Animal nutrition is the study of how animals consume, digest, and utilize nutrients found in their feed. It involves several elements that work together to ensure that the animal's body function properly.

Nutrient Requirement:
The nutrient requirement of animals varies depending on their type, age, size, and physiological state. The nutrients that animals require include carbohydrates, proteins, fats, vitamins, minerals, and water. These nutrients are essential for growth, reproduction, lactation, and maintenance of body functions.

Mode of Intake of Food:
The mode of intake of food is another critical aspect of animal nutrition. Different animals have different feeding behaviors, such as grazing, browsing, or predation. The way animals consume food influences the digestion and absorption of nutrients.

Utilization of Food in the Body:
The utilization of food in the body involves the processes of digestion, absorption, and metabolism. Ingested food is broken down into smaller molecules that can be absorbed by the animal's body. The absorbed nutrients are then transported to the various tissues and organs where they are utilized to support bodily functions.

All of the Above:
Animal nutrition includes all the above aspects and is essential for maintaining the health and productivity of animals. Proper animal nutrition ensures that animals grow and develop correctly, produce high-quality products, and remain healthy. It also helps reduce the risk of metabolic disorders and diseases.