Byproduct Feeds for Livestock: Economic and Nutritional Considerations

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

Key Takeaways

• Byproduct feeds offer economic advantages by leveraging secondary products from processing, but their true value is determined by cost per unit of usable nutrient, not per ton, necessitating dry matter conversion and nutrient-specific comparisons (e.g., cost per Mcal net energy for growing cattle).
• Critical quality control involves rigorous testing of each load for moisture, nutrient content, and potential contaminants like sulfur (risk of polioencephalomalacia in cattle), mycotoxins (in bakery waste), or excessive salt, as variability is inherent and book values are insufficient.
• Successful integration requires gradual introduction (10-14 days) to allow rumen microbial adaptation, preventing digestive upset, acidosis, or bloat, and necessitates careful ration balancing to account for specific nutrient profiles (e.g., high phosphorus in distillers grains, low calcium in soybean hulls).
• Storage and handling logistics are paramount; wet byproducts demand rapid consumption or specialized storage (bunkers, bags) due to spoilage and freezing, while dry byproducts require protection from moisture and pests, with all associated costs impacting the final economic viability.
• Comprehensive recordkeeping of delivery dates, feed test results, ration changes, and animal performance (intake, body condition, health events) is essential for defensible decision-making, early problem detection, and optimizing the safe and profitable use of byproduct feeds.

Feeding livestock is often the largest variable cost on a farm, and finding ways to reduce that expense without sacrificing animal health or performance is a constant challenge. This guide covers the practical use of byproduct feeds for livestock, including distillers grains for cattle, soybean hulls for sheep, and bakery waste in pig feed. It is written for livestock producers, farm managers, and agricultural advisors who want to evaluate alternative livestock feeds based on nutrition, economics, and on-farm logistics. You will learn how to source, store, ration, and monitor byproduct feeds safely, and you will see the decision points that determine whether a byproduct is a genuine bargain or a hidden cost.

At a Glance

The most important practical takeaways are these. First, byproduct feeds are not generic commodities. Each load can vary in moisture, nutrient content, and contamination risk, so you must test before you trust. Second, the true value of a byproduct is not its price per ton but its price per unit of usable nutrient. Third, you need a consistent ration, not just a cheap ingredient. Sudden changes in feed cause digestive upset, reduced intake, and lost performance. Fourth, storage and handling costs can erase the savings from a low purchase price, so account for those before you commit. Finally, keep records of every load, every test result, and every ration change so you can make defensible decisions and spot problems early.

Understanding Byproduct Feeds and Why They Matter

Byproduct feeds are the secondary products from food, fiber, and biofuel processing. When a mill processes wheat into flour, the bran and middlings are byproducts. When an ethanol plant ferments corn into fuel, the remaining distillers grains are a byproduct. When a bakery makes bread, the unsold or imperfect loaves become bakery waste. These materials have value as livestock feed, often at a price below traditional grains and oilseed meals.

The economic logic is straightforward. The primary processor has already paid for the crop, the transportation, and the processing labor. The byproduct is a secondary revenue stream, so it is often priced to move quickly rather than to maximize profit. For the livestock producer, this creates an opportunity to buy nutrients at a discount. But the opportunity comes with strings attached. Byproducts are variable, perishable, and sometimes contaminated. They are not complete feeds. They require careful ration balancing, storage planning, and monitoring.

The rise of the ethanol industry has made distillers grains for cattle a major feed category. A single ethanol plant can produce thousands of tons of wet distillers grains per day, and cattle feeders located within a reasonable trucking distance can capture real savings. Similarly, the human food industry generates steady streams of bakery waste, vegetable trimmings, and fruit pulp that can replace a portion of grain in pig and cattle rations. Soybean hulls, a byproduct of soybean crushing, have become a standard ingredient in sheep and cattle rations because they provide digestible fiber without the starch of corn.

The key to successful use of alternative livestock feeds is to match the byproduct to the animal and the production system. A high-fiber byproduct like soybean hulls works well in a ewe flock on a maintenance diet but poorly in a weanling pig ration. A high-fat byproduct like bakery waste works well for growing pigs but can cause butterfat depression in dairy cows if overfed. A high-sulfur byproduct like distillers grains can cause a thiamine deficiency in cattle if it displaces too much forage. Understanding these interactions is the difference between a profitable feed strategy and a costly mistake.

