Nutrition Exam 3 Lecture Notes Flashcards
Bioenergetics
energy metabolism, critical to animal nutriton
How much energy (kcal/g) is in carbohydrates, proteins, and lipids?
Carbohydrates = 4
Protein = 4
Lipids = 9
What is energy?
Energy = the capability to do work
Work = force x distance
Chemical energy = potential energy in food
Calories
Calorie (cal)
amount of heat required to increase the temperature of one gram of water by one degree Celsius
Kilocalorie (kcal): one thousand calories
Megacalorie (Mcal): one million calories
Joule
standard unit of energy (work)
energy required to displace 1 Newton, 1 meter
How many Joules does 1 calorie equal?
One calorie = 4.183 Joules
How is energy expenditure expressed?
expressed as units of energy per amount of time
Watt = 1 J/sec
Horsepower = 746 J/sec
What is the first law of thermodynamics?
energy can neither be created nor destroyed
Gross energy
total amount of energy consumed
amount of heat liberated when a feed sample is completely burned into carbon dioxide and water
determined by a bomb calorimeter
Digestible energy
amount of energy that is digested and potentially available for utilization
Digestible energy = gross energy (GE) - fecal energy (FE)
Metabolizable energy
energy used for metabolism
Metabolizable energy = digestible energy (DE) - urinary energy (UE) - gaseous energy
Net energy
represents the fraction of the total energy consumed that is utilized for production purposes
NE = metabolizable energy (ME) - heat increment (HI)
Heat increment (HI)
Heat increment = heat loss of eating animal - heat loss of fasting animal
Energy maintenance
energy required to maintain constant body weight
Goal: metabolize energy intake = energy expenditure
Positive energy balance = weight gain
Negative energy balance = weight loss
Metabolic consequences of energy imbalance
Weight gain or loss
Reduced fertility
Decreased productivity
Compromised immune system
Behavioral changes
Increased mortality
Management strategies to avoid energy imbalance
Optimize feed intake
Provide energy-dense feeds
Body condition scoring
Proper feeding management
Transition period management
Early detection and treatment
Obesity
Associated with excess energy intake
Commonly seen in companion animals and horses
Fatty liver disease
energy demands exceed intake
fat stores are mobilized
excessive NEFA accumulation in liver
most often seen in high producing dairy cows
Ketosis
body mobilizes large amounts of fat for energy
due to a lack of available glucose
results in buildup of ketone bodies in the blood
most often seen in high producing dairy cows
Pregnancy toxemia (aka pregnancy disease, lambing sickness, and twin-lamb/kid disease)
caused by low blood sugar (glucose)
onset often triggered by stress - nutritional, inclement weather
most prevalent in ewes/does carrying multiples and over- or under-weight ewes/does
Equine metabolic syndrome
disorder associated with insulin dysregulation
characterized by regional fat deposition and reduced ability to lose weight
commonly seen in ponies, donkeys, Arabians, and mustangs
increases the risk for laminitis
treated through diet and exercise management
What are vitamins?
“vital amines”
organic molecules
DO NOT provide energy
Needed in minute amounts
Classified based on solubility
General functions of vitamins
metabolism, growth and development, immune function, nerve function, blood clotting, bone health, vision, skin health, antioxidants
Fat soluble vitamins
A, D, E, and K
