MicrostockGroup

I only would send the 1st one.
Horse is overexposed.
Cat, at the edges you can see the shadowing of the lens hood.
Dog, bad background.

A possible problem with the first one is that it appears to be a heavy crop of the third.

What did you take it with? At what resolution? Unless you're using something huge such as a Hassie ... which I doubt ... it probably won't be high enough resolution for a calendar. Maybe even not enough for a magazine.

And don't sign everything with your initials.

Given this is a microstock oriented group I'm not sure if you're going too many people who have experience specifically dealing directly with pet calendar and magazine companies. But, here's my take:

1. Nice picture but leave it color and let the designer decide if they want to mess with the colors.
2. Looks oversaturated but I could see it on a calendar
3. Composition seems off but can be corrected
4. Too much going on in the background

And on all of them the vignetting is too abrupt and is more of a distraction than a design element.

Ok here are the origanal pictures before I messed them up I guess. I also replaced the one of the dog no one liked with another one of my photo's.
Any better? Thank you all for being honest.

Personally I wouldn't send them...

They look soft even from those small thumbs (unless you did something strange to them in photoshop).  Plus they look like snap shots, they're not particularly well composed or illustrating a subject.

Big calendar buyers tend to buy from established stock libraries (Alamy is used alot in the UK, so is Getty) so you might have more luck approaching that sort of supplier.

Plus you know, they don't really have the cute appeal.  They're all looking at things other than the camera, which sometimes works, but people like their cute fluffy animals to be looking at them from their calendar...

(I should justify this now by saying that one on my images was bought to be used in a calendar, pretty much for exactly what you're talking about).