A575
Nutrition - Physiology, Forage Analysis, 
and Preserving Forage Quality

essential nutrients | determining forage quality | use a reputable lab and accurate method of analysis | interpreting the forage analysis | definition of terms | plan for and preserve forage quality

Feed and feed delivery systems usually represent the largest expense on any dairy operation. In addition to providing an ideal nutritional balance for each cow, dairy rations should also make economic sense. Cow rations should be balanced on a least-cost basis. This means that feedstuffs and feedstuff amounts should be selected not only on nutrient quality and density, but based on cost efficiency as well.

The importance of good nutrition in dairy cattle suggests that it is essential for dairy producers, managers, herdsmen and those who handle cattle to have some basic understanding of how cows digest feed, what affects feed intake, how to monitor feeding programs, and how to identify nutritionally related problems. This knowledge will help them prevent health problems, and apply good management strategies that will maximize production and profitability.

Ruminant Physiology: Dairy cows are included in a class of animals known as ruminants. Ruminants have a unique physiology, and they have a unique ability to digest complex carbohydrates that most other animals cannot. They possess a large 4-compartment stomach, which enables the cow to utilize lower-quality, high-fiber forages.

1. The rumen is the largest of the 4 compartments of the cow’s stomach. It has the capacity to hold from 30-50 gallons of a fluid/forage mix. Essentially the rumen is a large fermentation vat, which holds a large microbial population. These organisms attach to and break down the ingested feed and produce volatile fatty acids (VFA’s), which are used by the cow for energy. The rumen is lined with small finger-like projections called papillae, which absorb the VFA’s.
2. The reticulum is the second compartment of the cow’s stomach. It is basically a small pouch in the bottom part of the abdomen and forward of the rumen. The lining of this compartment is honeycomb-like. This compartment is sometimes referred to as the "hardware stomach" because nails, wire, and other foreign objects settle here. This is where a magnet will rest when placed in a cow. Placing a magnet in a cow is done to prevent metal objects from causing "hardware disease" by puncturing the stomach lining.
3. The omasum is the 3rd compartment of a ruminant’s stomach and is a firm round structure. It is lined with many thin layers or  "leaves" of tissue. This portion of the stomach absorbs water and some nutrients.
4. The abomasum is the 4th and final compartment. Because it has glands that secrete acids just like the stomach of humans, it is sometimes known as the "true stomach." Occasionally, this stomach can become twisted or displaced to the left side of the cow’s body (left displaced abomasum or LDA) or the right (right displaced abomasum or RDA).

In addition to microbial fermentation, production of VFA’s, and passage of ingested feed through the 4 compartments of the stomach, ruminants undergo a special digestive process called "rumination." Strong rumen contractions serve to mix rumen contents and bring fluid and bacteria in contact with recently ingested feed particles. These contractions will occur least 1-2 times each minute. These contractions also help bring larger feed particles to the surface. The larger particles and fibers stimulate or "scratch" the area around the esophagus. This stimulates "rumination" or "cud-chewing." There are 4 steps in the rumination cycle.

1. Regurgitation:  When coarse materials stimulate the area around the esophagus, a small amount of this coarse material is regurgitated into the mouth by a reverse movement of the esophagus.
2. Re-chewing:  The coarse materials brought up from the rumen are re-chewed and broken down into smaller particles. A normal, healthy cow will spend 8-10 hours per day chewing her cud.
3. Re-salivation:  This part of the rumination cycle can be very important in high-producing dairy animals. When higher levels of concentrates or grains are fed, they are more rapidly fermented and broken down into VFA’s. Without some buffering, the VFA’s will lower the pH in the rumen to a level that can inhibit or even kill the fermenting bacteria. A cow will produce 20-30 gallons of saliva each day. This saliva contains buffers which stabilize the rumen pH. It is critical for adequate effective fiber to be present to stimulate rumination so this buffering effect may take place.
4. Re-swallowing:  The feed is then re-swallowed and if chewed to an appropriate length, it will eventually pass through the reticulum, omasum and abomasum.

