This method is carried out for the castration of male pigs

The correct option is Knife.

Castration is a common management practice in swine production carried out to prevent unwanted breeding, reduce aggressive behavior, and eliminate "boar taint" (a strong, unpleasant odor and flavor that can develop in the meat of intact male pigs as they reach sexual maturity).

Among the methods listed, the surgical method using a Knife (often a scalpel or castration knife) is the standard and most widely accepted practice for castrating male pigs, especially young piglets. During this procedure, a clean incision is made in the scrotum to expose the testicles, which are then pulled or cut to sever the spermatic cord.

Here is why the other options are not typical for castrating male pigs:
1. Burdizzo (Emasculatome): This tool crushes the spermatic cords without cutting the skin. It is primarily used for cattle and sheep, but is not suitable for pigs because their testicles lie closer to the body, making it difficult to secure the cord without causing severe tissue damage to the scrotum.
2. Elastrator: This method involves applying a tight rubber ring around the neck of the scrotum to cut off blood circulation, causing the scrotum and testicles to eventually wither and fall off. While common in sheep and goats, it is generally not recommended for pigs due to their anatomy and a significantly higher risk of complications, such as tetanus and incomplete castration.
3. Hot iron: This is used for dehorning or branding, not for castrating pigs.