There is always a lot of talk about ticks and the effect they have on dogs and cats, but did you know that ticks can also have a detrimental effect on cattle.
The tick that is of most concern to cattle in Australia is the Cattle Tick (Rhipicephalus microplus previously known as Boophilus microplus). Cattle ticks can be found year round in tropical or subtropical areas like the north of Western Australia, Northern Territory, Queensland and occasionally New South Wales.
The cattle tick is responsible for transmitting the potentially fatal disease Tick Fever or sometimes called Red Water. Tick fever occurs when one of three blood borne parasites, Babesia bovis, which is the most common accounting for over 80% of cases, Babesia bigemina or Anaplasma marginale are transmitted to cattle through the bite of an infected cattle tick. Once cattle are infected these organisms cause red cell destruction and attack various organs which can have severe symptoms and may even result in death.
The signs and symptoms of tick fever will vary slightly depending on which parasite is responsible, the severity of the tick infestation, the age and /or condition of the animal and the stage of the disease. Symptoms may include;
* Loss of appetite
* Weight loss
* Sudden onset of fever
* Red or brown coloured urine (not present in Anaplasma marginale cases)
* Reduced milk production
* Nervous signs like hindquarter weakness and muscle twitching
* Death, which usually results three weeks after infection but can occur at any point even within 24 hours.
If tick fever is suspected on a property a veterinarian should be contacted for advice immediately. The symptoms of tick fever are also symptoms of a number of other illnesses that affect cattle. Therefore the best and most accurate way to diagnose tick fever is through a blood smear tested in a laboratory. If cattle do contract tick fever it is very important to act quickly to control an outbreak and help minimise the impact and severity on the herd and reduce any potential loss of cattle. If diagnosis is made early there are treatments and medications available from veterinarians which may help cattle overcome the illness quickly. The whole herd should be closely monitored for signs of tick fever and any new suspected cases treated immediately. All cattle, if possible, should be treated with a suitable tickicide.
There are some management practices that farmers can follow to help prevent cattle from contracting tick fever. The best protection from tick fever is to vaccinate cattle. There is a choice of chilled or frozen vaccines that should be administered to calves between three and nine months of age or when cattle are being introduced into a cattle tick area from a tick free area. The vaccine only needs to be given once as it should provide lifetime protection. Keeping cattle tick free is also very important. Another management technique is to expose weaners, on purpose, to cattle ticks. This helps them develop their own immunity during the time that they are less susceptible due to some immunity received from the mothers colostrum. This can be risky as it is never completely known if an immunity has successfully been developed to the dangerous parasites. This can be done by using a tickicide and reducing movement of tick infested cattle onto a “clean” property. Bos indicus cattle and Bos indicus crosses are a lot less susceptible to ticks and babesiosis tick fever than the British and European breeds. However they are still susceptible to the less common strain of tick fever anaplasmosis.
Throughout Australia there are tick free borders which have been put in place to try and stop the spread of cattle tick from tick infested areas to tick free areas. In Queensland these cattle tick free areas are to the west of the Great Dividing Range and to the south of the Great Northern Rail Line. Along these borders and the Queensland to New South Wales border, there are tick treatment stations where any livestock, including cattle, horses, pigs or sheep must stop and be checked and sprayed with a tickicide. Although these tick free areas are not 100% free from cattle tick or tick fever, these management practices almost completely reduce the number and severity of tick fever outbreaks in tick free areas.
Tick fever can have a very serious economic impact on farmers with an outbreak substantially affecting their livelihood for years to come. Not only can an outbreak result in loss of livestock but the side effects can be detrimental and ongoing. There are a lot of additional expenses involved when there is a tick fever outbreak including increased mustering costs, veterinarian costs and treatment costs. The ongoing effects from a tick fever outbreak can include reduced fertility rates in bulls and cows, increased abortion rates in affected cows, loss of condition, reduced live-weight gain, decreased milk production and damage to the cattle hide. These are all good reasons as to why prevention of tick fever and good tick management is so important and should be undertaken when possible and particularly in high risk areas.
The following are a few websites with further information on cattle ticks, tick fever and tick fever management. Alternatively you can contact your state or territory agriculture government agency or even your veterinarian for more information.
Until next time,