We buried our DD's placenta (about 1 meter down) on my mother's farm and planted a lemon scented gum over it. I love the idea that my placenta has lived on within the tree (which has thrived BTW). I often think of the law of physics: energy can neither be created nor destroyed, it only changes form.

I wasn't so keen on planting my second two placentas. It was mainly just my first that I felt the need to preserve. I don't think they even asked me if I wanted them (hospital births). They asked me what i was going to do with my first because I had my DD at a birth centre and i don't think they disposed of them there either.

ETA: if you buried it about a meter down surely your dog couldn't reach it??? Maybe put something heavy over the top of it for a while?