What action does a milking machine perform at the end of the teat to remove milk?

The milking machine uses vacuum to facilitate the removal of milk from the cow's udder. When the milking unit is attached to the teats, it creates a vacuum that allows the milk to flow from the udder through the machine and into the storage container. This process mimics the natural suckling action of calves, which also creates a pressure difference to extract the milk.

Vacuum is essential because it helps to maintain the right pressure for efficient milk extraction without causing harm or discomfort to the animal. The vacuum pulls the milk out while allowing the necessary pulsation effect provided by the machine to massage the teat and stimulate milk flow. This action not only aids in collecting the milk but also helps to keep the teat in a healthy condition.

Other choices such as applying pressure, heat, or suction do not accurately describe the operation of a milking machine, as their principles differ significantly from the vacuum method used to safely and effectively extract milk.