Balancing Dairy Cow Rations with Homegrown Feeds

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-14

Key Takeaways

• Mandatory Feed Analysis: Prior to ration formulation, all homegrown feeds must be analyzed for dry matter, crude protein, neutral detergent fiber (NDF), and key minerals; reliance on visual appraisal or assumptions is economically detrimental and risks nutritional imbalances.
• Dry Matter Basis is Critical: Ration balancing must be performed on a dry matter (DM) basis to accurately account for variable moisture content in forages (silage, hay) and grains, ensuring consistent nutrient delivery irrespective of water content.
• Forage as the Foundation: Rations should be built around the available homegrown forages, with supplemental protein and energy sources added only after the forage's nutrient contribution is calculated and compared against the cow's specific requirements.
• Strategic Supplementation: While homegrown feeds can significantly reduce purchased feed costs, most operations will still require commercial mineral packs and potentially protein supplements to meet all nutrient requirements, particularly trace minerals and vitamins A, D, and E.
• Gradual Diet Transitions: Introduction of new batches of homegrown feeds or significant ration changes must be phased in over 7 to 10 days to allow rumen microbial adaptation, preventing digestive upset, milk fat depression, and potential metabolic disorders.
• Proactive Health Monitoring: Persistent signs of digestive upset (acidosis, bloat), ketosis, displaced abomasum, or unexplained milk production drops necessitate immediate consultation with a veterinarian or extension agent for diagnostic evaluation and corrective ration adjustments.

Feeding a dairy herd is often the single largest variable cost on a farm, and the gap between what you purchase and what you grow can determine your profitability in any given year. This guide explains how to build a balanced dairy cow ration using homegrown feeds as the foundation, while still meeting the energy, protein, fiber, vitamin, and mineral needs of lactating cows. It is written for dairy producers who want to reduce purchased feed costs, improve forage utilization, and make more informed decisions about ration formulation. You will learn how to sample and test feeds, calculate what your farm can supply, use simple spreadsheet or paper methods for balancing, and know when to call in a professional nutritionist or extension agent.

At a Glance

• Test every homegrown feed for dry matter, crude protein, neutral detergent fiber, and key minerals before you build a ration. Guessing costs more than testing.
• Balance rations on a dry matter basis, not as-fed basis, because moisture content varies widely between silage, hay, and grain.
• Start with the forage portion of the ration, then add supplemental protein and energy to meet the cow's requirements.
• Homegrown feeds can replace a large share of purchased feeds, but rarely all of them. Most farms still need a commercial mineral pack and sometimes a protein supplement.
• Introduce new homegrown feed batches gradually over 7 to 10 days to avoid rumen upset and milk fat depression.
• Keep written records of every feed test, ration calculation, and diet change. These records help you troubleshoot problems and make better decisions next year.
• Call a veterinarian or extension agent when cows show signs of digestive upset, ketosis, displaced abomasum, or unexplained drops in milk production that do not respond to ration adjustments.

Understanding the Basics of Ration Balancing

Ration balancing is the process of matching the nutrients a cow consumes to the nutrients she needs for maintenance, milk production, growth, reproduction, and body condition. A balanced ration does not mean a fixed recipe. It means a diet that meets the cow's requirements without excesses that waste money or cause health problems.

Dairy cows are ruminants, which means they have a four-compartment stomach and rely on microbial fermentation in the rumen to digest fiber and other feed components. This digestive system imposes limits on what you can feed. Cows need enough effective fiber to maintain rumen function and milk fat percentage, but too much fiber limits energy intake. They need protein, but too much degradable protein can cause high blood urea nitrogen and fertility problems. They need starch and sugar for energy, but too much can cause acidosis, laminitis, and milk fat depression.

The goal of ration balancing is to find the combination of feeds that meets all of the cow's nutrient needs simultaneously while respecting the limits of rumen function. This is why a ration cannot be built from a single feed. Corn silage alone does not supply enough protein. Alfalfa hay alone does not supply enough energy for high-producing cows. A balanced ration combines forages, grains, protein sources, minerals, and vitamins in the right proportions.

Key Nutrient Terms You Need to Know

Dry matter is the portion of a feed that is not water. When you compare feeds or formulate rations, you compare them on a dry matter basis. A cow eats a certain amount of dry matter per day, usually 3.5 to 4.5 percent of her body weight for lactating cows. A 1,400 pound cow producing 80 pounds of milk might consume 50 to 60 pounds of dry matter per day.

Crude protein is a measure of the nitrogen content of a feed, multiplied by 6.25. It includes both true protein and nonprotein nitrogen. For ration balancing, you also need to know the degradable and undegradable protein fractions, because rumen microbes use degradable protein while the cow herself uses undegradable protein that bypasses the rumen.

