Table 2 Short chain fatty acid concentrations (mmol/L) (A) CH and (B) HF steers ranked low (LRFI) and high (HRFI) RFI offered common dietary phases of Irish pastoral-based beef production systems; high-concentrate, grass silage and zero-grazed grass and a second high-concentrate diet during finishing phase. P values are derived using a Wilcoxon rank sum test to assess the differences between treatments.
Dietary Phase | High concentrate 1 | Grass silage | Zero grazed grass | High concentrate 2 | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
HRFI | S.D | LRFI | S.D | P value | HRFI | S.D | LRFI | S.D | P value | HRFI | S.D | LRFI | S.D | P value | HRFI | S.D | LRFI | S.D | P value | |
(A) | ||||||||||||||||||||
Acetic | 65.8 | 7.5 | 59.8 | 5.5 | NS | 57.9 | 7.3 | 62.7 | 14.9 | NS | 58.0 | 6.6 | 58.1 | 6.1 | NS | 63.6 | 11.2 | 66.9 | 9.2 | NS |
Propionic | 33.4 | 4.8 | 27.0 | 5.3 | < 0.05 | 13.0 | 3.4 | 15.0 | 4.6 | NS | 10.8 | 1.7 | 9.8 | 1.3 | NS | 22.2 | 4.8 | 24.1 | 5.6 | NS |
Isobutyric | 0.8 | 0.2 | 1.0 | 0.4 | NS | 1.2 | 0.3 | 1.4 | 0.3 | NS | 1.8 | 0.3 | 1.8 | 0.2 | NS | 0.9 | 0.4 | 1.1 | 0.5 | NS |
Butyric | 7.9 | 1.4 | 7.5 | 1.7 | NS | 10.9 | 3.0 | 11.4 | 2.8 | NS | 9.8 | 2.3 | 7.9 | 1.3 | < 0.01 | 12.1 | 4.2 | 12.7 | 3.0 | NS |
Isovaleric | 0.9 | 0.3 | 1.3 | 0.6 | NS | 1.9 | 0.5 | 1.7 | 0.2 | NS | 1.8 | 0.5 | 1.8 | 0.3 | NS | 1.5 | 0.7 | 2.6 | 1.4 | < 0.1 |
Valeric | 2.6 | 0.6 | 2.3 | 0.5 | NS | 1.7 | 0.4 | 1.4 | 0.1 | NS | 1.1 | 0.2 | 0.9 | 0.1 | NS | 2.9 | 1.0 | 2.7 | 0.6 | NS |
A:P ratio | 2.0 | 0.2 | 2.3 | 0.6 | NS | 4.7 | 1.1 | 4.3 | 0.4 | NS | 5.4 | 0.5 | 5.9 | 0.6 | NS | 3.0 | 0.8 | 3.0 | 1.1 | NS |
Total SCFA | 111.4 | 12.1 | 98.8 | 7.6 | < 0.05 | 86.5 | 11.9 | 93.6 | 22.3 | NS | 83.3 | 10.0 | 80.4 | 8.1 | NS | 103.1 | 15.1 | 110.1 | 10.2 | NS |
(B) | ||||||||||||||||||||
Acetic | 59.0 | 5.6 | 67.9 | 8.3 | < 0.05 | 54.5 | 5.3 | 58.0 | 5.1 | NS | 53.7 | 4.5 | 63.1 | 10.2 | < 0.05 | 65.2 | 6.7 | 72.0 | 11.8 | NS |
Propionic | 33.6 | 7.2 | 36.9 | 5.3 | NS | 13.6 | 1.0 | 14.1 | 2.4 | NS | 9.7 | 0.7 | 12.1 | 2.2 | < 0.05 | 20.8 | 5.1 | 25.1 | 6.9 | NS |
Isobutyric | 0.8 | 0.2 | 0.9 | 0.3 | NS | 1.2 | 0.1 | 1.3 | 0.2 | NS | 1.6 | 0.2 | 2.0 | 0.2 | < 0.05 | 1.2 | 0.4 | 1.0 | 0.4 | NS |
butyric | 9.2 | 6.3 | 9.2 | 2.1 | NS | 9.1 | 1.3 | 10.1 | 2.8 | NS | 8.5 | 1.4 | 10.1 | 2.4 | < 0.1 | 12.9 | 3.7 | 13.1 | 5.1 | NS |
Iso valeric | 0.9 | 0.4 | 1.1 | 0.7 | NS | 1.5 | 0.3 | 1.6 | 0.4 | NS | 1.7 | 0.3 | 1.9 | 0.3 | NS | 2.4 | 0.9 | 1.9 | 0.4 | NS |
Valeric | 2.5 | 0.6 | 3.1 | 0.6 | NS | 1.5 | 0.3 | 1.5 | 0.3 | NS | 1.0 | 0.1 | 1.3 | 0.2 | < 0.01 | 2.4 | 0.6 | 2.9 | 1.1 | NS |
A:P ratio | 1.9 | 0.6 | 1.9 | 0.3 | NS | 4.0 | 0.3 | 4.2 | 0.5 | NS | 5.6 | 0.6 | 5.2 | 0.5 | < 0.05 | 3.3 | 0.7 | 3.1 | 1.1 | NS |
Total SCFA | 105.9 | 11.2 | 119.1 | 12.9 | < 0.05 | 81.4 | 6.4 | 86.6 | 9.5 | NS | 76.1 | 5.9 | 90.4 | 14.4 | < 0.05 | 104.9 | 10.4 | 116.0 | 16.4 | NS |
