Effects of different levels of barely substitution by olive cake on Dalagh lamb fattening

At this study, the possibility of barely grain substitution with crude olive cake in Dalagh lamb fattening was investigated. 28 male Dalagh lambs with mean initial live weight of 30±1.1 kg were allocated into four groups with 7 lambs each in a completely randomized design. Lambs were fed four different rations for 93 days. The first group (control) was fed a commercial concentrate, but the second, third and fourth groups were fed a concentrate that barely grain was replaced by olive cake at 33, 66 and 100 per cent, respectively. Rations were similar in nutrient. At the end of experiment, five lambs from each treatment for the study of some carcass characteristics were slaughtered. The final live weight, dry matter intake, daily gain, feed conversion, hot and cold carcasses weight differed significantly between treatments (P<0.05). The results showed that the high level of olive cake inclusion (100 percent substitution) decreased (P<0.05) dry matter intake and also feed conversion and consequently resulted in low daily gain, final weight and carcass weight. The medium level of olive cake inclusion (33 and 66 percent) resulted in a significantly higher (P<0.05) feed conversion and daily gain compared to the control. There were no differences among groups in percentage of hot and cold carcasses, hand weight, fat-tail weight and fat-tail percentage. Feed cost per kg based on dry matter for diets 1 to 4 was 1010, 962, 905 and 859 Rials, respectively. In addition, feed cost per each kg carcass with considering daily gain and carcass performance for diets 1 to 4 was 20804, 15182, 15172 and 20840 Rials, respectively. The results of this study suggested the possibility of administration of up to 66 percent of olive cake to the concentrate for lamb fattening, considering the positive effects on the feed conversion, daily gain and carcass weight and also reducing production cost.