine pulmonary adenomatosis  

Figure 4: Multiple discrete tumour nodules (arrows) in the lung of a sheep with ovine pulmonary adenomatosis (Jaagsiekte). Photo: Cosme Sanchez.

Ovine abortion

Dublin diagnosed toxoplasmosis by serology in an abortion outbreak, while non suppurative encephalitis consistent with Toxoplasma spp. infection was found in a foetus submitted for post mortem from the same outbreak. In a separate abortion outbreak also investigated by Dublin, necropsy of submitted placenta revealed multifocal purulent necroplacentitis, while Clearview Chlamydia testing of tissues yielded a positive result; a presumptive diagnosis of enzootic abortion was made.  Kilkenny also diagnosed enzootic abortion in an outbreak it investigated on the basis of pathological findings and a positive Clearview Chlamydia test. Sligo reported several outbreaks of ovine abortion in March. Toxoplasma gondii was the abortifacient most commonly demonstrated but Chlamydophila abortus  was also diagnosed in some cases.