No. They make more of a "Merr!" sound than a deep, drawn-out "Muuuhh!" of a cow.
Wildebeest (gnu) are herd animals and their sounds probably help to keep the herd together.
No.
bull
The same sound any other cow would make, horned or not.
A cow bell has a metallic clank sound to it. There are many sound clips and videos on YouTube that demonstrate the sound of a cow bell.
No, they are not bovines (or belong in the subfamily Bovinae). They are, however Bovids (being included in the Family Bovidae). Wildebeest belong in the subfamily Alcelaphinae, not Bovinae like the domestic cow and bison do.
Mugido
A cow.
moo
Brown cow
Yes.
a Moo cow is a cow that goes moo! "Moo cow" is just a silly phrase meaning a cow, because, obviously, cows moo.
The sound would depend on the method in which the cow is dieing. If the cow is dieing of natural causes, the sound would probably be a final exhale.