MILK ENERGETICS

Leo Timms

Iowa State University

ENERGY REACTION VALUES

Reaction type energy value

kcal/mole

1. ATP--- ADP + P 7

UTP--- UDP + P 7

GTP--- GDP + P 7

2. ATP --- AMP + P + P 14

3. NADPH ---- NADP + ~ 3 ATP 21

MILK ENERGETICS 110 LBS. (50 l)

• Protein: 4% or 40 g / liter• 50 liter X 40 g/ l = 2000g synthesized protein• 2000 g /(100 g/ mole) = 20 moles AA in protein

• ENERGY NEEDED:

1. Formation of AA - tRNA: 14kcal / mole

ATP ------ AMP + P + P

2. 2 GTP / AA at ribosome 14 kcal / mole

TOTAL 28 kcal / mole

MILK ENERGETICS 110 LBS. (50 l)

• Fat: 4% or 40 g / liter• 50 liter X 40 g/ l = 2000g fat ( 50% made: 1000)• 1000 g /(256 g/ mole) ~ 4 moles palmitate (C16)

• ENERGY NEEDED:

1. 8 Acetate --- Acetyl CoA: 112 kcal / mole

ATP ------ AMP + P + P

2. 7 Acetyl CoA -- malonyl CoA 49 kcal / mole

3. NADPH ( 21kcal X 7 X 2) 294 kcal / mole

TOTAL 455 kcal / mole

MILK ENERGETICS 110 LBS. (50 l)

• Lactose: 5% or 50 g / liter• 50 liter X 50 g/ l = 2500g lactose• 2500 g /(360 g/ mole) = 7 moles lactose

• ENERGY NEEDED:

1. UTP ----- UDP- Galactose: 7 kcal / mole

UTP ------ UDP + P

2. UDP- galactose ----lactose + UMP 7 kcal / mole

TOTAL 14 kcal / mole

MILK ENERGETICS 110 LBS. (50 l)

Total energy expended for 50 kg milk

Component % moles kcal/m Total kcal %

Protein 4 20 28 560 23

Fat 2 (.5 X 4) 4 455 1820 73

Lactose 5 7 14 100 4

TOTAL 2480

MILK ENERGETICS 110 LBS. (50 l)

Caloric value of 50 kg milk

Caloric value NutritionalComponent grams per gram (kcal) value (kcal)

Protein 2000 4 8000

Fat 1000 ( 2000*) 9 9000 (18,000)

Lactose 2500 4 10,000

* total fat TOTAL 27,000 (36,000)

• ~ 2480 kcal invested to produce 36,000 kcal product!

MATERNAL SUPPORT OF LACTATION

Leo Timms

Iowa State University

MATERNAL LACTATION SUPPORT

MATERNAL LACTATION SUPPORT

• INCREASED DIETARY NUTRIENTS- increased feed intake

- increased GIT size- increased GIT absorptive capacity

• USE OF BODY RESERVES

• COMBINATION

MATERNAL LACTATION SUPPORT

• INCREASED DIETARY NUTRIENTS• rodents

- increased feed intake 300 - 400%- limited capacity to use body reserves

• COMBINATION• cows, goats, pig - extensive

• humans, guinea pigs - minimal/modest• mostly adipose/ some protein + glycogen

MATERNAL LACTATION SUPPORT

•USE OF BODY RESERVES• Elephant seals

* single pup * 28 day lactation* Pup averages 10%/ day BW gain!

* mother doesn’t eat / drink for 28 days• 42% loss in maternal BW

•58% reduction in body fat content• 14 % reduction in body lean weight

Milk Production

• A peak daily milk yield of 15 pounds (about 2 to 2.5 gallons) is not unusual.

• Pigs can easily convert milk – 4.5 lbs of milk= 1 pound of pig

Example: Litter of 10 pigs • Avg. birth weight (3 pounds)• Avg. wean weight (25 pounds)• @ 6 weeks of age

• 10 pigs gain 22 pounds each (220 pounds of total gain)

• Require 990 pounds of milk!

MATERNAL LACTATION SUPPORT

•USE OF BODY RESERVES• Blue whales

* Mother weighs 80,000 kg initially* mother gains 40-55,000 kg (pregnancy)

* single calf * 2500 kg at birth * 7 month lactation

• calf gains 80 - 100 kg / day• mother produces 90 kg milk / day

* mother eats very little for 7 months

MATERNAL LACTATION SUPPORT

•USE OF BODY RESERVES• Blue whales

• How much energy goes into 90 kg whale milk?• Where do nutrients come from if it doesn’t eat?• What is the nutritional value of that 90 kg milk?

• EXTRA CREDIT #4• email answers to me• ltimms@iastate.edu

25 pointsDUE AFTER

SPRING BREAK