Neutral detergent fiber is a measure of the plant cell wall components, primarily cellulose, hemicellulose, and lignin. It correlates with how full the cow feels and how much feed she can eat. Higher NDF forages are more filling and limit dry matter intake. For lactating dairy cows, total ration NDF should typically be 28 to 35 percent of dry matter, with at least 19 to 22 percent coming from forage.

Acid detergent fiber is a subset of NDF that includes cellulose and lignin. It correlates with digestibility. Lower ADF usually means higher energy value. For alfalfa, ADF of 30 percent or less is considered good quality. For grasses, ADF of 35 percent or less is a common target.

Net energy for lactation is the energy available to the cow for maintenance and milk production after accounting for losses in digestion and metabolism. It is expressed in megacalories per pound of dry matter. Good corn silage might have 0.70 to 0.75 Mcal per pound of dry matter. Good alfalfa hay might have 0.60 to 0.65 Mcal per pound.

Minerals and vitamins are required in specific amounts. Calcium, phosphorus, magnesium, potassium, sulfur, sodium, chlorine, and trace minerals like zinc, copper, manganese, and selenium must be supplied in the correct amounts and ratios. Most homegrown feeds do not supply all minerals in the right balance, which is why a commercial mineral supplement is almost always needed.

Step 1: Inventory Your Homegrown Feeds

Before you can balance a ration, you need to know what you have. Start by making a complete inventory of every feed you grow or produce on the farm. This includes forages, grains, and any crop residues you intend to feed.

For each feed, record the following information:

• Feed name and variety or hybrid
• Field or lot number
• Harvest date and stage of maturity at harvest
• Storage method (upright silo, bunker silo, pile, bag, dry bale, baleage)
• Estimated tons or pounds on hand
• Estimated dry matter percentage
• Your best estimate of quality based on previous tests or visual appraisal

Do not rely on memory. Write this down in a notebook or spreadsheet. You will need this inventory to calculate how many cow-days of feed you have and to decide what you need to purchase.

Estimating Feed Quantity

For hay, count the number of bales and weigh several representative bales. Multiply the average weight by the number of bales to get total weight. For large round bales, weight varies from 800 to 1,800 pounds depending on density and moisture. For square bales, weight varies from 40 to 120 pounds.

For silage in upright silos, use the silo capacity charts provided by the manufacturer or your extension service. For bunker silos and piles, measure the length, width, and depth of settled silage, and use a density estimate of 35 to 45 pounds of dry matter per cubic foot for corn silage and 25 to 35 pounds per cubic foot for haylage. These estimates are rough, so weigh loads as you feed out to refine your numbers.

For grain, use the number of bushels stored and the test weight per bushel. Corn at 15 percent moisture weighs about 56 pounds per bushel. Oats weigh about 32 pounds per bushel. Barley weighs about 48 pounds per bushel.

Converting to Dry Matter

Because feeds vary in moisture content, you must convert everything to a dry matter basis for ration balancing. The formula is simple:

Dry matter weight = As-fed weight x Dry matter percentage

For example, if you have 100 tons of corn silage at 35 percent dry matter, you have 35 tons of dry matter. If you have 50 tons of haylage at 45 percent dry matter, you have 22.5 tons of dry matter.

When you calculate how long your feed supply will last, use dry matter amounts. A cow eating 55 pounds of dry matter per day will consume about 10 tons of dry matter per year. If you have 100 tons of dry matter in corn silage, that is enough for 10 cows for a year, or 20 cows for six months.

Step 2: Sample and Test Your Feeds

You cannot balance a ration on visual appraisal alone. Forages vary enormously in nutrient content depending on plant species, maturity at harvest, soil fertility, weather, and storage conditions. A field of corn silage cut at the right moisture and well fermented might test 0.75 Mcal of net energy per pound of dry matter. The same field cut too dry or poorly packed might test 0.65 Mcal. That difference changes how much grain you need to feed.

Submit representative samples to a commercial forage testing laboratory. Your local extension office can recommend a laboratory and provide sampling instructions and bags. Most dairy nutritionists also work with specific laboratories and can help you interpret results.

How to Sample Forages

For dry hay, use a hay probe to take cores from the center of at least 15 to 20 bales. Sample bales from different fields and cuttings separately. Combine the cores into one clean plastic bag and label it clearly. Do not sample only the outside of bales, because the outer layer is often lower in quality.

For silage from an upright silo, sample after the silo has been opened and you are feeding from it regularly. Take samples from the face of the silage, avoiding spoiled areas. For bunker silos and piles, sample from the face at several locations and depths. For bags, sample from the freshly cut end. In all cases, take samples over several days and combine them for a composite sample.

For high-moisture grain, sample from several bags or from the storage structure and keep the sample refrigerated until you send it to the laboratory.

