UK - Farmers must understand that liver fluke cycles are changing if hefty production losses are to be avoided.
Prime fluke season used to be the November-December period but this has altered to January-March time, Oli Hodgkinson of Trefaldwyn Vets explained to a seminar at the recent Livestock Event at the NEC in Birmingham.
Mr Hodgkinson warned that this has made combatting Miracidium - the parasitic organism that lays the fluke eggs – a more complex task around the turn-out period.
He said that getting it wrong can cost a beef animal up to 200 pounds in liveweight gain.
“Seasonality is becoming far less discrete and farmers, therefore, need to use sustainable products at the appropriate time of the year and it is important to remember that no flukicide has persistent action,” said Mr Hodgkinson.
“If you treat cattle for fluke today, they can go outside tomorrow and pick up the miracidium which enables the fluke cycle to start again.”
If unsure, Mr Hodgkinson underlined the importance of diagnosis, whether by a blood enzyme test, post mortem or, in the case of chronic fluke, faecal egg counting.
Veterinary practices are happy to conduct faecal egg inspection under a microscope to see if there are eggs, he stated.
Blood enzyme tests, often done on individual cows, can also be taken to see if enzyme levels are high, an indication that the cow is suffering, explained Mr Hodgkinson.
He also urged farmers to use post mortems as a useful diagnostic tool, adding that vets are happy to conduct liver inspection.
“Call your vet when you have a dead cow in and ask them to look at the liver,” he advised.
“Don’t be afraid to talk the slaughtermen as well, they have some fantastic data about what is going on across your farm.”
This data can show whether or not your treatments are effective and possibly tell you if you should treat if you are not using flukicides, Mr Hodgkinson added.
In terms of timing treatment across the herd, Mr Hodgkinson recommended Triclabendazole and Albendazole, although warned that their efficacy greatly depends on what stage the fluke is at within the cycle and stated that no drug has ‘persistent action’.
He said that data shows Tricalbendazole is 90 per cent effective in the early stage of the fluke’s life – around 2-3 weeks.
This contrasts with Albendazole which is more effective at 11-12 weeks rather than early in the fluke’s like when it makes little impact into the parasite.
"Albendazole is ineffective until nine and a half weeks of age, when it becomes 50 per cent effective. A 90 per cent effeicacy can be achieved at 11-12 weeks," concluded Mr Hodgkinson.