When I try rotate goats with commands it works strange:
1) When I enter /data merge entity @e[type=goat,limit=1,sort=nearest]

Goat visually have Rotation:[-10f,0f] but in data he have [-90f,0f]
2) When I use /tp to goat, he rotates by steps

And finally when I reopen my world all goats rotated by me to Rotation:[-90f,0f] visually gets Rotation:[-10f,0f]