Mobs fail to jump blocks when following player

I am trying to get a cow to follow me into an enclosure. I have wheat in hand and am less than 5 blocks away from the cow. The cow has to jump up 1 layer to get to me. It just keeps jumping in place, I cannot get it to follow me up a single block jump.

I can get around this problem by placing half slabs or stairs and then having the cow follow me up that, but I expected the mob to be able to jump up a single block.

I also tried having seeds in hand and enticing a chicken to follow me up a series of jumps, but it has the same behavior.

Sheep have the same behavior when i am standing 1 layer above the sheep and holding wheat. The sheep has entered follow mode, but jumps in place upon encountering a block that is 1 higher than their current level.

Attaching a lead to the desired mob also works to get the mobs to jump up single layers.