Steps to reproduce

1. In a large grass place (flat world is good for this) spawn a cow.
2. Leash the cow, then walk backwards, pulling it with you.
3. Repeat steps (1) - (2), but with a baby cow.

Expected result

You hear grassy footstep sounds, and the occassional moo.

Actual result

From the baby cow you hear some grassy footseps, but also some loud wooden or metallic clunk. You hear more of these when it is closer to you.

This is weird and I do not consider a major bug but thought I would report it.  On several occasions now I have encountered naturally spawning baby cows with their walking sounds replaced with an iron golems stomp.  These have all been near a village and at first I thought that a golem had spawned underground and that was what I was hearing.  Digging revealed no golem and careful observation of the calves proved they were the source.  Calf takes step and 'thump'

On a possible related note (sound again anyway) I have also rode fairly long distances in a completely silent minecart.  This seems intermittent though.