Just make sure you don't try to steer or brake while actually on the grid as you'll just slide.
my commute includes a couple cattle grids so I hjust don't think about it and ride over them. A loose grip with your hands and standing up with legs bent is a good method for keeping the vibrations down. This also works as a method on rough descents
Bikes are far more resiliant than we give them credit for, so as long as you don't turn the front and drop it between the bars then you should be able to just ride over them.