Nutritional value of mixed silages of soybean (Glycine max (L.) Merrill) and sorghum (Sorghum bicolor)

• Grant number: 08/03170-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2008
• End date: May 31, 2009
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Antonio Fernando Bergamaschine
• Grantee: Marília Ribeiro de Paula
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

The feeding cost on cattle exploration may reach 70% of the cost production, where the protein sources are very expensive, because the soybean meal which is the reference, has its price governed by the international market and regulates the price of other protein sources. The production of a roughage rich in proteins such as soybean silage, can dispense the use of protein concentrate. The aim of this study is evaluate some of fermentation parameters (pH, N-NH3) and chemical composition of mixed silages, soybean and sorghum, so as consumption, digestibility and performance of steers Guzera. The silages will be constituted in the following proportions: T1 - 100% soybean; T2 - 66% soybean + 34% sorghum; T3 - 34% soybean + 66% sorghum; T4 - 100% sorghum, based on the green mass. The variety of soybean is MGBR - 46 (Conquest) and sorghum is a Volumax cultivar, and will be croped in stages R6/R7 of viscous/sticky seeds, respectively. It will be made four surface silos, approximately 8 tonnes each, as the treatments. During and after the construction of silages, it will toke samples for chemical analysis and others. It will be used 24 steers Guzera with 17±2 months of age and 236±30kg of live weight, arranged in blocks as its weights. There will be a period of 20 days for adaptation to confinement and silage. The silages will be provided 2 times a day (7 and 16 hours), allowing rests of up to 10%, and taking notes daily about amounts and rest of mass. The silage and the rests will be sampled three times a week. The trial period will be of 63 days (21x3) preceded by 20 days of adaptation. The animals will be weighed at the beginning and end of the adaptation period, and after on each 21 days. On the 7th week of the experiment, it will be collected samples of feces, directly from the floor for 5 days, at six thirty a.m. and three thirty p.m., where the samples are by animal. Samples of silage, rests and feces are incubated in vitro "by 144 hours and thereafter will be determined the FDA indigestible to estimate the production fecal and digestibility. The obtained data will be submitted to variance and regression analysis.