7. Energy Flashcards
Energy in animal nutrition
energy is the ability to do work
mechanical, chemical and thermal
feed contains chemical energy
many biological processes need energy
energy containing products produced in body
Energy in animal nutrition
animals need nutrients for activity, maintenance of body temperature, tissue production, biological processes
Best way to estimate amount of nutrients needed for all these different processes is by the energy required for them
compare energy required for these processes to chemical energy in feed
energy measurement : joules or calories
unit of energy currency in body is ATP
Energy losses in animal nutrition
Feed Gross Energy
Digestible Energy -undigested feed, microbial and endogenous excretion
Metabolisable Energy -methane urine
Net Energy - heat increment: increase in heat loss after the ingestion of a meal
net used for maintenance, milk, body and foetal growth
Dog energy in animal nutrition
K 99, inactive
132, active
160, very active
lactating bitches, daily ME requirement x3 daily maintenance requirement
cat energy in animal nutrition
sedentary, 50kcal
moderately active, 60kcal
very active, 70kcal
pregnant queens in late pregnancy need1.25x adult maintenance ME requirement per day
horse energy in animal nutrition
mature horse, 19.4Mcal
lactating mare, 33.7Mcal
2y.o. not in training, 23.5Mcal
2y.o. in training, 32.3Mcal
Heat Increment
heat increment is largest and most important for ruminants
increase in heat loss after digestion of a meal
differs for lactation, maintenance, fattening, pregnancy and growth
Heat increment depends on feed type
forage vs. concentrates
rumen digestion products: acetate, proprionate and butyrate
ruminants, heat increment large
Irish net energy system
NE best estimate of available energy in feeds
validated for dairy cows and beef cattle
routinely used in ireland for silage analysis
Feed NE values and Animal NE requirements expressed relative to NE content of barley
Feeds have two NE values: UFL/UFV
UFL dairy
1 UFL = NE content of 1kg of air dry standard barley for milk production, 1700kcal
animal requirements: maintenance and lactation
dairy heifers, ewe lambs
wintering animals
breeding male cattle
dairy goats
UFL meat production
rapidly growing steers, bulls, beef heifers
fattening steers, bulls, beef heifers, lambs
cattle with daily gains >1kg/day
Corrections for associative effects dairy cows
assumption made in diet formulation
that the UFL values of the diet are additive
feeding concentrates reduces forage digestibility
diet digestibility reduced as feeding levels increase
changes in body weight/BCS in dairy cows
1kg body weight loss supplies 3.5UFL
1kg of body weight gain requires 4.5UFL
loss of 1 unit BCS supplies 150UFL
gain of 1 unit BCS requires 200UFL
Pregnancy Requirements
dairy
UFL requirements increase in 7,8,9th months
0.9,1.6, 2.6 UFL
Beef
UFL requirements increase 6,7,8,9th months
0.56, 1.08, 1.86, 2.93
