[MUSIC] Hello and welcome back. We'll continue discussing the factors important for making high quality silage. Apart from plant my crops and the type of forage we are [INAUDIBLE], maturity at harvest, and forage [INAUDIBLE] or moisture at the [INAUDIBLE] are also very important for silage quality. The more mature the plant at the time of harvest the lower the digestibility and energetic value of the silage. Also more mature plants tend to have lower sugar content which may slow down silage fermentation and prolong the time to reach optimal pH. Dry matter of the forage in siling is perhaps the most important factor in silage making. The wetter the forage, the higher the fermentation rate, but also fermentation losses. Silage should not be made from forage that has 25% or less of dry matter. When dry matter is between 30 and 25% or lower, the use of silage preservatives such as organic acid is advisable. Forages with dry method in siling around 40% can be preserved well without any preservatives. The higher the dry matter, however, the more difficult packing the silage becomes, and losses may also increase. For most silages, the dry matter siling of around 32% to 40% will produce good results. Another critical factor in silage making is packing. It won't be an exaggeration to say that the first rule of silage making is pack, pack, and pack again. Packing is so important because most undesirable processes that may take place in silage require oxygen. Lactic acid bacteria, or the good bacteria in silage, on the other hand, hate oxygen. So by packing the silage as much as possible will get rid of the air which creates unfavorable conditions for harmful bacteria such as custrelia and favorable conditions for the lactic acid producing bacteria. The speed by which the silage is filled is also important. Ideally a silo should be filled within three to five days. In the real world the goal should be to fill a silo as soon as possible while continuously packing the material that is already in the silo. Having the right particle size of the forage entering the silo, is a precondition for successful packing. Recommendations for grass and alfalfa silages are to harvest at theoretical length of cut of three-eighths to half inch which is about 1 to 1.3 centimeters and for corn silage at half to three-quarters inch, which is 1.32 centimeters. The longer the cut and the dryer the forage, the more difficult packing will be to get the air out. Too short length of cut, however, is not going to provide the necessary effective fiber to the animal, which may result in, and increased milk fat test. Check the supplemental reading for this lecture for a formula of how to calculate the density of your silage. A good benchmark is 40 pounds per cubic feet which is about 640 kilograms per cubic meter. Another component of the siling process is silage preservatives. There is a long list of silage preservatives on the market including acids usually organic, for example, formic and benzoic acids. Enzymes typically intended to digest plant fiber thus providing additional sugars for fuel, silage fermentation, and microbial inoculants. The later categories most widely used and typically contains homolactic material designed to produce primarily lactic acid. Recently silage inoculants also contained bacteria called heteroactic that produce volatile fatty acids such as acetic and propionic which help preserve the silage phase when the silo is open. One important thing to remember about inoculants is that the viable microbial count specified on the back label is not always representing accurately the actual viable count that the inoculant will produce when applied to the silage. As a rule of thumb, inoculants should be supplying a minimum of 100,000 colony forming units. Which is a measure of the number of viable bacteria, of lactic acid bacteria per gram of wet forage. Another type of silage that deserves mentioning, is urea, or other non-protein nitrogen sources, such as anhydrous ammonium. These are added usually to corn silage, which has raw protein content, for two main reasons. First, to serve as a preservative because ammonia inhibits bacteria and second, to increase the silage protein content. Remember that the rumen microbes can utilize non-protein nitrogen to synthesize microbial protein. Recommendations are for around eight to ten pounds feed grad urea per ton of wet silage, which is four to five kilograms per metric ton. Even distribution of the urea is important, and the silage should not be too wet or too dry. Less that 30 or above 40% dry measure. Once the silage is in the silo and is packed well, it must be covered to prevent air penetration, spoilage, and nutrient losses. Some silage systems, such as tower silos, ag bags, or wrapped bale silage, are protected from the air. Bunkers or other type of open silos, however, must be covered, usually with plastic sheets. And then the plastic cover should be weighed down, usually with cut in half, old automobile tires, or bags filled with sand and gravel. Separate