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Table 2 Effect of treatments on milk composition and on the diurnal (day vs. night) variations in milk composition.

From: Acute heat stress brings down milk secretion in dairy cows by up-regulating the activity of the milk-borne negative feedback regulatory system

Treatments

Control (C)

SD

Cooling (D)

SD

Sun (E)

SD

Lactose Concentration (%)

Average

5.10a

0.11

5.05b

0.10

5.04b

0.13

Night

5.10a

0.09

5.05b

0.11

5.05b

0.12

Day

5.09a

0.11

5.04b

0.09

5.04b

0.12

Lactose Yield

Night, g h-1

91.81a

5.5

81.31b

5.4

70.61c

5.6

Day, g h-1

73.82a

4.9

70.62a

5.3

35.12b

5.9

Day/Night yield ratio

0.80a

0.09

0.87b

0.10

0.46c

0.08

Decrease in lactose yield, %

7.9a

1.5

18.1b

3.8

55.0c

5.5

Fat concentration (%)

Average

3.17a

0.08

3.25b

0.05

3.31c

0.09

Night

3.13a

0.07

3.05b

0.06

3.13c

0.07

Day

3.19a

0.05

3.35b

0.05

3.40c

0.09

Fat yield

Night, g h-1

56.31a

3.8

49.1b

3.5

43.81c

3.6

Day, g h-1

46.32a

3.7

48.6b

3.7

22.12c

5.1

Day/Night yield ratio

0.82a

0.07

0.99b

0.15

0.50c

0.12

Decrease in fat yield, %

7.8a

1.4

15.9b

1.1

49.5c

1.2

Protein Concentration (%)

Average

3.21a

0.07

3.31b

0.08

3.42c

0.07

Night

3.19a

0.08

3.17a

0.09

3.21b

0.07

Day

3.22a

0.06

3.38b

0.07

3.53c

0.08

Protein Yield

Night, g h-1

57.41a

3.9

51.01b

3.1

44.91c

4.5

Day, g h-1

46.72a

4.1

47.32b

3.5

22.92c

4.7

Day/Night yield ratio

0.81a

0.08

0.93b

0.15

51.0c

1.0

Decrease in protein yield, %

7.9a

1.5

15.8b

1.2

49.4c

1.8

  1. Values marked with different superscript numbers are significantly different within columns; values marked with different superscript letters are significantly different within rows.