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Livestock producers can suffer significant losses if their cattle are infected with flukes. Serious cases can even lead to livestock mortalities. Liver fluke affects the liver of ruminants while conical fluke invades the rumen and reticulum. Flukes cause the most damage to the animal’s small intestine while in the early stages of development.
Fluke infection is best identified through manure egg counts. Animals generally present with suppressed appetite, weight loss, and diarrhoea. Especially cattle in extensive farming operations are prone to death if infected.
Read more about the strategic and tactical treatment of liver fluke here.
Liver flukes
Dr Andy Hentzen of the Faculty of Veterinary Science at the University of Pretoria, who is also affiliated with Agri FARMACY, says liver fluke is one of the main parasitic diseases in livestock, not only in South Africa, but globally. Infection can, among others, lead to livestock mortalities, decreased production and reproduction, the rejection of livers by abattoirs, and secondary infections.
South Africa is home to the common and giant liver fluke, with liver fluke populations being maintained thanks to their intermediate host, the freshwater snail. The life cycle of the liver fluke has several stages of development outside and inside the animal. The eggs that animals excrete develop into larvae that attach to grass and leaves or survive under the water’s surface; when animals drink or graze, they ingest the parasites and become infected. The risk of infection is lower in drier years, but because regular water points can also serve as a source of infection, producers must remain vigilant.
Although liver flukes are but one of several sources of liver damage in animals, it doesn’t make the threat less serious. In this regard, livestock producers must make an effort to find out all they can regarding this parasite and manage it so as to prevent serious negative implications for their herds. Moreover, producers must have a firm understanding of other possible causes of liver damage, such as poisoning, and try to limit it as best possible.
Although the livers can heal when damaged, the connective tissue that forms during the recovery process means the animal’s liver cannot regain full function.
Manage the threat
According to Dr Hentzen, there is a strong connection between a healthy liver and optimal absorption and utilisation of microminerals by the animal. The liver stores and releases many of these minerals as needed. A key function of microminerals is maintaining the immune system of the animal, making it less susceptible to disease and infection.
A combination of different approaches can be employed to lessen the threat of liver fluke infection in a herd. Animals can be dosed with a flukicide that kills the liver flukes. They can also be restricted to grazing in areas away from marshes or standing water. If these areas cannot be fenced off, allow animals to graze there shortly after having treated them with a flukicide – the agent will still be in their systems and will kill any ingested liver fluke larvae in the digestive system.
Strategic burning of veld that plays host to liver flukes is another effective option. High-density grazing is also a good management aid, as it reduces the impact of liver fluke infection; also, the resting the veld for long periods interrupts the life cycle of the fluke.
Conical fluke
Much like liver fluke, conical fluke often leads to livestock deaths and production losses. The two parasites have very similar life cycles and symptoms.
Adult conical flukes settle in the rumen and reticulum of cattle. However, immature flukes cause the most damage to the small intestine of cattle, sheep, and goats. This leads to suppressed appetite, severe and foul-smelling diarrhoea, and weight loss.
The freshwater snail is also the intermediate host of the parasite. Infection in animals occur when they ingest some of the larvae attached to grass and leaves or when they drink standing water infested with these fluke larvae. Upon ingestion, tiny immature conical flukes are released into the small intestine, where they use suckers to attach to the intestinal wall, damaging the mucous membrane.
Lesions develop from which plasma proteins leak, causing the animal to ingest less fodder and limiting nutrient absorption. A drop in protein levels causes the animal’s throat to swell, an occurrence commonly known as bottle jaw.
Controlling these parasites involves keeping animals away from standing water, applying strategic dosing in January, May and August, and administering supplements such as multivitamins, vitamins B-plus and B-complex, and microminerals. – Andries Gouws, Stockfarm
For enquiries, contact Dr Andy Hentzen on 082 372 0307 or email andy@agrifarmacy.co.za or andreas.hentzen@up.ac.za.
