Current Findings in the Regional Veterinary Laboratories
March 2004
Bovine
BVD virus was identified in a stillborn calf examined by Dublin from a herd which experienced four abortion
/stillbirths in ten replacement heifers, which had been separated from the cows in the herd for grazing, last year.
Sligo diagnosed Neospora caninum infestation in a neonatal calf, which died within an hour of birth. The animal
was also persistently infected with BVD virus. Dublin diagnosed Purkinje cell damage consistent with
abiotrophy, clinical signs which are normally seen three weeks after birth, in a calf with clinical signs of head
bobbing since birth. In utero BVD infection is the suspect aetiology. Athlone investigated the birth of small
calves and weak-born calves with high perinatal mortality. Dam serology recorded high diagnostic salmonella
titres (> 1/40 “O” and 1/320 “H”) and low serum copper values.
Dublin diagnosed navel ill and E. coli septicaemia in a two-day-old calf that died suddenly. The Zinc Sulphate
Turbidity Test indicated 14 units of immunoglobulins. A serofibrinous peritonitis was diagnosed in another
neonatal calf that also died suddenly from a different farm. A four-day-old suckler calf that had been found dead,
with no history of previous illness, was presented to Limerick RVL. Post mortem examination showed that there
was complete volvulus of the abomasum. Athlone reported a number of cases of neonatal diarrhoea in calves
caused in the majority of cases by concurrent infection with E. coli and rotavirus. In one case faeces samples
from four calves all showed heavy cryptosporidia excretion. Kilkenny found that 22% of samples from calves
with a history of diarrhoea were positive for Rotavirus, 17% were positive for Cryptosporidia, five percent were
positive for Salmonella and two percent were positive for Coronavirus. Limerick found that 28% of faecal
samples tested were positive for Cryptosporidia, 25% for Rotavirus, six percent for Salmonella, two percent for
Coronavirus and one percent for E. coli. K99. Twenty four percent of samples tested by Kilkenny from calves
two to three weeks of age with a history of blood scour were positive for Coccidia. Blood samples from calves
less than three weeks of age tested by Kilkenny with the Zinc Sulphate Turbidity test (ZSTT) gave low readings
(< 20 units) in 60% of cases.
Sligo was presented with a one month old calf that died suddenly after what appeared to be colic. There was
diffuse emphysematous abomasitis, large numbers of Clostridium sordelli were demonstrated on a freshly
prepared impression smear from the lesions by FAT. Sligo had a diffuse monilial gastroenteritis in a two-weekold calf with no observable thymus tissue. A four-day-old calf submitted to Kilkenny had sunken eyes and was
very thin, although body fat stores were not completely exhausted. The abomasum had a dark red mucosa. The
serosa of the small and large intestines was moderately dark red in colour. The caecal mucosa was dark red and
contained yellow faeces of milk-like consistency. Only E. coli was isolated on routine culture but gram smears
of the intestine showed Clostridia like organisms and the FAT was positive for Clostridium sordellii. A
diagnosis of Clostridial enterotoxaemia was made. Kilkenny diagnosed several cases of Pasteurellosis during the
month of March. The most common finding was a severe consolidated pneumonia of the cranio-ventral lobes of
the lung with associated pleurisy (see 0403 Figure 2 – “Pasteurellosis in a four-week-old calf”- Photograph
Pat Kelleher). This was seen in calves from two days to six weeks old. Both Mannheimia haemolytica and
Pasteurella multocida were isolated. Forty percent of the lung tissue was blue-black, consolidated and clearly
demarcated from normal lung tissue in a four-week-old calf submitted to Kilkenny. Haemophilus somnus was
isolated from the lung and the FAT was negative for respiratory viruses. Kilkenny diagnosed several cases of
peritonitis during the month of March (see 0403 Figure 1 – “Peritonitis in a three-week-old calf” –
Photograph Pat Kelleher). Most cases in calves three to six weeks of age were associated with abomasal
ulceration and perforation. A number of cases in younger calves did not have a source of the initial infection
identified. A one-month-old calf submitted to Kilkenny with a history of sudden death after apparent recovery
from pneumonia had a massive pericarditis and epicarditis. There were no heart valve lesions and no reticulitis.
