Bodybuilding Cardio kind of seems like an oxymoron. One gets you bigger and the other makes you smaller but cardio will only help you in the long run.
In bodybuilding you need to work out all your muscles. It just so happens that your heart is also a muscle and it too needs to be put under stress so that it can be stronger. The way to do that is through cardio.
There's different types of cardio you can do. I'm going to focus on two.
High Intensity Interval Training (HIIT) and Low Intensity Steady State Training.
Both have their pros and cons and I'll let you decide which you prefer to do.
I actually prefer this one because you burn more calories doing so and I've found better results, as far as weight loss goes, with this one. This involves doing something very fast and intense for a short period of time and then slowing down for a rest period and then speeding back up again.
It usually is a total of 10-20 min but by the end of it your butt will be kicked and you will want to go home if you're doing it right.
The time goes by quicker because you're constantly switching it up and that's always better than cardio that seems to last forever.
This is a great option for when trying to drop weight quickly. 10-20 min a day and you will see major results very quickly.
If you'd like some ideas for exercises you can do follow these links.
Low Intensity Steady State. This would be the opposite. It's where you go at a moderate pace the whole time for an extended period of time.
LISS is a lot easier on the body than HIIT which is definitely one of the benefits. The down side is you have to work out for a lot longer to see the same effects of the HIIT workouts.
This improves cardiovascular stamina and can overall help you in the long run.
I'd say LISS is a good option if you're trying to bulk up because you won't burn as many calories and you can use those calories for lifting weights.
If you want some ideas for LISS workouts follow this link.
Part of building the body is not only the outside but the inside and heart health is just as important. What's the point of looking like an athlete and not being able to perform like one.
Applying a little bit of cardio into your routine will only benefit you in the long run. Although bodybuilding cardio sounds ridiculous you'll be leaner and just overall you will feel better. Who doesn't want that?
I personally prefer HIIT.
One reason being I don't want to spend another 45 min at the gym after already having lifted weights for 45 min.
Second I like to get in, work hard, and then get out. There's something very fulfilling knowing you gave it your all during this intensity cardio workout. As I said before I've also seen better results doing HIIT than LISS.
In the end it's for you to decide.