Evaluating the True Cost of Byproduct Feeds

The first question a producer asks is usually, "What does it cost per ton?" That is the wrong first question. The right first question is, "What does it cost per unit of the nutrient I need?" A feed that costs 60 percent of the price of corn but contains only 50 percent of the energy of corn is not a bargain. A feed that costs 80 percent of corn but contains 90 percent of the energy is a better deal.

To compare byproduct feeds on an equal basis, you need to know the nutrient content of each candidate feed and the nutrient requirements of your animals. The most useful comparison is on a dry matter basis. Byproducts vary widely in moisture. Wet distillers grains can be 65 percent moisture, while dried distillers grains are typically 10 to 12 percent moisture. If you compare prices on an as-fed basis, you are comparing water to grain. Always convert to a dry matter basis first.

Here is the calculation for a dry matter price comparison. Divide the as-fed price by the dry matter fraction. For example, if wet distillers grains cost $80 per ton as fed and contain 35 percent dry matter, the price per ton of dry matter is $80 divided by 0.35, which is $228.57. If dried distillers grains cost $220 per ton as fed and contain 90 percent dry matter, the price per ton of dry matter is $220 divided by 0.90, which is $244.44. On a dry matter basis, the wet product is actually cheaper, before you account for the extra water you have to haul and handle.

The next step is to compare on a nutrient basis. If you are feeding a growing beef animal and the limiting nutrient is energy, compare the cost per megacalorie of net energy. If you are feeding a lactating ewe and the limiting nutrient is protein, compare the cost per pound of crude protein. The formula is the same. Divide the dry matter price by the nutrient concentration. This gives you a cost per unit of nutrient that you can compare across feeds.

Do not forget the handling costs. Wet byproducts require specialized storage, often a bunker or a bag, and they freeze in winter. They are heavy to haul, and they spoil quickly in warm weather. Bakery waste can arrive in plastic-wrapped bales that require a bale buster to process. Some byproducts come in bulk tankers that require a pit or a pump. All of these costs eat into the apparent savings. A good rule of thumb is to add 10 to 15 percent to the purchase price to account for handling, storage, and shrink, and then compare that adjusted cost to your current feed.

Sourcing Byproduct Feeds and Verifying Quality

Once you have decided that a byproduct feed makes economic sense, the next step is to find a reliable source. Byproduct feeds come from food processors, ethanol plants, grain mills, bakeries, and rendering plants. Some are available directly from the processor, and some are brokered through feed dealers. The direct route is usually cheaper, but it requires more work on your part to verify quality and arrange logistics.

Start by contacting the processing plant in your area. Ask to speak with the byproduct sales representative or the plant manager. Ask what byproducts they produce, in what volumes, and on what schedule. Some byproducts are produced daily, and some are seasonal. Ask about the variability of the product. Does the nutrient content change with the source grain or the processing conditions? Ask for a typical nutrient analysis and for recent test results.

You should also ask about additives and contaminants. Some byproducts contain processing aids, preservatives, or residues from cleaning chemicals. Ethanol plants may add sulfur to control yeast growth, which raises the sulfur content of the distillers grains. Bakery waste may contain salt, sugar, and fat in variable amounts, and it may include packaging material if the bakery does not separate it. You need to know what is in the product before you feed it.

When you are considering a new source, take a sample and have it analyzed by a commercial feed testing laboratory. A standard analysis includes dry matter, crude protein, fat, fiber, ash, and often minerals. If you are feeding cattle or sheep, also test for sulfur. If you are feeding pigs, test for salt and consider a mycotoxin screen. The cost of a feed test is small compared to the cost of a feeding mistake.

Establish a sampling protocol. For dry byproducts, take samples from multiple bags or from multiple points in a bulk load. For wet byproducts, take samples from multiple locations in the pile or truck and mix them thoroughly. Store the sample in a sealed plastic bag and keep it cool until you ship it to the lab. Keep a record of the sample date, the source, and the test results.

Do not rely on a single test. Byproduct feeds vary from load to load. If you are feeding a byproduct on an ongoing basis, test each new load or at least test monthly. Keep a running log of nutrient values so you can adjust the ration as the feed changes. This is especially important for wet byproducts, which can vary in moisture from week to week.

