True friendship knows no boundaries, even when it comes to different species.

A dog named Rookie proved that recently when his best friend left the farm where they both lived.

His friend happened to be the family cow, who had taken on the role of his adoptive mother.

When Rookie’s owners fell on tough times, they made the difficult decision to sell the cow to a neighbor.

Rookie was devastated when the cow was taken away, and his cries of distress could be heard for hours.

After the cow left, the dog decided to take matters into his own paws.

Rather than simply adjusting to life without his friend, he ran away to be with her.

He successfully tracked her down, and the neighbor called his owners to come and pick him up.

Rookie had been just a puppy when he was adopted, so the bond between him and the cow was especially strong.

When his owners realized how much the two animals loved each other, they were so moved that they decided to buy her back. Hooray for Rookie!