Mr Charlton, I think you may be correct but there seem to be lots of Walts around on here.
Ernest, sorry if I have failed to home in on the gonad subject, I shall hang my head in eternal shame. Of course I should have said 'testicular' but I dont have as much time on my hands as you perhaps do. Did you PM Flying Frisbee to ask if had actually measured a horse's ass, if so, what breed and how old? If I can be assed I may do some research myself and ask some of my equestrian friends.