Which method is commonly used to control external parasites in livestock?

The use of pour-on insecticides is a widely accepted method for controlling external parasites in livestock. These formulations are applied directly to the skin of the animal, allowing the active ingredients to spread over the body and create a barrier that repels or kills parasites such as ticks, flies, and lice. This method is advantageous because it provides effective and targeted treatment without the need for extensive handling or restraint of the animals, thereby minimizing stress.

Pour-on insecticides also offer long-lasting protection, which is beneficial for livestock that may be exposed to re-infestations in their grazing environment. Their ease of application and effectiveness make them a popular choice among livestock producers.

In contrast, antibiotic treatment is primarily aimed at bacterial infections and does not address parasitic infestations. Vaccination plays a critical role in preventing infectious diseases but does not target external parasites. Fencing can help manage livestock and prevent the introduction of certain pests, but it is not a direct method for controlling parasites that are already on the animals. Therefore, pour-on insecticides are the most appropriate and effective choice for controlling external parasites in livestock.