Dairy Tutorial 4

Description

Tutorial 4—Lactating Cows In the CNCPSv4, lactation requirements are calculated independently from maintenance requirements. Lactation requirements are ranked third in nutrient priority for the animal (maintenance, pregnancy, lactation and growth). They are calculated as: ME required (Mcals/d) = Milk Production * (((Milk Fat * 0.0962) + 0.3512) / 0.644) MP required (gms/d) = (10 * Milk Production * Milk Protein) / 0.65 Where: milk production is kg/d Milk fat is % Milk protein is % True protein The 0.644 coefficient in the ME equation is the efficiency of use of ME to NE for lactation based upon the work of Moe et. al. The 0.65 coefficient in the MP equation is the efficiency of use of MP to net protein from the 1985 NRC. In other words, the model calculates the net energy and net protein required for the inputted milk production (and composition) and converts it to a metabolizable basis using these efficiency factors. Diet evaluation with the CNCPSv4 is accomplished by comparing required and supplied Mcals or grams rather than with concentrations of nutrients. The same is true when evaluating the amino acid adequacy of a diet. Amino acid content of tissue and milk protein used in the CNCPSv4 are as follows: Amino Acid Composition (g/100g) Amino Acid Tissue Milk protein Methionine 1.97 2.71 Lysine 6.37 7.62 Arginine 6.60 3.40 Threonine 3.90 3.72 Leucine 6.70 9.18 Isoleucine 2.84 5.79 Valine 4.03 5.89 Histidine 2.47 2.74 ...

Informations

• Publié par: Thuwyug
• Nombre de lectures: 21
• Langue: English

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Tutorial 4—Lactating Cows

In the CNCPSv4, lactation requirements are calculated independently from

maintenance requirements. Lactation requirements are ranked third in nutrient priority

for the animal (maintenance, pregnancy, lactation and growth). They are calculated as:

ME required (Mcals/d) = Milk Production * (((Milk Fat * 0.0962) + 0.3512) / 0.644)

MP required (gms/d) = (10 * Milk Production * Milk Protein) / 0.65

Where:

milk production is kg/d

Milk fat is %

Milk protein is % True protein

The 0.644 coefficient in the ME equation is the efficiency of use of ME to NE for

lactation based upon the work of Moe et. al.

The 0.65 coefficient in the MP equation is

the efficiency of use of MP to net protein from the 1985 NRC. In other words, the model

calculates the net energy and net protein required for the inputted milk production (and

composition) and converts it to a metabolizable basis using these efficiency factors.

Diet evaluation with the CNCPSv4 is accomplished by comparing required and supplied

Mcals or grams rather than with concentrations of nutrients. The same is true when

evaluating the amino acid adequacy of a diet. Amino acid content of tissue and milk

protein used in the CNCPSv4 are as follows:

Amino Acid Composition (g/100g)

Amino Acid

Tissue

Milk protein

Methionine

1.97

2.71

Lysine

6.37

7.62

Arginine

6.60

3.40

Threonine

3.90

3.72

Leucine

6.70

9.18

Isoleucine

2.84

5.79

Valine

4.03

5.89

Histidine

2.47

2.74

Phenylalanine

3.53

4.75

Tryptophan

0.49

1.51

For each amino acid, the following calculations are performed:

First, maintenance AA requirements are calculated as:

MPAAi = ((AATISSi * 0.01) * (FPN + ((SPA + UPA) * 0.65))) / EAAMi

Then pregnancy requirements:

PPAAi = (AATISSi * 0.01 * MPPreg * MPtoNPFactor) / EAAPI

Then lacatation

LPAAi = (AALACTi * 0.01 * (MPLact * 0.65)) / EAALI

And finally, gain

GPAAi = ((SWG * 1000) * (ProteinInGain / 100) * AATISSi * 0.01) / EAAGi

Where:

