Table 6.

Dietary energy partitioning of sows fed Control (CON; 187.4 g/kg crude protein), Optimal (OPT; 137.8 g/kg crude protein) or Optimal + Leucine (OPTLEU; 142.5 g/kg) diets between day 4 and 8 of lactation (early lactation) and between day 14 and 18 of lactation (peak lactation)¹

Item	Diet			SEM2	P-value
	CON	OPT	OPTLEU		OPT vs. CON	OPT LEU vs. CON	OPTLEU vs. OPT
Early lactation (day 4 to 8)
Number of sows	12	11	11
Feed intake, kg/d	4.9	4.9	4.6	0.10	0.899	0.102	0.135
Gross energy (GE), MJ/kg
Analyzed	17.24	17.10	17.33	–	–	–	–
Calculated	17.22	17.58	17.57
Digestible energy (DE), MJ/kg
Analyzed	15.22	14.90	14.77	0.10	0.062	0.006	0.571
Calculated	15.03	14.70	14.71
Metabolizable energy (ME), MJ/kg
Analyzed	14.84	14.64	14.52	0.20	0.766	0.507	0.904
Calculated	14.44	14.26	14.26
Corrected net energy (NEc), MJ/kg3	11.56	11.36	12.63	0.69	0.977	0.511	0.405
NElactation4	7.65	7.28	8.57	0.71	0.928	0.625	0.417
NEmaintenance5	3.91	4.07	4.16	0.15	0.536	0.233	0.822
Calculated	10.80	10.80	10.80
Peak lactation (day 14 to 18)
No. of sows	11	11	11
Feed intake, kg/d	6.8	6.7	6.3	0.1	0.865	0.034	0.049
Gross energy (GE), MJ/kg
Analyzed	17.24	17.10	17.33	–	–	–	–
Calculated	17.22	17.58	17.57
Digestible energy (DE), MJ/kg
Analyzed	15.22	14.90	14.77	0.10	0.062	0.006	0.571
Calculated	15.03	14.70	14.71
Metabolizable energy (ME), MJ/kg
Analyzed	14.81	14.67	14.45	0.20	0.887	0.427	0.709
Calculated	14.44	14.26	14.26
Corrected net energy (NEc), MJ/kg3	10.01*	12.16	11.25	0.69	0.087	0.418	0.623
NElactation4	7.13	9.26*	8.13	0.71	0.105	0.584	0.506
NEmaintenance5	2.88*	2.93	3.14	0.15	0.952	0.221	0.349
Calculated	10.80	10.80	10.80

¹Data are least squares means; energy is presented as MJ/kg feed

²Maximum value of the standard error of the means

³ NE_c(MJ/kg feed ) = NE_milk(MJ/kg feed) + NE_maintenance(MJ/kg feed). NE was higher (P < 0.05) than calculated NE in OPTLEU diet during early lactation and tended to be higher (P = 0.057) in OPT diet during peak lactation

⁴ ${\mathrm{NE}}_{\text{lactation}}\left(\mathrm{MJ}/\mathrm{kg}\text{feed}\right)=\frac{\text{Milk energy output}\left(\mathrm{MJ}/\mathrm{d}\right)-\text{Milk energy from body}\left(\mathrm{MJ}/\mathrm{d}\right)}{\text{Daily feed intake}\left(\mathrm{kg}/\mathrm{d}\right)}$. NE_lactation was lower than (P < 0.01) calculated NE in each experimental diet during both early and peak lactation

⁵${\mathrm{N}\mathrm{E}}_{\mathrm{m}\mathrm{a}\mathrm{i}\mathrm{n}\mathrm{t}\mathrm{e}\mathrm{n}\mathrm{a}\mathrm{n}\mathrm{e}}\left(\mathrm{M}\mathrm{J}/\mathrm{k}\mathrm{g}\mathrm{f}\mathrm{e}\mathrm{e}\mathrm{d}\right)=\frac{0.310\times {\mathrm{B}\mathrm{W}}^{0.75}\left(\mathrm{M}\mathrm{J}/\mathrm{d}\right)}{\mathrm{D}\mathrm{a}\mathrm{i}\mathrm{l}\mathrm{y}\mathrm{f}\mathrm{e}\mathrm{e}\mathrm{d}\mathrm{i}\mathrm{n}\mathrm{t}\mathrm{a}\mathrm{k}\mathrm{e}\left(\mathrm{k}\mathrm{g}/\mathrm{d}\right)}$

^*Main effect of period (early and late) was significant (P < 0.05).