Distillers Grains for Cattle

Distillers grains are the most widely used byproduct feed in the cattle industry, and for good reason. They are high in protein, high in energy, and rich in phosphorus. They are also palatable, and cattle adapt to them readily. The two main forms are wet distillers grains and dried distillers grains with solubles, often abbreviated as DDGS.

Wet distillers grains contain about 30 to 35 percent dry matter and are typically fed at 20 to 40 percent of the ration dry matter in growing and finishing cattle. They are cheaper per unit of dry matter than the dried product because the drying cost is eliminated, but they are heavy to haul and they spoil quickly. In warm weather, wet distillers grains can begin to spoil within three to five days. You need a concrete pad or a bunker silo to store them, and you need to feed them fast enough to stay ahead of spoilage. In winter, wet distillers grains freeze into a solid mass that is difficult to handle.

Dried distillers grains contain about 88 to 90 percent dry matter and store well in a dry bin or shed. They are easier to handle and can be transported longer distances. The drying process adds cost, so the dried product is more expensive per unit of dry matter. Dried distillers grains also flow well in a mixer wagon and can be blended into a total mixed ration without difficulty.

The nutrient profile of distillers grains is the reason they work so well in cattle rations. They contain about 27 to 35 percent crude protein on a dry matter basis, and much of that protein is undegradable in the rumen, which means it bypasses the rumen and is absorbed in the lower digestive tract. This makes distillers grains an excellent protein supplement for cattle on low-quality forage. They also contain about 9 to 12 percent fat, which boosts the energy density of the ration.

The main caution with distillers grains is sulfur. The sulfur content can range from 0.3 to over 1.0 percent on a dry matter basis, depending on the source and the processing method. High sulfur intake can cause a condition called polioencephalomalacia, often called polio, which is a thiamine deficiency that affects the brain. Symptoms include blindness, head pressing, incoordination, and recumbency. Polio is a medical emergency, and affected animals need immediate veterinary treatment.

To avoid sulfur toxicity, keep the total sulfur content of the ration below 0.4 percent of the dry matter for cattle on high-concentrate diets and below 0.3 percent for cattle on high-forage diets. This means you need to know the sulfur content of your distillers grains and your water. Well water in some regions is high in sulfur, and that can push the total over the limit. Test both the feed and the water before you formulate the ration.

Another consideration with distillers grains is phosphorus. The phosphorus content is about 0.8 to 1.0 percent on a dry matter basis, which is higher than most grains. This is an advantage if you are feeding growing cattle because it reduces the need for supplemental phosphorus. But it can be a problem if you are feeding breeding animals on pasture, because excess phosphorus in the manure can build up in the soil over time. If you spread manure on the same fields year after year, monitor soil phosphorus levels and adjust your fertilizer program accordingly.

For dairy cows, distillers grains can be fed at 10 to 20 percent of the ration dry matter. The fat content can cause milk fat depression if the total fat in the ration exceeds about 5 percent of dry matter. Work with a nutritionist to balance the ration and monitor milk fat percentage on the bulk tank.

Soybean Hulls for Sheep

Soybean hulls are a byproduct of soybean processing. When soybeans are crushed to extract oil, the hulls are removed and can be sold as a feed ingredient. Soybean hulls are high in fiber, about 34 to 38 percent neutral detergent fiber on a dry matter basis, but that fiber is highly digestible. They are low in starch and moderate in protein, about 12 percent crude protein on a dry matter basis.

Soybean hulls are an excellent feed for sheep, especially for ewes in mid to late gestation and for growing lambs on a forage-based diet. The digestible fiber provides energy without the starch load of corn, which reduces the risk of acidosis. Soybean hulls are also a good supplement for sheep on low-quality forage because they provide energy without depressing fiber digestion in the rumen.

The most common form is pelleted soybean hulls. The pelleting process makes the product easier to handle and reduces waste, but it also makes the particles smaller and more dense. Fine particles can increase the rate of fermentation in the rumen, which can lead to bloat if sheep consume too much too quickly. Introduce soybean hulls gradually over 10 to 14 days, and make sure sheep have access to long-stem forage to maintain rumen function.

