Fattening performance of lambs of different Awassi genotypes, fed under cost-reducing diets and contrasting housing conditions

Abstract

High feed-cost constraints are currently threatening the livelihoods of farmers fattening lambs in developing Middle Eastern countries. Reduced-cost feeds and adequate management alternatives are needed for more efficient lamb-fattening systems. Therefore lamb fattening performances of different Awassi sheep genotypes, on different diets and fattening environments, were therefore evaluated. Two trials were conducted. The first trial was conducted on-farm in northern Syria to assess the fattening performance of Syrian Awassi, and Turkish x Syrian Awassi crossbred lambs, and the suitability of 2 cost-reducing feeding diets compared to the traditional spring fattening diet of grazing green barley with supplementation (C): intensive feeding based only on concentrate and barley straw (D1) and semi-intensive grazing on vetch (Vicia sativa) with minor supplementation using the same D1-mix (D2). Lambs of both genotypes did not significantly differ in weight gain in the 49-day fattening period. There were no significant differences in weight gains among C, D1 and D2 diets: 14.4, 15.3 and 15.9 kg/lamb, respectively. The 02 diet reduced feeding costs by 20% and promoted high growth, notwithstanding its beneficial soil effects. The second trial was conducted on-station at the International Center for Agricultural Research in the Dry Areas (ICARDA), Syria, to assess the fattening performance of lambs of the above 2 genotypes in addition to Turkish x (Turkish x Syrian) crossbred lambs, both in indoor and outdoor conditions. Paralleling the first trial, live weight gains of the 3 genotypes did not differ significantly. Fattening lambs under a more favorable and healthier outdoor environment using a simple shed, avoiding negative effects of lack of ventilation and high temperature, produced significantly more live weight gain (5.8 kg) per lamb than indoors. No differences in smell, taste, juiciness and tenderness were found among genotypes in the second trial, confirming no negative effects of using these diets in the first trial, reported elsewhere. There were no statistical differences in smell, taste, juiciness and tenderness, in the meat with the distinct diets or the fattening (indoor/outdoor) environments. Both trials showed that whereas no gains could be expected by using the Turkish genotype for fattening, vetch grazing and molasses are suitable options for reducing high feed costs and could be safely used by farmers without compromising meat quality. Raising animals in a more favorable and healthier environment outdoors under a simple shed can also translate into substantial revenue in large batches of fattened lambs with considerable benefit for fattening systems. (C) 2010 Elsevier B.V. All rights reserved.