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
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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9
0
5
10
15
20
25
30
35
40
45
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
15
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
5
10
15
20
25
30
35
40
45
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)