Composição químico-bromatológica, avaliação sensorial e de estabilidade aeróbia de silagens de sorgo aditivadas com ureia e realocadas

Abstract

The objective was to analyze the effect of aerobic exposure time of relocated forage sorghum (Sorghum bicolor (L.) Moench) silages and addition of urea levels in sorghum silages with aerobic exposure, through chemical-bromatological analysis and aerobic stability. The experiments were conducted at the premises of Universidade Federal do Oeste do Pará, campus Santarém-PA. Chapter 1 - is a literature review with description of sorghum, silage reallocation, urea as an additive and aerobic exposure. Chapter 2 - "Effects of aerobic exposure of relocated forage sorghum (Sorghum bicolor (L.) Moench) silages". The entirely randomized design was used with 30 experimental bins, with 10 treatments (silage not reallocated, 0, 6, 12, 18, 24, 30, 36, 48 and 60 hours) and 3 repetitions. After sensory evaluation of the nutritional and health aspects of the silages, they were classified as "Good to Very Good". The relocation of sorghum silages promoted a significant effect (P<0.05) on the contents of mineral matter, organic matter, acid detergent fiber, neutral detergent fiber, ethereal extract, total digestible nutrients, and dry matter digestibility. The aerobic exposure times, did not promote greater silage stability over 60 hours. Chapter 3 - "Effect of the use of urea levels in sorghum silages submitted to aerobic exposure, on the chemical-bromatological composition and aerobic stability". The experimental design used was entirely randomized, in a 5 x 2 factorial scheme, composed of five levels of urea (0; 0.5; 1 .5; 2.5 and 3.5% based on dry matter) and two aerobic exposure times 0 and 72 hours. There were four repetitions per treatment, totaling 20 experimental bins. For data regarding gas losses, dry matter losses, and dry matter recovery, only the 0 hour time was used. After 100 days of storage the silos were opened, weighed, and had silage samples collected for analysis at 0 and 72 hours. There was an increasing effect (P<0.05) for crude protein at 0 h, with increased levels, reaching 7.5%. The addition of urea promoted effect (P<0.05) for dry matter, mineral matter in relation to the time of 72 hours of anaerobic exposure. There was a significant effect on the variables of ether extract, insoluble nitrogen compounds and insoluble protein, the addition of urea promoted changes in the times 0 and 72 hours. The addition of urea and aerobic exposure of up to 72 hours of the silages promoted changes in fermentation and aerobic stability remained stable until 84 hours.