The flora or microbial population in the rumen is a sensitive and dynamic part of the cow’s entire digestive process. In many ways, feeding a cow is really a matter of feeding the bacteria in a cow’s stomach. The microbes are what break down the fiber and complex carbohydrates into VFA’s that the cow can then absorb and use as energy. After fermenting and digesting in the rumen, the bacteria pass along with ingested feed into other compartments of the stomach and into the small intestine. These bacteria are then digested and broken down by the cow and may supply 50-70% of the cow’s protein requirement. Any factor that will enhance bacterial growth and fermentation in the cow’s rumen will enhance the cow’s energy, protein intake from bacteria, and how well complex carbohydrate is digested in the rumen. Conversely, anything that will inhibit microbial growth in the cow’s rumen will result in reduced energy and protein gained from bacteria. The microbial population in the rumen of the cow is very sensitive to pH, stress, sudden feed changes, or swings in intake. Large changes in feed should be done in steps, and 2 weeks should be given for bacterial populations to adjust to new feeds or significant ration changes. Every effort should be made to keep intakes steady, effective fiber levels adequate (to promote cud-chewing) and forage/grain ratios monitored to prevent acidosis.

Essential Nutrients: In the milking dairy cow, 6 essential nutrients are required to maintain health and balance in the diet. These nutrients must be found in adequate levels and in the right proportions to support milk production and health.

1. Water: Water is often called the most important nutrient. Total body water ranges from 56 – 81% in adult dairy cattle. Milk is 85-88% water. Any situation that will adversely affect consumption of water will affect milk production faster and to a greater degree than any other nutrient. Lactating cows require up to 55 gallons of clean, fresh water per day and more in times of high temperature and humidity.
2. Carbohydrates: Carbohydrates provide energy necessary for rumen bacteria and protozoa to grow, multiply, and to ferment and digest feeds in the rumen. Carbohydrates are also the main energy source to fill the cow’s requirements for maintenance, reproduction and lactation.
3. Protein: Protein is the main structural component of organs and soft tissues in the body. A constant supply is necessary for maintenance, growth, and repair of these tissues throughout life. Lactation requires more protein in the milking cow than for any other bodily function.
4. Fat: Fat is the most calorie dense of the nutrients. In a high-producing animal, it is very difficult to ingest enough feed to supply all the energy needs for maintenance and milk production. The addition of fat is a good way to increase the energy density of the ration. There are several different sources of fat and limits on the amount that can be fed. Fats, when fed in excess can adversely affect the fermentation process in the rumen.
5. Fiber: Although fiber can be considered a complex carbohydrate, it serves another important function in the rumen of a cow. Effective fiber (fiber with sufficient length) is necessary in the diet of cattle to stimulate rumination.
6. Vitamins and Minerals: Vitamins are components of the diet necessary for certain metabolic and physiologic functions. There are two types of vitamins: fat-soluble and water-soluble. Cattle can synthesize water-soluble vitamins in their digestive tract, but the fat-soluble vitamins need to be supplemented especially after forages have been stored for some time. Minerals are elements or compounds found in soil and feed. They are usually divided into macro minerals and trace minerals. Minerals have been studied extensively for many years and minimum daily requirements have been well established. Different forms of mineral compounds, however, are able to be absorbed more readily than others. This should be taken into consideration when determining the amount to be fed in the ration.

1. Determining Forage Quality:

1. Begin with a forage analysis: The majority of the diet of a milking cow is forage. She will obtain the majority of her essential nutrients from these feeds. To adequately balance the requirements of a high-producing cow, a high-quality, detailed feed analysis should be performed.