For a ewe flock on pasture, soybean hulls can be fed at 0.5 to 1.5 pounds per ewe per day, depending on forage quality and stage of production. In late gestation, when the lambs are growing rapidly and the ewe's rumen capacity is reduced, soybean hulls provide a concentrated source of energy that is easy to digest. In early lactation, soybean hulls can support milk production without causing the fattening that can come from heavy grain feeding.

For growing lambs, soybean hulls can replace a portion of the corn in a finishing ration. The lower starch content reduces the risk of acidosis, and the digestible fiber supports rumen health. A typical finishing ration for lambs might include 30 to 50 percent soybean hulls on a dry matter basis, along with corn, a protein supplement, and minerals. Work with a nutritionist to balance the ration for your specific lambs and your feed inventory.

The main caution with soybean hulls is the calcium to phosphorus ratio. Soybean hulls are low in calcium and relatively high in phosphorus. If you are feeding a high proportion of soybean hulls to growing wethers, the calcium to phosphorus ratio can drop below the recommended 2 to 1, which increases the risk of urinary calculi, or water belly. This is a blockage of the urinary tract that is often fatal in wethers. To prevent it, add limestone or another calcium source to the ration to bring the calcium to phosphorus ratio to at least 2 to 1, and make sure the sheep have free access to clean water at all times. Ammonium chloride can also be added to the ration to help prevent calculi formation.

Another consideration is the particle size of soybean hulls. If you are feeding loose soybean hulls, sheep may sort through the feed and leave the fines, which reduces the nutritional value of what they actually consume. Pelleted soybean hulls reduce sorting and waste. If you are feeding loose hulls, mix them thoroughly with other feed ingredients and consider adding a small amount of molasses to bind the fines.

Storage of soybean hulls is straightforward. They are dry and have a low moisture content, so they store well in a bin, a shed, or under a tarp. Protect them from moisture, because wet soybean hulls will mold and spoil. Check stored hulls regularly for signs of heating or mold, and use older stock before newer stock.

Bakery Waste in Pig Feed

Bakery waste is a broad category that includes bread, buns, rolls, pastries, cookies, and other baked goods that are unsold, damaged, or past their sell-by date. It is a high-energy feed that is well suited to growing and finishing pigs. The energy comes from the starch in the flour and the fat in the shortening and oils. Bakery waste is low in protein, typically 10 to 12 percent crude protein on a dry matter basis, and it is low in fiber.

The main advantage of bakery waste in pig feed is cost. Bakeries are often willing to sell their waste at a low price, or even give it away, because they need to dispose of it. If you are located near a bakery, the trucking cost may be low enough to make bakery waste a genuine bargain. The main disadvantage is variability. The composition of bakery waste changes with what the bakery is producing. One load might be mostly white bread, and the next might be mostly donuts. This variability makes it difficult to formulate a consistent ration.

Before you feed bakery waste to pigs, you need to know what is in it. Ask the bakery for a list of ingredients and for any information about the types of products that are typically discarded. Ask about packaging. Some bakeries separate the waste from the packaging, and some do not. Plastic packaging can cause intestinal blockages in pigs, and it is not acceptable in a feed. If the bakery cannot guarantee that the waste is free of packaging, do not use it.

Bakery waste is often high in salt. Bread and other baked goods contain salt, and the salt content can vary from 1 to 3 percent on a dry matter basis. Pigs can tolerate a certain amount of salt, but too much causes salt poisoning, which affects the brain and can be fatal. The symptoms include tremors, seizures, and coma. To avoid salt poisoning, limit bakery waste to no more than 20 to 30 percent of the ration dry matter, and test the bakery waste for salt before you feed it. Provide plenty of clean, fresh water at all times.

Bakery waste is also a risk for mycotoxins. Mycotoxins are toxic compounds produced by molds, and they can develop in bakery waste if it is stored improperly or if the raw ingredients were contaminated. The most common mycotoxins in bakery waste are aflatoxin and vomitoxin, also called deoxynivalenol or DON. Aflatoxin affects the liver and immune system, and vomitoxin reduces feed intake and causes vomiting. If you are feeding bakery waste on a regular basis, have it tested for mycotoxins, especially if you are feeding breeding animals or young pigs.

