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- Ticks can cause major economic losses, both directly and indirectly.
- Chemical treatments remain the most widely used method of tick control. However, resistance to these agents is increasing.
- Non-chemical tick control measures include genetic resistance in livestock, veld management practices, and the use of natural pathogens and predators.
- When new animals are introduced to a farm, they should be quarantined for 30 days.
- Selecting the appropriate chemical class of tick control agent is critical.
Ticks can cause major economic losses, both directly and indirectly. According to Dr Luther van der Mescht, a parasitologist at the University of the Free State, direct losses result from reduced cattle productivity due to tick infestations, while indirect losses stem from tickborne diseases.
“It is estimated that a single feeding female Asian blue tick consumes enough blood daily to cost the host animal around 1g in weight. In some regions, animals may carry between 1 000 and 2 000 ticks at a time, amounting to a substantial cumulative blood loss,” he explains.
Chemical treatments remain the most widely used method of tick control. However, resistance to these agents is increasing, highlighting the urgent need for new approaches. Effective management must account for environmental conditions, production systems, and the farm’s socio-economic realities. An integrated plan should therefore combine chemical and non-chemical methods. The challenge, however, is that many non-chemical strategies remain untested under South African conditions.
Chemical tick control
There are four main approaches to chemical tick control, says Dr Van der Mescht. Absolute suppression is a method typically used in tick-free areas or eradication programmes. Animals are treated at short intervals, requiring a long-term commitment not only to structured application but also to continuous monitoring for chemical resistance.
Opportunistic treatment involves treating animals for ticks when they are already gathered for processing or other management practices.
Strategic control involves intensive treatments during the tick season to ensure that all immature tick stages are exposed to lethal concentrations of the agents. The focus is on targeting the first generation of ticks early in the season, as reducing their numbers drastically limits subsequent generations.
The selective approach is based on a threshold infestation level of fully engorged female ticks per animal (for example 20 per animal). Once this threshold is reached, treatment is applied.
Dr Van der Mescht recommends a structured approach to developing an effective tick control plan:
- Step 1: Identify treatment groups. “Cattle differ in their susceptibility to ticks based on age, sex, and breed. In addition, not all camps on a farm bear the same tick burden, so it is essential to group animals accordingly.”
- Step 2: Assess the required level of control, as not every group needs the same intensity of treatment. Animals in pens with lighter infestations require less intervention than those in high-burden areas. Young calves (up to around nine months old) typically carry fewer ticks than older animals, and females generally have fewer ticks than males. It is also important to evaluate the abundance of different tick species and understand their seasonal patterns.
- Step 3: Identify available vaccines against tickborne diseases and include them in the farm’s annual vaccination schedule.
Grazing management
Non-chemical tick control measures include genetic resistance in livestock, veld management practices that suppress tick burdens, and the use of natural pathogens and predators.
Among these, grazing management is one of the most important non-chemical strategies. The principle lies in resting or rotating camps, with rest periods long enough to break the tick life cycle. “Research indicates that a rotation cycle of at least 30 days in the warm, humid regions of the country can help suppress tick populations. However, more studies are needed to fully quantify the effect.”
In terms of cultivated pastures, alternating between grazing and cash crops has proven effective in limiting tick population build-up.
Fire can also play a role: Wildfires kill ticks and drastically reduce infestations. While not universally popular, burning remains a common practice, particularly in the high rainfall sourveld areas of South Africa.
Biosecurity is essential
The spread of the Asian blue tick from the warm coastal regions to the Highveld is largely driven by the movement of animals between farms. “Biosecurity is crucial, whether between camps on the same farm or across different farms. Be aware of the local tick resistance situation and ensure animals are dipped with an effective product before being moved.”
Healthy animals generally have stronger immune systems, but environmental stressors, such as unhygienic conditions, can compromise the animal’s immunity. When new animals are introduced to a farm, they should be quarantined for 30 days and properly dipped to prevent ticks from spreading on the veld.
Selecting the appropriate chemical class of tick control agent for a farm is critical. While long-acting products can simplify management, they also prolong exposure, increasing the risk of ticks developing resistance. Strategic rotation of different chemical agents should therefore be carefully planned. “Producers will also benefit from performing resistance tests to guide effective tick control strategies.” – Izak Hofmeyr, Plaas Media
For more information, email Dr Luther van der Mescht at VanDerMeschtL@ufs.ac.za
