My 4 month male border collie bite my 2 year old female on the neck. It has gotten bad enough that we have had to shave her 3 different time due to hot spot. Every time we throw a ball, or my golden runs out of the water or just simply iis walking, my bc run and bite her neck. She doesn't put him in his place because she can with stand alot. The problem now is that she can't do anything with out him chasing her and biting her. He does not do this with any other dog male or female, Only with my Golden retriever. I try to use a vibrate collar and he just ignores it. He know HEY mean back off but he ignores me every time now. I let them run free when we go hiking and he still does it, i don't know how to get him to stop. Thanks in advance.