Table 5.

Effects of cattle breed, Holstein or Angus, and basal diet, grain or forage, on ruminal VFA

		Grain1		Forage1			P-value2
Item	Time after feeding, h	Angus	Holstein	Angus	Holstein	SEM	Diet	Breed	Diet × Breed
Animals,n		5	6	6	6	—	—	—	—
Acetate, mM						4.1	0.05	0.25	0.47
	0	32.3	33.5	44.5	45.7		0.06
	3	44.6	44.6	44.5	46.7		0.04
	6	51.3	56.7	49.6	48.0		0.03
Propionate, mM						2.8	<0.01	0.55	0.20
	0	11.7	13.6	12.5	12.7		0.12
	3	19.6	19.9	14.4	13.8		0.09
	6	25.3	26.7	17.8	16.7		0.05
Butyrate, mM						1.2	<0.01	0.92	0.13
	0	7.8	8.1	5.9	6.7
	3	9.6	8.3	6.3	6.8
	6	9.8	9.6	7.6	7.7
Total VFA, mM						12.1	<0.01	0.51	0.62
	0	64.0	61.3	70.4	71.9		0.11
	3	73.9	79.1	72.0	74.3		0.10
	6	91.0	100.6	81.3	78.0		0.08
A:P3						0.3	<0.01	0.84	0.35
	0	2.9	2.7	3.6	3.7
	3	2.4	2.4	3.1	3.4
	6	2.2	2.3	2.9	2.9

¹Grain = diet contained 71% cracked corn, 20% grass hay, 7% soybean meal, and 2% mineral and vitamin supplement; Forage = diet contained 9.25% cracked corn, 80% grass hay, 8.75% soybean meal, and 2% mineral and vitamin supplement.

²There were no Diet × Breed × Hour interactions (P ≥ 0.12) nor Breed × Hour interactions (P ≥ 0.39); there was a Diet × Hour interaction (P ≤ 0.01) on acetate, propionate and total VFA, but not for butyrate and A:P ratio (P ≥ 0.58); there was an effect of Hour (P < 0.01) for all VFA measured.

³acetate:proprionate.