Effects of the dietary nonfiber carbohydrate content on lactation performance, rumen fermentation, and nitrogen utilization in mid-lactation dairy cows receiving corn stover

Table 6 Ruminal fermentation variables in dairy cows fed 3 experimental diets

Items^c	Treatment^d			SEM	P-value
Items^c	AH	L-NFC	H-NFC	SEM	P-value
pH	6.28	6.42	6.37	0.05	0.09
Ammonia nitrogen, mg/dL	21.4	23.7	21.1	0.85	0.06
Total VFA, mmol/L	120^a	111^ab	106^b	3.08	0.02
Molar proportion, mmol/100 mmol
Acetate	64.8	65.3	65.8	0.28	0.06
Propionate	20.7^a	19.7^b	19.2^b	0.32	0.02
Butyrate	10.4	10.8	10.6	0.23	0.43
Isobutyrate	0.96^b	1.03^a	1.07^a	0.03	0.01
Valerate	1.40	1.42	1.31	0.04	0.15
Isovalerate	1.72	1.75	1.95	0.07	0.08
Acetate: Propionate	3.15^b	3.32^ab	3.44^a	0.06	0.02

^a-bLeast squares means within a row with different superscripts differ significantly (P < 0.05)
^cThe results are from rumen fluid samples collected 3 h post-feeding. VFA = Volatile fatty acids
^dAH = Total mixed rations containing alfalfa hay; L-NFC = Total mixed rations containing corn stover with a low content of non-fiber carbohydrates; H-NFC = Total mixed rations containing corn stover formulated to have similar non-fiber carbohydrate concentrations as the AH diet

ISSN: 2049-1891