ration evaluation

Question 1

what is the important input cost in animal production systems

Answer 1

feed

Question 2

what percent of the cost of production is feed

Answer 2

50-70%

Question 3

what are the 3 components of animal production and feed

Answer 3

• feed for animal maintenance (fixed)
• feed for production (varies)
• feed for replacement animal (fixed)

Question 4

what is “feed for animal maintenance”

Answer 4

• body size and environmental conditions
• ability to perform “everyday” activities

Question 5

what is “feed for production”

Answer 5

• growth
• milk production
• reproduction

Question 6

what is “feed for replacement animal”

Answer 6

• animals must be raised to replace current production animals
• heifers, steers, gilts, chicks
• goal is max efficiency at entry level (24m vs 48m to raise replacement)

Question 7

what do long feed out periods carry a lot of

Answer 7

“maintenance cost”

Question 8

why is higher production efficient

Answer 8

• every farm has a goal
• some farms better than others
• low yielding herds at risk of leaving industry
• evolution to capture efficiency
• evolution of nutrition

Question 9

what is fixed relative to

Answer 9

production

Question 10

what are the benefits of energy budget

Answer 10

• economic
• environment
• resource use

Question 11

what is energy budget directly influenced by

Answer 11

management factors

Question 12

what do larger herds tend to have

Answer 12

better/dedicated managers and consultants

Question 13

what is the amount of certaintly of iron and calcium

Answer 13

varies widely - “OK” window is larger

Question 14

what is the amount of certaintly of energy/protein

Answer 14

tighter “OK” window

Question 15

what are the two ways nutrient requirement measurements are presented

Answer 15

1. amount of nutrient
2. densisty basis

Question 16

what is the nutrient density requirement equation

Answer 16

nutrient amount / total DM intake of the animal

Question 17

what is the dry matter content of the corn silage?

100lbs corn silage (AF); 35lbs corn silage (DM)

Answer 17

35/100 = 35% DM

Question 18

what is the moisture content of the corn silage?

100lbs corn silage (AF); 35lbs corn silage (DM)

Answer 18

100-35 = 65% water (moisture)

Question 19

a horse consumes 20lbs (AF) of timothy hay that is 90% DM. What is the dry matter intake of hay for the horse?

Answer 19

20lbs of hay X 0.90 (%DM) = 18lbs of dry matter

Question 20

haylage DM decreases to 30%. how much haylage should the producer now feed?

DMlbs - 6.75

Answer 20

6.75 lbs (DM) haylayge / 0.30 (DM%) = 22.5 lbs (AF) of haylage

Question 21

what is the equation of dry matter to as fed

Answer 21

(DM lbs ) / (%DM) = as fed lbs

Question 22

what is the equation of as fed to dry matter

Answer 22

(AF lbs) X (%DM) = dry matter lbs

Question 23

nutrient densities

Answer 23

• measures on dry matter and as fed basis
• most laboratory analysis contain both

DM will be more dense

Question 24

CP of 20%; DM of 40%. what is the CP% of AF?

Answer 24

nutrient density DM X DM% = nutrient density AF

20% DM CP X 40% DM% = 8% AF CP

Question 25

CP of 20% DM; DM% of 40%; cow consumes 30 lbs/day (AF). How much CP does she get from haylage?

Answer 25

method 1: * 30lbs hay X 40% = 12lbs DM of hay * 12 lbs of DM hay X 20% = 2.4 lbs of protein method 2: * 20% DM CP X 40% DM = 8% AF CP in hay * 8% X 30 lbs = 2.4lbs of protein

Question 26

you want to feed 2lbs of protein to a cow using soybean meal which has a 48% AF CP level. How much soybean meal should u feed?

Answer 26

2lbs of protein / 48% (CP%, AF) = 4.16 lbs SBM (AF)

Question 27

know how to do person square example - solving a mix - create a mix with 16% CP (AF) with shelled corn (9% AF CP) and soybean meal (48% AF CP)

Answer 27

* 18% SBM * 82% Corn

Question 28

how do you solve for two nutrients

Answer 28

* need at least two feed ingredients

Question 29

how to solve for 3 nutrients

Answer 29

* 3 feeds * 3 equations * find the point where all 3 lines intersect * sol. might not exist

Question 30

what does linear programming allow us to do

Answer 30

formulate rations with "nutrient winows" rather than absolute amounts

Question 31

what is the objective of linear programming

Answer 31

identify ingredients/ amounts that minimize cost

Question 32

what are some key concepts in linear programming

Answer 32

* meet/exceed energy requirements * meet/exceed protein requirements * "fit" the dry matter intake capacity of the described animal * be within a range of nutrient levels

Question 33

what are the steps in linear programming

Answer 33

* describe objective * identify decision variables * find optimal solution * (+/-) evaluate sensitivity analysis

Question 34

what variables do you have control over

Answer 34

* amount of corn silage fed/day * amount of soybean meal fed/day

Question 35

what does LP tell us

Answer 35

the optimal amount to feed of each ingredient

Question 36

what are RH values or constraints

Answer 36

things you cannot change (DM, mcals, protein, ADF)

Question 37

what are matrix coefficients

Answer 37

variables (type of feeds and amounts)