The idea of בכור regarding animals, still applies today. The Torah tells us that ALL first borns are sanctified to Hashem-including animals. This means that one who raises cattle is supposed to be aware of when the females give birth to their first offspring.
If this offspring is a male, it has immediate Kedusha. The Torah forbids us to work that animal or to use it's shearing for any purpose as it is tampering with Hekdesh.
The sanctity of this first born animal ends when the animal gets a blemish. After this, the animal loses its sanctity and can be used for any purpose and can be eaten.
Israeli farmers are aware of this law and have come up with two solutions. One, is to take the animal to pasture and wait for it to develop a מום, blemish. The second solution is to sell the fetus to a non-Jew, usually a Druze. The Druze technically owns the animal and after birth the animal is bought back by the Jew. This is similar to selling Chametz on Pesach.
It is very interesting to see these ancient laws come back in our time, as Jews return to their ancestral homeland.