For example, when you are saying there is a cow, you would use the collective tou (头)，and therefore say that there is a ‘head’ （头）of cow.
You cannot use one classifier noun and try to fit it to all. Although you use the classifier ‘head’ to count the a cow, you cannot use the same classifier to count the number of persons. When you say that you see a ‘head’ of man, it can sometimes be interpreted as an insult. When you are describing a specific number of persons, you should use the classifier ge (个) .
You should note that there is a series of collectives for the counting of animals alone. For example, you don’t use ‘head’ to count elephants. You would simply use the word zhi (只).
As such, it can be quite confusing for foreigners when they are introduced the concept of classifier. For that reason, I would suggest that you simply use the most general classifier ge (个) to describe anything that you’re not sure about. In this instance, even when it is more appropriate for you to say a ‘head’ of cow, it is still acceptable if you say that there is a ‘ge’ of cow.
As far as I can imagine, using ge as classifier for any object is the safest way. Using other words into the risk of impropriety, and it can create unnecessary problems as a result.
You may find Makoto’s article on this subject useful. Read more …
Thanks publicenergy for the picture.