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The successful control of liver fluke

The successful control of liver fluke

Liver fluke is a parasite of cattle and sheep. Like most parasites, it can only be picked up off grass. It has a 12 week life cycle within the animal’s liver, in which time it can cause severe damage. Martina Harrington gives advice on how to manage it.

Liver fluke is estimated to cost at least €90m to the Irish industry. Economic losses caused by liver fluke are mainly associated with a decrease in meat and milk production. Depending on the degree of infection, liver fluke may cause a reduced meat production of up to 20% in cattle and up to 30% in sheep, and a reduction in milk production of up to 8% in cows. To control it effectively, we must understand it.

Life cycle within the animal

Day one, liver fluke larvae is ingested by the animal and moves into the rumen

Early Immature FlukeEarly Immature Fluke

From there it starts to work on burrowing out of the rumen, into the blood and moving into the liver, this can take up to two weeks. At this stage it is an early immature fluke – this is the earliest any product can kill liver fluke - two weeks after ingestion.

Immature FlukeImmature Fluke

The fluke is now in the liver, growing and burrowing its way through while causing damage; the extent of this damage depends on the amount of liver fluke ingested. Six weeks after ingestion, the liver fluke becomes an immature liver fluke.

Adult FlukeAdult Fluke 

It keeps moving on towards the bile duct and at around 10 – 12 weeks after ingestion, the fluke is now a mature or adult liver fluke. It moves into the bile duct and it starts to lays eggs. One adult can lay up to 50,000 eggs per day. These move into the rumen and are passed out in the faeces contaminating your pasture.

Early immature liver fluke 1-5 weeks, Early immature liver fluke tunnel through the liver severing blood vessels and destroying liver cells. Loss of liver function, anaemia and even death can occur. Damage continues unless early immature liver fluke are eliminated by a flukicide that kills all 3 stages of liver fluke. Immature liver fluke 6-9 weeks, Unless killed, second stage immature liver fluke

The progression of fluke through the liver.

The control of fluke

It is here you have to consider a couple of questions

  1. Do I have liver fluke on my farm?
  2. What level of liver fluke have I?
  3. What should I treat with?

Do I have liver fluke on my farm?

There are two main pathways to know if you have liver fluke on your farm.

  1. The Beef HealthCheck report you receive from your factory or on ICBF.
  2. Dung sampling.

Beef HealthCheck report

For every batch of cattle slaughtered at a Beef HealthCheck participating factory, farmers will receive a report indicating a disease score relating to any liver and lung conditions present at slaughter. See an example in Figure two. If you have not treated and you have a clear report every time the chances are that you do not have liver fluke on your farm. If you have liver damage but no live liver fluke, this means you have fluke, but you treated and the treatment worked. If you have live liver fluke, then you may have an issue, depending on if you have or have not treated. If you treated and you still have live fluke, you may have built resistance to the dose you used. You now need to talk to your vet.

Beef HealthCheck report - Factory

LIVER RESULTS LUNG RESULTS
Liver lesions result in reduced performance Lung lesions result in reduced performance
1 Normal Liver: No liver abnormalities detected. 1 Normal Lung: No lung abnormalities detected.
2 Liver damaged by fluke but no live fluke: Fluke may not be observed because the animal has (i) been treated and cured (ii) has under gone 'self cure' or (iii) live fluke may have been present but not observed. 2 Limited lung damage: This animal had limited lung damage as a result of pneumonia. Pneumonia in cattle is caused by viral and/or bacterial infection.
3 Liver damaged by fluke and live fluke present: Live fluke may be present because: the animal was (i) not treated for fluke (ii) re-infected after a previous treatment (iii) treated with a product that only kills adult fluke, leaving young fluke alive (iv) given a product to which the fluke have become resistant. 3 Extensive lung damage: This animal had extensive lung damage as a result of pneumonia. Pneumonia in cattle is caused by viral and/or bacterial infection. 
4 Liver other: Liver damage due to other causes. Examples include liver tumours or cirrhosis. 4 Lung other: Lung damage due to other causes. Examples include abscess or tumour.
5 Liver abscess: Abscesses may occur following gut damage from a high grain diet or as an extension of infection from a 'navel ill' or other infection.  

Where evidence of liver or lung damage is found, consult your veterinary practitioner for advice. Further information on improving herd health, including control of liver fluke, other parasites and IBR, can be found at www.beefhealthcheck.ie

Beef HealthCheck report example - Factory

TAG SEX AGE (mths) CARCASE (kg) LIVER SCORE LUNG SCORE
IE 12 34567 8 0001 E 20 330 1 3
IE 12 34567 8 0002 C 22 360 3/5 1
IE 12 34567 8 0003 D 40 400 2 1
IE 12 34567 8 0004 B 44 500 1 1
IE 12 34567 8 0005 E 19 340 1 2
IE 12 34567 8 0006 C 20 350 1 4
IE 12 34567 8 0007 D 56 410 4 1

You can also locate your Beef HealthCheck report when you log in to your ICBF account. It’s under Services> Animal Health Ireland,>Beef HealthCheck. It’s an excellent report and you can go back to 2016, look up different batches and select lung, fluke, pneumonia etc.

