Intake, growth and carcass characteristics of young ostriches given concentrates with and without pasture
2002
Nitzan, R. | Barkai, D. | Nitsan, Z. | Landau, S.
Although ostriches are herbivores, their diets in commercial farming in Israel consist mainly of concentrates. The objective of this study was to evaluate an alternative for fattening ostriches aged 10 to 30 weeks, which combines pasture with concentrate feeding. Chicks were allotted to three treatments. Diet of group C40 consisted of concentrate only, provided at 40 g/kg body mass (m(b)). Groups CG20 and CG30 received concentrate at 20 and 30 g/kg m(b), respectively, and grazed 4 to 6 h/day on lush green alfalfa (Medicago sativa), sown barley (Hordeum vulgare), natural pasture or sulla (Hedysarum coronarium). During the last 10 weeks of experiment, groups CG20 and CG30 were merged into one group, managed as CG20 and grazed natural pasture, sulla, alfalfa, or vetch (Vicia sativa). Ostriches from group CG20 and CG30 consumed 390 (s.e. 30) g and 260 (s.e. 20) g DM per day at pasture, i.e. 0.46 and 0.28 of their total daily intake, respectively. Pasture intake for CG20 was higher (P < 0.05) than for CG30. Intake of pasture (both grazing treatments combined) was twice as much as on natural pasture or alfalfa as on barley. These results were consistent with the ostriches' preference for forbs rather than grasses in the natural pasture. The mean organic matter digestibility was 0.84 (s.e. 0.01), ostriches gained at 347 (s.e. 13) g/day, and the food conversion ratio was 3.05 (s.e. 0.16), with no effect of group. Also, grazing did not affect the dressing rate (0.47, s.e. 0.015) or the size and mass of the different parts of the gastro-intestinal tract, with the exception of the glandular and muscular stomachs, which were proportionately 0.4 (P < 0.05) heavier in grazing birds. Lower (P < 0.05) fat content (33.8 v. 26.5 g/kg) but not tenderness, of a selected muscle (fibularis longus) was found for grazing birds. This study suggests that, in young ostriches, grazing lush green pasture may reduce concentrate intake by proportionately 0.4, without altering growth performance or carcass yield and quality.
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