You can ask Bovy to list cows with certain partial ID information. For example,
Find eartag 2345
would list animals with "2345" in their tag. This can also be called "tag" or "EID". It can be useful to replace a missing tag.
This works on other items too, like barn name.
Even without using "find", Bovy will use partial matches, for example
Which cows are daughters of 29H ?
could be used to find ABS daughters.
This is for finding animals based on some search term. If you want to know where a cow is, such as her pen number, just ask
Where is cow 1234 ?