Q: What kind of animal is best to slaughter for Udhiyah?
A: Slaughtering other types of animals, besides camels, cows, sheep, or goat, is not sufficient.
The best is a camel then a cow, so long as there is only one person responsible for the sacrifice and it is not shared with others, followed by sheep/goat. This is because the larger animals are more costly and have more meat which is more beneficial to the poor. If the camel or cow are split between seven people, slaughtering seven sheep or goats is more rewarding due to the larger volume of blood spilled as a ritual sacrifice.
From each type, the fattest and then the most expensive is best. The animals which are entirely white or a mixture of white and black are preferred.
Imam Ahmad is quoted to have said, “I do not prefer that the Udhiyah be done except with sheep. It is better than goat.
Slaughtering more of the same animal, if cheaper than one is better than one which is more expensive.
The gender of the animal is of no consequence.
Source: Sharh Muntaha