the animal
Eland is a type of Asian Antelope
Buffalo is not really an antelope, but it is the closest relative to the antelope where the name ends with an o.
Kudu
Kudu
Oribi
Eland is an antelope
Uganda Kob is a type of antelope found in Africa.
eland
Gazelle
calf (baby antelope)
Oribi is a small African antelope
A three letter African antelope is the "gnu", which ends in a "u" not a "you". The more common name for the gnu is the wildebeeste, but that won't fit into your crossword puzzle.