The form of bakery waste matters. Some bakeries sell their waste as whole loaves and buns, which need to be processed before feeding. You can run the waste through a hammermill or a roller mill to break it into smaller pieces, or you can mix it with other feed ingredients in a mixer wagon. Some bakeries sell their waste already ground or pelleted, which is easier to handle. Whole loaves are difficult for pigs to eat efficiently, and they can lead to waste and sorting.

When you introduce bakery waste into a pig ration, do it gradually over 10 to 14 days. Pigs need time to adapt to a new feed, and a sudden change can cause digestive upset and reduced intake. Start with 10 percent of the ration and increase it slowly to the target level. Monitor feed intake and pig behavior during the transition period.

For growing and finishing pigs, bakery waste can replace a portion of the corn in the ration. A typical inclusion rate is 15 to 30 percent of the ration dry matter. Because bakery waste is higher in fat than corn, it provides more energy per pound. But the fat content also means that bakery waste can become rancid, especially in hot weather. Rancid fat has a reduced energy value and can cause off-flavors in pork. Store bakery waste in a cool, dry place and use it within a few weeks of delivery.

Do not feed bakery waste to young piglets or to gestating sows without careful ration balancing. Piglets have a limited capacity to digest fat, and sows can become overly fat if they consume too much energy. For lactating sows, bakery waste can be included at modest levels, but the ration should be balanced by a nutritionist.

Corn Gluten Feed and Other Byproducts

Corn gluten feed is a byproduct of the wet milling of corn. It is lower in protein than distillers grains, about 18 to 21 percent crude protein on a dry matter basis, and higher in fiber. It is a good feed for cattle and sheep, especially when it is priced below corn and soybean meal. Corn gluten feed is palatable and can be included at 20 to 40 percent of the ration dry matter for growing and finishing cattle.

The main caution with corn gluten feed is the calcium to phosphorus ratio. It is very low in calcium and high in phosphorus, with a calcium to phosphorus ratio of about 1 to 5. This is a problem for growing wethers and for any animal that needs a calcium to phosphorus ratio of at least 1.5 to 1. Add limestone or another calcium source to balance the ration, and monitor for urinary calculi in wethers.

Cottonseed meal is a byproduct of cottonseed processing. It is high in protein, about 41 to 45 percent crude protein on a dry matter basis, and it is an excellent protein supplement for cattle and sheep on low-quality forage. The main caution is free gossypol, a compound that is toxic to young animals and to breeding animals. Free gossypol can cause reduced fertility in bulls and rams, and it can be toxic to calves and lambs. Limit cottonseed meal to no more than 1 pound per head per day for mature cattle and to less for young animals. Do not feed cottonseed meal to young calves or lambs.

Citrus pulp is a byproduct of orange and grapefruit processing. It is high in energy and low in protein, about 6 to 7 percent crude protein on a dry matter basis. It is a good feed for beef cattle and sheep, especially in the Southeast where citrus processing is common. Citrus pulp is palatable and can be included at 20 to 30 percent of the ration dry matter. The main caution is spoilage. Citrus pulp is high in moisture when it comes out of the processing plant, and it spoils quickly. It can be ensiled or dried, but both options add cost.

Wheat middlings, often called midds, are a byproduct of wheat flour milling. They are moderate in protein, about 15 to 18 percent crude protein on a dry matter basis, and moderate in fiber. They are a good feed for pigs, cattle, and sheep. The main caution is rancidity. Wheat middlings contain fat that can become rancid in hot weather, which reduces the energy value and can cause off-flavors in pork and milk. Store middlings in a cool, dry place and use them within a few weeks.

Ration Formulation and Balancing

A byproduct feed is an ingredient, not a complete ration. You must balance the ration to meet the nutrient requirements of your animals, and you must account for the nutrients in the byproduct. The first step is to know the nutrient requirements of your animals. These are published by the National Research Council for each species, and they vary by age, weight, stage of production, and expected performance. Your extension agent or a livestock nutritionist can help you find the right requirements for your situation.

The second step is to know the nutrient content of all of your feed ingredients, including the byproduct. Use the results from your feed tests, not the book values, because the actual nutrient content can vary from the average. The third step is to formulate a ration that meets the requirements for energy, protein, minerals, and vitamins. This can be done by hand with a spreadsheet, or you can use a commercial ration balancing program.

