Stalks treated or not treated with anhydrous ammonia, ammonium sulfite, urea were examined in a series of feeding experiments to determine the relative efficacy of these treatments to increase the nutritional value of barley straw. In the experiment. As shown in Figure 1, diets containing barley straw treated with ammonia and ammonium sulfite were more digestible than diets containing untreated straw (P < 0.05). In the experiment. 2. Heifers fed ammonia-treated straw had the highest average daily gain (ADG) and voluntary feed intake (VFI), followed by heifers fed urea-treated straw, followed by ammonium sulfite-treated straw . Heifers fed untreated straw had the lowest ADG and VFI (P < 0.05). Although ammonium sulfite treatment improved straw digestibility, the relatively low VFI resulted in lower ADG than animals fed other treated straw. The low PFD is due to the high sulfur content of the diet. Anhydrous ammonia and urea were found to be the most effective chemicals for enhancing the nutritional value of barley straw. Although ammonium sulfite is as effective as anhydrous ammonia in increasing straw digestibility, its use is not recommended because the application rates required for effective treatment can lead to decreased feed intake. Key words: urea, anhydrous ammonia, ammonium sulfite, straw, digestibility, cattle
We examined the relative effectiveness of anhydrous ammonia, ammonium sulfite, and urea treatments on the nutritional value of ruminant barley straw in two feeding experiments. In the first experiment, diets containing barley straw treated with ammonia and ammonium sulfite were more digestible than untreated straw diets (P < 0.05). In the second experiment, ADG and ammonium sulfite free feed intake (FAI) were highest in heifers consuming ammonia-treated straw. Then came straw treated with urea, and then straw treated with ammonium sulfate. Heifers fed untreated straw showed the lowest ADG and IAL (P < 0.05). Although the ammonium sulfate treatment improved straw digestibility, relatively low IAL resulted in lower ADG than the other two straw treatments. In explaining this low IAL, foods contain high levels of sulfur. Anhydrous ammonia and urea were found to be the most effective chemicals for enhancing the nutritional value of barley straw. Although ammonium sulfite was not as effective as anhydrous ammonia in improving straw digestibility, its use is not recommended due to the observed decrease in feed intake at the required application rates. Key words: urea, anhydrous ammonia, ammonium sulfite, straw, digestibility, cattle