What Tests to Request

A standard forage test for dairy cows should include:

• Dry matter
• Crude protein
• Acid detergent fiber
• Neutral detergent fiber
• Lignin (optional but useful for predicting fiber digestibility)
• Net energy for lactation (calculated, not measured)
• Calcium, phosphorus, magnesium, potassium
• Sulfur (especially for corn silage and forages grown on sandy soils)
• Trace minerals (zinc, copper, manganese, iron) if you suspect deficiencies or toxicities
• Nitrate (for forages that may have been stressed by drought or excessive nitrogen fertilization)
• Starch (for corn silage and small grain silage)
• In vitro dry matter digestibility or neutral detergent fiber digestibility (optional, adds cost but improves ration accuracy)

For grains, test dry matter, crude protein, starch, and the same minerals. For corn, also request a test for mycotoxins if you suspect mold or if the crop was stressed.

How Often to Test

Test every new crop or cutting. Do not assume that this year's corn silage is the same as last year's. Even within a season, forages can change as you feed from different parts of a storage structure. Test again when you switch to a new silo, a new cutting of hay, or a different field of grain.

For long-term storage, test once at feedout and again halfway through the storage period. Silage continues to ferment and nutrient values can shift slightly.

Interpreting Your Test Results

Your laboratory report will list nutrient values on a dry matter basis. Compare your results to typical values for your area and to the needs of your cows. Your extension service or nutritionist can help you interpret unusual results.

Pay special attention to dry matter. Corn silage should be 30 to 38 percent dry matter for best fermentation. Haylage should be 35 to 55 percent dry matter depending on storage system. Hay should be 85 to 90 percent dry matter. If dry matter is outside these ranges, adjust your feeding rates to account for the moisture difference.

Crude protein below 7 percent in corn silage or below 14 percent in alfalfa suggests the crop was overmature or stressed. Protein above 22 percent in alfalfa suggests very immature forage that may be too wet and may cause bloat.

Neutral detergent fiber above 45 percent in alfalfa or above 55 percent in grasses means the forage is overmature and will limit intake. Neutral detergent fiber below 30 percent in alfalfa means the forage is very leafy and may not provide enough effective fiber.

Step 3: Calculate Your Cow Herd's Nutrient Requirements

Every cow has specific nutrient requirements based on her body weight, milk production, milk fat percentage, stage of lactation, and whether she is pregnant. The National Research Council's Nutrient Requirements of Dairy Cattle, now updated by the National Academies of Sciences, Engineering, and Medicine, provides the standard requirement tables used in the United States.

You can find requirement tables in extension publications, in ration balancing software, or from your nutritionist. For a simple estimate, use these general guidelines for a mature cow weighing 1,400 pounds:

• Dry matter intake: 3.5 to 4.5 percent of body weight, or 49 to 63 pounds per day
• Net energy for lactation: 0.31 Mcal per pound of dry matter for maintenance, plus 0.30 Mcal per pound of milk for milk production
• Crude protein: 16 to 18 percent of dry matter for early lactation, 15 to 17 percent for mid-lactation, 13 to 15 percent for late lactation
• Calcium: 0.6 to 0.8 percent of dry matter
• Phosphorus: 0.35 to 0.45 percent of dry matter
• Magnesium: 0.25 to 0.30 percent of dry matter
• Potassium: 1.0 to 1.5 percent of dry matter

For a more accurate estimate, use a ration balancing program or the requirement tables for your specific cow weight and production level. Many extension services offer free or low-cost ration balancing tools online.

Grouping Cows by Production

Cows at different stages of lactation have different nutrient needs. A cow producing 100 pounds of milk per day needs much more energy and protein than a cow producing 40 pounds. Feeding all cows the same ration means either overfeeding the low producers, which wastes money and causes fat cows, or underfeeding the high producers, which costs milk and causes health problems.

If you have more than 20 milking cows, consider grouping them by production level or stage of lactation. Common groupings are:

• Fresh cows, 0 to 30 days in milk, high energy and protein
• High producers, 30 to 120 days in milk, highest energy and protein
• Mid-lactation cows, 120 to 200 days in milk, moderate energy and protein
• Late lactation and pregnant cows, 200+ days in milk, lower energy and protein

Each group can receive a slightly different ration, with the homegrown feeds allocated to the groups that need them most.

Accounting for Dry Cows

Dry cows have much lower requirements than lactating cows, but their nutrition affects the health of the next lactation. Overconditioning dry cows, feeding too much energy, or feeding too much calcium can cause problems at calving, including milk fever, retained placenta, and fatty liver.

Dry cows should receive a lower energy ration, typically 0.58 to 0.62 Mcal of net energy per pound of dry matter, and lower calcium, around 0.4 percent of dry matter. They need adequate protein, 12 to 14 percent, and enough fiber to maintain rumen function. Separate dry cows from lactating cows and feed them a different ration.

Step 4: Build the Ration Around Your Forages

The first step in ration formulation is to decide how much forage to feed. Forage should make up 45 to 60 percent of the total dry matter in a lactating cow ration. This ensures adequate fiber for rumen function and milk fat production.

