Dry matter loss in sugarcane silage treated with chemical and microbiological additives / Perda de matÃria seca em silagem de cana â de â aÃÃcar tratada com aditivos quÃmicos e microbiolÃgicos




Sugarcane is a viable forage for feeding bovine, since it has a high potential for producing dry matter, of high energy content, per hectare. The concentrated harvesting of the sugarcane for ensilaging may be an alternative to the traditional feeding management of daily harvesting fresh forage. The ensilaging may facilitate the management of the herd, allows the use of the forage during the rainy season of the year, and maximize the efficiency of cultural practices, among other advantages. However, consequences of the alcoholic fermentation of the sugarcane are the high sucrose loss and the low aerobic stability of the unloaded silage. Experiment 1 evaluated the use of chemical and microbiological additives in sugarcane silage. Around 9 kg forage samples were ensiled in 20 l buckets. A 4x3 factorial arrangement of treatments was adopted. Chemical additives: Control, potassium sorbate (0.05% of fresh weight, FW), urea (1% of FW) and calcium hydroxide (1% of FW). Microbiological additives: Control, L. plantarum and L. buchneri (both at 1 x 106 cfu/g of FW). Each one of the twelve possible combinations of treatments was replicated six times in each day of silage opening: 7, 14, 28 and 77 after ensilaging. There was no treatment effect on the 126-hour heating of the unloaded silage (P>0.13). The inclusion of calcium hydroxide reduced the NDF content from 79.9% of DM to 69.2% (P<0.01). Both urea and calcium hydroxide increased silage pH, being the increase more accentuated on day 77 (P<0.01 for the interaction between chemical additive and day of opening). This increased pH was associated to the occurrence of 39% of silages with clostridial fermentation in the urea treatment and 56% in the calcium hydroxide treatment, only during day 77 of silo opening (P<0.01, Chi-Square). The association of sorbate with microbiological additives increased the DM content at 7 and 77 days of ensilaging, while the urea association with inoculum had a positive action only on day 77 (P=0.04 for the interaction among chemical additive, microbiological additive and day of opening). Experiment 2 evaluated the loss in nutrient mass, along 767 days of ensilaging, of nine 1.9 kg pure sugarcane samples. The NDF content increased from 47.0% of DM to 68.7%. Silage loss, proportionally to the original, was: 32.8% for toluene DM, 44.1% for oven DM, 18.3% for NDF and 67.0% for the non-NDF DM. Experiment 3 evaluated the loss of nutrient mass and the heating following unloading of sixty 7.9 kg sugarcane samples ensiled for 40 days. The three treatments were: Control, L. plantarum (1 x 106 cfu/g of FW) or L. buchneri (6.6 x 105 cfu/g of FW). The ensilaging increased the sugarcane NDF content from 47.5% of DM to 70.5%. On average, the losses in nutrient mass were: 23.9% for toluene DM, 34.0% for oven DM, 1.9% for NDF and 62.9% for the non-NDF DM. While L. plantarum reduced, L. buchneri increased the loss of 100oC DM loss (P<0.05), in spite of the small biological magnitude of the effect (1.6 percentage units). It was not detected a treatment effect on silage heating following unloading. The ensilaging of the sugarcane induced a significant increase in NDF content of the fresh forage and a high nutrient loss. The association between potassium sorbate and microbial inoculum improved the action of homo as well as heterofermentative microorganisms. However, the effect of microbial inoculants on DM loss and content was small. The use of urea was not promising. The use of calcium hydroxide in sugarcane ensiled for less than 28-day periods, may be a way to reduce the fiber content of the feed. The use of additives capable of increasing pH, during prolonged periods of ensilaging, may increase the risk of occurring clostridial fermentation of the sugarcane.


sugarcane nutriÃÃo animal cana-de-aÃÃcar silage dry matter zootecnia materia seca silagem animal nutrition

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