I have a year old miniature hereford steer who is a bit lethargic, and breathing heavily. He is eating, though not with as much enthusiasm as her usually does....all the others are fine, they are all vaccinated regularly, in a great field, clean water, etc. He stomach also seems a bit distended....any way worms could cause this? He was wormed in February, but I can't think of anything else......anyone have any ideas??