Growth Performance, Blood Metabolites and Carcass Traits of Growing Lambs Raised on Berseem Silage Ration

Abstract

This study was conducted to determine growth performance, feed efficiency, feed utilization, blood metabolites and carcass characteristics of growing lambs raised on berseem silage treated with formic acid and concentrate feed mixture (CFM) ration. Berseem clover was chopped at 2-3 cm of length and wilted for 24 hr then ensiled with 0.5% formic acid treatment (BSF). After 60 days from ensiling process, fermentation characteristics of ensiled berseem were immediately examined. Twelve growing crossbreed lambs were randomly assigned to two groups. First group (6 lambs; 23.0±1.68 kg) was raised on starter concentrate feed mixture (CFM) plus berseem hay as a control ration. The second group (6 lambs; 22.5±1.68 kg) was raised on CFM plus BSF. Growth trial was continued for 6 months. Daily weight gain (DWG), relative growth rate (RGR), voluntary feed intake, feed conversion, economic efficiency, blood parameters were examined. Digestibility trials were conducted in the last month of the experiment to determine the utilization and feeding value of tested rations. At the end of experiment, three lambs of each group were slaughtered to determine carcass traits and anatomy of digestive tract. The main results proposed that lambs raised on BSF plus CFM had higher total gain, DWG and RGR (P<0.01) than that in control group especially in last two months. Feed conversion (kg DMI/kg gain) was better in lambs fed BSF ration than control (8.56 vs. 12.46 kg). The most profit and economic efficiency (1.38 LE and 97.5%, respectively) were in BSF group. The most of nutrient digestibility, nutritive value and quality index were higher (P<0.05) in BSF ration compared with control ration. Rumen parameters values were higher (P<0.05) in animals fed BSF rationcompared with control ration. Plasma glucose concentration did not differ significantly between two groups, but differed significantly (P<0.01) with the advancement of age. Whereas, total protein and globulin were (P<0.05) significantly lower in lambs fed BSF ration than those fed control ration. The activity of AST and ALT was (P<0.05) greater in control group than those in BSF group. Hot carcass, longissimus dorsi weight and yield grade value were greater (P<0.05) in BSF than control. Most of anatomy traits of digestive tract did not differ significantly between two groups. It could be concluded that growing lambs raised on wilted BSF plus CFM had the highest growth performance, feed conversion, economic efficiency, quality index, feed utilization, normal health status and better carcass traits compared with traditional rising system based on berseem hay plus CFM ration.