Table 9 Monthly volatile fatty acid (VFA) analysis of manure

Acetic

48.3 bc^* ± 2.2

50.7 ab ± 0.7

46.3 c ± 1.6

51.1 ab ± 1.6

51.4 a ± 1.5

Propionic

18.5 c ± 1.4

21.0 b ± 1.6

24.4 a ± 1.4

22.0 b ± 0.7

21.1 b ± 1.0

Isobutyric

2.0 a ± 0.1

1.6 ab ± 0.1

1.2 bc ± 0.3

1.0 c ± 0.2

1.0 c ± 0.4

Butyric

23.6 a ± 1.5

22.6 a ± 1.2

23.2 a ± 0.9

22.0 a ± 1.2

22.9 a ±1.1

Isovaleric

4.1 a ± 0.6

1.5 b ± 0.1

1.2 b ± 0.2

1.0 b ± 0.1

1.0 b ± 0.3

Valeric

3.5 a ± 1.4

2.6 a ± 0.9

3.7 a ± 0.6

2.9 a ± 0.2

2.6 a ± 0.8

TVFA (mM)

113.7 b ± 10.6

156.1 a ± 11.8

149.2 a ± 18.1

114.5 b ± 9.1

122.5 b ± 13.7