Browsing by Subject "nurmiheinäsäilörehu"

Agriculture contributes greenhouse gas emissions (GHG) to the environment. Agricultural emissions represent 12 % of total GHG emissions in Finland. Nitrous oxide (N2O) has atmospheric lifetime of 110 years and its global warming potential is higher than that of carbon dioxide. Ammonia (NH3) emitted from animal manure is a major air pollutant contributing the formation of aerosols. Nitrate (NO3-) leaching to ground and surface waters together with phosphorus (P) could cause eutrophication. It is important to decrease these emissions because global emissions from agriculture continues to increase every year. The relationship between nitrogen intake and nitrogen excretion was investigated using data from 21 peer-reviewed publications. The objective of this research was to evaluate how dietary proportion of legume silages affect the partitioning of nitrogen excretion between urine, feces and milk in dairy cattle. Effects of legume silage proportion on dry matter intake (DMI), crude protein level, milk yield, energy corrected milk yield (ECM) and milk components were also investigated. The statistical analysis was conducted using regression analysis with linear and quadratic mixed models. Increased legume content in the diet increased nitrogen intake. Replacement of grass silage with clover silage increased the amount of nitrogen excreted in urine and feces, and increased the proportion of nitrogen excreted in urine. At the same time the proportion nitrogen excreted in milk decreased. Clover increased milk yield but milk fat concentration decreased. Replacement of maize silage with clover silage increased nitrogen excretion in feces. The proportion of nitrogen excreted in milk decreased. Urine N excretion (g/d or %) was not affected by the level of clover in the diet. Quadratic model showed that increasing the proportion of clover it the diet decreased milk and ECM yields curvilinearly. When maize silage was replaced with alfalfa silage milk and ECM yields increased curvilinearly to the point where alfalfa proportion reached 30 % of the dietary dry matter. Alfalfa also increased fecal N excretion but nitrogen excretion in urine and milk decreased. According to the results replacement of grass or maize silage with legume silage decrease nitrogen efficiency. This is evidenced by the low efficiency of converting dietary nitrogen into milk nitrogen, with a concomitant increase in urine or fecal N.