Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Does this Kenmore vacuum make a lot of noise? Is it so loud it will scare a cat or a dog when it is running?
Document: I suspect that all along they needed to actually get into the head to make the repair on the height adjustment but they are running out of spare parts as they changed the design several year ago.So they took another few days before deciding they could not replace the power head, probably in the color we had, and they gave us a credit toward a new vacuum cleaner.
This vacuum does not have enough suction to be useful. I was replacing an older Kenmore progressive canister vacuum that had developed a short after almost 15 years of use. This new vacuum can barely suck up dust, the older vacuum could still suck up a craftsman screw driver.I ended up taping the suction control to the fully on position on this new vacuum as it was way to easy to bump it and make is slide to a lesser setting.
If you clean for a living, you know your vacuums. Mary does not care how good looking a vacuum cleaner is, or how many different attachments there are, she just wants something that sounds like a jet engine and has a lot of suction. The Kenmore progressive 21614 is not that vacuum. I'm not convinced it's hopeless, but there are some challenges to using it. First, Sears completely confuses you as to what type of bag goes in the vacuum.
vacuum performs excellently in all functions. The only problem we had with this vacuum that it would intermittently not turn on at the wand switch after you moved the canister (especially if you moved the canister by pulling on the hose).I tracked this problem to the quick disconnect on the canister which has three pin plugs and a plastic module "connector" head. You need to make sure the locking tab clicks into place when you plug this connector into the canister.
The ONLY thing I really like about this vacuum is the small power head for dog hair and that it now fits in the canister. The wand is covered with thick plastic which makes it virtually unusable alone. The crevice tool is small and short with extra holes to weaken the suction if you can fit it somewhere. The extra holes are unnecessary as there is a suction lever on the wand.
This vacuum has now lasted my family for many years and we are so pleased. It's super easy to use, works on all surfaces and the attachments make it super easy to clean such items as ceiling fans, wall corners (top and bottoms), baseboards, under furniture, cracks and crevices and more. It also works fantastic on our wood floors and linoleum as well as several different types of carpeting. IF you can afford one of these, or find one in a thrift shop, BUY IT NOW! !
I have a C bag in there right now, and I'm not even sure it is correct. And, since Sears is downsizing its customer service, the former vacuum cleaner experts have merged with housewares (at least in my Sears) and the housewares people are just as confused as me. I even tried to figure it out on-line and could not. Second, the vacuum cleaner has a lot of fiddly attachments. We lost the combo tool almost immediately and don't know what we'd do with it anyway.
The only reason I give this 4 stars and not 5 is because of the bulky head - the older model had a slimmer head that could get everywhere, but ohhhh ... am I so glad to have this vacuum again! Great sucction - even with our mountains of dog hair, glides super smooth over carpet and hardwood and linoleum ... multifunctional. LOVE the attachments - makes dusting, reaching hard to reach places and the upholstery attachment works PERFECT on our microfiber couch. BUY THIS! !
Then I opened the canister to look at the bag.Vacuum bags used to have a small rubber gasket to seal against the inserted hose; the bag lacked this feature. After just one round of vacuuming, the compartment of the vacuum had a lot of dust and dirt external to the bag and on the small square filter leading into the engine compartment. Without this gasket, the dust isn't all filtered through the bag's filter media, and the vacuum is not providing anything close to the advertised 'hepa' filtration.
If anything changes, I'll update my review, but right now I am so glad to be dog hair free!
Answer: As others have suggested it will depend on the cat or dog.  My suggestion would be to introduce your animal to the noise and machine over a period of time, a few weeks.  Let them see it first and give treats, do this a few times over a week or so.  Next run the vac in area away from animal and give treats while it is running.  Brief exposure the first times.  Begin to expose to noise closer and watch for a reaction.  Animal will tell you when is too much.