What is the primary method used to identify pigs?

Ear notching is the primary method used to identify pigs because it is a simple, effective, and low-cost technique. Each pig can be marked with distinct notches in its ears, and these notches can be used to represent various information such as the pig's litter number and individual identification. This system allows for easy visual identification, especially in farms where large numbers of pigs are kept.

Additionally, ear notching is less invasive compared to methods like branding or microchipping, which may cause more stress to the animals. It also avoids the potential complications associated with branding, such as infection, and the need for specialized equipment in the case of microchipping.

The method chosen for identification in livestock often reflects considerations of cost, efficiency, animal welfare, and the ability to maintain accurate records, all of which make ear notching a preferred option in swine management.