the level and digestibility of amino acids and P in the various diets.Differences in the amount of minerals excreted with manure between farms can be attributed to various animal and feed factors. This extremely low level of efficiency and between farm variability leaves room for decreasing mineral excretion by improving the efficiency of retention in the pig. However, since grower-finisher pigs produce the majority of the manure on a typical farrow-to-finish operation, typical values for these operations would be similar to the values shown for grower-finisher pigs. Starter pigs are slightly more efficient than sows. Overall, approximately two-thirds of N and P intake is excreted in manure (Table 1). As long as minimum requirement levels of Cu and Zn are maintained, the excretion of these minerals in pig manure is not a concern the focus then switches to N and P excretion. In some countries, like the Netherlands, growth-promoting levels of Cu and Zn are no longer allowed in finisher pig diets due to the impact on the environment. In Canada, the federal Feeds Act limits the maximum level of Cu and Zn in the diet to 125 ppm and 500 ppm respectively, but in the U.S. These minerals act as growth promotants when included at levels much higher than minimum requirements. 5-25 ppm Cu and 50-125 ppm Zn for the various classes of swine). In general, Cu and Zn in pig diets are much higher than the minimum requirements for normal performance ( i.e. The most promising and practical of these strategies focus on two main principles - minimizing input and maximizing the efficiency of utilization. Most of these strategies are quite simple and can significantly affect the bottom line. Excretion of nutrients in swine manure can be substantially reduced by a number of strategies, depending on individual farm situations. Nitrogen and P also represent two of the most expensive nutrients in a swine ration. Potassium ( K) should also be considered as it affects the fertilizing value of manure. There are a number of options available to pork producers interested in reducing nutrient output in manure.
0 kommentar(er)
