Let’s take a look at the animals used by the Israelites in the bible laid out by economic value.
Herd animals like Bulls are the most expensive because they can pull plows, their skin can be sold as leather, cows make milk, and they are the largest of the kosher farm animals so they provide the most meat.
Flock animals like goats and sheep are not as big as bulls but are still good for meat. Plus goat’s milk is consumed and sheep fleece and goat’s wool can be used for clothing.
Birds like pigeons and turtle doves have the smallest amount of meat and the only secondary products are eggs and feathers. I’m not sure how valuable feathers were in the Ancient Near East, but either way, birds are the cheapest.
Donkeys and Camels are unclean and not for eating or sacrifice, but are good for work like carrying equipment and supplies. Donkeys even are used to pull the blow with yokes. These animals are more valuable than birds in the markets but since they can’t be eaten, sacrificed, or used for clothing, they are well below clean mammals. Based on the firstborn male sacrifice rules in Ex 13:11-13, Ex 34:19-20, and Num 18:15-17, unclean animals had to be killed outside the camp or substituted with a clean flock animal that could go on the altar. Unclean animals like leaven bread cannot go on the altar. Human firstborn males were required to be substituted for five shekels of silver.
Male bulls have special value because of their work capacity; they are big and offer the most meat. However, males in general, are more expendable than females, since one male can impregnate a whole herd/flock. If the gender ratio is less efficient (more males than females), then the reproduction output compared to the amount of land the livestock takes up will be more of a loss. Female lambs produce 1 to 3 (let’s say 2) babies on average. So an average rate of 2 babies per cycle with a male/female ratio of 70/30 makes 60 babies, but the opposite of 30/70 can make 140 babies per cycle. In other words, if you have only enough room on your land for 100 sheep and there are 70 males to 30 females, the males that aren’t making babies are a waste of space, and they may be better off being rented out or sold for their material or meat value in the short term. Also, females produce milk, which is a commodity to be sold. Males can be used as passive income since they can be rented out to reproduce with people who have mostly females. However, overall it’s more efficient for the female count to be greater than or equal to the male count.
Just think about how the value of the animal played into the sacrificial system for the Israelites, this was not an easy decision as livestock was considered a long-term asset, like stocks today, and those that had less had more to lose. Yet God promised to bless them and provide for them as long as they kept his commands (Deut 28:1-14), so they had to trust God’s promises. Sacrificing a bull was expensive, and flock animals weren’t simple gifts either. In many scenarios the poor were given the option of sacrificing birds instead (Lev 12:8, 14:21). Unclean animals like donkeys were allowed to be kept by Israel but they could not be sacrificed on the altar. If there were dedicated full as firstborns and killed it was outside the camp, otherwise they were substituted like humans. If you want to learn more about clean vs unclean animals check out my article on that here.