Just when I was wishing I could post in a video to show how GREAT my dog is moving the cattle for me, how he has become reliable , a real partner, we have this serious bump in the road. Pride goe-eth before the fall!

Last week moving heifers down a 300 yard lane, a twice daily occurrance (out to pasture, back in for the night) my pup hit the hot wire in the lane while working around the bunched up herd--they were trying to graze the lane, he was pushing them.
Now, he's decided that the lane is dangerous. In fact I'm not sure that he doesn't think the electricity came off the calf, have noticed a general backing - off of effort while moving cattle. It MAY have come off the calf, he had them so bunched up. Not so keen on rounding up these same heifers when they are in their 5 acre day pasture bordered by hot wire.
I've tried leashing him and giving super treats, but he's not the same, he's frightened. Yesterday he didn't even want me to put the leash on, we got done with that (I thought) about a year ago.
Any suggestions would be appreciated.

By way of background, he is a super fearful dog. Had an incident with a dishwasher (he used to put his bowl in and take it out of the dishwasher) --he got tangled up in the bottom rack and hasn't been near the dishwasher since. So he's fearful and takes
hurts to heart.
I need him to get back to work. My cattle are so tame I can hardly move them without him. In fact, they just don't move at all without The Pinker. They don't fear me at all, and they know when the dog is there it's time to move --without the dog, the cattle just stand there.

You have to use the lane?

Is there a reason the fence needs to be on while you're moving the cattle?

This is kind of tough. I've had a couple of electric fence incidences before with the dogs and, while they're more cautious the next time around, they just work through it because the drive to work over rides the fear of the fence.

If you need to use treats to get him to work cattle, he's probably in way over his head you need another dog.

The only way you're probably going to get him to work there again is by taking a huge step back, steering clear of the lane for several week and just doing stuff that is super easy for him. Once his over confidence is higher, you can try the lane again (with the fence turned off!) I think it would be very counterproductive to try anything around the lane while everything is so fresh in his head.

Poor Guy Those fences hurt bad! I have no experience with a true herding dog, but it would be my instinct to go back to easy basics and help him regain confidence. Could you borrow a 4 wheeler or an air horn until then? I'd have hime move just a couple through there once he's comfortable with crossing that area during walks (just passing through there mid way through the walk a few times, but make it random- skip it the first walk or two so he isn't suspicious)and has successfully worked a couple in a more neutral area. Good luck and my symapathy to Pinker. I was shocked in the armpit once and thought my my jaw exploded so I can't imagine how it would feel to a little guy like him.

He moved bulls today, and horses too (I never let him move horses but they had escaped)
He worked the heifers into a more distant pasture --- but I had to carry him down the lane. When I opened the gate for the more distant pasture, he circled the cattle and brought them for me but wouldn't come within 30 feet of the gate handle that was snapping on the ground. Even after I picked it up, he wouldn't come near. He got it done w/o help (all I did was open and shut gate) but was clearly scared of the electricity.
Treats he gets for "here", which is his "stop herding" default. He does not need treats for routine herding, but treats help him pay attention when he decides to do things his way, or if I am doing something different or non-routine.
No treats needed for sheep!

Is it doable to turn it off while he's working?

I pretty much don't blame him for not wanting to get near it again. To desensitize him to it, I'd have to have it off.

How wide/narrow is that lane?

I can shut the fence off while moving the cattle. That's a good idea Mara and might give him confidence, or at least avoid another shock. My feeling is one more good shock and he might be park himself on the lawn and watch me work.

That's what I would do, then. I actually would not do this desensitizing if the electricity wasn't going to be off when he's in there.

Then I would carry him all the way through, then start putting him down for a very brief time, and then gradually and (and then randomly) changing the length of time. Then having him follow you for a couple of steps .... you know the drill.

This dog has a pretty anxious/fearful history, but he does so well with you, with patient and gradual desensitizing. Of course this will take more than some of his past triggers because he has actually been injured, rather than just fearing injury. But I'm betting on success because of what you have done with him in the past.

The lane is 3 fat cows wide. Older cows "line out", walk like elephants at the circus, and there's plenty of room on each side. The young stock crowd each other and move in no particular order, and occasionally the ones in front will stop to graze causing bunching up of the ones in back.
Because I do rotational grazing I have to have hot wire.
I understand fear of the wire. We keep it at about 4000 volts minimum and
sometimes while fencing I'm slightly reluctant to touch it even after I know I have shut it off!