Hi OP. I've got a couple of comments: 1) If she is that freaked out by the clippers, you are not going to be able to use the milder owner administered drug but should have the vet's sedation. They may appear sedated with the mild stuff but that goes right out the window when their fear object approaches them and the adrenalin starts pumping. 2) I had to desensitize one of my guys one time in fairly short order for clipping (he had cushings and desperately needed a summer cut because of heat). I used a kid's battery operated toy (it was a little plastic chain saw with chain that actually moved and was just a tad noisier than electric clippers), started it up and using the advance and retreat method had him accepting it in three days. I think my success came quickly with him as I didn't tie him so he knew he could leave it got too much, I started at such a distance from him that he showed no interest at all (going back and forth in a parallel fashion rather than straight at him), moved in towards him just enough to catch his attention then back to repeating the back and forth movement till he settled and repeating those steps until I was right up beside him. The first few times I touched him with the toy, I gave a treat right away and after that it was business as usual. This might work with your girl.
P.S. I second TrailHorseRider's concern on the seemingly arbitrary clipping requirement. I think you should get a good understanding of the necessity for clipping and you'll get that by asking questions of your trainer or barn manager. When you do find out, I wouldn't mind if you let us know the rationale.
Last edited by Chevaux; 08-24-2013 at 04:36 PM.