No, the Giant Elk is given only one Action (and no Bonus Actions), and thus can only choose to do one of the available actions.
The text for Charge reads (MM, pp325)
If the elk moves at least 20 feet straight towards a target and then hits it with a ram attack...
Your Actions(and specifically those for Attacking) are as follows (MM, pp325)
- Ram
- Hooves
The Charge means you are choosing the Ram Attack.
The next round, if the creature is still prone, you may attack with the Hooves. Otherwise, it's just another Ram attack without the charge (unless you take the OA to move away and run again at them.)
And as Andras says, there ARE beasts like the Elephant (MM, pp322), that have viable Bonus Actions available to them.
Trampling Charge. If the elephant moves at least 20 feet straight toward a creature and then hits it with a gore attack on the same turn, that target must succeed on a DC 12 Strength saving throw or be knocked prone. If the target is prone, the elephant can make one stomp attack against it as a bonus action.
The (Giant) Elk, however, is not one of them.
Best Answer
No
The stat block for a tiger lists these actions:
Compare this to the stat block of a polar bear:
The tiger stat block lacks the multiattack option which would allow both a claw and a bite attack. They could normally only use both during the same turn if they moved at least 20 feet towards their target, then made a successful claw attack and had the target fail their save, before using making the bite attack as a bonus action. Aside from that it would require some special effect like the haste spell to allow it.