Animal Nutrition K.Launchbaugh USDA-ARS BLM Photo K.Launchbaugh

Animal Nutrient Requirements  Maintenance = Basal Metabolism + Minimum Movement + Foraging On a yearly basis requires greatest amount of energy by the animal. Depends on species - Cow > Sheep > Deer Domestic vs Native - Most wildlife species have the ability to vary their basal metabolic rate with season.

Animal Nutrient Requirements  Maintenance Depends on Age - Young > Old For example basal metabolic rate of sheep:  birth = 132 kcal/m 3  15 weeks = 68 kcal/m 3  6 years = 52 kcal/m 3

Animal Nutrient Requirements  Growth - important energy demand in young animals and pregnant females  Reproduction – energy need in last trimester of pregnancy for females important for males during breeding season

Animal Nutrient Requirements  Lactation - greatest energy requirement of mature females above maintenance. Requires 45% greater energy supply than maintenance.

Changes in Demand over Year Energy & Nutrient Requirements Yearly Change in Demand for Pregnant Female Range Herbivore (i.e., Cow, sheep, elk, deer) Winter Spring SummerFall Last Trimester Birth & Lactation Weaning Maintenance

Animal Nutrient Requirements  Level of activity 15% greater energy required for standing compared to lying down % more energy needed for range animals than stall-fed animals.

Animal Nutrient Requirements  Environmental conditions affect the amount of energy needed by animals Cold environments require more energy for maintenance. Hot environments require more water for perspiration.