Start with the forage you have the most of or the forage that is lowest in quality, because it is the hardest to feed at high levels. Work through your inventory from lowest quality to highest quality, allocating forage to the appropriate groups of cows.

Example Forage Allocation

Assume you have 100 acres of corn silage yielding 20 tons per acre at 35 percent dry matter. That is 700 tons of dry matter, or enough for 70 cows for a year at 55 pounds of dry matter intake per day. You also have 50 acres of alfalfa haylage yielding 4 tons of dry matter per acre, or 200 tons of dry matter, enough for 20 cows for a year.

If you have 70 milking cows, you can feed corn silage as the primary forage and alfalfa haylage as a secondary forage. If you have 100 milking cows, you need to purchase additional forage or feed less forage and more grain.

Forage Quality and Intake

Forage quality determines how much the cow can eat. High-quality forages with low NDF are less filling and allow higher dry matter intake. Low-quality forages with high NDF limit intake and milk production.

As a general rule, for every 1 percent increase in forage NDF above 30 percent, dry matter intake decreases by about 0.4 pounds per day. A cow fed a ration with 40 percent forage NDF will eat about 4 pounds less dry matter than a cow fed a ration with 30 percent forage NDF. This lower intake means less energy, which means less milk.

If your homegrown forages are low in quality, you have three options: feed more grain to compensate, purchase higher quality forage, or accept lower milk production. The most economical choice depends on the cost of grain, the cost of purchased forage, and the price of milk.

Step 5: Add Supplemental Feeds to Meet Requirements

Once you have set the forage portion of the ration, calculate the nutrients the forages supply and compare them to the cow's requirements. The difference is what you must supply with supplemental feeds.

Energy Supplements

Corn grain is the most common energy supplement in dairy rations. It is high in starch, which provides readily available energy. Feed corn grain at 2 to 8 pounds per cow per day for lactating cows, depending on forage quality and milk production.

Other homegrown energy supplements include:

• Barley, which is more rapidly fermented than corn and should be rolled or ground
• Oats, which are lower in energy but higher in fiber and protein than corn
• Wheat, which is highly fermentable and should be limited to 4 to 6 pounds per cow per day
• Triticale, similar to wheat in feeding value
• Molasses, which is high in sugar and can improve palatability but should be limited to 2 to 3 pounds per cow per day

If you grow small grains, you can feed the grain, the straw, or both. Small grain straw is low in energy and protein and is better suited to dry cows or growing heifers than to lactating cows.

Protein Supplements

If your forages are legumes like alfalfa or clover, they may supply enough protein for moderate producing cows. If your forages are grasses or corn silage, you will likely need to add protein.

Homegrown protein sources include:

• Soybeans, which must be roasted or extruded to inactivate trypsin inhibitors, or fed raw at limited amounts
• Canola meal, which is a byproduct of oil extraction and is usually purchased, not grown
• Field peas, which are high in protein and can be fed raw
• Lupins, which are high in protein but must be processed and limited to avoid alkaloid toxicity
• Sunflower meal, which is a byproduct and is usually purchased

Most farms growing their own protein feeds grow soybeans. Raw soybeans can be fed at 3 to 4 pounds per cow per day, but they contain oil that can depress milk fat if fed at higher levels. Roasted soybeans can be fed at 5 to 6 pounds per cow per day.

Byproduct Feeds

Many dairy farms purchase byproduct feeds from local processing plants. These include:

• Corn gluten feed, a byproduct of wet corn milling, moderate in protein and energy
• Distillers grains, a byproduct of ethanol production, high in protein, energy, and phosphorus
• Soybean hulls, a byproduct of soybean processing, high in fiber but highly digestible
• Cottonseed, high in energy, protein, and fiber, but limit to 4 to 6 pounds per cow per day
• Bakery waste, high in energy but variable in composition

These byproducts can be economical additions to a ration based on homegrown feeds, but they add cost and variability. Test byproducts for nutrient content and moisture, and adjust the ration when you change suppliers or batches.

Step 6: Balance Minerals and Vitamins

Homegrown feeds rarely supply all the minerals and vitamins that dairy cows need. Calcium, phosphorus, magnesium, and trace minerals are often deficient or imbalanced. Vitamins A, D, and E are low in stored forages and grains.

A commercial mineral and vitamin premix is the safest way to meet these requirements. Your nutritionist or extension agent can help you select a premix that complements your homegrown feeds. The premix should be formulated for your specific forage program, not a one-size-fits-all product.

Common Mineral Issues with Homegrown Feeds

High potassium forages, especially those grown with heavy manure or fertilizer applications, can cause milk fever and grass tetany in dry cows and fresh cows. If your forages test above 2.5 percent potassium, feed a negative dietary cation anion difference diet to dry cows or use an anionic mineral supplement.

Low magnesium forages, common in grasses grown on sandy soils or soils with high potassium, can cause grass tetany. Feed magnesium oxide at 0.3 to 0.4 percent of dry matter for lactating cows and 0.5 percent for dry cows.

