Animal Energetics Flashcards
The Maintenance State
- When body weight and body energy content is constant, an animal is said to be in the maintenance state 2. In the maintenance state, the energy of food available to an animal is completely utilized. 3. All of metabolizable energy (ME) from a diet ultimately is released as heat ME Intake = heat production of the animal (kcal/day)
Define Maintenance Energy Requirement (MER)
The amount of metabolizable energy (ME) needed to sustain the maintenance state
MER is the sum of what four general categories of activity?
- Heat increment 2. Basal metabolism 3. Physical activity 4. Body temperature regulation
Define MER - heat increment
Energy used in digestion, assimilation, and metabolism of food.
The heat increment in ruminant compared to simple stomached animals is large, greater than 30% of MER. Nutritional consequences of this are that ….
- Feeding is advantageous for survival in very cold temperatures. 2. Feeding is hindrance in very warm temperatures because the added body heat reduces food intake and production dependent on food intake.
Define MER - Basal metabolism
- The largest component of MER is in basal metabolism. 2. Basal metabolism is mostly processes of cellular maintenance.
The energy need (or use) of basal metabolism is called the….
basal metabolic rate (BMR)
Basal metabolic rate (BMR) is determined from heat production under a strict, defined set of conditions:
- Post-adsoprtive state 2. Awake 3. At rest 4. Thermoneutral environment
BMR is dependent on what?
The body weight (mass) of the animal
A commonly used approximation of BMR is also called what?
“Resting energy requirement (RER) or “resting energy expenditure”
BER equation is used to estimate RER; what are two equations to find RER?
- RER (~BMR) = 70 x Mkg.75 (kcal/day)
- RER = 30 x Mkg + 70 (kcal/day)
- linear transformation of RER equation for DOGS between 2 and 45 kg
MER - Physical Activity
Energy of physical activity energy is variable in animals at the maintenance state
Ex - foraging versus bunker-fed steer; activity of dogs etc. - has to do with normal activity, light work, moderiate work and heavy work
MER - Body Temperature Regulation
- Energy expended in processes is improtant to thermal regulation
- Cold environment - shivering and non-shivering thermogenesis
- Hot environment - panting, gular fluttering, and sweating
- Varies with enviornemntal temperature, humidity, wind
- MER increases with decreasing temperatures - has to do with body temperature regulation
MER estimation using body weight for adult dogs:
MERdogs = RER x activity factor (kcal/day)
RER = 70 x Mkg.75 (kcal/day)
*activity factor decreases for neutered adults and for inactive/obese dogs
MER estimation using body weight for cats
MERcats = RER x activity factor (kcal/day)
RER = 70 x Mkg.75 (kcal/day)