I think the 1st image is excellent but not with landscape orientation, (horses ears are very important to the owner of the horse as they give indication of mood at the time) just spin your camera to portrait & I think you're definitely onto a winner there, very nice exposure, focus & pose. Not bad at all for a 1st go
2nd Doesn't look noisy at all on my monitor so I wouldn't worry about it. Stepping slightly to your left would have improved the composition though IMO & brought in some eye contact which is always invaluable for pet portraits.
Overall, very nice for a first set of images, I'd work on images like the 1st if it were me as I can definitely see potential there