High phosphorus byproducts like distillers grains can cause calcium-phosphorus imbalances. Keep the calcium to phosphorus ratio above 1.5 to 1 in the total ration.

Selenium deficiency is common in many regions. Feed selenium at 0.3 parts per million of dry matter, either through a mineral premix or through selenium yeast. Do not exceed this level, because selenium is toxic at high doses.

Vitamin Supplementation

Stored forages lose vitamin A activity over time. By six months of storage, most of the vitamin A in hay and silage is gone. Vitamin D is produced by sun-cured hay but is low in silage. Vitamin E is low in stored feeds.

A complete mineral and vitamin premix should supply vitamin A at 60,000 to 100,000 international units per cow per day, vitamin D at 15,000 to 25,000 international units, and vitamin E at 500 to 1,000 international units for lactating cows. Dry cows need higher vitamin E, around 1,500 to 2,000 international units per day, especially in the last three weeks before calving.

Step 7: Use a Ration Balancing Method

You can balance rations with paper and pencil, a spreadsheet, or commercial software. The method you choose depends on your comfort with math and the complexity of your feeding program.

The Pearson Square Method

The Pearson square is a simple method for combining two feeds to achieve a target nutrient level. It works for one nutrient at a time, usually crude protein or energy.

To use the Pearson square for crude protein, write the protein percentage of feed A in the upper left corner, the protein percentage of feed B in the lower left corner, and the target protein percentage in the center. Subtract diagonally and take the absolute values. The results give you the proportions of each feed.

For example, to mix corn silage at 8 percent protein with soybean meal at 48 percent protein to achieve a 16 percent protein mixture:

• Write 8 in the upper left, 48 in the lower left, 16 in the center
• Subtract 8 from 16 to get 8 parts of soybean meal
• Subtract 16 from 48 to get 32 parts of corn silage
• The mixture is 32 parts corn silage to 8 parts soybean meal, or 80 percent corn silage and 20 percent soybean meal

The Pearson square is useful for simple mixtures but does not account for multiple nutrients at once. Use it as a starting point, then check the resulting ration for other nutrients.

The Algebraic Method

For a ration with multiple feeds and multiple nutrient constraints, you can set up a system of equations. This is tedious by hand but manageable for two or three feeds.

For example, to balance a ration for energy and protein using corn silage and a protein supplement, set up two equations:

• Total dry matter = pounds of corn silage + pounds of protein supplement
• Total protein = protein in corn silage + protein in protein supplement

Solve the equations simultaneously to find the pounds of each feed needed.

Spreadsheet Ration Balancing

A spreadsheet is the most practical method for most farms. Set up columns for each feed, rows for each nutrient, and formulas that calculate the nutrient contribution of each feed and the total ration.

Your spreadsheet should include:

• Feed name and dry matter percentage
• As-fed pounds fed per cow per day
• Dry matter pounds fed per cow per day
• Crude protein, NDF, ADF, net energy, calcium, phosphorus, and other nutrients
• Total pounds of each nutrient in the ration
• Nutrient percentage of the total dry matter
• Comparison to the cow's requirements

Start with your forage amounts, add supplements, and adjust until the ration meets all requirements. This iterative process is how professional nutritionists work, just with more sophisticated software.

Commercial Ration Balancing Software

Several commercial software programs are available for dairy ration balancing. These programs use the most current nutrient requirement models and can account for multiple constraints, feed costs, and cow groups. They also include feed libraries with typical nutrient values for common feeds.

Your nutritionist or extension agent can help you use these programs. Many are available as subscriptions and can be used on a computer or mobile device. The cost is usually justified by the savings in feed costs and the improvement in milk production.

Step 8: Monitor and Adjust the Ration

A ration is not a static document. It must be adjusted as feeds change, cows change, and weather changes. Monitor the following indicators and adjust the ration accordingly.

Milk Production and Composition

Track milk production per cow per day and milk fat and protein percentages. A sudden drop in milk fat percentage below 3.0 percent may indicate too much starch or too little effective fiber. A drop in milk protein percentage may indicate inadequate energy or protein intake. A drop in both may indicate a palatability problem or a feed change.

Compare your actual milk production to the production level you used in ration formulation. If cows are producing more than expected, increase energy and protein. If they are producing less, reduce supplements to avoid wasting money.

Dry Matter Intake

Monitor how much cows actually eat. Weigh feed delivered and weigh or estimate refusals. If dry matter intake is below target, check for feed spoilage, palatability problems, overcrowding at the feed bunk, heat stress, or health problems. If intake is above target, the ration may be too low in energy density.

Body Condition Score

Body condition scoring is a visual and tactile assessment of fat cover on the cow's back, ribs, and tailhead. Score cows on a 1 to 5 scale, with 1 being emaciated and 5 being obese. Lactating cows should score 2.5 to 3.5, with fresh cows at the lower end and late lactation cows at the higher end.

