In the whole of 2010, the cash loss in England, Scotland and Wales due to sheep livers condemned for fluke infestation was just over £1 million, according to Dr Phil Hadley from Eblex.
In the whole of 2010, the cash loss in England, Scotland and Wales due to sheep livers condemned for fluke infestation was just over £1 million (£1,040,213) at current market values less pet food realisation, according to Dr Phil Hadley from Eblex.
He says this is based on Food Standards Agency data that 7.23% of sheep livers – 995,419 in number – were rejected for fluke.
If the impact of fluke on sheep performance was also taken into account, the loss would be considerably larger, adds Pfizer vet Andrew Montgomery.
“The majority of disease outbreaks are seen in early/mid-winter due to ingestion of infective cysts shed onto pasture late summer through to early winter,” he said. “However, finishing lambs may not show clinical signs of acute fluke, yet the FSA figures prove that a significant number are carrying sufficient fluke at slaughter for their livers to be condemned.”
Where liver fluke is a known threat, Mr Montgomery advises a triclabendazole-based treatment in the autumn to ensure that all life-cycle stages including early immature are killed, thereby reducing the risk of acute fluke disease. Otherwise, he cautions that an autumn flukicide that doesn’t kill the early immature stage can allow them to develop into adults during the following two to three months, potentially causing acute liver damage or the impaired growth rates associated with chronic fluke disease.
He said: “In ewes and lambs alike, it is crucial that an autumn fluke treatment kills the early immature stages. If a mixed infestation of worms and fluke is being treated, then a single-dose treatment of moxidectin-triclabendazole is appropriate.”
An important issue in fluke control is the occurrence of suspected triclabendazole-resistant fluke. On investigation, Mr Montgomery reports that treatment failures are usually due to factors other than resistance.
However, for suspected cases of triclabendazole resistance, he says Pfizer’s team of field-based livestock vets is available to investigate, identify the scale of the problem, and promote better management practice.