In many offices when you see a crowd gathering, it's most likely one of three things: someone brought cake, someone brought their newborn baby or someone brought their pet.

On Friday, the world will concentrate on the latter of those three things. June 21 is Bring Your Dog to Work Day.

The day was created in 1999 by Pet Sitters International to celebrate dogs as companions and encourage pet adoption. It's estimated 300 businesses allowed their employees to bring their dogs (and cats) into work that first year, and the number is believed to have grown larger in the past 21 years, with some companies opening their doors to pets 365 days a year.

Studies show bringing pets to the office can lower workplace stress by encouraging employees to get up out of their desks occasionally to interact with the animals or their co-workers. But there are a few things you need to consider before letting Fido pack up his briefcase.

Ask first

Most obvious, of course, is to make sure your employer is comfortable with it. These days, as offices have become more relaxed, a greater number of companies are allowing employees to bring in animals. Giants like Google and Amazon, trying to please pet-loving millennials, have given the thumbs-up to four-legged creatures walking their hallways. But not everyone is a pet lover, so get the OK from the higher-ups.

Designate pet-free zones

As much as some co-workers will love your pet, others will see a giant allergy trigger as soon as he or she walks through the door. Even those with allergies can love pets, but you still need to be aware of people who suffer from allergies and take the appropriate action. It's smart to make sure some parts of your office are off-limits to pets. At the very least, keep dogs and cats out of the co-worker's space.

Avoid boredom

While you might like to look down at little Snuggles in her basket under your desk, don't assume your pet is having a blast. Make sure to bring chew toys or balls to keep them entertained as well as a bed to make sure they're comfortable.

Pet-proof your workplace

We think about child-proofing a lot more than pet-proofing, but the fact is animals can die from hazards at home or, in this case, work. No one wants to read another story like the one about the dog who lost his tongue in a paper shredder. Make sure pets don't chew on electric cords or get into potentially hazardous items in garbage cans or a co-worker's purse.

Have a crate

While you might love that adorable little doggy bed that fits snuggly under your desk, veterinarians suggest having a crate in the office to serve two purposes — to keep the dog away from people or places in the office where they shouldn't be while also giving the animal a sanctuary that is theirs alone.

Avoid accidents

Make sure your pets are potty-trained before they come to work. As much as you hate to clean up accidents in your home, it's much worse if your dog piddles on the work carpet. Yuck. To avoid being shunned at the company picnic, clean up accidents as soon as possible. The Humane Society website has good advice for cleaning up pet urine.

Veterinarians advise you to keep your eye on your pet to see if he or she is stressed. If they don't seem to feed off the energy of Bonnie in accounting or Jared in IT, keep them home. You might have to work for a living, but they don't.

Other holidays this week

  • Monday, June 17: Cherry Tart Day
  • Tuesday, June 18: Go Fishing Day
  • Wednesday, June 19: Martini Day
  • Thursday, June 20: Vanilla Milkshake Day
  • Friday, June 21: Summer Begins
  • Saturday, June 22: Onion Rings Day
  • Sunday, June 23: Pink Day