Sugar Versus the Intuitive Choice of Foods by Livestock

I T HAS been known for centuries that livestock, and animals in general, have food preferences. It has also long been known that cattle, for example, prefer forage from well-fertilized pastures over that from non-fertilized pastures, other things being equal. Observations along this line have led many persons to believe that grazing animals are wise in their ways and know intuitively that vegetation on the fertilized soil is richer and better balanced in food nutrients than that on the unfertilized soil; consequently, the fertilized forage is better for them. Such an ability to choose foods is a faculty, or gift, which even human beings cannot, be said to possess. A particularly interesting negative example of “food choice” is that of animals in pastures refusing to eat grass whose growth has been influenced by their droppings (Fig. 1). Some pastures of small size become almost worthless because they are highly spotted with untouched bunches of lush, dark-green, healthy-looking, manure-affected grass. The normal, or unaffected, grass may be mediocre, or even poor, in appearance; yet it will be eaten to the complete exclusion of the lush grass. Various reasons have been offered in order to explain this phenomenon and the present paper is an attempt to throw further light on the matter. +