border collie/pregnant or not?

Question
I found my dog in the garden tonight locked to a male dog looking something like a English Foxhound? What are the chances she is pregnant? If I find out who the dog belonged to can I sue? I'm not sure if she is in on heat and she is 5 years old February 2001.

Answer
Its very likely she's both in heat and pregnant now. You cannot sue the male dog's owner as being the owner of the bitch you are legally responsible for either owning a spayed bitch or keeping her up where a male cannot get to her. you can tell if she's in heat by turning her over and looking at her vulva. If it's big, round and looks swollen and has a pink or clear discharge then yes she's in heat.  A male dog usually will not mount (and won't be allowed by the female to mount) unless she is in breedable condition.  

Your options are:
take your dog to the vet for immediate spaying

immediately take your dog to the vet for a hormone shot to prevent pups, then get her spayed

raise a litter of half-breed pups that will likely end up in a kill shelter eventually