MPAAi is maintenance amino acid required (gms/d) for the ith AA

AATISSi is the amino acid composition of tissue for the ith AA

FPN is metabolic fecal nitrogen (gms/d)

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SPA is scurf protein (gms/d)

UPN is urinary protein (gms/d)

EAAMi is the efficiency of use of the ith AA for maintenance

PPAAi is pregnancy amino acid required (gms/d) for the ith AA

MPPreg is the metabolizable protein requirement for pregnancy

MPtoNPFactor is the efficiency of use of protein for pregnancy

EAAPi is the efficiency of use of the ith AA for pregnancy

LPAAi is the lactation amino acid requirement for the ith AA

AALACTi is the amino acid composition of milk protein for the ith AA

MPLact is the metabolizable protein required for lactation

EAALi is the efficiency of use of the ith AA for lactation

GPAAi is the ith AA gain requirement (gms/d)

SWG is shrunk weight gain (kg/d)

ProteinInGain is the proportion of protein in the SWG

EAAGi is the efficiency of use of the ith AA for gain.

During a diet evaluation, the following are calculated:

ME allowable milk

MP allowable milk

AA allowable milk

Days to change a body condition score.

These calculations provide an index of diet allowable production and energy balance of

the animal for a particular diet.

This tutorial is a continuation of tutorials 2 and 3. It uses the data from a 500-cow herd.

Three groups of cows will be analyzed: Fresh (<40 DIM), First-calf heifers, and Mature

cows (This follows the grouping of the farm). The Fresh group will be walked through

stepwise and evaluate; inputs and selected results for the other groups are provided.

Let’s start the tutorial now!

Step What to do

1

Load the simulation.

Select File, Load Simulation from the menu. Select the

simulation named Tutorials 2 to 5 for t3.

2

Create the groups.

Group 1 Name: Fresh cows, with 60 lactating cows

Group 2 Name: Pens 1 and 2, with 250 lactating cows

Group 3 Name: Pen 3, with 130 lactating cows

For all groups, enter 175 days to feed.

FYI: Pens 1 and 2 are mature cows, Pen 3 is the first calf heifer group.

3

Bring in feeds.

The following feeds are already loaded:

1998 Corn Silage

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1999 Grass silage

Grass hay

Corn meal

Whole cotton

Homer meal

TMR weighbacks

Soy hulls

Soy 48

Gluten 60

Molasses

Heifer mineral mix

Dry cow mineral mix

We will need these in addition:

AlfSil 20Cp40Ndf17LNDF

Beet Pulp – Dehy (605)

Calcium – Sulfate (806)

Dicalcium – Phosphate (810)

Limestone (813)

Magnesium – Oxide (816)

Magnesium Sulfate

Minvit 2

Salt (831)

Sodium – Bicarbonate (832)

Zinpro 4-Plex

After you bring these feeds in, re-order them to be in the following order:

1998 Corn Silage

AlfSil 20Cp40Ndf17LNDF

1999 Grass silage

Grass hay

Corn meal

Whole cotton

Homer meal

TMR weighbacks

Soy hulls

Soy 48

Gluten 60

Beet Pulp – Dehy (605)

Molasses

Heifer mineral mix

Dry cow mineral mix

Dicalcium – Phosphate (810)

Limestone (813)

Calcium – Sulfate (806)

Salt (831)

Sodium – Bicarbonate (832)

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Magnesium – Oxide (816)

Magnesium Sulfate

Minvit 2

Zinpro 4-Plex

Then change the names of the feed you just brought in to:

Original name

New name

AlfSil 20Cp40Ndf17LNDF

1999 Alfalfa silage

Beet Pulp – Dehy (605)

Beet pulp

Calcium – Sulfate (806)

Ca Sulf

Dicalcium – Phosphate (810)

DiCal

Limestone (813)

Limestone

Magnesium – Oxide (816)

Mag Ox

Magnesium Sulfate

Mag Sulf

Minvit 2

Trace min vit pack

Salt (831)

White salt

Sodium – Bicarbonate (832)

Sodium Bicarb

Zinpro 4-Plex

4 Plex

4

Save the simulation as Tutorials 2 to 5 for t4.

