Urea som kvävekälla till växande ungnöt
The purpose of this study was to examine whether urea could be an option as a nitrogen source for young cattle, the study was limited to risks related to feeding, growth and feed efficiency. Microbes in ruminants have the ability to convert nitrogen to protein, this has been highlighted by beef producers as they are in search of cheap protein feed resources. Urea can be a worthy source of nitrogen for growing young animals, because of its high nitrogen content and the low price. Studies have shown that the replacement of a portion of the total protein content by urea in diets with low content of crude protein, like corn silage, may improve animal growth and feed efficiency. Replacement of all the true protein with urea can result in reduced feed intake and microbial growth. It´s probably because urea only supply ammonia nitrogen and not the important bacterial growth factors such as amino acids, peptides and branched chain fatty acids that microbes require for efficient protein production. There are also risks related to the feeding of urea, ammonia poisoning and feed refusal may occur at irregular involvement in the feed, and too little carbohydrate relative to protein in the rations. The use of products, such as slow release urea, which release ammonia at a slower rate and more synchronized with the degradation of carbohydrates in the rumen can improve the overall efficiency of nitrogen but also reduce the toxicity risk of urea feeding.