parasite

Is it ok to give both a topical pour-on and injectable dewormer to an animal?

When I was feeding fawns yesterday 6/12 I found a worm thing in the grass. It looks like some kind of parasite and I'm not sure if it came from a fawn.   Does anyone have an idea?

Last night I noticed an abscess on the midsection of one of my fawns. It was about the size of a quarter and raised. I was able to express a small amt of bloody liquid and then something popped out. It was a larva about 1/2" long and 1/8" in diameter. Transparent white in color. Right away I...