text: // Video 5.1 accompanies this exercisee
  
  // It’s time to figure out which cows are in line for a first breeding.
  // Your awesome prototype skills are making life easy on the cowboy-devs,
  // and now they’ve asked you to use your new functions to find out how many
  // cows from the lists below have not had calves yet.
  //
  //  1. Create a numPriorityCows variable, and then call your countForBreeding(
  //     function on each of the four array lists below to calculate the correct
  //     total.
  //  2. Add an alert message with numPriorityCows in the following format:
  //
  // Herd-merger has indicated <number> cows of top breeding priority.
  //
  // Use the following code in your solution:
  
  var canyonCows = [
    {name: "Bessie", type: "cow", hadCalf: "Burt"},
    {name: "Donald", type: "bull", hadCalf: null},
    {name: "Esther", type: "calf", hadCalf: null},
    {name: "Burt", type: "calf", hadCalf: null},
    {name: "Sarah", type: "cow", hadCalf: "Esther"},
    {name: "Samson", type: "bull", hadCalf: null},
    {name: "Delilah", type: "cow", hadCalf: null}
  ];
  
  var valleyCows = [
    {name: "Danielle", type: "cow", hadCalf: null},
    {name: "Brittany", type: "cow", hadCalf: "Christina"},
    {name: "Jordan", type: "bull", hadCalf: null},
    {name: "Trevor", type: "bull", hadCalf: null},
    {name: "Christina", type: "calf", hadCalf: null},
    {name: "Lucas", type: "bull", hadCalf: null}
  ];
  
  var forestCows = [
    {name: "Legolas", type: "calf", hadCalf: null},
    {name: "Gimli", type: "bull", hadCalf: null},
    {name: "Arwen", type: "cow", hadCalf: null},
    {name: "Galadriel", type: "cow", hadCalf: null},
    {name: "Eowyn", type: "cow", hadCalf: "Legolas"}
  ];
  
  var badlandsCows = [
    {name: "Voldemort", type: "bull", hadCalf: null},
    {name: "Maleficent", type: "cow", hadCalf: null},
    {name: "Ursula", type: "cow", hadCalf: "Draco"},
    {name: "Draco", type: "calf", hadCalf: null},
    {name: "Joker", type: "bull", hadCalf: null},
    {name: "Chucky", type: "calf", hadCalf: null},
    {name: "Samara", type: "cow", hadCalf: "Chucky"}
  ];
  
  Object.prototype.noCalvesYet = function() {
    if (this.type == "cow" && this.hadCalf == null) {
      return true;
    } else {
      return false;
    }
  };
  
  Array.prototype.countForBreeding = function() {
    var numToBreed = 0;
    for (var i = 0; i < this.length; i++) {
      if (this[i].noCalvesYet()) {
        numToBreed++;
      }
    }
    return numToBreed;
  };
  
  // set up your numPriorityCows variable
  
  
  // alert the correct message with the total
  