Table 2.

Effects of forage to concentrate ratio and dietary sunflower oil supplement on intake, and apparent ruminal and total tract nutrient digestibility in lactating dairy cows

	Treatment1					P-value3
Item, unit	L	LSO	H	HSO	SEM2	FC	SO	FC×SO
Intake, kg/d4
DM	19.0	18.6	23.3	20.7	0.78	0.004	0.088	0.18
OM	17.3	16.9	21.6	19.2	0.72	0.003	0.090	0.18
CP	2.90	2.82	3.49	3.10	0.122	0.009	0.088	0.22
NDF	7.95	7.66	6.73	5.89	0.257	0.001	0.050	0.29
pdNDF5	6.37	6.14	5.32	4.66	0.201	0.001	0.051	0.30
WSC6	0.32	0.28	0.53	0.46	0.018	0.010	0.040	0.37
Starch	2.57	1.94	7.18	5.83	0.167	0.001	0.001	0.042
Apparent ruminal digestibility, %
OM	39.6	37.0	43.4	42.3	1.54	0.005	0.14	0.59
CP	–13.8	–10.7	–16.4	–6.6	2.77	0.78	0.049	0.24
NDF	50.6	48.7	39.3	30.2	1.64	< 0.001	0.016	0.069
pdNDF	64.2	61.7	50.3	38.7	1.98	< 0.001	0.012	0.059
Starch	85.6	80.3	90.9	89.5	3.63	0.038	0.24	0.47
Apparent total tract digestibility, %
OM	70.9	71.0	75.7	72.2	0.384	< 0.001	0.003	0.002
CP	67.5	69.2	68.9	69.7	1.00	0.38	0.26	0.72
NDF	57.8	59.3	50.9	44.5	1.43	< 0.001	0.12	0.026
pdNDF	70.2	69.6	57.2	48.6	1.53	< 0.001	0.009	0.016
Starch	98.8	98.4	99.2	98.9	0.21	0.059	0.17	0.91
GE	66.9	68.3	73.2	69.9	1.10	0.007	0.36	0.053
Ruminal proportional digestibility, %
OM	55.9	52.6	57.4	58.6	2.16	0.028	0.44	0.13
NDF	87.6	82.3	76.9	67.2	2.45	0.002	0.022	0.40
pdNDF	91.4	88.6	87.7	78.8	2.56	0.039	0.062	0.28
Starch	86.6	81.6	92.0	90.5	2.45	0.041	0.25	0.51

¹Refers to diets based on low (0.35) or high (0.65) concentrate ratio supplemented with 0 (L and H, respectively) or 50 (LSO and HSO, respectively) g/kg of sunflower oil on a DM basis.

² n = 16 measurements; error degrees of freedom 6.

³FC, effect of forage to concentrate ratio in the diet; SO, effect of sunflower oil supplement; FC × SO, interaction of FC and SO.

⁴Intake data is reprinted from Ventto et al. (2017), The Nutrition Society, published by Cambridge University Press.

⁵pdNDF, potentially digestible NDF.

⁶WSC, water soluble carbohydrate.