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Table 2 Feed intake, milk production and composition and carbon dioxide emission of lactating Holstein dairy cows (na = 111)

From: Characterization and mitigation option of greenhouse gas emissions from lactating Holstein dairy cows in East China

Itemsb

Mean

Minimum

Maximum

SDc

Animal description

 Age, months

51.7

36.3

89.9

12.7

 Parity number

2.8

2.0

5.0

1.0

 Days in milk, d

138

104

182

19

 Metabolic weight, kg

136.5

116.4

160.1

9.5

 Dry matter intake, kg/d

23.1

17.6

33.7

2.6

Milk production and composition

 Milk yield, kg/d

38.1

25.9

53.7

6.9

 Feed efficiency, kg/kg

1.65

0.62

2.32

0.29

 Milk fat yield, g/d

1414

545

2222

272

 Milk protein yield, g/d

1247

446

1991

236

 Total milk solids yield, g/d

4720

1811

6295

786

 FCM yield, kg/d

36.4

29.8

54.8

6.6

 ECM yield, kg/d

37.2

31

55.1

6.7

Greenhouse gas emissions

\( {\mathrm{CH}}_{4\left({\mathrm{CO}}_2-\mathrm{eq}\right)} \), g/d

8304

5392

11,190

1151

\( {\mathrm{CH}}_{4\left({\mathrm{CO}}_2-\mathrm{eq}\right)} \)/DMI, g/kg

359.4

227.1

492.6

48.3

\( {\mathrm{CH}}_{4\left({\mathrm{CO}}_2-\mathrm{eq}\right)} \)/MW, g/kg

61.1

41.1

86.6

9.3

\( {\mathrm{CH}}_{4\left({\mathrm{CO}}_2-\mathrm{eq}\right)} \)/ECM, g/kg

229.5

149.8

455.0

48.1

 Total CO2, g/d

19,201

14,412

24,145

2004

 Total CO2/DMI, g/kg

831.5

575.2

976.7

84.1

 Total CO2/MW, g/kg

141.3

101.1

183.5

17.3

 Total CO2/ECM, g/kg

531.1

343.3

1095.6

102.8

  1. an, number of observations in the data set
  2. bFeed efficiency, milk yield ÷ dry matter intake (kg/kg). FCM Fat-corrected milk (kg/d) = 0.4 × milk yield (kg/d) + 15 × fat yield (kg/d). ECM Energy-corrected milk (kg/d) = milk yield (kg/d) × [(38.3 × fat (%) × 10 + 24.2 × protein (%) × 10 + 16.54 × lactose (%) × 10 + 20.7) ÷ 3140]. \( {\mathrm{CH}}_{4\left({\mathrm{CO}}_2-\mathrm{eq}\right)} \), the CH4 emission in the experiment was expressed as CO2 equivalent, \( {\mathrm{CH}}_{4\left({\mathrm{CO}}_2-\mathrm{eq}\right)} \) (g/d) = CH4 emissions (g/d) × 25. DMI dry matter intake (kg/d). MW metabolic weight (kg). Total CO2, total CO2 production (g/d) = \( {\mathrm{CH}}_{4\left({\mathrm{CO}}_2-\mathrm{eq}\right)} \) (g/d) + CO2 production (g/d)
  3. cSD Standard deviation