A new feed additive composed of urea and soluble carbohydrate coated with wax for controlled release in ruminal fluid.

Urea is a compound widely used as a feed additive for ruminants; however, when used profusely, it can lead animals to intoxication. Another factor that affects the effectiveness of urea is the lack of synchronization between the nitrogen and the availability of carbohydrates, necessary for better development of the ruminal microbiota. In order to circumvent these problems and improve the efficiency in urea use, the present study developed two new nutritional additives (F16 and F17) with different carbohydrate sources. One of the products developed (F16) used sugarcane molasses as a carbohydrate source, while the other (F17) used cassava starch. In addition to the carbohydrate source, both products contained the same amounts of urea, sulfur, calcium carbonate and were coated with carnauba wax. The supplements developed and two other commercial products based on extruded urea (UE) and polymer-coated urea (UP) were tested for solubility and cumulative gas production. The wax used in the coating process of the developed products (F16 and F17) proved to be efficient in reducing the solubility of the ingredients used. During chemical composition analysis it was verified that both supplements developed contained protein equivalent above 150% of crude protein. The cumulative gas production showed a higher production related to the product F17 (p < 0.05). Through thermogravimetric analysis, it was found the chemical integrity of the ingredients that make up the supplements developed. Therefore, is possible to reduce the solubility of urea using carnauba wax as a coating material. The formula with cassava starch associated with urea (F17) had a better synchronization during the degradation of its ingredients.

Calorimetry, physicochemical characteristics and nitrogen release from extruded urea.

Our hypothesis was that extrusion of urea associated with corn may reduce N solubilization and increase the nutritional quality of this food for ruminants. We aimed to physically and chemically characterize a corn and urea mixture before and after the extrusion process. It was evaluated morphological differences by scanning electron microscopy, nitrogen solubilization, and compound mass loss by thermogravimetry. In scanning electron microscopy, extruded urea showed agglomerated and defined structures, with changes in the morphology of starch granules and urea crystals, differing from the arrangement of the corn and urea mixture. The extruded urea maintained a constant nitrogen release pattern for up to 360 min. In thermogravimetry, extruded urea presented a higher temperature to initiate mass loss, that is, the disappearance of the material with increasing temperature, but the mass loss was lower when compared to the first event of the corn and urea mixture. In conclusion the process of extrusion of urea with corn modifies the original structures of these ingredients and controls the release of nitrogen from the urea, maintaining in its formation an energy source optimizing the use of nitrogen by ruminal bacteria, because the more synchronized the release of starch (energy) and nitrogen, the better the use by ruminal microorganisms.

Biofuel by-product can replace partially corn in supplement for Angus × Nellore heifers: productive performance and meat characteristics.

The aim of this is study was to test the hypothesis that corn can be partially replaced by crude glycerin (at a level of 50%) without affecting performance, ingestive behavior, ruminal parameters, meat composition, and fatty acids profile on the meat of heifers. Sixty-four intact plus four rumen cannulated Angus × Nellore heifers (359.0 ± 12.15 kg BW) were used. The cannulated animals received the same diets as the intact ones to determine the ruminal N-NH3 concentration, pH, and chewing activity weekly. All heifers were maintained in Brachiaria brizantha pasture and supplemented with a concentrate containing corn, soybean meal, urea, premixed minerals, and glycerin partially replacing corn. A completely randomized experimental design was used, with two treatments (corn ground or glycerin + corn ground). The inclusion of crude glycerin (high fat) decreased nutrients intake and ruminal N-NH3 concentration in the rumen but increased lipid intake. Inclusion of glycerin had no effect (P > 0.05) on ruminal pH, daily gain, performance, time spent eating, rumination, idling, or water intake. The moisture, ash, and protein contents of meat were not affected (P > 0.05) by crude glycerin intake. Crude glycerin increased saturated fatty acids (C14:0, C16:0, and C18:0) and decreased unsaturated fatty acids (C18:2n6c and C20:1) in meat. Despite the reduction in nutrient intake, we recommend crude glycerin to replace corn in concentrate because glycerin did not impair the performance, meat composition, and ruminal pH. Therefore, crude glycerin is a by-product that can partially replace corn in diets efficiently.