[PHP] niewbie - call methods from another class

[MEM]

Hello, I have something like this:
 
$stmt = $this->_dbh->prepare("INSERT INTO DOG (name_dog, race_dog, id_vet)
VALUES (?, ?, ?)");
             
             $stmt->bindParam(1, $this->getNameDog() );
             $stmt->bindParam(2, $this->getRaceDog());
             $stmt->bindParam(3, ????????????????????);
             
              
             $stmt->execute();
       }
 
To make this insert function work, I need to fill the id_vet database column
with some values. 
I cannot use $this->getIdVet() because this method is not in dog class, is
on the veterinary class. 
So my question is:
How can I access the getIdVet() that is on the veterinary class to put it on
the insert dog method? 
 
 
Thanks a lot,
Márcio