What is the most common permanent method of swine identification?

Ear-notching is considered the most common permanent method of swine identification because it involves creating a unique set of notches in the ears of pigs. These marks provide a reliable system for identifying individual animals within a herd, as each pig can be assigned a specific pattern of notches that corresponds to its identification number. This method is not only durable but also visible, allowing for easy recognition and record-keeping.

Ear-notching is widely used in the swine industry because it is effective in maintaining a permanent record that can be tracked throughout the animal's life, from birth to slaughter. This is especially important for breeding records and genetic management.

Other methods mentioned, such as tagging, can be temporary and may not last for the life of the animal. Microchipping, while a technologically advanced method, is not commonly utilized in traditional swine management due to cost and practicality concerns. Branding, although it can be permanent, is less common in swine because it can cause pain and distress, making ear-notching a more humane and practical choice for identification.