Torta de crambe na alimentação de bovinos em pastejo

Abstract

The objective of this work by evaluating nutritional parameters such as total dry matter intake, ruminal and blood nitrogen balance in steers supplemented with crushed crambe to replace soybean meal, and to assess the quality of the forage Brachiaria brizantha Marandu, were used five steers castrated male fitted with rumen cannula, dewormed with an average weight of 526 kg. The animals were kept in individual paddocks B. brizantha Marandu in 5x5 Latin square design. The supplements were evaluated isonitrogenous (180 g / kg protein) and were provided in the amount of 8 g / kg body weight per day, soybean meal substituted in the ratios of 0, 2.5, 5, 10 and 15% crambe crushed. To evaluate the in situ supplements, they were packed in bags of non-woven fabric (TNT -100 g/m2) size of 5.0 x 5.0 and incubated in the rumen of animals in times of 48, 24 , 12, 6, 3 and 0 h. To evaluate ruminal parameters (pH, ruminal ammonia (NH3-N) and short-chain fatty acids), samples were collected rumen fluid before providing supplement and 2, 4, 6 and 8 hours after supplementation. The dry matter intake (DMI) was estimated by use of an external indicator (titanium dioxide), for ten days and an internal indicator (iADF), obtained after 144h incubation in situ. Stool samples were collected for five days at 6, 8, 10, 12, 14, and 16 to 18:00 to determine fecal flow. The urine collections were made in the form "spot", four hours after the supply of the supplement for determination of creatinine, total nitrogen, purine derivatives, and to estimate microbial protein synthesis and nitrogen balance. Blood samples were collected by jugular vein puncture and were used Vacutainer ® tubes with heparin. The resulting plasma levels were determined in plasma urea and creatinine by colorimetry using the commercial kit (Gold Analisa ®). The collection of forage consumed by animals (extrusive) was performed using rumen emptying the 15th experimental day, after fasting for 12 hours solid. Replacing up to 15% of soybean meal with crambe crushed supplement alters the chemical composition of the supplements, but does not influence the in vitro digestibility of dry matter. The concentrates had an average effective degradability of dry matter (DM) and crude protein (CP) degradability and low for neutral detergent fiber (NDF). The crambe crushed supplement consumption increases, however, this is consumed more slowly as it increases the concentration of tart; without changing the total dry matter intake and total tract digestibility of nutrients. Supplementation with increasing levels of crambe crushed had a direct effect between pH and ruminal ammonia concentration. Since the highest values of NH3-N were observed in the same time interval in which the pH was more acidic. The crambe crushed reduced the concentration of short chain fatty acids in the rumen fluid up to 6 hours after ingestion of the concentrate. The crambe crushed presented ruminal DM and CP for more than crambe meal and cake ground into sieve sieve of 1 mm and 3 had the highest degradability of CP and NDF. The crambe crushed increased plasma urea, but did not alter the consumption of nitrogen intake, urinary excretion of urea and creatinine, allantoin concentration, purine derivatives, purines absorbed, microbial nitrogen, microbial crude protein (PBmic) and efficiency microbial (Emic) animals. The inclusion of the crambe crushed altered urinary N excretion without altering the fecal N, providing a positive nitrogen balance.