These wolves can attack opponents, or stand guard for about 4 to 6 hours. Several rats, any number between 5 and 10, can be summoned to assist a vampire. If ordered to attack, they do so with great reluctance, as it is not within their nature. But they can do some damage, especially in numbers. Their primary purpose is to warn of intruders, distract opponents, or to quietly retrieve small objects.
Summoned creatures have their limitations.
They are normal animals, so are subject to the normal desires of any animal. They can tire, and need food and drink to survive. They must find their own way to the vampire's location, and the time it takes for them to arrive depends on where the vampire is. However, a group of cats would be there in an instant. Lycanthropes are immune to a vampire's summons.