During a bulk, cardio is something you must gage closely. There is a fine line between doing too much and too little cardio.
When we bulk, cardio is used to increase your metabolism, control body fat, and most importantly, increase the amount of calories we can intake.
Think of your body like a car. Cardio is your body preheating the engine. When you preheat your engine, your car will operate at a higher performance, as opposed to taking off from a cold start.
The same thing applies for the body. Start your day off with a moderate amount of cardio, around 20-30 minutes. This will prime your body so it will metabolize and process your upcoming meals more efficiently.