5

Edit the feed composition. Hint: watch your units!

For these feeds, use book values and these feed costs:

Beet pulp

$100/ton

Ca Sulf

$500

DiCal

$500

Limestone

$500

Mag Ox

$500

Mag Sulf

$500

White salt

$500

Sodium Bicarb

$500

4 Plex

$1000

For these feeds, enter the following composition (watch units!):

1999 Alfalfa silage

Trace min vit pack

Cost ($/t)

$35.00

$1000

Homegrown

True

False

DM

40.20

99.00

NDF (%DM)

44.30

0

Lignin (%NDF)

17.60

0

CP (%DM)

20.10

0

SolCP (%CP)

65.00

0

NDFIP (%CP)

18.00

0

ADFIP (%CP)

6.47

0

Fat (%DM)

4.10

0

Ash (%DM)

9.37

100

Ca (%DM)

1.37

0

P (%DM)

.34

0

Mg (%DM)

.27

0

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Mg (%DM)

.27

0

Cl (%DM)

.00

0

K (%DM)

2.89

0

Na (%DM)

.16

0

S (%DM)

.24

0

Co (ppm)

0

0

Cu (ppm)

8

100

I (ppm)

0

500

Fe (ppm)

416

0

Mn (ppm)

42

10

Se (ppm)

0

200

Zn (ppm)

31

500

Vit A (KIU/kg)

0

2500

Vit D (KIU/kg)

0

1000

Vit E (IU/kg)

0

750

6

Save the simulation.

7

Enter the description inputs for the group.

The first group we will work with is the

Fresh cows.

Enter the following inputs:

Animal Type: Lactating Cow

Age: 47 months

Sex: Cow

Current Body Weight: 1400 lbs SBW

Mature Weight: 1515

Breed Type: Dairy

Days Pregnant: 0

Days since calving: 30

Lactation Number: 4.0

Calving Interval: 13

Exp. Calf Birth Weight: 95

Age At First Calving: 22

8

Enter the production inputs for the group.

Enter the following inputs:

Rolling herd average: 22000

Milk production: 75.0

Milk Fat: 4.00

Milk Protein: 3.50 Crude Protein

Milk Price: $11.00 /cwt

Body Condition Score: 3.00 (on a Dairy Scale)

Breeding System: Straightbred

Breed: Holstein

9

Enter the management/environment inputs for the group.

Enter the following inputs:

Additive: None

Added fat in diet: Should not be checked

Wind Speed: 1

Prev. Temperature: 40

Prev. Rel. Humidity: 40

Temperature: 40

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Relative Humidity: 40

Hours in Sunlight: 0

Storm Exposure: should not be checked

Hair Depth: .25

Mud Depth: 0

Hide: Thin

Hair Coat: No Mud

Cattle Panting: None

Minimum Night Temperature: 50

Activity: Large free-stalls Close parlor

10

Enter the ration for the group.

Enter the following ration:

1998 Corn silage:

10.907 lbs DM/d

1999 Grass silage:

4.675

Grass hay:

2.654

Corn meal:

9.542

Whole cotton:

2.222

Homer meal:

3.339

Soy 48:

2.680

Gluten 60:

.823

Molasses:

2.537

Dry cow mineral mix:

1.575

DiCal:

.250

Limestone:

.525

White salt:

.260

Sodium Bicarb:

.260

Total DMI should be:

42.245 pounds per day

Summary results should look like this:

Entered milk: 75.0

ME allowable milk: 56.5 lbs/day

MP allowable milk: 70.4 lbs/day

LYS allowable milk: 71.8 lbs/day

Days to Loose 1 Condition Score: 66

Rumen N balance: 24 g/d

Peptide balance: 23 g/day

eNDF balance: 1.4 lbs/day

Pred. DMI: 43.90 lbs/day

11

Save the simulation.