Score cows at calving, at peak lactation, at mid-lactation, and at dry-off. If cows are losing excessive condition in early lactation, increase energy density. If cows are gaining too much condition in late lactation, reduce energy density.

Manure Consistency

Manure consistency reflects rumen function. Normal dairy cow manure is moderately firm, forms a patty, and contains some fiber particles. Loose, foamy, or very watery manure may indicate acidosis or excessive starch. Very firm, dry manure may indicate inadequate water intake or too much fiber.

Check manure daily. If you see undigested grain in the manure, the grain may be processed too coarsely or fed at too high a level. If you see long fiber particles, the forage may be chopped too long or the cow may be sorting the ration.

Rumen Fill and Health

Rumen fill is assessed by looking at the left side of the cow behind the ribs. A cow with good rumen fill has a full, slightly bulging appearance. A cow with poor fill looks hollow and may have a displaced abomasum or other digestive problem.

Monitor cows for signs of acidosis, including reduced intake, diarrhea, laminitis, and low milk fat. If you see these signs, reduce starch, increase effective fiber, or add a buffer like sodium bicarbonate at 0.3 to 0.5 percent of dry matter.

Step 9: Manage Feed Storage and Feeding Losses

Homegrown feeds lose nutrients during storage and feeding. These losses can be substantial if you do not manage them properly. Reducing losses is often the cheapest way to increase feed supply.

Silage Storage Losses

Poorly packed silage, slow filling, and inadequate covering cause spoilage and dry matter losses. Target a packing density of at least 15 pounds of dry matter per cubic foot for bunker silos and piles. Use a tractor to pack continuously while filling, and cover the silage immediately after filling with plastic and tire sidewalls.

Surface spoilage on bunker silos and piles can be 5 to 15 percent of the dry matter if not managed. Remove spoiled silage before feeding and discard it. Do not feed moldy silage, because it may contain mycotoxins that reduce intake and cause health problems.

Hay Storage Losses

Hay stored outside loses dry matter and nutrients from weathering. A well-made haystack with good drainage and a cover can lose 5 to 10 percent of dry matter. Uncovered hay on the ground can lose 20 to 30 percent. Store hay under cover or in a well-drained area with a tarp.

Feeding Losses

Cows waste feed when it is contaminated with manure, pushed out of reach, or allowed to heat or spoil in the bunk. Feed fresh feed daily, push up feed several times per day, and clean out refusals regularly. Target feed refusals of 2 to 5 percent of the feed offered.

Shrink

Shrink is the difference between the feed you harvest and the feed you actually feed. It includes storage losses, spoilage, and waste. Total shrink for silage is often 10 to 20 percent. For hay, shrink is 5 to 15 percent. For grain, shrink is 2 to 5 percent.

Account for shrink when you calculate your feed inventory. If you have 100 tons of dry matter in corn silage and expect 15 percent shrink, you really have 85 tons of feedable dry matter.

Step 10: Evaluate the Economics

The goal of using homegrown feeds is to reduce feed costs, but you must know what your homegrown feeds actually cost to produce. Calculate the cost per pound of dry matter and per unit of energy and protein for each homegrown feed, and compare it to the cost of purchased feeds.

Cost of Production

For each homegrown feed, add up all costs:

• Seed, fertilizer, lime, and pesticides
• Fuel, machinery, and labor for planting, harvesting, and storage
• Storage structures and their maintenance
• Interest on operating capital
• Land cost or rent
• Insurance and property taxes on land and equipment

Divide the total cost by the tons of dry matter produced to get cost per ton of dry matter. Divide by the pounds of dry matter to get cost per pound.

Comparing to Purchased Feeds

Compare the cost per pound of dry matter, per Mcal of net energy, and per pound of crude protein for your homegrown feeds to the same costs for purchased feeds. This comparison tells you which feeds are economical and which are not.

For example, if your homegrown corn silage costs $0.06 per pound of dry matter and provides 0.70 Mcal per pound, the cost per Mcal is $0.086. If purchased corn grain costs $0.10 per pound of dry matter and provides 0.90 Mcal per pound, the cost per Mcal is $0.111. In this case, the corn silage is a cheaper source of energy than the corn grain.

Opportunity Cost

Consider the opportunity cost of growing feed on land that could grow something else. If you can sell corn for $5 per bushel and your corn silage yields the equivalent of 200 bushels per acre, the silage is worth $1,000 per acre before harvest and storage costs. If your silage cost is above this value, you are better off selling the corn and buying feed.

Partial Budgeting

Use a partial budget to evaluate a change in your feeding program. A partial budget includes:

• Added income from the change
• Reduced costs from the change
• Reduced income from the change
• Added costs from the change

If added income plus reduced costs is greater than reduced income plus added costs, the change is profitable.

