Although the ensiling process appears quite simple, many factors can affect what type of fermentation takes place in a silo (Figure 1). For example, the buffering content of the forage mass can have an effect on silage fermentation. Alfalfa has a high buffering capacity in comparison to corn. Thus, it takes more acid production to lower the pH in alfalfa than in corn silage, resulting in the former being more difficult to make. The dry matter content of the forage can also have major effects on the ensiling process via a number of different mechanisms. First, drier silages do not pack well and thus it is difficult to exclude all of the air from the forage mass. Second, as the dry matter content increases, growth of lactic acid bacteria is curtailed and the rate and extent of fermentation is reduced. (For example, acidification occurs at a slower rate and the amount of total acid produced is less).
Thirdly, clostridia tend to thrive in very wet silages and can result in excessive protein degradation, DM loss, and production of toxins. Where weather permits, wilting forage above 30-35% DM prior to ensiling can reduce the incidence of clostridia because these organisms are not very osmotolerant (they do not like dry conditions).
Delayed filling that results in excessive amounts of air trapped in the forage mass can have detrimental effects on the ensiling process. Another factor that can affect the process is the amount of water soluble carbo hydrates (WSC) present for good fermentation to take place. Hirsch and Kung (unpublished data, University of Delaware) showed that WSC dramatically decreased and DM losses increased when corn forage was not immediately packed into silos after chopping (Figure 2). Losses increased as delay was prolonged. The types and numbers of bacteria on the plant also have profound effects on silage fermentation. Natural populations of lactic acid bacteria (LAB) on plant material are often low in number and heterofermentative (produce end products other than lactic acid). In addition, if air is not removed from the silage mass, other types of fermentation can occur. Some important management practices that will help in making high quality silage are listed in Table 1.
Although the ensiling process appears quite simple, many factors can affect what type of fermentation takes place in a silo (Figure 1). For example, the buffering content of the forage mass can have an effect on silage fermentation. Alfalfa has a high buffering capacity in comparison to corn. Thus, it takes more acid production to lower the pH in alfalfa than in corn silage, resulting in the former being more difficult to make. The dry matter content of the forage can also have major effects on the ensiling process via a number of different mechanisms. First, drier silages do not pack well and thus it is difficult to exclude all of the air from the forage mass. Second, as the dry matter content increases, growth of lactic acid bacteria is curtailed and the rate and extent of fermentation is reduced. (For example, acidification occurs at a slower rate and the amount of total acid produced is less).Thirdly, clostridia tend to thrive in very wet silages and can result in excessive protein degradation, DM loss, and production of toxins. Where weather permits, wilting forage above 30-35% DM prior to ensiling can reduce the incidence of clostridia because these organisms are not very osmotolerant (they do not like dry conditions).Delayed filling that results in excessive amounts of air trapped in the forage mass can have detrimental effects on the ensiling process. Another factor that can affect the process is the amount of water soluble carbo hydrates (WSC) present for good fermentation to take place. Hirsch and Kung (unpublished data, University of Delaware) showed that WSC dramatically decreased and DM losses increased when corn forage was not immediately packed into silos after chopping (Figure 2). Losses increased as delay was prolonged. The types and numbers of bacteria on the plant also have profound effects on silage fermentation. Natural populations of lactic acid bacteria (LAB) on plant material are often low in number and heterofermentative (produce end products other than lactic acid). In addition, if air is not removed from the silage mass, other types of fermentation can occur. Some important management practices that will help in making high quality silage are listed in Table 1.
การแปล กรุณารอสักครู่..