12

Evaluate the group— Diet adequacy

.

1. The first question raised by this ration is the difference between entered

and predicted DMI. Why are these cows consuming less?

a. Is the entered ration correct?

b. Is there a high percentage of 1

st

calf heifers in this group?

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c. Is the group described adequately?

i. Specifically is body weight correct or was it a guess?

d. Are animal numbers kept current?

e. Are the animals under stress?

2. Ruminal N balance is 107% of requirement. The recommendation for

ruminal N balance is 100 to 110%, therefore this is adequate.

3. Rumen peptide balance is 113%. This is not a true requirement for

bacterial growth. Diets less than 100% will not maximize NSC microbial

growth, however diets greater than 125% usually can be reformulated to

improve nitrogen balance.

4. If MP balance is positive, excess peptides and ruminal N balance and

excess MP result in a urea cost. The urea cost is the energetic cost

(added to maintenance energy requirements) to convert ammonia to urea

in the kidney’s for nitrogen excretion. Since this diet is deficient in MP, the

calculated urea cost is zero.

5. MP from bacteria in this diet is 1252 gms. MP from undegraded feed is

1047 grams. A goal in formulation with the CNCPSv4 is to have at least

50% of the total MP be of microbial origin. This diet achieves that goal.

6. Rumen health can be assessed using one of two values (effective NDF

balance or Predicted Ruminal pH). Predicted Ruminal pH below 6.25

results in a depression of SC microbial growth and fiber digestion. A

typical lower limit for Predicted ruminal pH is 6.28. This diet has a

predicted ruminal pH of 6.41 suggesting that diet NSC levels (currently

38.7%) may be increased.

7. The Predicted MUN of this diet is 12 mg/dl. Animals in this group typically

have an MUN of 16-18 mg/dl. The low value in this diet is the result of MP

being deficient.

8. Total fat in this diet is 4.0%. This fat is 100% vegetable origin and is from

two feeds (Whole cotton and Homer meal). No added fat is used in this

diet as an intake depression is possible.

9. Days to lose one body condition score are predicted to be 66. This value

(along with the ME allowable milk of 56.5 lbs/day) is a concern. If these

cattle in this group were to produce 75 pounds as inputted and remain in

this pen for 40 days, they would lose ½ of a body condition score before

peak milk production. Energy levels of this diet need to be evaluated and

changed so that reserves loss is decreased. Typical recommendations for

days to change one body condition score are at least 100 days.

10. This ration is 43% forage. The model does not consider feeds such as

cotton, beet pulp, or soy hulls as forage. A 43% forage diet is on the low

side of acceptable. If inventories allow, increasing the forage level is

suggested.

11. The next step in diet evaluation is amino acid adequacy. While all amino

acids are listed on the Amino Acid report, the confidence interval around

all but MET and LYS is large. With the factorial system used, branched

chain amino acids typically appear as first limiting, however data to

support this is very limited. MET and LYS are the only amino acids that

Page 8 of 10

should be considered at this time. In this diet, MET is just balanced at

101% and LYS is deficient at 97% of requirement. Additional LYS could be

added. Rulquin and Schwab ratios are also calculated by the model and

can be used if desired.

12. Mineral balance of this diet is a weak area. Since the mineral mix is

designed around the requirements of another group, additional minerals

are added at the farm. This results in adequate macro minerals, and

questionable micro levels. The diet is:

Adequate in Ca (22 gm excess)

Adequate in P (0 gm balance)

High in Mg (.42%)

High in K (1.54%)

Very high in Na

(98 gm excess)

Very high in Cl (139 gm excess)

Adequate in S (.28%, 6 gm excess)

Very high in Co (4.10 ppm)

Very high in Cu (116.31 ppm)

Very high in I (7.35 ppm)

High in Fe (354.97 ppm)

Very high in Mn (379.02 ppm)

High in Se (.43 ppm)

Very high in Zn (355.23 ppm)

Very high in Vit A (17.94 KIU/kg)

Very high in Vit D (4.44 KIU/kg)

High in Vit E (111.57 IU/kg)

These micro-mineral levels are unacceptable. This mineral pack has to be

reformulated.

