Abstract
Climate change and global warming continue to be topics of scientific debate and public interest. The increase in greenhouse gases (GHG) in the atmosphere has been touted as one of the main causes of climate change, since they increase the potential for global warming. In livestock, the most important greenhouse gases are CH4 and N2O, but may also occur CO2 emissions on small scales. Emissions occur through enteric fermentation and manure from organic ruminants. Nutritional techniques such as the use of ionophores, glycerol, tannins, saponins, essential oils (canola oil, garlic, flaxseed, sunflower, etc.), lipids, vaccines, polyclonal antibodies, pasture management techniques and breeding have been used as strategies to manipulate rumen fermentation and reduce GHG emissions. Although some dietary strategies have been proposed to reduce the production of methane from ruminants, few have shown a persistent decrease, primarily in in vivo assays. Given this context, this project aims to evaluate the use of different additives and dietary supplements in ruminant feed as a nutritional strategy aimed at mitigating CH4 via enteric fermentation, determined by ex-situ (micro-rumen) and SF6 tracer techniques measurement of methane. Besides CH4, other variables will be measured as SCFA, pH, NH3-N, relative energy loss (PER), ingestive behaviour, total and differential count of protozoa in the rumen contents. In addition to this experiment, we intend to evaluate the production of CH4, N2O and CO2 in the feces of animals through digesters already made for this purpose. Six experiments and six subexperimentos compose the present research project. With the first five experiments, the objective is to evaluate the use of different additives and dietary supplements in ruminant feed by ex-situ technique (micro-rumen). The experiment six aims at studying nutritional requirements, partition the energy consumed and quantify methane emissions from enteric by SF6 tracer gas technique in dairy heifers of Holstein, aiming at the establishment of norms and standards for maximum nutritional and feed efficiency environment. As with all other five experiments, in subexperiment six will be measured CH4, N2O and CO2 in the feces of animals through digesters. (AU)