The effects of substituting concentrate by chopped and fresh homeground mulberry forage were evaluated in an experiment with fattening lambs lasting 126 d from weaning. The basal forage diet was composed by Pennisetum purpureum, Panicum maximun ‘Likoni’ and sugarcane. Forty-eight entire Pelibuey lambs (initial BW 20.6 kg) were randomly allocated in 4 experimental groups according to treatments which consisted on the level of supplementing (or not) the basal diet with mulberry forage: M-1: mulberry at 1% of BW (DM basis); M-0.75: mulberry at 0.75% plus 0.1 kg/lamb/d of concentrate; M-0.50: mulberry at 0.50% plus 0.2 kg of concentrate; and M-0: supplementing basal diet with 0.3 kg of concentrate (Control). Average daily gain (ADG, g/d) was significantly affected (P < 0.01) by the supplementation regimen with M-1 lambs yielding the lowest ADG (100.2 g/d). No differences in ADG among the other groups were observed (124.7; 125.4 and 128.9 g/d for the treatments M-0.75, M-0.50 and M-0, respectively). Feed conversion was 11.6, 9.9, 10.3 and 9.7 kg DM/ kg of BW gain for M-1, M-0.75, M-0.50 and M-0 lambs, respectively. Differences in final BW at slaughtering and hot or cold carcass yields were coherent with those found in growth performance. Supplementing with mulberry forage at 0.75% of BW was the feeding alternative showing the best productive response. Results are shown in Table 1. Table 1. Performance data

Item	Diet				SEM
M-1	M-0.75	M-0.50	M-0
Initial BW, kg	20.5	20.7	20.7	20.7	0.38
Final BW, kg	29.6b	32.2a	32.3a	32.8a	0.57
BW change, kg	9.1b	11.5a	11.6a	12.1a	—
ADG, g/lamb/d	100.2b	124.7a	125.4a	128.9a	3.08
Total feed intake, g DM/lamb/d	835.8b	908.2a	953.7a	930.0a	7.0
Average feed intake, g DM/kg BW	33.4	34.3	36.0	34.8	—
Average feed intake, g DM/kg BW0.75	74.6	77.9	81.7	79.1	—
Feed conversion, kg DM/kg BW gain	11.6a	9.9c	10.28b	9.70c	—
Hot carcass weight, kg	11.5b	13.3ab	13.5a	13.7a	0.30
Cold carcass weight, kg	11.2b	13.0ab	13.2a	12.8ab	0.28
Gastrointestinal tract weight, kg	8.5	9.4	7.7	7.9	0.25
Offal’s weight, kg	0.8	1.0	1.0	0.9	0.03
Perirenal and mesenteric fat, kg	0.95	1.2	0.93	1.12	0.09
Hot carcass yield, %	40.2b	41.0ab	43.2a	43.4a	0.45
Cold carcass yield, %	39.3	40.2	42.2	40.8	0.57

^a,bValues with different superscripts in the same row differ at P < 0.05 (Tukey test).