The objective was to estimate DE and ME content in corn stover (CS) and CS treated (CST) with Ca(OH)₂ for swine. The Ca(OH)₂ was added to CS in the amount of 6.6% of the DM in CS, with enough water to raise moisture content in CST to 50% (wet basis). After 7 d, CST was sun dried and both CS and CST were pelleted (9 mm). Dietary treatments were a basal diet (97.28% corn), and the basal diet with 30% of either CS or CST added at the expense of corn. The experiment was a RCBD based on initial BW, and each treatment had 8 block replicates (barrows; 90 ± 0.7 kg BW). Feed was offered to provide 2.5 times the energy maintenance requirement. It was assumed that CST had 10% more energy than CS, based on preliminary data from an in vitro organic matter digestibility (Boisen and Fernandez, 1997). Pigs were placed in metabolic crates and allowed 7 d of adaptation, followed by 4 d of total collection of feces and urine. The DE and ME values in ingredients were calculated by the difference procedure. Data were analyzed using the PROC GLM procedure of SAS. Pairwise comparisons were used for treatment means separation. Measured DE and ME values in corn (Table 1) were 2% smaller or less than published values (NRC, 2012). Feed intake was not different between CS and CST. Chemical treatment of CS increased (P ≤ 0.06) its DE and ME by 43 and 34%, respectively (Table 1), perhaps because it increased (P < 0.05) digestibility of dietary NDF (17.7 vs. 29.2%; SEM = 3.22) and ADF (17.5 vs. 35.7%; SEM = 2.20). In conclusion, chemical treatment of CS with Ca(OH)₂ increases its energy value in swine. Table 1. Energy value (kcal/kg DM) of corn, corn stover (CS), and CS treated with Ca(OH)₂ (CST) in pigs (90 ± 0.7 kg BW)

Item	Corn	CS	CST	SEM	CS vs. CST, kcal (%)
DE	3,864a	914b	1,306c	106	392 (43%)
ME	3,758a	917b	1,229c	105	312 (34%)

^a–cWithin rows, means with different superscript differ (P ≤ 0.06)