"Sheep give us meat and milk."
Translation:Cừu cho chúng tôi thịt và sữa.
According to Wiktionary "loài" (or "loại") means "species".
If I recall correctly it's used somewhere else in this course as "loại người" to mean "mankind", so I'm guessing it acts kind of like a classifier for a whole category or species of animals, whereas "con" would be more appropriate for a single specific animal.
This is just my speculation as an amateur of the language though.