Okay, you seem sincere in wanting feedback. It's a little hard for me to critique a photo that was taken over 20 years ago. Typically people looking for CC are looking to improve a specific image, and with this particular image you certainly aren't going to have the chance to redo it. However, should you find yourself in the midst of dog photography again, you might want to recreate something similar with a different dog.
For me personally, this image misses the mark. The flash wasn't quite strong enough to freeze motion, so the whole thing comes off as a little smudgy. I think this would have worked better with a larger flash unit, as I suspect this was taken with on-board flash. (TBH, though, on board flash is making a very retro comeback, so maybe that's okay here.)
The string breaks up the frame, as well as the resulting shadow, and not being a dog sport/competition person, I don't really know why that string is there in the first place.
I do like the composition, in that you kept all of the dog in the frame - no small limb chops, which people frequently do. I probably would clone or crop out that very little bit at the top of the frame which isn't the grass - it draws my eye away from the dog.
You mentioned you'd like to print this. I would probably sharpen it slightly to offset some of the blur, but definitely don't go overboard as you'll then just make it look like you tried to get rid of the blur - you won't be able to do that well.
This image is much more interesting overall; I suspect your dog image has sentimental value that isn't translated to a viewer, but nonetheless important for you.
This image has a good composition; I might extend the canvas at the top slightly to move the horizon line to the bottom third line, but it's not egregious where it is. I would definitely back away from the strong vignette - it isn't even centered on the image, and it just kind of closes the image in, IMO. I'd also be inclined to brush a bit of exposure back on the wheels of the tractors, just to open up the detail there with the harsh sun coming down.
This image seems to have a weird artifact on it, not sure if you over sharpened or added grain, but it's really noticeable in the sky and detracts from the image overall, I think. I also shoot film and don't inherently mind grain, but this comes across as splotchy, not fine grain like film would be.
The lighting here is a strong, hard light, and you used it well to help tell your story. I think with the few editing tweaks I mentioned you can have a much more dynamic final result.
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