Comparison of a grazing- with an indoor-system of lamb fattening in Greece

The objective of this work was to compare two different :Lamb fattening sys tems. Twenty weaned male crossbred (Karagouniko x Boutsiko) lambs were divi ded into two equal groups (29 kg average body weight). Lambs of group A wer e kept exclusively on pasture for fattening, while lambs of group B were ke pt indoors in individual pens and fed 200 g of hay/lamb/day and concentrate s ad libitum. Food intake and growth rate were recorded regularly and food conversion ratio was determined in both groups. Herbage growth (by HFRO swa rd stick), herbage yield (by cages) and herbage intake (by n-alkanes) were also determined. All lambs were slaughtered after 60 days and carcass chara cteristics were determined. The average DMI was 2.15 and 1.60 kg/lamb/day, and the average BW gain 200 and 246 g/day for groups A and B, respectively. Food conversion ratio was in favor of lambs of group B (10.75 vs. 6.52 kg DM/kg BW gain and 1.80 vs. 1.09 kg of dietary CP/kg BW gain), but feeding c osts (2.2 vs. 3.35 USD/kg carcass) and labor costs were in favor of lambs o f group A. The carcass weight of lambs kept on pasture was lower (P < 0.05) by 2.2 kg, but omental (P < 0.05) and perinephric (P < 0.001) fat were sig nificantly heavier in animals of group B. It was concluded that the system of fattening lambs on pasture can allow for a higher margin to the farmer b ecause of the lower inputs and the products of higher value, compared to th e indoors fattening system. Moreover, this grazing system, operating under conditions of pronounced traditional character, can be physically, biologic ally and economically sustainable. (C) 1999 Elsevier Science B.V. All right s reserved.