General terms:
* Feed trough
* Trough
* Manger (especially for horses)
* Feed bunk (usually for cattle)
More specific terms:
* Hay rack (for hay)
* Water trough (for water)
* Grain bin (for grain)
* Silo (for silage)
The best term to use depends on the context. For example, if you are talking about a trough for horses, you would likely call it a "manger". If you are talking about a trough for cattle, you would likely call it a "feed bunk".