There were many adhesions of both lungs to ribs. The left lung appeared normal and the right lung contained
some consolidated tissue. The gross findings suggested that Pasteurella spp. might have been the cause of the
initial pneumonia.
Salmonellosis was diagnosed by Dublin in two three-month-old calves with typical typhoid nodules on
histopathology. Six other calves had died on the farm during the outbreak. Intussusception was the cause of
death identified by Dublin in one of a group of twenty, ill thrifty six-month-old calves, of which three have died
after acute illnesses. This calf also had purulent bronchopneumonia confined to the apical lobes of the lung.
Sligo diagnosed a case of Focal Symmetrical Encephalomalacia (FSE) in a two and a half month old calf
presented in lateral recumbency. Clinical signs included opisthotonus, nervous signs. Following euthanasia,
necropsy examination revealed a dry vacant lesion in the brain in the area of the cerebral peduncle. Follow up
histopathological examination disclosed multiple haemorrhages and multiple foci of malacia, a fibroid necrosis
of blood vessel walls and leakage of protein around the larger vessels. Similar changes in the mid brain. Two
six-week-old calves that were submitted to Kilkenny for PME had a history of staggering around the field in
distress and “something wrong with the head”. They died before the practitioner arrived on the farm. Both had
very pale musculature and haemorrhages on the thymus. Kidney lead levels of 887 and 1300 mol/kg were
detected and lead poisoning was confirmed. An old battery with evidence of recent licking was located in the
field where the cattle had been grazing.
A twelve-month-old bought-in bullock was presented to Kilkenny for PME. It had been scouring badly for a
week and two other animals from the same source had also died. This animal had moderate fat stores. There
were petechial haemorrhages on the epicardium of the right atrium. Suspect ulcers were seen on the hard palate
and in a small area of the colonic mucosa. BVD virus was isolated from the samples submitted for PCR testing.
Kilkenny found that ninety percent of blood samples tested for BVD SNT had a titre of >= 1/8. In nonvaccinated animals this indicates that these animals had been exposed to the BVD virus at some stage during
their life and had developed natural immunity.
On a field visit by a Cork Laboratory Research Officer with a veterinary practitioner there was a pause from the
herd problem investigation when the owner sought their advice on a change in conformation of a recently
purchased in-calf heifer (see 0403 Figure 3 - "Flying Scapula in an in-calf heifer - Photograph Stephen Murphy,
Sliabh Luchra Veterinary"). The dorsal borders of the scapulae of the heifer were well above the thoracic spines,
conforming to the clinical description of "flying scapula". This rare condition may occur in a number of young
fattening cattle at the same time (Hannam and others, Veterinary Record (1994) 134, 356) or as an isolated case
in adult cattle (Weaver, A. D. (1997) Lameness in Cattle 3rd edn Ed P.R. Greenough W. B. Saunders p 195).
Speculation as to the cause covers rupture of the ventral serrate muscle and vitamin E/selenium myopathies. The
heifer showed no discomfort. Serum creatine kinase (CK) value was 1450 iu/l. While this is above the normal
CK range of 50 - 130 iu/l it does not indicate primary extensive muscle damage but suggests some local muscle
fibre tearing. A Belgian Blue bull, aged five and a half years, from an Artificial Insemination (AI) Station
necropsied by Cork, died from clostridial myositis (blackquarter) of the left semimembranosus muscle. C.
