to warm up everyday when  i hit the gym i run /jog a half a mile at 5.0-7.0 mph to get my heart rate up and being that im trying to bulk up , is this a bad idea? does it burn away my muscle? should i consider another way to warm up ? thanks

its not bad, i always do a five minute cardio warmup each time, but its light cardio where i dont push myself. 

as long as your eating loads regularly shouldnt make a difference.

WHAT I DID
I used to warmup doing cardio. Running on the threadmill, on the row machine, eliptics or the stairs 5-15 min.

WHY I DO NOT
Why I don`t do it anymore? I found more useful warming up the muscles I`m about to train, rather than just getting my heart`s rate up, also, I kinda get exhausted for getting nowhere in 5-15 min. doin cardio on a machine.

THIS I DO
What I do now are ligth sets of exercises that warm up the muscle Im about to train. for example, when doing pecs and back I do 4 light supersets of push ups and chin-ups. Do 8 push ups, then 8 chin-ups, inmediately move to push ups for 10 reps now and then 10 chin-ups, again 10 push ups and 10-8 ching-ups and then the last set I do 10 push ups and try to get 8-10 chin-ups. That really prepares my muscles (pecs,back,tri`s and bi`s) for a hard pecs and back workout, plus it also get my heart`s rate up.

Conclusion
What works for me, maybe won`t work for you - just figure it out by trying at least once.