Table 1.
Rumen volatile fatty acids from lactating Holstein, Jersey, Holstein-Jersey crossbreed dairy cows at 3, 93, 183, and 273 days in milk
| VFA (% total)a | Days in milk | ||||
|---|---|---|---|---|---|
| 3 | 93 | 183 | 273 | SE | |
| Acetate | 65.30 c | 66.71 b | 67.75 ab | 68.53 a | 0.51 |
| Propionate | 18.55 a | 18.01 a | 16.07 b | 14.71 c | 0.41 |
| Butyrate | 9.98 ab | 9.52 b | 10.22 a | 10.01 ab | 0.27 |
| Isobutyrate | 0.83 b | 0.86 b | 0.87 b | 1.06 a | 0.03 |
| Valerate | 0.93 ab | 0.99 a | 1.01 a | 0.82 b | 0.04 |
| Isovalerate | 0.84 a | 0.72 a | 0.70 a | 0.76 a | 0.05 |
| Lactate | 3.44 b | 3.29 b | 3.38 b | 4.12 a | 0.15 |
| A:Pb ratio | 3.59 c | 3.80 c | 4.26 b | 4.69 a | 0.12 |
| Total VFAc (mM) | 144.5 a | 112.8 b | 118.7 b | 105.2 b | 6.41 |
aMeans are based on Holstein (n = 7), Jersey (n = 8), and Holstein-Jersey crossbreed (n = 7)
Means within a row without a common letter differ (P < 0.05); b acetate:propionate; c volatile fatty acids