1. Obtain a representative sample: A test taken from a single spot in a particular forage may be not representative and prone to errors. Sample 20 bales randomly or silage in 8-10 different spots to eliminate the possibility of sampling errors. Take separate samples from each "lot" of feed. A lot would be defined as forage of a separate or distinct cutting, variety, stage of maturity, or field. Forage that is rain-damaged, has excessive weeds or grass, and has been handled differently (such as raking, or was delayed in being harvested) would also be considered different lots. Each lot should be sampled individually. The sample should be placed in a plastic bag and sealed to retain the moisture level. Samples should be kept cool, if possible, during transit to the laboratory.
2. Sampling dry hay: Sample square bales from the butt end with a 12-18 inch long probe that is at least 3/8 inch diameter. Probe the bale at right angles to the bale, not slanted up, down or sideways. Sample round bales from the round side, and not the flat ends. All sampling devices must have a sharp cutting tip. When collecting samples of dry hay, do not: hand mix samples, divide samples before sending to the laboratory, or obtain samples by taking flakes from a bale.
3. Sampling silage in a pit or bunker silo: Sample silage from a pit or bunker silo by collecting 10-12 handfuls of silage from different areas across the face of the pit. Avoid the top and sides where spoilage may have occurred. It is best to collect samples after silage has been removed from across the whole face. Significant changes can occur in silage that has been exposed to air for more than 24 hours. For large pits or bunkers, or if silage has been brought from different lots or fields, it should be sampled on a monthly basis.
4. Sampling silage in a bag: Silage in bags should be tested by collecting 8-10 samples from small holes cut in the bag along the entire length. Sample on the side least exposed to the heat of the sun, and collect from deep inside the bag. Forage close to the surface of the bag may have experienced changes due to the heating and cooling that occurs on the bag from the sun. Re-seal the sample holes with tape approved for sealing silage bags.
5. Sampling from an upright silo: Two or three samples should be collected during each feeding for 3-4 feedings. These samples should be mixed and a representative sample of the mixture taken for the lab analysis. If more than one lot is packed into the silo, samples should be taken on a regular basis (usually monthly) to detect changes that may occur as new lots are encountered.

2. Use a reputable lab and accurate method of analysis: Not all laboratories and methods used to analyze forages are equal. To achieve an optimum balance of nutrients, and maximize production in high-producing animals, accurate forage analyses are essential.

1. Choosing a forage testing lab: A voluntary certification program has been developed and is administered by the National Forage Testing Association to help improve or maintain laboratory performance. Certified laboratories have demonstrated that their testing procedures give results within acceptable levels of variance. This does not mean that a laboratory which is not certified, does not have the ability to analyze forages correctly.  However, it does give producers and nutritionists an indication of which laboratories have at least met the requirements of the National Forage Testing Association. For a listing of certified forage laboratories contact:

   National Forage Testing Association
   P.O. Box 371115
   Omaha, NE 68137
   (402) 333-7485

2. Wet Chemistry Analysis: The wet chemistry analysis is the traditional and most commonly used laboratory method and is based on sound chemical and biochemical principles. This method is older, slower and usually is more costly. This method is also the standard by which other methods are compared and is typically more accurate.
3. Near Infrared Reflectance Spectroscopy (NIRS) Analysis: The Near Infrared Reflectance Spectroscopy (NIRS) analysis dries and grinds samples and then exposes them to near infrared light. Light that is reflected from the sample is then detected and analyzed by the computer. Nutrient amounts can be detected because the computer compares the reflected light patterns to previously tested samples that had values determined by wet chemistry analysis. This newer method of analysis is faster and cheaper, but accuracy depends on good calibration. Calibration is developed from comparing an adequate number of samples similar in composition to the sample being tested. Without good calibration, NIRS can have serious errors. Often NIRS analysis tends to underestimate fiber levels, particularly neutral detergent fiber (NDF). Because NDF is used in calculating the relative feed value (RFV) of forages, the RFV is often overestimated in NIRS calculations.

