Increasing levels of concentrates to dairy cows on pasture

Karin Alvåsen and Eva Spörndly

Department of Animal Nutrition and Management

Swedish University of

Agricultural Sciences

AIMS OF GRAZING EXPERIMENT

• to quantify how step-wise decreases in concentrate proportion affects milk production

• to register grazing and ruminating time

• to validate the cows ability to compensatea lower concentrate intake with a higherpasture intake

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TREATMENTS AND FEEDING

• Five treatments:

- 20% of energy requirement

- 30% covered by concentrates

- 40%

- 50%

- 60%

• All cows were given 4 kg DM

silage inside at milking 3

Treatment Concentrate1

20% (n = 6) 3.6

30% (n = 5) 5.0

40% (n = 6) 7.4

50% (n = 5) 8.9

60% (n = 5) 10.8

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CONCENTRATE FEEDINGduring the experiment

1 kg DM

COMPOSITION OF THE PASTURE

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Crude protein1 149 ± 20

Neutral Detergent Fibre1 423 ± 53

Metabolisable energy2 10.8 ± 0.5

1 g per kg DM ; 2MJ/kg DM ; mean ± SD

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Study part I: GRAZING BEHAVIOUR

MATERIAL & METHODS

• Three cows from eachtreatment group

• IGER Behaviour Recorder measure jawmovements

• 24 hour per cow

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ANALYSIS

GRAZE® software

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0

5

10

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20

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30

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40

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50

20 30 40 50 60

Be

hav

iou

r (%

)

Concentrate level (% of energy requirement)

a

b

bc

c c

Grazing time(% of total time) during 24 hours recording (P < 0.05)

Study part II: MILK YIELD & MILK COMPOSITION

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Increased concentrate levelwith 10% gave 1.5 kg higher milk yield

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0

5

10

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20

25

30

20 30 40 50 60

kg m

ilk

Concentrate (% of energy requirement)

abb

c

a

bc

MILK COMPOSITIONin relation to % concentrate of energy requirement

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Treat. Fat Protein

20% 4.5a 3.6a

30% 4.2b 3.6a

40% 4.3ab 3.5a

50% 4.3ab 3.6a

60% 4.2b 3.6a

1 Mean ; (P < 0.05)

Milk fat and protein content (%) during the trial1

DISCUSSION

Dry weather Response at high/low yield

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What results could havebeen obtained at a higherherbage allowance?

Perhaps higher yield atlow concentrate levels

No difference in responsebetween high and lowyielders – Reason?

Too few cows in relationto treatments

CONCLUSIONS

• ECM and milk yield increased by 1.5 kg for each 10% increase of the concentrate level

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+ 1 kg concentrate + 0.8 kg milk

• Increase of concs from 20%-40% reduced milk fat, butprotein content was unaffected by concentrate level

• Increased concentrates led to reduced grazing time

• Extra concentrates are economical up to 60 % of energy requirement as long as 1 kg extra concentrate costs less than 0.8 kg milk

ACKNOWLEDGEMENTS

• Financing of project:

Farmers Foundation for Agricultural Research (SLF)

• Contribution for EGF participation:

Royal Swedish Academy of Agriculture and Forestry (KSLA)

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THANK YOU FOR YOUR ATTENTION!

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MATERIAL AND METHODS

• 10,5 ha pasture

• Dominating species: meadow fescue, smooth meadow grass and white clover

• Rotation: 6 paddocks

• 3-5 days in same paddock

• Pastures were topped after grazing

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Study part I:

PASTURE RECORDINGS

PASTURE ALLOWANCE

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Pasture mass was measured by cutting plot sub-samples at 3 cm

Pasture allowance=Herbage mass

Number of cows x days grazing

Treatment ECM1 (kg) Concentrate (kg DM)2

20% (n = 6) 28,2 ± 4,9 3,6 ± 0,5

30% (n = 5) 26,2 ± 7,1 5,0 ± 0,8

40% (n = 6) 29,7 ± 5,9 7,4 ± 1,3

50% (n = 5) 28,6 ± 4,2 8,9 ± 1,1

60% (n = 5) 27,7 ± 6,7 10,8 ± 1,6

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Milk yield (kg ECM) at the start of the trial and concentrate ratio during the trial (Mean ± SD)

1 ECM (Energy Corrected Milk) Mean of two test milkings before the trial started (week 20 and 22); 2 During the trial (week 25 – 30)

INFORMATION OF COWS IN THE TRIAL

COMPOSITION OF THE PASTURE

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Crude protein1 149 ± 20

Neutral Detergent Fibre1 423 ± 53

Metabolisable energy2 10.8 ± 0.5

1g per kg DM ; 2MJ/kg DM ; mean ± SD

Less concentrate = Improved profitability?

• Can dairy cows compensate a reduced concentrate ratio with an increased

pasture intake?

• Will milk production be maintained?

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0

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20 30 40 50 60

Be

hav

iou

r (%

)

Concentrate level (% of energy requirement)

ab

b b

a a

Ruminating time (% of total time) during 24 hours recording (P < 0.05)