Get reliable rangeland science

Animals are born knowing what to eat. It’s innate. But if diet selection is truly innate, consider this scenario:
To cut the high cost of winter feeding, an animal scientist feeds beef cows ammoniated straw. Half of the cows maintained themselves on the straw while the others did not. 
If animals know what to eat, why did this occur?
The fact is animals are not born knowing what to eat. They need to learn which foods to eat and which foods to avoid. Learning about foods is essential regardless of the quality of the food or its toxicity. Understanding some basic principles of behavior can help managers improve animals’ acceptance of new foods.