Performance of indigenous and exotic×indigenous sheep breeds fed different diets in spring and the efficiency of feeding system in crop–livestock farming

Genetic variation in feed efficiency may have a significant impact on sheep production in integrated crop livestock
farming systems in dry areas, where the shortage and poor quality of feed is widespread. Thus, the present study
was carried out to investigate the effects of sheep genotype and feed source on liveweight gain, feed conversion
efficiency and dry matter (DM) intake in feedlot lambs finished on diets based on low-cost forages or a high-cost
concentrated feed as a means of assessing the efficiency of this feeding system. Early weaned lambs of the
purebred fat-tailed Akkaraman breed were compared with synthetic Anatolian Merino (0·80 German Mutton
Merino×0·20 Native Akkaraman) breed. The lambs were kept in individual pens for 8 weeks and fed four diets:
daily harvested forages of triticale (T), Hungarian vetch (HV), a triticale-Hungarian vetch mixture (T+HV), and a
concentrate-based feed (CF). Lamb liveweight gain (LWG) was monitored during the early (18 April–16 May) and
late (17 May–13 June) spring periods. Diet×period and diet×breed interactions were detected in LWG of the
lambs. Lambs from both genotypes on the concentrate-based diet had higher liveweight gains, DM intakes and
better feed conversion ratios compared with lambs finished on the forage-based diets. The LWG of lambs offered
triticale forage decreased from 177 g/head/day in the early spring to 95 g/head/day in the late spring period, as
plant maturity increased. Liveweight gains did not change for the other forage rations during the same period. The
LWG of Akkaraman lambs were similar for both the early (189 g/head/day) and the late (183 g/head/day) spring
periods, whereas Anatolian Merino lambs gained 41 g/head/day less LWand had 3·8 higher feed conversion rate
for the late spring period compared with the early spring period. The present study showed that fat-tailed
Akkaraman lambs were better able to utilize forages with low nutritive value compared to Anatolian Merino
lambs, and may be better suited to semi-arid areas, where crop and livestock are highly integrated in the farming
system.