So you need to create an Animal object for each animal you have. Depending on the answer to the comment for file formatting, you can easily instantiate a class simply using a constructor.
class Animal
{
int height;
DateTime date_of_birth;
float age;
int max_age;
public Animal(int height, DateTime date_of_birth, float age, int max_age) {
this.height = height;
this.date_of_birth = dob;
this.age = age;
this.max_age = max_age;
}
}
Then fill in the values with your data, which you would do from whatever file you have (i.e. XmlDocument, TextReader). Should be able to read in each node or line and through it into a loop to create animal objects as needed.
Animal first = new Animal(5, new DateTime(), 5, 10);
Animal second = new Animal(2, new DateTime(), 3, 11);