1

Effects of different feeding systems on

milk composition and processability: Outdoor grazing on pasture vs. indoors feeding on TMR

European Grassland Federation, Cork

June 18, 2018

Arunima Gulati

Teagasc Food Research Centre, Moorepark

Feeding Systems

Indoors offered

Total Mixed Ration

TMR

Grazing on

Perennial ryegrass -White clover

GRC

Profiling milk from Grass: Comparative effects of different dairy cow feeding systems on

milk composition, processability and product manufacture

Grazing on

Perennial ryegrass

GRS

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Characteristics of Pasture based feeding systems

• Natural environment

• Cost competitive

• Lower enteric emissions

• Inclusion of white clover fixes atmospheric Nitrogen

Characteristics of Indoor

feeding offered TMR

• Protection from heat/cold

stress

• Consistent feed composition

• Higher milk yield

• 20 Holstein-Friesian cows allocated to each of the three herds: GRS, GRC and TMR

• Herds balanced: breed, lactation no., calving date, and pre-experimental

milk yield and milk solids yield.

Teagasc study on Pasture vs. TMR

feeding systems

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GRS Milk TMR Milk

- Composition

- Protein and element

profiling

- Fatty acid profiles

- Volatile compounds

- Flavour

Compositional/

sensory

properties

- Heat stability

- Rennet gelation

Processability

characteristics

Product

forming

characteristics

Composition

Biochemistry

Yield/losses

Texture

Functionality

Volatiles

Sensory

Cheddar

Maasdamer

Mozzarella

SMP, WMP

Cheese

Powders

Composition

Physical properties

Applications

GRC Milk

Results

Milk composition / physico-

chemical characteristics

Rennet Gelation & Mozzarella

cheesemaking characteristics

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Effect of feeding system: Composition

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• GRS milk:

• highest mean levels of total solids

(TS), protein, casein (P < 0.05)

• TMR milk:

• Highest content of lactose (P < 0.05)

• GRC milk

• Intermediate of GRS and TMR for

mean TS, protein, casein, lactose

content. But had highest proportion

of as2-casein.

3.2

3.4

3.6

3.8

4.0

4.2

116 136 156 176 196 216

Pro

tein

(%

)

4.5

4.7

4.9

5.1

116 136 156 176 196 216

Lac

tose

(%)

Days in Lactation, DIL

• No difference between GRS, GRC

or TMR milk for:

− mean levels of whey protein, NPN

or Urea

− mean level of serum casein as %

of total casein (3.7 – 6.25 %)

− mean proportions of as1, b- or k-

caseins

Effect of feeding system: Milk Elements

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• GRS milk had higher

concentrations of Ca, P

and Na than GRC or TMR milk

(P < 0.05)

• GRC milk had lowest levels of

Se, Cu and Zn

• TMR milk had highest level

of Se, Cu and Zn

115

125

135

145

155

116 136 156 176 196 216

Ca

(mg

100 g

-1)

Days in lactation, DIL

90

95

100

105

116 136 156 176 196 216

P (m

g 1

00 g

-1)

Days in lactation, DIL

20

40

60

80

100

120

116 136 156 176 196 216

Cu

(m

g k

g-1

)

Days in lactation, DIL

10

15

20

25

30

116 136 156 176 196 216

Se (

mg

kg

-1)

Results

Milk composition / physico-

chemical characteristics

Rennet Gelation & Mozzarella

cheesemaking characteristics

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Effect of feeding system: rennet gelation and cheese

manufacture

Rennet gelation of GRS milk superior to that of TMR milk

• Higher gel-firming rate (dG'/dt) : P < 0.05

• higher gel firmness at 40 min, G'40: P < 0.05

30

60

90

120

150

116 136 156 176 196 216

Ge

l s

tre

ng

th a

t 4

0 m

in,

G' 4

0 (

Pa)

Days in lactation, DIL

Rennet

addition

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Rennet

Gelation:

Prerequisite

in cheese

making

• Cheese yield from GRS milk or GRC milk was significantly higher than that of TMR

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Effect of feeding system: cheese manufacture

GRS TMR GRC

Mid Lactation

Item GRS GRC TMR

Fat recovery (%) 73.0a

75.1a

72.8a

Protein recovery (%) 76.9a

75.8a

76.9a

Actual yield, Ya (kg/100 kg milk) 9.3b

9.7a

8.7c

Late Lactation

GRS GRC TMR

71.8a

72.2a

72.9a

75.6a

75.8a

77.1a

11.5a

11.0a

10.1b

Late Lactation

GRS GRC TMR

71.8a

72.2a

72.9a

75.6a

75.8a

77.1a

11.5a

11.0a

10.1b

Mid Lactation

Item GRS GRC TMR

Fat recovery (%) 73.0a

75.1a

72.8a

Protein recovery (%) 76.9a

75.8a

76.9a

Actual yield, Ya (kg/100 kg milk) 9.3b

9.7a

8.7c

• no effect on cheese composition or recoveries of fat and protein from milk to

cheese, or characteristics over ripening, proteolysis, water binding capacity,

firmness, cohesiveness, chewiness,…

• Cheese from GRS milk or GRC milk significantly ‘yellower’ than cheese from

(GRS and GRC cheeses: higher b* colour coordinate).

• In mid-lactation, cheese from GRS milk had highest mean flow and loss tangent

over storage time. This effect was not observed in late lactation

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Milk from cows grazed outdoors on pasture differed from milk from cows

offered TMR indoors in several respects

Compared to TMR milk, pasture-based milk was characterized by

high concentrations of protein, casein, Ca, P

lower content of Se, Cu or Zn

stronger rennet gelation

higher Mozzarella cheese yield

‘yellower’ cheese

The type of pasture affected the extent of difference between pasture- and TMR-

based feeding systems

Conclusion

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Thank You

Prof. Tim Guinee

Dr. Mark A. Fenelon

Dr. Jennifer J. McManus

Dr. Deirdre Hennessey

Dr. Eva Lewis

Dr. Michael O’Donovan

Norann Galvin

Catherine Mullins

Jimmy Flynn

Anne Marie McAuliff

Sarah Cooney

Teagasc Farm Staff

Moorepark Technology Ltd. Staff

Acknowledgement