Table 3.
Effect of pasture type, season, and time on in vitro volatile fatty acids concentration.
| 4 h | 24 h | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Autumn | Spring | Autumn | Spring | p-Value | ||||||||||||
| Variable | LS | HS | LS | HS | LS | HS | LS | HS | SEM | P | S | P × S | T | T × P | T × S | T × P × S |
| VFA concentration (mM) | ||||||||||||||||
| Total VFA | 30.7 | 32.9 | 37.1 | 38.3 | 58.0 | 62.7 | 72.3 | 74.2 | 1.95 | † | *** | n.s. | *** | n.s. | * | n.s. |
| Acetate | 21.0 | 22.1 | 26.2 | 24.8 | 39.1 | 40.6 | 47.1 | 47.7 | 1.60 | n.s. | *** | n.s. | *** | n.s. | n.s. | n.s. |
| Propionate | 7.06 | 8.05 | 8.61 | 10.8 | 12.7 | 15.5 | 17.7 | 19.3 | 0.514 | *** | *** | n.s. | *** | n.s. | ** | n.s. |
| Butyrate | 1.54 | 1.60 | 1.41 | 1.87 | 4.21 | 4.85 | 5.07 | 5.88 | 0.185 | ** | ** | n.s. | *** | n.s. | ** | n.s. |
| BCVFA | 1.08 | 1.18 | 0.91 | 0.86 | 1.93 | 1.65 | 1.73 | 1.41 | 0.090 | ** | *** | n.s. | *** | n.s. | n.s. | n.s. |
| Acetate | 68.4 | 67.0 | 70.2 | 64.7 | 67.5 | 64.8 | 65.2 | 64.3 | 1.07 | *** | n.s. | n.s. | † | n.s. | n.s. | n.s. |
| Propionate | 23.0 | 24.5 | 23.4 | 28.1 | 21.9 | 24.8 | 24.4 | 25.9 | 0.58 | *** | *** | n.s. | n.s. | n.s. | n.s. | ** |
| Butyrate | 5.02 | 4.81 | 3.90 | 4.91 | 7.26 | 7.76 | 7.00 | 7.93 | 0.432 | n.s. | n.s. | n.s. | *** | n.s. | n.s. | n.s. |
| BCVFA | 3.52 | 3.68 | 2.48 | 2.30 | 3.33 | 2.65 | 2.40 | 1.90 | 0.319 | † | *** | n.s. | n.s. | n.s. | n.s. | n.s. |
| A:P | 3.00 | 2.74 | 3.05 | 2.30 | 3.08 | 2.61 | 2.67 | 2.48 | 0.121 | ** | * | n.s. | n.s. | n.s. | n.s. | † |
| (A + B):P | 3.19 | 2.93 | 3.21 | 2.48 | 3.41 | 2.92 | 2.96 | 2.78 | 0.112 | *** | * | n.s. | n.s. | n.s. | n.s. | * |
HS: high sugar pasture; LS: standard cultivar pasture; SEM: standard error of the mean; P: pasture type; S: season; P × S: interaction between pasture type and season; T: time of incubation; T × P: interaction between time and pasture type; T × S: interaction between time and season; T × P × S: interaction between time, pasture type and season; VFA: volatile fatty acids; BCVFA: isobutyrate + isovalerate + valerate; A:P: acetate: propionate ratio; †: p ≤ 0.1; p *: p ≤ 0.05; **: p ≤ 0.01; ***: p ≤ 0.001; n.s.: not significant.