Effect of treating Tumbleweed with urea and molasses on chemical composition and digestibility of its silage

The optimum proportion of urea to molasses in order to enrich forage part of the ruminant ration has been assumed as an important enhancer of the livestock animal performance. This proportion could change depending on type or chemical composition of the forage part. Therefore, the purpose of the current study was to investigate whether digestibility and composition of the Tumbleweed (Gundelia tournefortii) forage could be affected by treating with different proportions of urea and molasses during ensiling process. The first experiment was designed as a 3×3 factorial experiment in completely randomized design with five replicates to study the chemical composition and in vitro digestibility of TF regarding to enriching them by different levels of urea (0, 4% and 6%) and molasses (0, 5 and 10%) for 45 days. In the second experiment, in vivo digestibility of selected ensiling treatments was measured. The results of the first experiment showed that NDF and ADF contents of silages decreased significantly due to enriching by "4% urea% molasses" and "6% urea% molasses", compared to control. Moreover, dry matter digestibility and digestible organic matter of the dry matter were higher significantly in the groups which treated by "4% urea 10% molasses" and"4% urea 5% molasses" compared to untreated control group. According to the result of second experiment, CP and NDF digestibilities were improved by enriching silages with "4% urea% molasses" in comparison with dry tumbleweed. It was concluded that the treatment of silages with 4% urea plus 5 or 10% of molasses would be the best ratio for the enrichment of tumbleweed silages.