In the moments of danger during a bullfight, a strong, expert matador will grasp the bull by the horns and so prevent it from tossing him.
By extension the proverb means that when faced by perils or difficulties we should beet them fearlessly, not try to evade them.
As the jeep rounded the bend, the soldiers in it saw that the road ahead was blocked by a mod of rebels.
‘What do I do now?’ asked the driver.
‘Step on it,’ said the corporal in charge, ‘and cut straight through ’em.’
The driver brought down his foot on the accelerator, the jeep shot forward, the insurgents broke up in disorder and scrambled up the banks on either side of the road.
‘Always take the bull by the horns,’ said the corporal with a satisfied grin as they continued on their way.