2018 has been a year of wind, snow, droughts and fodder shortages. The important job of housing is now coming; where cattle are finally put on to what’s left of the permanent conserved forages and grains for the winter. With farms reporting variable amounts of fodder and many farmers worrying whether they will have enough for another prolonged winter, it is imperative that farmers take steps to ensure what fodder they have is utilised as efficiently as possible.
One important way of ensuring good utilisation of feed for all stock is ensuring that animals are parasite free. If unchecked, heavy infestations of internal parasites such as liver fluke, stomach worms and gut worms and external parasites such as biting lice, can cause sickness, ill-health and even death in extreme cases. However, it is much more usual for these parasites to cause chronic issues resulting in, ill-thrift, poor food conversion efficacy and inappetence. This year of all years, farmers cannot afford to have their animals not correctly utilising the valuable feeds they have gathered. Therefore, correct and timely parasite treatment is needed.
Housing is the ideal time to rid your animals of parasites. Cattle can pick up internal parasites only while grazing at pasture. This is because the parasites are located on the pasture and cannot survive on silage, hay or other conserved grasses. When cattle are housed, they cannot pick up new infections until turnout the following spring. Effective anthelmintic treatments at or during housing should deal with any parasitic problems until stock return to pasture next year. Veterinary advice should be sought to help estimate and measure the likelihood of infestations and the most appropriate treatments for your farm. Withdrawal periods of the parasitic treatments available should be always born in mind when treating animals.
The main parasites we have to be wary of this year include stomach worms, lungworms, liver fluke (Fascioliasis) and Biting lice.
Trichostrongylosis (Ostertagiosis) is a member of the roundworm family. These parasites cause Parasitic Gastroenteritis (PGE), of which there are two types. Type 1 PGE is caused by the presence of large numbers of roundworms within the intestine. They feed on the intestinal lining, thereby depriving the bovine host of nutrients. Post housing, this can show as mild diarrhoea, poor coats, lack of thrive and inappetence. Type 2 is caused by immature worms burrowing into the lining of the intestine and re-emerging in large numbers mid-winter causing outbreaks of severe diarrhoea.
Lungworm (Dictyocauliasis) is caused by a roundworm which effectively lodges itself within the windpipes of the infected animal. This leads to obstruction of the airways, along with collapse of the air sacs (known as alveoli) within the lung. It is not uncommon for bacterial or viral pneumonia to develop secondary to lungworm infestation. Lungworm is most commonly seen in young grazing stock, which cough when excited or roused. It can also play an important role in the background in outbreaks of pneumonia post housing. The duration of the life cycle of these worms is similar to that of the roundworms. However, part of the development is spent on pasture within a cyst-like structure. Therefore, the immature worm can quite easily overwinter. This allows the infestation to persist from one grazing season to the next.
There are three classes of wormers that can be used to effectively treat internal worms. White and clear wormers are widely recommended to effectively clear adult and immature roundworms in the weeks post housing. Bimectin® Injection is an excellent and effective choice. It offers convenience, with only a single low-volume dose required to effectively treat and control a broad range of internal and external parasites which may impair the health of cattle. Bimectin Injection is also absorbed quickly to reach and kill parasites.
Bimectin Pour-On contains 5 mg of ivermectin per ml and delivers effective, long-lasting control against a wide range of internal and external parasites in cattle, in one convenient low-volume application. Bimectin Pour-On penetrates quickly to reach and kill parasites. Pour-on presentations facilitate ease of application and reduced stress on treated animals, and is also Beef Quality Assurance-friendly, since no injection is required.
Liver fluke (Fascioliasis) is caused by a specific flatworm, known as Fasciola hepatica. This parasite has a life cycle with an intermediate host, the mud snail on pasture. Once ingested, the early immature fluke spend 4 weeks approx. migrating to the liver, where they spend the next 4 or so weeks migrating through until at roughly 8 weeks post-ingestion the now adult liver fluke arrives at the bile duct and start producing fluke eggs. It is the mature fluke which causes most of the chronic fluke conditions which are of most economic consequence to the farmer. 50% of Irish livers are condemned at meat plants, but damaged livers are only the tip of the iceberg. Chronic fluke causes lack of thrive, poor appetite, and reduced weight gain in up to 20% in cattle and up to 30% in sheep.
There can be a reduction in milk production of up to 8% in cows, both suckler and dairy. Fertility can suffer in breeding stock. Beef cattle affected by fluke may take an extra 80 days to reach market weights due to reduced FCR.
Severe infection due to immature stages may cause death due to anaemia in young animals, particularly in lambs. Acute liver fluke can occasionally result in sudden death by triggering certain clostridia diseases of cattle, Immature stages of the liver fluke are also able to survive in a cyst-like structure, in pasture, similar to Dictyocaulus. The encysted fluke can survive in this state for up to 2 years. This has knock on effects for control measures as it means that once fluke is established, control programmes must be followed year-in, year-out.
There are a multitude of actives available to treat fluke in cattle. It is important that farmers get veterinary advice on what stages of fluke a product treats and when is the most effective time post housing to treat.
Triclabendazoles are the only flukicides that kill all stages of fluke. Endofluke contains triclabendazole 100mg per mL, and is licenced for cattle, including dry dairy cows*, and sheep. Endofluke is licenced for the treatment of adult, immature and early immature stages of liver fluke susceptible to triclabendazole in cattle and sheep and can be given two weeks post housing.
Albendazoles are effective against roundworms and mature stages of roundworms.
Endospec 10% SC contains albendazole 100 mg per mL, with the addition of selenium and cobalt, and is a broad-spectrum multi-purpose anthelmintic for the control of mature and developing immature forms of gastrointestinal roundworms, lungworms, tapeworms and adult liver fluke in cattle and sheep. The product is also ovicidal against fluke and roundworm eggs.
Bimectin Plus contains Ivermectin and Clorsulon, two potent anthelmintics. Clorsulon is a potent flukicide, causing adult liver fluke to become unable to metabolise sugar and to die of starvation. Timely use this powerful combination allows you to control adult liver fluke, stomach worms and lungworm in one injection.
Another overlooked but very common winter disease is biting lice ( Bovicola bovis). Lice spend their whole lifecycle on the coat of cattle and they thrive and multiply best on the heavy winter coats and short dark days of the late autumn and winter. Biting lice feed on skin debris, blood and scabs and is a reddish-brown louse about 2 mm long with a brown head. It is mostly found on the neck, shoulders, back and rump of the animal and is visible to the naked eye.
The eggs, or nits are glued singly to hairs and hatch in about two weeks. The nymphs, or immature stages, resemble the adults but are smaller. They mature in about three weeks. Adults live two to three weeks and females lay about one egg per day. Symptoms of Lice include, biting, scratching rubbing, hair loss and general ill thrift.
Any farmer who has had animal suffering from live in winter will not have to be told about the effect of lice on the production and growth rate of cattle. Lice can be an especially important cause of economic loss when cattle are in poor condition or if infestations are heavy. With lice, prevention is preferred before any of the above symptoms become evident. Prevention is successfully carried out using a synthetic pyrethroid pour on such as Ectospec or Dectospot. In heavily affected outbreaks repeat treatments 3 weeks apart is often advised by vets to ensure complete elimination of the eggs. all in-contacts must be treated concurrently to avoid infestation.
*Endofluke: Cattle milk for human consumption may only be taken from 48 hours after calving. Not intended for use during lactation or within 45 days of calving.