3. Interpreting the forage analysis: The following is a sample of a detailed forage analysis and a table of interpretation:

• Crude Protein: The total protein in a feed ingredient estimated from the total nitrogen measured.
• Available Protein: Protein that is not damaged or bound and is available for use by the animal.
• Unavailable Protein: Protein that is unavailable to the animal. Heat damaged protein is found in this fraction.
• Neutral Detergent Crude Protein: This is protein that is contained within the neutral detergent fiber of the forage. Typically this fraction contains the slowly digested protein and the bound or unavailable protein.
• Soluble Protein: This protein is completely soluble (dissolves) in the rumen and is rapidly converted to ammonia.
• Degradable Protein: The portion of the protein that is degraded in the rumen.
• Total Digestible Nutrients (TDN): This is a measure of the total digestible energy in the forage.
• Net Energy Lactation, Maintenance, Gain (NEL,NEM NEG): This is a measure of the energy density of the feed and represents how much energy per pound of feed will go toward meeting the total energy requirement of the lactating cow, the cow needing only to maintain condition, or the cow needing to gain weight.
• Acid Detergent Fiber (ADF): This value represents the fiber portion of the forage that is left after treatment with detergent in acid conditions. Its value essentially is the indigestible and poorly digestible portions of the plant and can thus be used to estimate digestibility of the forage when fed.
• Neutral Detergent Fiber (NDF): This value represents the fiber portion of the forage that is left when treated with a neutral detergent. Its value is essentially the digestible and indigestible portions of the cell wall. Neutral detergent fiber is inversely related to dry matter intake. This means that as the NDF in forages increases, animals will be able to consume less of the forage.
• Crude Fat: A measure of the total fat in the forage.
• Lignin: Lignin is an indigestible non-carbohydrate component in forage. It increases in forages as they mature.
• Non-Fiber Carbohydrates (NFC): This value approximates the carbohydrates that can be rapidly fermented in the rumen and usually represents pectins, starches, and sugars.

4. Have a fermentation analysis done on fermented feeds: Fermentation analysis is becoming a popular tool in determining the quality and palatability of ensiled forages. A quality fermentation analysis can measure and calculate the following levels that result from the fermentation process: pH, total acidity, Volatile Fatty Acid (VFA) profile, total VFA, and ammonia. These levels can give a picture of how the fermentation proceeded, how well the silage is preserved, and how palatability may be affected by the fermentation process.

5. Fiber Digestibility: This is a new tool for evaluating forages. Traditionally, fiber digestibility was estimated from acid detergent fiber (ADF). The ADF fraction of forage contains lignin. Lignin is essentially the portion of the fiber in forage that is unavailable to the cow for digestion. Therefore, as the lignin and ADF fraction increases, the total digestibility of a feed will decrease. Researchers and nutritionists noticed that there were great variations in fiber content of forages grown in the Northeast. As this was examined further, it was found that in addition to variations in fiber content, variations in fiber digestibility were noted. These variations in digestibility were associated with certain plant and environmental factors including hybrid type (variety), maturity, temperature, moisture, and fertilization. Currently there are two methods available to estimate fiber digestibility:

1. In vitro (in the lab) - In this method, a small amount of the forage is ground up and mixed with rumen fluid. It is then incubated at a controlled temperature for a period of time (generally 30 hours, which is the approximate time for forage to remain in the rumen of a mid-lactation cow). After the 30 hours, the values of in vitro true digestibility (IVTD) and digestible NDF (dNDF) can be determined. This method has the advantage of being relatively quick and cost efficient, but the accuracy of results is questioned because of the grinding of samples. When samples are finely ground, they tend to show higher digestibility and less difference between samples.
   
