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Twenty-two heifers from a group of 31 died within days of each other due to rumen fluke, vets concluded following a postmortem.
The farmer found 11 dead animals on a Friday morning, after they had previously been seen without any clinical signs of any problem on the Wednesday afternoon.
When he found the dead heifers, all of the rest of the 31 heifers were also sick. They were weak, lying down, had diarrhoea and were dehydrated.
The incident, which happened in Co Kildare, was reported in the Regional Veterinary Laboratory (RVL) monthly report for September 2016.
Athlone RVL investigated the deaths of the seven-month-old dairy replacement heifers.
Another 11 heifers died in the following days
On testing, the sick heifers were found to have abnormally low protein and high urea in their blood, as well as low calcium and magnesium in their blood.
Another 11 heifers died in the following days, resulting in the farmer losing 22 of the batch of 31 dairy replacements.
Postmortem
When the dead heifers were examined in a postmortem, the RVL vets found large numbers of rumen fluke attached to the mucosa of the small intestine. They also found parasitic tracts in some of the livers and damage to the duodenum.
The inside of a rumen with rumen fluke attached to the wall.
They concluded that the severe intestinal damage due to the large numbers of fluke larvae was sufficient to cause the clinical signs described in the disease outbreak.
Migratory tracts in the liver also pointed to a liver fluke infestation alongside the rumen fluke.
Similar case
In a similar case, rumen fluke was diagnosed as the cause of death in three dead cows submitted to the Central Veterinary Research Laboratory (CVRL) in Backweston, Co Kildare.
The cows had acute-onset severe diarrhoea and did not respond to antibiotic treatment before they died. Other milking cows in the herd had similar issues.
The vets found large numbers of rumen fluke in the cows’ forestomachs and large numbers of larval fluke visible throughout 24m of the intestine from the duodenum to the ileum.
Urgent advisory note
The vets noted that while rumen fluke is a relatively frequent finding in many cattle and sheep carcase submissions to the RVLs, it is usually considered an incidental finding and not the cause of death.
However, during September 2016, rumen fluke was diagnosed as a cause of disease and death in a number of submissions to the RVLs.
The increased number of diagnoses was enough to prompt the RVLs to issue an urgent advisory notice to all veterinary practices to consider rumen fluke as a differential diagnosis in outbreaks of acute diarrhoea or sudden death in cattle and sheep.
Sheep management: liver fluke forecast and dealing with rumen fluke
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