Table 1.

Experimental substrates introduced to the vessels used for in vitro rumen fermentation^a.

Diet	Basal substrate		Protein supplement dosing			BCAA introduced with supplements
	Grass silage (mg DM)b	Compound feedc (mg DM)b	mg DMb	% of diet DM	% of diet CP	Val (mmol)b	Ile (mmol)b	Leu (mmol)b
Control	400	400	–	0.0	0.0	–		–
SBM Dose 1	400	400	13.5	1.7	5.0	0.003	0.002	0.004
SBM Dose 2	400	400	75.3	8.6	23	0.016	0.013	0.023
SBM Dose 3	400	400	290	27	53	0.062	0.052	0.088
WHEY Dose 1	400	400	8.22	1.0	5.0	0.004	0.004	0.006
WHEY Dose 2	400	400	45.7	5.4	23	0.023	0.022	0.036
WHEY Dose 3	400	400	176	18	53	0.088	0.085	0.139
YMP Dose 1	400	400	16.0	2.0	5.0	0.003	0.002	0.003
YMP Dose 2	400	400	89.0	10	23	0.017	0.012	0.019
YMP Dose 3	400	400	343	30	53	0.065	0.047	0.074

^aDM, dry matter; CP, crude protein; SBM, soybean meal; WHEY, whey protein; YMP, yeast-derived microbial protein; BCAA, branched-chain amino acids.

^bAmount introduced into 40-mL cultures.

^cCommercial compound feed Lypsykrossi for dairy cows (Suomen Rehu Ltd., Finland).