Table 6. Metabolizable energy (ME; kcal/kg; means and standard deviation, SD), were determined in feline digestibility studies and compared to those calculated using predictive equations.

	All Cat Foods		Dry Cat Foods		Canned Cat Foods
	(n = 227 studies)		(n = 173 studies)		(n = 54 studies)
	Mean	SD	Mean	SD	Mean	SD
Measured ME	3369	1374	4107	410	1005	189
Calculated ME using modified Atwater factors a	3316	1288	4017	306	1069	153
Delta b	−53	224	−90	241	64	81
Absolute Delta c	173	151	201	160	83	61
Calculated ME using NRC predictive equations d	3308	1297	4010	343	1059	153
Delta b	−61	240	−96	261	54	88
Absolute Delta c	180	170	210	182	86	55
Calculated ME using new predictive equation e	3369	1372	4107	395	1004	195
Delta b	0	82	0	90	−1	42
Absolute Delta c	63	52	71	55	35	29

^aPredicted ME using equation with modified Atwater factors [4].

^bThe difference between measured and estimated ME.

^cThe absolute value of the difference between measured and estimated ME.

^dPredicted ME using NRC [2] equations.

^ePredicted ME using equation developed from the experimental animal feeding studies.