chauvoei was detected. Blackquarter is primarily a disease of young stock, a disease against which they are
usually vaccinated. Adult cattle rarely contract the disease. In theory, the cosseted rearing and the subsequent
sheltered life of an AI bull limits reinforcement of the immunity of calfhood vaccination leaving them vulnerable
to infection. Bovine viral diarrhoea (BVD) virus was detected in a cow examined post mortem by Cork. The cow
was one of two, calved cows, from the same dairy herd. They both had had fever, intermittent diarrhoea,
evidence of interference with blood clotting and anaemia. Viral detection could only be done on one cow. On
post mortem both cows had petechial and ecchymotic haemorrhages throughout and the cow in which BVD
virus was detected had substantial haemorrhage into the abomasum from an erosion on the abomasal mucosa
near the omasal orifice. Caudal vena cava thrombosis was diagnosed by Dublin in a dairy cow, which had failed
to respond to treatment for pneumonia and developed haemoptysis.
A number of investigations by Cork onto fertility problems in dairy herds found no evidence of inclusion of
infectious diseases. In most cases body score condition was low and negative nutrional balances were
demonstrated by blood profiles in lactating cows. As the time post calving is the maturing time for the ova of the
next pregnancy such stresses may contribute to early embryonic failures and account for some of the returns to
service. Athlone diagnosed Cold Cow Syndrome in a dairy herd. The animals presented with severe milk drop,
weakness, diarrheoa and hypothermia. The cows had been let out onto lush new pasture during the previous
twenty-four hours. A number of tests carried out on blood samples and faeces did not establish an aetiology. The
cows were removed from the pasture. Recovery was quick and uneventful.
Sheep
Campylobacter coli was isolated from aborted lambs submitted to Cork from two flocks. There had been fifteen
abortions from 130 ewes in one flock and four abortions from 140 ewes in the second. Athlone reported
Salmonella dublin abortion in ewes. The lambs were in advanced decomposition at abortion but mortality among
the aborting ewes was not reported. Salmonella dublin was cultured from swabs taken from uterine discharge.
Seven out of 11 blood samples submitted for testing following an abortion storm in a Donegal flock were
positive for EAE. Two of samples were positive for toxoplasma. Kilkenny diagnosed a number of cases of
Toxoplasma abortion in ewes. This was based on both serology testing of the foetus and histopathology of the
brain of the foetus.
Dublin diagnosed E. coli K99 enterotoxaemia from two lambs submitted from a flock that had lost about a
hundred lambs, these two lambs also had very low ZST indicating poor passive transfer of immunoglobulins.
Dublin diagnosed listeriosis in two-month-old lambs that had nystagmus prior to death. Classical
histopathological lesions were evident in the brain stem and liver. Athlone investigated sudden death of a small
number of two to three week old lambs in a well managed flock that had had very high perinatal mortality last
year due to Pasteurellosis and Colisepticaemia. Post-mortem examination showed no gross change and no
infectious agent was isolated. It was speculated that Hypomagnesaemia in the lambs on a full milk diet during a
very cold spell of weather with high wind chill may have been a factor. Liver cobalt values were also marginal
and this may be significant when grass takes over from milk as the main dietary constituent if there is evidence
of ill-thrift later on. Two three-week-old lambs were submitted to Kilkenny for PME. One lamb had sunken eyes
and green/brown dung on the perineal area. The rumen and abomasum were small. Both large and small intestine
were almost empty. The rumen and abomasum of the second lamb contained grass. The rumen was a lot larger
than the abomasum. The carcase was oedematous. Caecal faeces was green and of very fluid consistency. The
rectum contained a small amount of sticky green faeces. E. coli was the only organism isolated. Faeces from
both animals were strongly positive for coccidia. A diagnosis of coccidiosis and mis-mothering was made.
Athlone investigated ill-thrift in December-born lambs. Faecal strongyle egg counts and coccidial oocyst counts
were very high. Nematodirus egg counts were also significant.
