Dogs likely don't live long enough for microplastics to be a big problem. We haven't seen an increase in cancers in dogs in recent years like we have with people.
They're main exposure to microplastics would be from toys, water, dishes, and low-quality food, anyway. This nose guard would be a small drop in the bucket.
> We haven't seen an increase in cancers in dogs in recent years like we have with people.
Some folks say we have, that it's still similar to the cancer rate in humans and higher than the cancer rate seen in animals that aren't pets. https://www.cnn.com/2017/02/03/health/dogs-cancer-partner
although it also seems like it's not something that's been being tracked very well https://www.veterinarypracticenews.com/evidence-based-medici...