Stampedes: Make pigs more viable, make cows more fun

Pigs currently are outdone by every farm animal. The only advantage is its ride ability, however weak it is. Cows are the premier farm mob, giving milk, meat, and leather. We could make the pig better, but we could instead implement a nerf (or a fun feature) to cows.
Cow nerf: Cows in real life are extremely dangerous. Children may need to know this, but why not make it fun? Let's make cows stampede!
Stampede: Cows will begin running at speed slightly higher than a player's sprint. If they run into wooden blocks, they will launch them into the air, where they land, they will be replaced. If they run into foliage, it will be destroyed.(applies to glass as well) If they run into stone, a cow will turn in a direction unobstructed and not against the flow of the other cows. Once the first cow turns in a direction, the other cows will turn in the same direction.If a cow runs into a mob other than a cow, the mob will take 4 hearts of damage. This will pile up, the more cows you have.
What causes them: A cow taking damage will cause it to go into stampede mode. It will go into a direction away from the cause. All cows in 20 block radius of the first cow will move in the same direction. Lightning will also cause stampedes. A stampede will last from 1-10 minutes.