Beef HealthCheck report ICBF

Beef HealthCheck report ICBF

Beef HealthCheck report - ICBF

Dung Samples

A dung sample can be used to see if there are fluke eggs present; however you must remember that this will only tell you if you have adult liver fluke in your animals, i.e. they have to be more than 12 weeks old. If your animal only picked up larvae 4 weeks before they were housed and you test at housing, you won’t pick up the presence of those immature fluke in the sample.

What level of fluke have I?

Here you have to use the knowledge of your farm. Liver fluke require a mud snail to complete its life cycle outside of the animal, mud snails are found in and around water, therefore it makes sense that liver fluke is more prevalent on wetter farms. If you have wetter parts of your farm, rivers or ponds you can still have liver fluke on what is maybe a mostly dry farm.

Also remember, one adult fluke can lay up to 50,000 eggs per day. For each larvae (miracidium) entering a snail, several hundred cercaria are released. In favourable conditions (>10oC and wet) one snail can produce 1,000’s of offspring.

eggs, miracidium, mud snail, cercaria, metacercariae

Life cycle of Fluke - Theo De Waal - UCD

Mud Snail

Mud Snail

What should I use to treat liver fluke?

Once you have assessed the level of threat on your farm you can begin to decide what product to use.

There are different products that control the three different stages in the liver fluke life cycle.

If you feel that you have a high burden and you may have cattle in on high levels of meal, or cows in calf, you should look to treat early and kill everything so as to avoid damage to the liver.

Only a product containing the active ingredient Triclabendazole can kill all three stages of fluke; early immature, immature and adult liver fluke. You wait for two weeks after housing and go in and treat. Examples are Fasinex, EndoFluke, Tribex, Cydectin, Triclamox.

If you feel you have an intermediate burden, i.e. you have wet parts to your farm and the year has been warm and wet, you might say, I will go in and kill the immature stages and the adult liver fluke. To do this you must use the active ingredients – closantel, rafoxanide or nitroxynil. These will kill any liver fluke over 7-8 weeks old. So you house, wait 7-8 weeks and treat with products like Closamectin, Solantel, Flukiver or Ridafluke.

If you know you have a level of liver fluke but you are at a very low risk, you have a mainly dry farm and the year has been relatively dry you might say I have a low level of threat so I am going to treat animals when the fluke are adults, then you can use products that have the active ingredients Albendazole, Clorsulon or Oxyclozanide. Examples are Albex, Endospec, Bi-Mectin plus, Ivomec Super. Levafas diamond and Zanil are the exception to this rule at housing as they are a levamisole which is otherwise known as a yellow drench. While this will kill the adult fluke and lungworm, it only partially kills stomach worms. There is an ostertagia type two stomach worm that it does not kill. This can often continue its development later in the housing period and cause severe scouring in animals.

Even if you have a low burden, it is still wise to treat, as stated above, adult liver fluke will lay thousands of eggs that will infect your pasture the following year.

Liver fluke treatment is really farm and year specific, you should talk to your advisor or vet for advice.

The other issue to remember when treating for liver fluke is, the withdrawal dates for the drugs, some can be very long, so if you are finishing cattle, you need to be careful choosing and may need to dose early.

In the Future Beef programme we encourage all farmers to take a faecal egg sample at Christmas after treatment to ensure their dosing policy for all parasites, not only fluke has worked. If the dung is clear after 12 weeks it has worked, if not a discussion has to be had with the advisor and vet as to what went wrong and corrections made.

Product list for the control of fluke

Active Ingredient Sample product Dose after
cattle housed
  Admin route Withdrawal
Triclabendazole Endofluke 10 % 2 weeks Early Oral drench 56 days
  Fasinex 240 2 weeks immature , Oral drench 56 days
  Tribex 10 %   immature ,
adult fluke
Oral drench 56 days
  Cydecdectin
Triclamox
6 weeks   Pour on 143 days
Closantel Closamectin ini 7 weeks   Injection 49 days
  on
Closamectin Pour-
7 weeks Immature ,
adult fluke
Pour - on 58 days ( was
28 days )
  Solantel 7 weeks   Pour - on 63 days
  Flukiver 5 % bovis 8 weeks   Injection 77 days
Rafoxanide Ridafluke 7 weeks Immature ,
Adult Fluke
Oral Drench 60 days
Nitroxynil Trodax 8 weeks Immature ,
adult fluke
Injection 60 days
Albendazole Albex 10 % 10 -12 weeks Adult Fluke Oral drench 14 days
  Endospec 10 % 10-12weeks   Oral drench 14 days
Clorsulon Bi mectin plus 10 -12weeks Adult Fluke Injection 66 days
  Ivomec super 10-12 weeks   Injection 66 days
Oxyclozanide Levafas Diamond 10-12 weeks Adult Fluke Oral Drench 28 days
  Zanil 10-12 weeks   Oral Drench 13 days