Replacement of urea by encapsulated nitrogen in confined steer diets

• Grant number: 07/03193-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2007
• End date: July 31, 2008
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Antonio Fernando Bergamaschine
• Grantee: Lucas Jado Chagas
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

The fast and high ruminal hydrolysis rate of the urea can not be synchronized with the degradation rate of source energy of the diet, causing lesser efficiency of use of the nutrients, with economic and ambient damages. Some technologies have been developed in the direction to diminish the hydrolysis speed of the urea, as it was of the amiréia, and more recently of optigen. The objectives of this work will be to evaluate the intake and the digestibilitty of the nutrients, as well as daily weight gain the alimentary efficiency of confined steers receiving diets containing optigen in replacement to the urea. Thirty six steers of the race guzerá with alive weight between 380 and 410 kg and age between 26 e 32 months will be used. The compositions of the concentrations that will compose the treatments will be the following: T1 - maize + cotton meal + urea; T2 - maize + urea; T3 - maize + 66% urea + 34% optigen; T4 - maize + 34% urea + 66% optigen. The forrage one will be sorghum silage. Before the beginning of the experiment a period of adaptation to the confinement of 20 days, when the animals will receive sorghum silage, 2 kg concentrated (50% maize + 50% cotton meal) and mixes mineral. After this period the animals will be weighed and distributed to the treatments in agreement its weights, forming blocks. The experiment will have duration of 99 days, having been 15 days of adaptation to the diets and three periods of 28 days of evaluations. The animals will be weighed at the beginning of the experiment and later to each 28 days. The diets will be balanced to allow to profit of 1,2 kg/day with expectation of consumption of dry matter of 2,4% PV, beyond 10% of leftovers, and synchronizing IN fermentável and PDg rúmen. The feeding will be offered to 8 and the 16 hours in equal parts. The offered amounts and the leftovers will be registered daily. The silage and the concentrates will be showed three times per week, and the leftovers of second a sixth fair. The fecal production will be esteem using it indigestível FDA as marker. The excrements will be collected individually in the floor of box the two times per day (7 and 16 h) during five days, between 42° and 46° day of the experiment. The data will be submitted the analysis of variance and the averages compared for the Tukey test with the level of 5% of significance.