Table 4.

Volatile fatty acid (VFA) at 4, 24, and 48 h after incubation of concentrate mixtures with different CP level

Items	CP levels in concentrate (%)				SEM	Contrastd
	10	13	16	19		L	Q
Total VFA (mM)
4	22.4	23.1	23.8	22.9	0.32	ns	ns
24	62.8	62.6	63.3	62.6	1.34	ns	ns
48	82.0	81.5	83.2	81.7	1.36	ns	ns
VFA (mM/100 mM)
Acetate
4	65.5	66.6	66.4	65.4	1.64	ns	ns
24	60.4	61.4	61.2	52.6	0.53	ns	ns
48	62.8	62.9	63.2	62.6	0.49	ns	ns
Propionate
4	22.4	22.1	21.7	22.7	1.70	ns	ns
24	25.3a	25.1	23.9	23.0	1.42	ns	ns
48	20.9	20.6	19.4	19.4	0.50	ns	ns
Butyrate
4	9.2	9.2	10.7	8.9	1.73	ns	ns
24	12.7	11.9	12.9	12.3	0.50	ns	ns
48	12.0	11.6	12.1	12.1	0.35	ns	ns
Acetate/propionate
4	3.0	3.1	3.1	2.9	0.17	ns	ns
24	2.4a	2.4ab	2.6bc	2.7c	0.05	**	ns
48	3.0	3.1	3.3	3.3	0.10	ns	ns

^a,b,cValues within a row with different superscript letters are significantly different (p<0.05).

^dL, linear; Q, quadratic; ns, non-significant.

^**p<0.01.