Trigger animtaion when hit

Hi guys, im not a very experienced scripter and never used c# before (actionscript 2 and little 3 only). Trying to get an object’s animation to play when it gets hit by another object. i’ve tried to search out a solution in js and c# but none is working (getting close to c# though). Can eanyone see what im doing wrong?

using UnityEngine;
using System.Collections;

public class cowHit : MonoBehaviour {
	public GameObject otherObj;
	public GameObject resultObj;
void OnTriggerEnter(Collider otherObj)

what did you attach it too out of interest?