1. MILK ENERGETICS Leo Timms Iowa State University

2. 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

3. 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

4. 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

5. 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

6. 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

7. MILK ENERGETICS 110 LBS. (50 l) Caloric value of 50 kg milk Caloric value Nutritional Component 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!

8. MATERNAL SUPPORT OF LACTATION Leo Timms Iowa State University

9. MATERNAL LACTATION SUPPORT

10. INCREASED DIETARY NUTRIENTS - increased feed intake - increased GIT size - increased GIT absorptive capacity USE OF BODY RESERVES COMBINATION

11. 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

12. 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

13. 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!

14. 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

15. 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 points DUE AFTER SPRING BREAK