13

Evaluate the group—Nutrient Excretion.

View the Herd Analysis Report. This diet

is 36.9% home grown. Most farms would have this group at a level of >45%

home grown. It is depressed on this farm partially due to the grass hay, which is

purchased from a neighboring crop farmer. Average N, P, and K purchased are

77, 77, and 58%, respectively and are typical for most herds. Increasing forage

levels will result in lowering these values. The group will produce 612 tons of

manure during this 175-day period.

14

Tips for reformulation.

This diet has many areas where it can be improved. The

following should be investigated:

1. Dry matter intake. What can be done to increase DMI?

2. Total ME of the diet needs to be increased to improve energy balance.

3. Total MP needs to be increased if these cows are to produce at the

inputted level.

4. NSC levels could be increased.

5. If inventory allows, forage levels could be increased.

6. Peptide levels could be lowered slightly.

7. LYS levels could be increased.

8. Reformulate the mineral mix.

Page 9 of 10

15

Inputs for other groups.

Pens 1 and 2

Pen 3

Animal Type:

Lactating Cow

Lactating Cow

Age:

47

24

Sex:

Cow

Cow

Current Shrunk Body Weight:

1400

1300

Mature Weight:

1515

1515

Breed Type:

Dairy

Dairy

Days Pregnant:

50

50

Days since calving

140

140

Lactation number

4.0

1.0

Calving Interval:

13

13

Exp. Calf Birth Weight:

95

95

Age At First Calving:

22

22

Rolling herd average

22000

22000

Milk production

96.0

80.0

Milk fat

4.00

4.00

Milk true protein

3.30

3.26

Milk price

11.00

11.00

Body Condition Score:

2.90

3.25

Breeding system

Straightbred

Straightbred

Breed

Holstein

Holstein

Additive

None

None

Added fat in diet

No

No

Wind Speed:

1

1

Prev. Temperature:

40

40

Prev. Rel. Humidity:

40

40

Temperature:

40

40

Relative Humidity:

40

40

Hours in Sunlight:

0

0

Hair Depth:

.25

.25

Mud Depth:

0

0

Hide:

Thin

Thin

Minimum Night Temperature:

50

50

Activity:

Large free-stalls

Close parlor

Large free-stalls Close

parlor

Rations: feed the same ration to both groups. For Pen 3, after entering the ration,

click on the Production tab, and then click on the Ration tab. In the Intake Scalar

box, enter 85%.

1998 Corn silage

17.25

1999 Alfalfa silage

10.00

Corn meal

12.00

Whole cotton

4.00

Homer meal

4.00

Soy 48

3.75

Page 10 of 10

Gluten 60

.75

Beet pulp

1.85

Molasses

1.00

DiCal

.25

Limestone

.50

Ca Sulf

.30

White salt

.25

Sodium Bicarb

.45

Mag Ox

.05

Mag Sulf

.15

Trace min vit pack

.08

4 Plex

.03

Total

56.66

16

Selected output from groups.

Summary results should look like this:

Pens 1 and 2

Pen 3

Entered milk:

96.0

80.0

ME allowable milk:

92.3

78.2

lbs/day

MP allowable milk:

95.1

80.6

lbs/day

MET allowable milk:

94.8

82.2

Lbs/day

Days to Loose 1 Condition Score:

329

274

Rumen N balance:

83

71

g/d

Peptide balance:

26

27

g/day

eNDF balance:

1.5

1.3

lbs/day

Pred. DMI:

56.55

49.65 lbs/day

17

Save the simulation.