When you are using byproduct feeds, pay special attention to the following nutrients. Protein is important, but so is the type of protein. Some byproducts, like distillers grains, are high in bypass protein, which is useful for cattle on high-forage diets. Others, like bakery waste, are low in protein and may require supplemental soybean meal. Fiber is important for rumen health. Byproducts like soybean hulls and corn gluten feed are high in fiber, but the fiber is highly digestible. Fat is important for energy, but too much fat can cause digestive upset and milk fat depression. Sulfur is a risk with distillers grains and some other byproducts. Calcium and phosphorus must be balanced, especially with byproducts that are high in phosphorus.

When you introduce a byproduct into the ration, do it gradually over 10 to 14 days. This gives the rumen microbes time to adapt to the new feed, and it reduces the risk of acidosis, bloat, and feed refusal. Start with a small amount and increase it slowly to the target level. Monitor feed intake, manure consistency, and animal behavior during the transition period.

Storage and Handling of Byproduct Feeds

Proper storage is essential for byproduct feeds. The storage requirements vary by the type of byproduct and its moisture content. Dry byproducts, like dried distillers grains, soybean hulls, and wheat middlings, can be stored in a bin, a shed, or under a tarp. They need to be protected from moisture, because wet feed will mold and spoil. They also need to be protected from rodents and birds, which can contaminate the feed and spread disease.

Wet byproducts, like wet distillers grains and citrus pulp, require more careful management. They spoil quickly in warm weather, so you need to feed them within a few days of delivery. They can be stored on a concrete pad and covered with a tarp, or they can be stored in a bunker silo. In winter, wet byproducts freeze, which makes them difficult to handle. You may need to use a skid steer or a tractor with a bucket to break up the frozen material.

Bakery waste requires special handling. It often comes in large bales wrapped in plastic, and you need a bale buster or a mixer wagon with a bale processor to break it up. It can be stored outside, but the plastic wrap will degrade in sunlight, so store it in the shade or under a tarp. Check bakery waste regularly for signs of mold or spoilage, and do not feed spoiled material.

When you are planning your storage, think about the flow of feed on your farm. You want to store the byproduct close to where you will feed it, to minimize hauling. You also want to store it so that you use the oldest material first. This is called first in, first out, and it reduces the risk of spoilage. Write the delivery date on each pile or bin, and keep a record of what you have on hand.

Common Mistakes and How to Avoid Them

The most common mistake with byproduct feeds is assuming that all loads are the same. They are not. Moisture, nutrient content, and contamination can vary from load to load, and even within a single load. Test every load, or at least test frequently, and adjust the ration accordingly.

The second most common mistake is feeding too much too quickly. Byproduct feeds are often very palatable, and animals will eat them readily. But a sudden change in the ration can cause digestive upset, acidosis, bloat, and feed refusal. Introduce byproducts gradually over 10 to 14 days.

The third most common mistake is ignoring the mineral balance. Many byproducts are high in phosphorus and low in calcium, which can cause urinary calculi in wethers and rams. Others are high in sulfur, which can cause polio in cattle. Test for these minerals and balance the ration.

The fourth most common mistake is forgetting the water. Some byproducts, like wet distillers grains, contain a lot of water. This water counts toward the animal's water intake, but it is not a substitute for clean, fresh drinking water. Always provide free access to clean water, especially when feeding high-salt byproducts like bakery waste.

The fifth most common mistake is not accounting for handling costs. A cheap byproduct can become expensive when you add the cost of trucking, storage, and processing. Calculate the true cost per unit of nutrient before you commit to a byproduct.

The sixth most common mistake is not monitoring animal performance. Byproduct feeds can change the growth rate, milk production, and body condition of your animals. Weigh animals regularly, monitor milk production, and adjust the ration as needed. If performance drops, investigate the cause before it becomes a bigger problem.

Decision Thresholds for Using Byproduct Feeds

How do you know when a byproduct feed is a good deal? The decision comes down to a few key thresholds. First, the price per unit of nutrient must be lower than your current feed. Calculate the cost per pound of crude protein and the cost per megacalorie of net energy for both the byproduct and your current feed. Choose the feed that provides the nutrient at the lower cost.

