Getting grilled by my date's dad about my job as a butcher.

So I went out with this girl last weekend, and things were going pretty well. We ended up at her place, and her dad was there. He asked what I do for a living, and I told him I'm a butcher. Right away, he starts going on about how it must be messy and gross. He even asked if I ever feel bad about the animals, like I'm some kind of monster. I tried to explain the skill and care that goes into it, but he just nodded and changed the subject. It was so awkward, and I could tell he looked down on my trade. Has anyone else dealt with people who just don't get what we do? How do you handle those conversations without losing your cool?