Study the sweet sorgh urn silage comparing to corn silage on tIle performance of finishing calves

In accordance to the national sorghum project in Iran, this research was conducted to investigate the yield of forage and feeding value of sorghum silage in comparison to the corn silage. At first step, a variety of sweet sorghum (named sufra) was cultivated, in farm of research station of Golpaygan. Agronomic parameters recorded during the forage production and the forage harvested and ensiled when the seeds were at dough stage. At the second step, sorghum silage and corn silage were compared in the diet of fattening male calves for 120 days. In a completely randomized design, 32 yearling male calves with 229:!::1.2 Kg initial weight, were used to estimate their feeding performances with two types of silages (sorghum and corn), using four finishing diets. In the diets which, contained 40% silage (DM basis), corn silage was substituted with sorghum silage in amount of: 1) 0.00, 2) 33, 3) 66 and 4) 100 percent respectively. Regarding the agronomy parameters, sorghum seed requirement was much lower (4 vs. 30 Kg/hectare) than that of the corn. Irrigation period was also different among the two crops with three times less for sorghum. However, the amount of forage yield per hectare was relatively similar for both crops. During the 120 days of feeding trial, average daily gain were 1037, 1068, 1010 and 1157 g for the diets 1, 2, 3 and 4 respectively which were not significantly different. The average dry mater intake was 7.50, 7.56, 7.74 and 8.06 kg, respectively which, was not significantly different among the diets. Feed conversion ratio was 7.23, 7.07, 7.66 and 6.59, respectively and no significant difference was observed among the treatments. It can be concluded that feeding performance of the sorghum silage is similar to the corn silage with the advantages of agro my parameters including lower seedling and less irrigation. Key words: finishing calves, corn, sorghum, silage.