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TICKS have a negative impact on the production of cattle. They cut a small hole in the skin and insert their mouthparts into the opening, thus attaching themselves to their host, thereby causing damage to hides and skins as well as damage organs such as the udder, scrotum and the ears of cattle.
The wounds around these areas will often get infected with bacteria and might be attacked by flies.
Also less well known is the effect known as “tick worry” — which is the suppressive effect on the appetite of the animal due to a component in the tick saliva.
Good supervision and management is required for intensive tick control as some tick species are potential transmitters of diseases such as heartwater, redwater, anaplasmosis and tick toxicoses.
Heavy infestations have a negative effect on the growth rate and production of the animals — which means compromising meat and milk production. Sporadic deaths due to tickborne disease can still occur and vaccination should be practised.
Tick control
Prevention is by tick control. You could either use a pour-on or a plunge-dip or spray-dip if you have the facilities for this. Pour-ons can be easier to use and you do not need additional facilities, but these are more expensive
Plunge dip: If a plunge dip is well designed it is the most effective method of wetting animals.
A plunge-dip is a construction that allows for complete immerse of livestock in a liquid that contains a parasiticide. Plunge dips are either fix and made of concrete. Plunge dipping remains the most efficient and economic method for periodically treating a very large number of animals against ticks <http://parasitipedia.net/index.php?option=com_content&view=article&id=2530&Itemid=2804>, flies <http://parasitipedia.net/index.php?option=com_content&view=article&id=2423&Itemid=2807>, mites <http://parasitipedia.net/index.php?option=com_content&view=article&id=2531&Itemid=2805>, lice <http://parasitipedia.net/index.php?option=com_content&view=article&id=2424&Itemid=2808> and other external parasites. This is still the case in many cattle farms in the country where thousands of cattle have to be dipped monthly or even weekly.
Plunge dipping is the most cost-effective method if large numbers of animals are involved.
Spray races: well designed and managed races will achieve good wetting but spot treatment may still be needed under tails and in ears. There must be sufficient arches and wetting nozzles to achieve good wetting.
Hand or mechanical spraying: this is the most expensive and difficult method to do successfully. The minimum volume of application is 5 litres and it may require as much as 10 litres to get good wetting.
Pour-ons: this method is convenient but application must be precise. The remedy takes time to spread over the body. Pyrethroid pour-ons can cause irritation and resistance can develop rapidly.
Injection with macrocyclic lactones: this is a convenient method of control but only effective against blue ticks.
Tick-borne diseases
Prevention of tick-borne diseases is by tick control, as already mentioned, as well as vaccination. Vaccination is best done in calves under 6 months of age and one dose is sufficient.
The heartwater vaccine is given in the vein, and it must be done by a veterinarian. Because these are live vaccines, signs of disease can occur and treatment may be needed following vaccination, especially for the heartwater vaccine. Contact your veterinarian for advice on these vaccines.
Redwater
Signs of redwater are fever, lack of appetite, red urine, pale to yellow gums and eyes, and sometimes nervous signs such as difficulty in walking.
This disease can lead to death if an affected animal is not treated in time. Treatment involves keeping the cattle calm.
They should not be driven over long distances and should be injected with Berenil or Imizol. The dose for Berenil is 5 ml of made up solution (1 packet mixed with 12,5 ml of sterile water) for each 100 kg .
Dips for cattle
There are five main groups, namely: Pyrethroids: examples are deltamethrin, flumethrin, and cyhalothrin.
They are effective against ticks and flies which is useful in dairies where fly borne disease such as three-day stiffsickness need to be controlled.
The disadvantages are irritation of pyrethroid pour-ons at certain times of the year. Pyrethroids are oxpecker-friendly unless they are in combination with organophosphates.
Amitraz: is very effective against all tick species and mites. The dip causes the ticks to detach almost immediately and “hotfoot” aimlessly around on the animals. These ticks then die sometime later. Amitraz is very safe for mammals including humans and oxpeckers. It is suitable for dairy animals but doesn’t control flies.
Organophosphates: chlorphenfinvos is the commonly used organophosphate on cattle. It is effective against all species of ticks as well as lice. It has become effective again following a long period of disuse due to the development of resistance.
The organophosphates are the most toxic of the dips and must be diluted, used and disposed of with extreme care. Don’t use in areas where oxpeckers occur.
Macrocyclic lactones (MLs): This group contains the remedies ivermectin, moxidectin,doramectin, etc. They only work against blue ticks and because the remedy is injected into the animal, the tick must first feed before the remedy takes effect, so there is still the possibility of disease transmission.
The MLs are especially useful in areas where only blue ticks are a problem or where they are resistant to other dips. They are also effective against roundworms and mites.
Insect Growth Regulators (IGRs): An example of this group is fluazuron which is available as a pour-on. It is important to understand that IGRs do not affect adult ticks but inhibit the immature stages, resulting in a gradual reduction of tick numbers and the prevention of eggs being laid.
The IGRs control blue ticks and as with MLs there is an initial delay in the effect of the remedy. IGRs are not registered for use in dairy cattle.
Why dips sometimes appear not to work.
Farmers become annoyed when there are still ticks present after dipping or ticks reappear rapidly on their cattle after dipping.
It is important to understand the many factors that can play a role in the efficacy of dips. Here is a list of some of these:
Poor application:
The dip may be too weak due to over dilution or under replenishment. This often occurs due to the capacity of the dip tank being underestimated. Testing of the dip wash will establish if the concentration is sufficient.
The dip tank may be too shallow and doesn’t wet the heads of the animals.
Wetting in a spray race may be poor due to structural and functional defects.
With hand or mechanical spraying, problems are almost always due to insufficient dip being used to wet the animal.
Dipping Intervals
MLs take time to act because the ticks have to feed before there are any effects.
Pyrethroids can take up to two days to kill ticks and some stay attached despite being dead, especially the males.
Pour-ons may take 2-3 days to spread over the animal and their effect on the lower body areas (belly and legs) will be slower than on the head and neck.
Ticks may climb on animals after the residual effect is past (after 3 days). This occurs especially when farmers put animals in new camps which are alive with thousands of hungry ticks.
Other reasons:
Rain and wet grass washes off dip.
The animals used for stirring the dip are not returned to the dip when it is at the proper concentration.
IGRs will not kill adult ticks.
When there is a massive population of ticks due to warm wet conditions, frequent dipping is required to reduce the numbers.
Resistance can be suspected when a dip group has been used for long periods of time. Ticks can be collected and tested for resistance.
Product is damaged, under standard or expired.
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