Question

I recently heard about a vaccine that can be given to calves to build immunity to lungworm. The vaccine is called Huskvac and is sold under the Bovalis name. Is this product available in Ireland? If it is, would you recommend its use in suckler calves? Is a vaccine like this any good and are there advantages to using a vaccine compared to a wormer?
Also, do poor quality feeds/grass and/or mineral deficiencies leave calves more susceptible to parasites?

Reply

There have been vaccines against lungworm developed for many years now. The original vaccine was called “Dictol” and, as you mentioned yourself, there is an Intervet vaccine called “Huskvac”. However, “Huskvac” is not available in Ireland currently. It could be imported from the UK via your veterinary practitioner if he/she was able to obtain permission from the Irish Medical Council, the body that controls the products that are available. Vaccination has been and remains a viable alternative to dosing in the control of disease due to lungworm. The vaccine is an aqueous suspension of third stage-infective Dictyocaulus viviparus (lungworm) larvae partially inactivated by ionizing radiation. The basic vaccination scheme involves two oral doses of 25ml at a dosage interval of approximately 4 weeks.

Lungworm immunity is maintained from season to season by the exposure to lungworm larvae, which in most cases occurs from the grazing of normal pastures after vaccination. A single dose prior to each season’s turnout will boost immunity where such exposure has not occurred, e.g. extensive use of anthelmintics or if using reserved or clean pasture for a large part of the grazing season. Routine vaccination of housed or suckled young stock prior to exposure to field lungworm challenge will help protect the calves and help reduce the levels of pasture contamination with lungworm larvae.

The advantages of the use of a vaccine against lungworm versus the use of wormers are twofold: i) unlike many of the wormers, just two doses are enough to protect the animal for the year, while many wormers require multiple doses; ii) the ever worsening problem of anthelminthic resistence is avoided which is a major plus for the future control of this disease. As I already said, these vaccines have been available for many years. It is not very clear why they have not taken off and become routinely used in most countries as their efficacy is not questioned – perhaps farmers have found the use of anthelminthics (wormers – oral doses, injectables and pour-ons) more convenient. Nevertheless, the bottom line is – they are not available currently in Ireland.

The answer to your other query, i.e. do poor quality feeds/grass and/or mineral deficiencies leave calves more susceptible to parasites?, is a very definite YES. The immune system, of all animals, is very sensitive to the general health of the animal’s body as a whole. Anything that can lead to illthrift, including poor diet, mineral deficiencies such as selenium, copper and iodine deciencies, as well as concurrent disease will lead to immunosuppression leaving the animal in question more susceptible to all infections – viral, bacterial and parasitic. Hence the importance of herd health in the overall prevention of disease on-farm and the maintenance of animal welfare and herd profitability.

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