Common Mistakes in Balancing Rations with Homegrown Feeds

Not Testing Feeds

The most common and most costly mistake is feeding untested forages. Visual appraisal cannot tell you the protein, energy, or mineral content of a feed. A $50 feed test can save hundreds of dollars in wasted supplement or lost milk production.

Balancing on As-Fed Basis

Mixing feeds by weight without accounting for moisture is a recipe for an imbalanced ration. A cow fed 30 pounds of wet silage is getting a different amount of dry matter than a cow fed 30 pounds of dry hay. Always convert to dry matter.

Overfeeding Corn Silage

Corn silage is an excellent feed, but it is low in protein and can be high in starch. Feeding too much corn silage without adequate protein and fiber can cause low milk fat, acidosis, and displaced abomasum. Limit corn silage to 50 to 60 percent of the forage dry matter and balance with legumes or other forages.

Underfeeding Effective Fiber

Effective fiber is the fiber that stimulates chewing and rumination. It comes from forages with a particle length of at least 1.5 inches. Finely chopped silage, very mature hay, and pelleted feeds provide little effective fiber. If cows are not ruminating enough, milk fat drops and acidosis risk increases.

Ignoring Dry Cow Nutrition

Feeding the same ration to dry cows and lactating cows, or feeding dry cows too much energy, causes problems at calving. Dry cows need a lower energy, lower calcium ration. Overconditioned dry cows have more calving difficulty, more retained placentas, and more metabolic disease.

Making Sudden Feed Changes

Cows need time to adjust to new feeds. The rumen microbial population takes 7 to 14 days to adapt to a new diet. Sudden changes cause acidosis, off-feed, and milk fat depression. Introduce new feeds gradually over 7 to 10 days.

Not Accounting for Refusals

If cows are eating only 90 percent of the feed you offer, the ration they actually consume is different from the ration you formulated. Weigh refusals and adjust the ration to account for sorting and waste.

Forgetting Water

Water is the most important nutrient. Cows need 30 to 40 gallons of water per day for maintenance and milk production. Inadequate water intake causes reduced feed intake and milk production. Provide clean, fresh water at all times and check waterers daily.

Using Outdated Requirement Values

Nutrient requirements change as cows change. Use current requirement tables and update them as your cows' production and stage of lactation change. Do not use the same ration for a fresh cow and a late lactation cow.

Decision Thresholds: When to Buy Feed vs. Grow More

The decision to grow more feed, buy feed, or reduce herd size depends on your costs, land base, and milk price. Use these thresholds to guide your decisions.

Land Availability

A dairy cow needs about 2 to 3 acres of cropland to produce her annual forage and grain needs, depending on yield and quality. If you have less land than this per cow, you will need to purchase feed or reduce herd size.

Feed Quality

If your homegrown forages consistently test below 0.60 Mcal of net energy per pound of dry matter, you are feeding low-quality forage. Purchasing higher quality forage or grain may be more economical than feeding low-quality homegrown forage, because the purchased feed supports higher milk production.

Feed Cost per Unit of Nutrient

Compare the cost per Mcal of energy and per pound of protein for homegrown and purchased feeds. If purchased feeds are cheaper per unit of nutrient, buy them. If homegrown feeds are cheaper, grow them.

Milk Price

Higher milk prices justify higher feed costs. When milk price is high, you can afford to purchase supplements to maximize production. When milk price is low, you may need to reduce purchased feeds and accept lower production.

Financial Risk

Growing your own feed requires capital for land, equipment, seed, fertilizer, and storage. Purchasing feed requires less capital but exposes you to market price risk. Consider your financial situation and risk tolerance when deciding how much feed to grow.

Monitoring and Recordkeeping

Good records are essential for successful ration balancing. Keep the following records for each group of cows:

• Ration formulation and date
• Feed test results and dates
• Feed inventory and dry matter amounts
• Milk production per cow per day
• Milk fat and protein percentages
• Dry matter intake
• Body condition scores
• Health events, especially digestive problems, ketosis, and milk fever
• Feed costs and prices
• Weather events that affect feed quality or intake

Review these records monthly and adjust the ration as needed. At the end of the year, review the entire feeding program and plan for the next year.

Feed Bunk Management Records

Record the amount of feed offered and refused each day for each group. This tells you whether cows are eating enough and whether the ration is palatable. It also helps you calculate feed costs accurately.

Milk Production Records

Dairy Herd Improvement records, or the records from your milk tester, are essential for monitoring the effects of ration changes. Compare production before and after a ration change to evaluate the change. Give the change at least two weeks before judging the results.

Health Records

Record every health event, including the diagnosis, treatment, and outcome. Look for patterns. If several cows develop ketosis in early lactation, the ration may be too low in energy. If several cows develop milk fever at calving, the dry cow ration may be too high in calcium or potassium.

