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Losses due to condemned sheep livers In the whole of 2010, the cash loss in England, Scotland and Wales due to condemned sheep livers was just over £1 million, according to Dr Phil Hadley from Eblex.[1] 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 full impact of fluke on sheep performance was also taken into account, the loss would be considerably larger, adds Pfizer vet William Sherrard. “The majority of disease outbreaks are seen in the autumn through to mid-winter, due to ingestion of infective cysts found on the pasture in late summer through to early winter,” he says.[2] “However, lambs may not show clinical signs of acute fluke, yet the FSA figures prove that a significant number are carrying sufficient fluke at slaughter.” Dealing effectively with fluke requires an understanding of its life-cycle. The fluke eggs hatch and enter into the mud snail during the early part of the summer provided the ground conditions are damp, before emerging from the snail and developing into infective cysts on the pasture, if weather conditions are damp from late summer onwards. Sheep ingest infective cysts off the pasture and they develop through early immature then late immature stages before maturing into egg-laying adults. It takes about 12 weeks for the adults to develop from the time they are ingested by the sheep. The adults are found in the bile ducts and lay large numbers of eggs which pass out in the dung. The significance of these stages is in choice of flukicide, because some kill adults only (e.g. clorsulon), others will kill late immature and adults (e.g. closantel, nitroxynil) while triclabendazole kills all three.