2. In situ (in the live animal) - In this approach the ground up forage is placed in a nylon bag and placed inside the rumen of a fistulated cow. (A fistulated cow is one that has an opening surgically placed through the left flank area and into the rumen. A plastic device is then placed into the opening. The plastic device prevents rumen material from escaping out into the abdomen or to the outside, and has a cap that can be removed when needed for entry into the rumen.) The bag is removed at intervals to measure the amount of undigested material. Upon completion, this method may provide forage and NDF digestibilities as well as digestion rates. This method has the disadvantage of being costly per sample, but the results come from a true rumen environment. Once the digestibility of sampled forages are determined, rations may be adjusted for NEL and forage feeding rates (if digestibility is poor). Generally, fiber digestibility is mainly used only when animal performance is not equal to predicted or formulated values, and after all other areas of feeding management and forage analysis have been explored. As levels of production continue to increase, however, evaluating fiber digestibility will become another tool to help increase productivity and profitability on progressive dairy farms.

6. Considering Cows on Pasture: Lactating dairy cows on pasture present a unique challenge to nutritionists balancing rations due to the fact that pasture forage quality and pasture forage intake are so variable. However, the same basic principles of nutrition apply, and when done systematically, a balanced feeding program can be achieved. First, obtain an accurate estimate of forage quality. This may be done by sampling pasture forage in random spots for analysis. Tables produced from studies that evaluate nutrient composition of different pastures may also estimate forage quality. Keep in mind that estimates may not allow for the variation created by different varieties of forage, soil fertility, fertilization, and forage management practices.

BUY THIS MANUAL NOW and have access to this article and 100's of others just like it!

2. Plan for and Preserve Forage Quality: Forage represents the greatest portion and least expensive source of nutrients in the cow’s diet. Using high quality feeds will enable the dairyman to feed lesser quantities of more expensive sources of energy and protein, thus lowering total feed costs. Better quality feeds also tend to be more palatable and more digestible (although exceptions to the latter do occur). This promotes better intake, better utilization of feed, and higher milk production. Nutritionists will agree that when the best quality feeds are utilized, it is much easier to make ration formulations balance. Working toward producing, harvesting, and/or purchasing the best quality feeds is the best way a dairyman can make his/her operation more profitable. The following are principles for putting up the best quality forages:

1. Alfalfa Hay:

1. Cut at the "best" stage of maturity - At flower initiation or "bloom" stems increase in fiber and lignin. Lignin is the portion of the plant that is totally indigestible. Realize the higher yield that comes from more mature alfalfa is due to heavier stalks and stems filled with indigestible fiber and lignin. The optimum time to harvest is the mid to late bud stage.
2. Minimize weather losses - The risk of bad weather makes hay harvesting challenging. Depending on the area of the country, unconditioned alfalfa hay may require up to 30 hours of sunshine (3 days) to field dry for storage. Rain damages hay by leaching soluble carbohydrates and proteins from the plant and increasing the tendency of leaves to shatter. Hay that receives 2.5 inches of rain after cutting may have dry matter losses of over 50%. Not much can be done to control the weather, but trying to reduce field drying time by conditioning and also by baling hay at higher moistures may be considered to try to reduce field losses. Drying agents, organic acids, anti-fungal agents, and aerobic bacterial inoculants are all methods of conditioning that have been used with some success in enabling hay growers to put hay up at higher moisture contents.
3. Reduce respiration losses - The cells in alfalfa continue to respire (breath, use energy, grow, use cell machinery) until the plant moisture falls below 40%. Under normal drying conditions this will account for a 2-8% loss in dry matter. In poor drying conditions this loss may increase to 16%. It is recommended that mowing be done early in the morning so that the maximum amount of drying may occur on the first day. Hay cut in the afternoon will delay drying, extend the period of respiration, and result in greater losses. The use of mechanical or chemical conditioners will also help reduce drying time and thus reduce respiration losses.
4. Minimize mechanical losses - The number one loss that occurs in stored, dry alfalfa hay comes from leaf shattering during mechanical handling, such as raking and baling. Plant moisture content is one of the major factors in contributing to excessive field losses from mechanical handling. The leaves dry 3-5 times faster than the stem and are very brittle by the time the crop is ready to bale. Because leaves contain 70% of the protein, 90% of the vitamins, and more than 65% of the digestible energy, it is critical to try to reduce leaf losses. This can be done by baling at higher moistures (above the optimal 15-18%) and by using products to minimize spoilage. A second factor that contributes to mechanical losses by shattering leaves is the type of baler. Conventional small rectangular balers range from 3-8% loss, whereas large round baler losses maybe as high as 15%. Raking is another factor that can contribute to mechanical losses in alfalfa hay. Losses as high as 15-25% can occur from raking. Management practices that reduce the need for raking will reduce leaf losses and greatly improve hay quality.
5. Minimize heat damage - Baling hay above 20% moisture content will increase the risk of spoilage and heat damage by fungi and other organisms. These microorganisms break down complex starches and sugars in the plant. This process generates heat. Heating during storage results in loss of carbohydrate (energy), damage to the protein resulting in lower digestibility, and a browning reaction of the hay which results in a drop in total nutritive value. This reaction may be minimized by putting up hay at the proper dry matter or by using drying agents, organic acids, anti-fungals, or aerobic bacterial inoculants to help preserve hay put up at higher moisture contents.
6. Reduce storage losses - The effects of weather and the environment can significantly affect dry matter losses in stored alfalfa hay. Most of the losses occur on the outer 3 inches of the exposed bale and especially where the bale comes in contact with the ground. In large round bales stored outside, this exposed area can represent as much as 21% of the bale. By covering alfalfa, hay losses can be reduced from 17% to 6%. These losses are dependent upon rainfall, ability of the bale to shed water, and length of storage. Generally, the losses with bales stored outside are considered to be approximately 3 times greater than bales stored under cover. A producer should seriously compare the cost of a new hayshed against the losses accumulated on forages stored outside. Many times the forage losses will be significant enough to pay for the new storage shed.

