Here are some ways to get rid of ticks on cows:

Remove ticks by hand
Use fine-pointed tweezers or a tick removal device to grasp the tick as close to the skin as possible and pull upward with steady pressure. Avoid twisting or jerking the tick, as this may break off its mouthparts. You can then burn the tick.
Use chemical treatments
There are several chemical treatments that can be used to kill ticks on cows, including pour-ons, injectable treatments, dips, and sprays:
Macrocyclic lactones: These treatments, such as ivermectin, abamectin, and moxidectin, kill ticks immediately and are usually applied as a pour-on or injection.
Insect growth regulators: These treatments, such as fluazuron, prevent ticks from growing a new exoskeleton as they molt from one life stage to another. They are usually applied as a pour-on and can remain effective for up to 12 weeks.
Plunge dips and sprays: These treatments can be applied five times, 18–21 days apart, to reduce tick numbers on your farm.
Triatix stock spray: This spray can be used weekly for cattle, sheep, and goats to control ticks and tick-borne diseases.
Start in the spring and end in the fall
Begin treating your cows in the spring when tick numbers increase, and end in the fall to reduce the number of eggs that contaminate the pasture.