Any more info on the manure - is it really fresh stuff or has it been rotted for a period of time (>few months)?
From memory, stables clean out and stack the stuff in piles until it can be disposed of - I don't know how quickly brandlings would migrate into a fresh pile, but my money would be on them being brandlings. However I also don't know much about horses or their parasitic infestations...
Having said that, I certainly wouldnt use it without rotting down unless I knew it to be well rotted.
Stack it and leave till autumn, when it will have rotted down considerably and temperatures within the stack will have effectively sterilised it. Then dig it in to the beds which will be containing next year's plants that would benefit from it (not carrots, for instance - I believe that too rich a soil causes forking).