Table 5.

Effects of xylooligosaccharides (XOS), exogenous enzyme (EXE) and their combinations on energy intake and output, and utilization efficiency in lactating Jersey cows

Item	CON1	XOS	EXE	XOS + EXE	P-value
Energy intake and output, MJ/d
GE intake	397.3 ± 4.25	405.3 ± 6.72	401.8 ± 8.41	395.0 ± 5.22	0.72
Fecal energy output2	116.5 ± 1.05a	112.6 ± 1.80b	114.9 ± 2.26a	115.3 ± 1.57a	0.03
Urinary energy output3	11.5 ± 1.15	11.2 ± 1.46	11.5 ± 1.01	11.4 ± 1.91	0.52
CH4-E output	22.4 ± 1.35a	20.2 ± 1.01c	21.0 ± 1.46b	20.9 ± 1.71b	< 0.01
DE intake4	280.4 ± 0.46b	293.7 ± 0.25a	287.1 ± 0.77a	278.6 ± 0.20b	< 0.01
ME intake5	246.9 ± 2.55c	262.9 ± 3.26a	254.4 ± 3.42b	250.4 ± 1.89b	< 0.01
Milk energy output	97.5 ± 5.77d	110.4 ± 9.46a	102.1 ± 8.52c	104.7 ± 7.69b	0.03
Energy utilization efficiency
DE intake/GE intake, %	70.6 ± 2.59c	72.6 ± 3.36a	71.5 ± 4.03b	70.3 ± 2.17b	< 0.01
CH4-E output/GE intake, %	5.61 ± 0.412a	5.01 ± 0.571c	5.22 ± 0.217b	5.25 ± 0.639b	< 0.01
Milk energy output/GE intake, %	24.6 ± 1.52c	27.2 ± 1.73a	25.4 ± 1.06b	26.5 ± 1.17b	< 0.01
kl6	0.614 ± 0.1170	0.629 ± 0.1461	0.613 ± 0.1352	0.620 ± 0.1191	0.47

¹CON Control (no feed additives), XOS 25 g/d per cow, EXO 15 g/d per cow, and XOS + EXE Combination of XOS and EXE. Data are given as mean ± standard error of means

²Fecal energy output is calculated based on GE intake and estimated GE digestibility according to Ramin and Huhtanen [28]

³Urinary energy output is calculated according to Guinguina et al. [30]

⁴DE Digestible energy. DE intake is calculated as GE intake − fecal energy output

⁵ME Metabolizable energy. ME intake is calculated as GE intake − fecal energy output − urinary energy output − CH₄-E output

⁶k_l = efficiency of ME use for lactation

^a–cMeans within a row with different superscripts are significantly different (P < 0.05)