A newborn baby is commonly referred to as an "infant." This term typically applies to babies from birth up to one year old. In the first few weeks of life, they are often specifically called "neonates."
A baby is called a newborn immediately after birth.
A baby antelope.
Infanticide
A baby star is a newborn star. It is called "protostar."
Simply enough a baby.
newborn baby fish are called fry.
A newborn baby girl is referred to as a niña recién nacida.
young tigers are called cubs and newborn tigers are called whelps
We call baby seals pups.
baby
If you are referring to a goat, then a baby would be a kid.
This fine hair is called "lanugo."