From Worms Knowledge Base
Mad cows are a herded weapon. This means that the number of mad cows fired can be set by pressing a number key from 1 to 5. Once the desired number of cows in the herd is set, pressing space will activate the firing of the cows. When space is pressed, a cow will be released from the worm once every 25 frames until the number of cows selected have been released, and the turn timer will freeze until all cows have been released. After all cows have been released, the turn will end and retreat time will start.
After release, a cow walks at a horizontal rate of 2 pixels per frame along the ground, and will explode if it hits a wall which is 5 pixels higher than its present walking surface. A cow will jump if it reaches a drop more than 4 pixels lower than its present walking surface. The mad cow jumps at a 45° angle and the jump has a random initial velocity between 1.25 and 1.75 pixels per frame (5.21% and 7.29% of a grenade's full firing power). When the cow hits a wall during its jump, it will bounce off the wall instead of exploding. When it bounces off a wall, there is a 6.25% chance of the cow turning around and travelling in the opposite direction. This same 6.25% chance of turning around occurs when the cow lands after bouncing off a wall.
A mad cow's collision mask is a rectangle which is 7 pixels wide and 5 pixels tall (same as with most other weapon objects).
In the past, a bug existed in Worms Armageddon which allowed a player to release double the number of mad cows than the selected herd size by jumping and pressing space (or even jumping while holding space, which was easier) after releasing the last cow in the selected herd. All but one of the extra cows released by exploitation of this bug were subtracted from the team's weapon arsenal, but the releasing of cows was not halted by the number of mad cows in the arsenal reaching zero. Also, in the past, a loophole could be exploited through means of message injection. It was possible to set the herd size to 0 or a number above 5, the former allowing the release of an unlimited number of cows, even if the team had only one cow in its weapon arsenal. Both the cow-doubling glitch and this loophole were closed by Deadcode with the release of version 3.5 Beta 1 of the Beta Update on 2002-08-09.