Effects of replacing barley with different processed corn on performance, carcass quality, rumen parameters and profitability of Afshar feedlot lambs

Barley as native cereal is the main source of carbohydrates in fattening sheep in Iran. However, since the starch in barley has higher degradation rate than corn starch, it may cause metabolic disorders such as acidosis and decrease growth performance. Furthermore, the feeding value of a cereal grain is a function of several factors: its nutrient content, different physical and chemical characteristics that influence on digestibility, palatability as it changes feed intake, and associative interactions with the digestive process. In this study, the effect of replacing barley with different processed corn on performance, dry matter digestibility, rumen metabolites and carcass characteristics in Afshari fattening lamb were investigated. On the other hand, change in ration composition has economic and financial effects in addition to the nutritional effect. Decision making about ration composition or changing it ignoring these financial and economic effects, could result in negative consequences. Different ration compositions could simultaneously have different cost and revenue effects and eventually different profitability consequences. So, this study has also tried to investigate all positive and negative economic consequences of replacement barley with different processed corn in fattening lambs.
Material and The protocol used in this study was approved by the Animal Ethical Committee at Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran with respect to animal experimentation and care of animals under study. The feeds were formulated according to NRC (1985) recommendations for fattening sheep with equal quantity of energy and protein as 7 treatments including 1) 40% Barley (control) , 2) 20% Grinding Corn, 3) 40% Grinding Corn, 4) 20% Steam Flaking Corn, 5) 40% Steam Flaking Corn, 6) 20% Pelleting Corn and 7) 40% Pelleting Corn (Table 1). Five Afshari ram lambs were allocated to each treatment. The animals kept in a separate pen individually for 84 days (May to July, 2015) in animal research farm of Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. Growth performance data were analyzed as a completely randomized design using the general linear model (GLM) procedure of SAS software (SAS 2003). The significant differences between treatment means were detected by Tukey-Kramer test at p Animals had a daily body weight gain from 167 to 225 gr/day and mean FCR about 8.46. There was no significant difference between dietary treatments for final body weight, daily weight gain, FCR and gross profit (P Replacing barley with processed corn in feed composition of fattening lambs could have some positive consequences. It could improve body gain, feed conversion ratio and dry matter intake that means improve of growth performance. But, its net effect on the profitability depends on the relative price of barley to corn. In this study, in spite of greater market price of corn than barley and then more feed costs, this replacing could improve profitability. Among the corn based rations, the 40% pelleting corn ration created better growth rate compared to the other processed corn.