When to Call a Veterinarian or Extension Agent

You can handle many ration adjustments yourself, but some situations require professional help. Call a veterinarian or extension agent when:

• Multiple cows show signs of digestive upset, including off-feed, diarrhea, bloat, or sudden drops in production
• Cows develop ketosis, milk fever, or displaced abomasum
• Milk fat percentage drops below 3.0 percent and does not respond to ration adjustments
• Cows are losing excessive body condition despite adequate feed intake
• Feed tests reveal toxic levels of nitrates, mycotoxins, or minerals
• You are making a major change to your feeding program, such as switching from a total mixed ration to component feeding
• You are building a new ration from scratch and have limited experience with ration formulation
• Cows have unexplained health problems that may be related to nutrition

A veterinarian can diagnose health problems and rule out infectious causes. An extension agent or nutritionist can help you formulate a ration, interpret feed tests, and evaluate the economics of your feeding program.

Frequently Asked Questions

How much grain should I feed to a dairy cow on a forage-based ration?

The amount of grain depends on forage quality and milk production. A cow producing 60 pounds of milk per day on good quality alfalfa and corn silage might need 10 to 14 pounds of grain dry matter per day. A cow producing 100 pounds of milk might need 20 to 24 pounds. Start with a ration formulated by a nutritionist or extension agent, then adjust based on milk production, body condition, and manure consistency. Do not feed more than 8 pounds of grain per feeding, because large meals of starch can cause acidosis.

Can I feed only homegrown feeds and no purchased supplements?

It is possible but rarely practical. Most homegrown feeds do not supply balanced minerals and vitamins, and many are deficient in protein or energy for high-producing cows. You can reduce purchased feeds substantially, but you will almost always need a commercial mineral and vitamin premix, and often a protein supplement. If you want to minimize purchased feeds, choose forages and grains that complement each other, such as alfalfa for protein and corn for energy.

How do I know if my corn silage is good enough to feed?

Have it tested by a commercial laboratory. Good corn silage should have 30 to 38 percent dry matter, 7 to 9 percent crude protein, 40 to 50 percent NDF, and 0.68 to 0.75 Mcal of net energy per pound of dry matter. It should smell sweet and fermented, not like butyric acid or mold. The kernels should be cracked or processed so the starch is available to the cow.

What is the best way to introduce a new batch of silage to the cows?

Gradually mix the new silage with the old silage over 7 to 10 days. Start with 25 percent new silage and 75 percent old silage, then increase the proportion every few days. Watch for changes in intake, manure consistency, and milk fat percentage. If cows go off feed or milk fat drops, slow the transition.

How do I prevent milk fat depression when feeding high levels of corn silage?

Milk fat depression is caused by low effective fiber and high starch in the ration. Keep forage at 45 to 55 percent of dry matter, with at least 19 to 22 percent of the dry matter as forage NDF. Include some long-stemmed hay or haylage to provide effective fiber. Limit corn silage to 50 to 60 percent of the forage dry matter. Avoid feeding finely ground grain and keep the ration particle length adequate.

Should I feed raw soybeans to my dairy cows?

Raw soybeans can be fed at 3 to 4 pounds per cow per day, but they contain trypsin inhibitors that reduce protein digestion and oil that can depress milk fat. Roasted or extruded soybeans are better, because heat processing inactivates the trypsin inhibitors. If you feed raw soybeans, limit the amount and monitor milk fat percentage.

How do I balance a ration for dry cows?

Dry cows need a lower energy ration, around 0.58 to 0.62 Mcal of net energy per pound of dry matter, and lower calcium, around 0.4 percent of dry matter. Feed 12 to 14 percent crude protein and adequate fiber. Limit corn silage and other high-energy feeds. Use a mineral premix formulated for dry cows, not lactating cows. Separate dry cows from lactating cows and feed them a different ration.

What should I do if my cows are not eating enough of the ration I formulated?

First check feed quality. Smell and look at the feed for mold, spoilage, or heating. Check water availability and quality. Check for overcrowding at the feed bunk and ensure every cow has space to eat. Check for heat stress and provide shade and ventilation. If the feed is palatable and the environment is good, have the ration analyzed for nutrient content and compare it to the cows' requirements. The ration may be too high in NDF, which limits intake, or too low in energy, which causes the cow to reduce intake.

Related Farming Guides

This section will be populated programmatically with links to other farming guides on this site. Check back for related articles on dairy cow nutrition, forage production, herd health management, and feed storage.

Related Clinical & Scientific Guides

• Evaluating Feed Additives for Dairy Cow Performance
• Dairy Barn Fire Safety: Design and Prevention Measures
• Dairy Cow Pregnancy Loss Records and Review

References

• National Mastitis Council: https://www.nmconline.org/
• USDA APHIS Dairy Cattle Health: https://www.aphis.usda.gov/livestock-poultry-disease/cattle
• FAO Dairy Production and Products: https://www.fao.org/dairy-production-products/en/
• FAO Animal Production and Health: https://www.fao.org/animal-production/en/
• WOAH (World Organisation for Animal Health): https://www.woah.org/en/home/

This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.