I'm unfamiliar with interspecies animal sex being part of the natural order.
I'm not even sure pet ownership itself or raising livestock is a "natural order" but it happened.
What exactly is "natural order" in human society today? probably nothing about today's society and life is "natural order" anyway, we have people living in polluted crime ridden paved over concrete jungles in tiny cubicles called apartments and condos, we don't walk to work we ride a man-made machine that unnaturally burns fossil fuels unnaturally extracted from the ground.
We wear artificial clothing, eat processed and manufactured as well as altered food, chemically altered water and on and on.
When we have pains we take pills and potions or have unnatural surgery performed, women have been conditioned to have birth in a HOSPITAL for so many years that when you hear of an ordinary home birth the story goes someone called 911 for an emergency AMBULANCE.
We have an entire generation of fat, overweight people who sit in front of the TV and eat greasy fatty processed food, and their kids doing the same.
I have a young and FAT neighbor near work who mows her little postage stamp sized lawn with a John Deere TRACTOR- the stupidist thing I've ever seen!
Like I said, probably almost nothing today is natural, "normal" or some kind of "natural order"
When sex is for recreation, then it doesn't matter what the acts are- none produce offspring anyway, masturbation doesn't, women past menopause can't get pregnant, men with vasectomies can't produce children and condoms along with B.C. pretty well ensure pregnancy won't happen either- so proably none of those are "natural" or follow a "natural order" either.