2. Alfalfa Haylage:

1. Harvest at proper maturity - Similar to dry alfalfa hay, harvesting at the right time is the key to preserving quality haylage.
2. Put haylage up at the proper moisture - Some of the advantages of haylage are that there are lower field losses from mechanical processing and respiration of the plant. There is also a greater ability to put the crop up at the ideal maturity because less rain-free weather is needed for harvesting. Putting haylage in storage at the correct moisture will perhaps have the greatest impact on the quality of the product preserved. Direct cut silage normally contains 75-85% moisture. When ensiled directly, this leads to high levels of seepage, and low temperature fermentations where undesirable clostridial organisms may grow. This produces silages that are sour, and have unpleasant odors. This causes the silage to be unpalatable and greatly reduces animal intake. Ideally the forage should be cut and left to wilt to reduce the moisture content to the optimum levels. This amount of time will vary depending on geographic location, but should result in a moisture content around 65%. Problems may also occur with haylage if producers allow too much wilting to occur before ensiling. When haylage is ensiled too dry (40-55% moisture) or if ensiling conditions are not perfect, heating or yeast and mold growth can occur.
3. Length of cut - Chop length is a fine balance that needs to be considered carefully. Large forage particles are difficult to pack and will trap air. This will lead to conditions that favor heating and mold growth. Longer stems are also more difficult to handle with unloading systems. Haylage may be chopped finer, but forages that are too fine may lead to decreased milk butterfat levels, decreased rumination (cud chewing), decreased salivation, and an increase in the incidence of acidosis. The ideal chop length is 3/8 to 1/2-inch theoretical cut. This normally results in about 15-20% of the particles being over 1.5 inches and the rest being 3/8 to 1/2-inch.
4. Use bacterial inoculants - Alfalfa hay contains less plant sugars than corn silage, small grain silages, and grasses. The alfalfa plant also contains natural buffering agents, which reduce the ability of bacteria to reduce the pH during the fermentation process. These two factors make it difficult to obtain a good fermentation on alfalfa haylage unless a good quality inoculant is used.

