Dark subject against dark background improvements?

This is my first DSLR and hopefully the start of something I've wanted to pursue for a long while. I eventually would like to compose more artistic photos, but right now, I'm concentrating on photographing the dogs and puppies I work with. I bought a D600 and although it's probably more than what I need to start with, I wanted something that I use right away but that would grow with me as I learn more. That said, I know I have a whole lot to learn and appreciate any feedback anyone has to offer. Most of our training during the winter takes place inside a not so very well lit training room or an old school with about the same lighting. Natural light shines in through some windows and there are some fluorescent lights, but overall the lighting seems to stink. I would prefer to learn how to shoot without a flash because it's can be distracting to the puppies. I am also still trying to figure out how to minimize red eye and still be able to catch the action I'm looking for. I think I'm getting better, but one thing I'm having trouble with is how to get the dog's dark muzzle to stand out against a dark bite sleeve when the dog is biting in a way that the decoy's body creates a shadow. Aside from using a flash, what settings can I manipulate that would help the dog's muzzle stand out against the equipment? I've included a picture as an example and will try to upload some more to my gallery ...once I figure all that out. Thanks to all in advance for any assistance!

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Nikon D600; Nikkor 80-200mm at 80mm; f 2.8 at 1/200; ISO 5000; Exposure Comp. +2.0EV; Matrix Metering; WB Auto 1,0,M1.

Hopefully that's the correct information I should include!

Welcome....Have read of your manual....Who knows you might learn something about it from it...

I've not read the manual cover to cover ...that's a lot to absorb at once. I am reading and referencing sections as I go and trying to take in as much as I can remember at once. The trouble with using the manual for this particular issue is the manual is a guide to how to use the camera and not so much how to improve my photos. If I knew what I needed to adjust, then I could reference that section of the manual, but I'm not sure what needs to be adjusted. Does that make sense?

I'm not sure where your light source that is on the hand...Wouldn't that light be better placed on the part you wish to see...It is quite bright on the hand and I think the camera would have metered for that...

Rick, he was already at ISO 5000

Looks like some flash is required, but i would use some kinda diffuser. Onboard flash is pretty fierce at close range, so I've used medical tape over the flash in the past. Its kinda white / opaque and will take some of the harshness out of the result and help spread the light more. (I use offboard flash now with diffuser but as you're a beginner, I wont go into that) This will also mean you'll freeze the action better, which in turn means you could lower that ISO to something less noisy. You will need to experiment with your settings when using the onboard flash. You may find that you get TOO much light, but thats easily remedied with your settings

As a last resort, you can ( depending on the shot ) bring up the exposure in PP, but this can bring up even more noise, especially as you've already used a noisey ISO setting.

If that was the result at f/2.8 and ISO 5000, you need either a flash or to photograph the dogs in a brighter area.

You have to add light somehow. Shoot outside or somewhere where there is more light.

It looks to me like the photo is just underexposed. As you can see from the example Pierro posted, with a brighter exposure you can see better.

I would imagine that our poster, who made just 2 posts, and hasnt been here for nearly 7 weeks to even post a response to the thread he started, has moved on.