Sligo investigated the death of fifteen Blackface Mountain lambs on a lowland farm, where they were being
wintered having been purchased from a number of sources. Ten of these were necropsied in Sligo RVL and all
of them were in very poor body condition and had severe parasitic gastroenteritis, with high strongyle egg
counts. On further investigation it emerged that defects in the anthelmintic control programme had allowed
these lambs to pick up heavy burdens of worms on heavily contaminated pastures and parasitic gastroenteritis
had combined with marginal levels of nutrition in causing the deaths.
Dublin diagnosed twin lamb disease and hypocalcaemia in two ewes submitted from a flock with high death
rates close to term. Sligo reported that chronic fasciolosis caused the death of a ewe on an organic farm, where
there had been several cases of ill-thrift in ewes. Sligo reported that Clostridium sordellii was identified in
smears from the abomasum and intestinal wall of a ewe that died with a braxy-like syndrome. This organism is
being increasingly recognised as a cause of clostridial enterotoxaemia in adult sheep addition to its wellrecognised role in causing emphysematous abomasitis in lambs.
Other Species
Pasteurella multocida was isolated by Dublin from suppurative pneumonia in tissues from two of three pigs
submitted from a herd with a history of ill-thrift / weight loss in weaner pigs.
Athlone investigated the death of twelve-year-old Hunter within twenty-four hours of being treated for colic. The
animal died suddenly on-route to a Veterinary Hospital. Post-mortem examination showed a massive
intraperitoneal haemorrhage establishing the cause of death. Aneurysms were found on the external iliac artery
and on the circumflex iliac artery and these had ruptured with the resultant haemorrhage. This was the fourth
animal in the yard to die after presenting with similar signs over a period of six months. Faecal samples taken
from a number of the remaining horses all showed strongyle egg counts on examination.
Losses in the second week of life in broiler breeders was ascribed by Cork to omphalitis/yolk sac infection. Such
deaths are usually at their maximum at three to four days of age and then tail off. In this flock the infection was
not as rampant, manifesting itself as localised peritonitis and adhesions. Dublin diagnosed haemorrhagic enteritis
due to Clostridia perfringens in a racing pigeon, one of a number to die in the loft. Dublin diagnosed Gumboro
in emaciated chickens presented for slaughter where 50% had died prior to transport. Four six-week old broiler
chickens were submitted to Limerick RVL following the death of approximately 40 from a batch of 100. All four
chickens had ascites and enlargement of the heart. A diagnosis of broiler ascites was made. It is thought that
pulmonary hypertension develops as a result of the high oxygen demand of the rapidly growing bird, combined
with the restricted space for blood flow through the bird’s lungs that cannot grow as fast as the rest of the body.
This leads to right ventricular enlargement and eventual right ventricular failure.
Dublin diagnosed Clostridia perfringens entertoxaemia in two nine-month-old fallow deer from a group of ten
deer that died shortly after been let out. Both deer presented with haemorrhagic enteritis. This herd had a
problem with winter inanition due to high worm burdens; it is thought that consequent immunosupression may
have contributed to this outbreak.
Kilkenny examined two one-day-old pups. One pup showed a swollen liver on examination. The second pup had
severe pneumonia and a swollen liver. Histopathology showed severe congestion of the organs and a mild
thickening of the meninges. Streptococcus canis was isolated on culture from the lung and kidney. A diagnosis
of Streptococcal septicaemia was made. Dublin diagnosed fading puppy syndrome due to ICH in pups submitted
with hepatitis, the litter of five was lost. A valuable racing greyhound died and was presented to Limerick RVL
for post-mortem examination. The history was that a horse broke into the field and frightened the dog. The dog,
when discovered appeared to be cold and shivering. The animal died a few hours later. Post mortem examination
revealed some bruising of the right ribcage, and one cracked rib- evidence of a traumatic injury, quite possibly a
kick from the horse. While the injuries were not thought to be sufficient to kill the dog, it is believed that the dog
went into shock and that this lead to the death of the dog.
Fig.1
Fig.2
Fig.3