3. Corn Silage:

1. Selection of hybrid - Because good quality corn silage can contain up to 50% grain, corn silage could really be considered a grain/forage mix. This grain content helps to make corn silage unique in the fact that it is so high in energy. Because of this unique quality, producers should do all they can to maximize the energy produced per acre.
   Four criteria should be used in selecting a corn hybrid for corn silage. First, determine if the corn will reach its proper maturity in the area it is grown in. Second, consider the yield of harvested material. Selecting a hybrid that will not mature completely before harvest will negatively affect the energy in the harvested silage as well as yields. Third, select corn for grain content in the silage at harvest. Fourth, select corn with good stover (the entire plant excluding the ear) digestibility. Both of these last criteria can vary greatly between hybrids. Do not be fooled, however, into products promoting high-fiber, highly digestible corn silage. By selecting for higher total digestible fiber instead of a higher level of digestibility, the increase in fiber will decrease the total digestible nutrients and energy in the plant. This defeats the unique advantage of this plant.
2. Plant population - The stand at which corn is planted will greatly affect silage quality and yield. Silage corn can often be planted at 10-15% over the recommendation for dry grain corn. This will greatly increase yield and profitability.
3. Fertilization - Adequate and proper fertilization is necessary for gaining the greatest economic value from the corn plant in terms of yield and nutritional value. Many factors affect the fertilization types and rates including time of application, soil type, plow down crops, manure application, and plant populations.
4. Maturity at harvest - Maturity at harvest is very important because it affects the following 3 things: grain content, moisture content, and stover digestibility. Maturity can be determined by locating the milk line of the kernel. The milk line is the interface between the liquid and solid portion of the kernel and is measured starting at the tip. Corn silage quality and animal intake studies have shown that the optimum maturity for harvest is when the milk line is 1/2 to 2/3rds of the way down the kernel. This level of maturity should produce the optimum levels of grain, moisture, and digestibility. It should be noted that this is only a general "guideline" and that factors such as location, weather, and hybrid type can cause variations in the ideal maturity for harvest. Maturity and moisture should be checked frequently just prior to the beginning of harvest.
5. Storage consideration - Similar to any ensiled feed, care should be taken to put up feed quickly, pack it tightly to exclude as much oxygen as possible, and cover it promptly. Even though corn silage has much more starch and sugar in the plant than alfalfa, a quality silage inoculant is still recommended. Many farmers have the false impression that inoculation is not beneficial or needed with corn silage. Several strains of bacteria must be present to obtain a complete fermentation. Without inoculation, the farmer is just gambling that all the necessary bacteria are present.
6. Length of cut - Like haylage, length of cut can negatively affect the fermentation if it is too long, or negatively affect rumination in the cow if it is too short. The ideal chop length is 5/8-inch theoretical cut length. When dealing with frosted corn silage that has a reduced moisture content, chopping to a shorter length and the addition of water should be considered.

1. Stored forages should be labeled according to lot. If large amounts of different forages are stored in one location, a detailed map of the location of each lot of forage may be necessary.
2. Label dry forages with permanent spray paint, or some type of marker that will not be taken, lost, or destroyed by environmental conditions. Ensiled feeds in bags should have field, lot, and/or cutting written on the bag in permanent ink.
3. Reasonable estimates should be made to determine quantities of forages for future use. This will help avoid sudden and drastic feed changes that may affect cows negatively.
4. Keep the analysis records of forages tested. This will help to compare lots, cuttings, varieties/hybrids, and different crop years.

 

Acknowledgments: Much of the information contained in this discussion has come from the following sources:

1. Pioneer Forage Manual. 1995.
2. Mike Hutjens. Hoard’s Dairyman Feeding Guide. 1998.
3. "Applied Dairy Nutrition and Problem Solving Seminar." AABP Meeting. 1999.

The information above provides only a brief overview of the importance of nutrition, the digestive process of ruminants, and the importance of a quality feed analysis and storage. Please refer to the following pages for additional information on formulating rations, using feed delivery systems, maximizing dry matter intake, tools to monitor rumen health, and the feeding of essential nutrients in detail.