plastic sheets should overlap and be taped, particularly around the silo walls. If the silo is a bunker type or the base of the pile if it is a pile silage. The cover should be inspected for leakage and holes, particularly if in a windy place. Newer plastic material such as oxygen barrier fumes have much lower oxygen permeability than the regular polyethylene and can reduce significantly silage losses. To properly ferment, silage should be stored for at least 30 to 45 days before being fed. Silage fermentation may actually increase the energetic value of the original forage, particularly true with corn silage. However, feeding unfermented silage could cause decreased milk production. Once the silo is open air and oxygen acts as the surface as the silage and undesirable microorganisms such as yeast and molds start to grow. Therefore managing the open silage surface is also very important in order to insure the high quality of the silage the cow gets. The key is to reduce exposure to air as much as possible. This can be achieved by using various silage cutters, or block. Or simply carefully moving continuous surface layer of the silage. As a rule of thumb, a minimum of 6 inch, or about 15 cm silage should be removed from the silo surface everyday. And more should be removed in the summer. Remember that any manipulation that leaves a pile of loose silage will lead to high nutrient losses and poor quality silage. Finally, when we start feeding new silage, we should always analyze it for chemical composition to be able to more accurately predict it's notative value and properly include it in the ration. What are the most important silage quality analysis we should pay attention to? The first one is silage pH. It should be below four for corn silage and below 4.5 to five for legume silages. Another one is lactic acid. For corn and legume silages, the target is around 4 to 7% of the silage dry matter. Butyric acid is an indication of clostridia fermentation and should be very low, below 0.1%. Or completely absent from good quality silage. For legume silages, which usually undergo extensive which is a breakdown of the plant proteins, ammonia nitrogen should be less than 10% of the total silage nitrogen. Here's an example of a lab report for chemical analysis of alfalfa. The first thing to note is that the analysis was done by NIR or near-infrared reflectance spectroscopy. NIR analyses are considerably less expensive than wet chemistry, and commercial laboratories have accumulated large spectral databases for common feeds which is an important prerequisite for accuracy of this analysis. Following the sample identification data, the first line in this report shows dry matter content of the haylage, which is 46.2%. Consequent analyses are usually interpreted on a dry matter basis. Protein bases, as in the case with protein fractions. This particular lab here structured the report into several categories, including proteins, fiber, carbohydrates, minerals, qualitative analysis, and energy and index calculations. Some important analysis in the proteins category include crude proteins, soluble protein, ammonia NAEF and NDF protein both being proteins bound to fiber. Rumen Degraded Protein is also an important indicator for legume forages and is 83% of the total protein in this stage. In the fiber category we find a couple different values for neutral [INAUDIBLE] fiber. The a in front of NDF means that the sample was treated with amalyse enzyme to remove starch. And the OM after NDF means that NDF is expressed on an organic meta basis. In the carbohydrates category, it is worth noting the high soluble fiber value, which can be calculated at around 38% of the neutral detergent fiber. In this sample and represents pectins and other soluble polysaccharides. Concentration of total ash and important minerals are listed under the minerals category. Note the high calcium and potassium content of this which is typical for legume forages. pH and silage acids are listed on the qualitative analysis. Silage pH is below five, which is an indication of good [INAUDIBLE] fermentation. And lactic acid is above 4% of the dry matter, which is within the goal of 4 to 7% for legume forages. Being at the lower range is a reflection of the relatively high parameter content of this scalage. Note that this lab here stated that the NIR analysis is an excellent prediction potential, which means that they have accumulated a large database for alfalfa hayage and are confident in their prediction equations. In the energy and index calculations we find calculated total digestible nutrients or TDN and energy values for this haylage and other estimated foliage characteristics such as relative feeding value and non fiber carbohydrates. Overall, this slap analysis report indicates that our haylage is of a good quality and reemphasizes the importance of knowing forage composition before attempting to include it in rations for dairy cows. This is the end of today's lecture, next we will discuss feed processing. [MUSIC]