Second, the handling and storage costs must not erase the savings. If you need to build a new bunker or buy a bale buster, add that cost to the byproduct price. A good rule of thumb is to add 10 to 15 percent to the purchase price to account for handling, storage, and shrink. If the adjusted price is still lower than your current feed, the byproduct is a good deal.

Third, the quality must be consistent enough to formulate a ration. If the byproduct varies wildly in moisture or nutrient content, you will spend more time testing and adjusting, and you will have more risk of a feeding mistake. A byproduct that is consistent and predictable is worth more than one that is variable.

Fourth, the supply must be reliable. If the byproduct is only available seasonally, or if the processor can shut down without notice, you need a backup plan. Do not build your entire feeding program around a byproduct that might not be available next month.

Fifth, the byproduct must be safe for your animals. This means testing for contaminants like mycotoxins, sulfur, salt, and packaging material. If you cannot verify the safety of the byproduct, do not feed it.

Monitoring and Recordkeeping

Good recordkeeping is essential when you are using byproduct feeds. Keep a log of every load you receive, including the date, the source, the quantity, and the price. Record the results of every feed test, including the dry matter, crude protein, fat, fiber, and minerals. Record the ration you are feeding and any changes you make.

Monitor your animals closely when you are feeding byproducts. Watch for changes in feed intake, body condition, manure consistency, and behavior. Weigh animals regularly, or at least evaluate body condition scores on a monthly basis. For dairy cows, monitor milk production and milk fat percentage. For breeding animals, monitor conception rates and the health of newborns.

If you see a problem, investigate it quickly. A sudden drop in feed intake could be a sign of a spoiled batch of byproduct. A case of bloat could be a sign that the ration is out of balance. A case of polio in cattle could be a sign of excess sulfur. Keep records of any health problems and any treatments, so you can look for patterns.

Work with your veterinarian and your extension agent. They can help you interpret feed test results, diagnose health problems, and adjust your ration. They can also help you develop a herd health plan that accounts for the risks of byproduct feeding.

When to Call a Veterinarian or Extension Agent

Some situations require professional help. Call your veterinarian immediately if you see signs of polio in cattle, including blindness, head pressing, incoordination, or recumbency. This is a medical emergency that requires immediate treatment. Call your veterinarian if you see signs of salt poisoning in pigs, including tremors, seizures, or coma. Call your veterinarian if you see signs of urinary calculi in wethers, including straining to urinate, kicking at the belly, or a swollen sheath. This condition can be fatal if not treated promptly.

Call your veterinarian if you see a sudden increase in illness or death in your herd or flock. This could be a sign of a contaminated batch of byproduct, a nutritional deficiency, or an infectious disease. Do not wait to see if the problem resolves on its own.

Call your extension agent if you need help with ration formulation, feed testing, or economic analysis. Extension agents have access to resources and expertise that can help you make better feeding decisions. They can also help you connect with nutritionists and other specialists.

Call your extension agent if you are considering a new byproduct feed and you are not sure how to evaluate it. They can help you calculate the true cost, identify the risks, and develop a feeding plan.

Frequently Asked Questions

Can I feed byproduct feeds to all classes of livestock?

No. Each byproduct has specific uses and limitations. Distillers grains work well for cattle but are less suitable for pigs and poultry because of the fiber and sulfur content. Soybean hulls work well for sheep and cattle but are too fibrous for young pigs. Bakery waste works well for pigs but can cause milk fat depression in dairy cows. Match the byproduct to the species, age, and production stage of your animals.

How do I know if a byproduct feed is a good deal?

Calculate the cost per unit of the nutrient you need. Compare the cost per pound of crude protein and the cost per megacalorie of net energy between the byproduct and your current feed. Add 10 to 15 percent to the byproduct price to account for handling, storage, and shrink. If the adjusted cost is lower, the byproduct is a good deal.

How long can I store wet distillers grains?

Wet distillers grains can be stored for three to five days in warm weather before they begin to spoil. In cooler weather, they may last a week or more. They can be stored longer in a bunker silo or in a bag, but they should be fed within a few weeks. Freezing extends the storage life but makes handling more difficult.

Can I feed bakery waste to my pigs?

Yes, bakery waste can be a good feed for growing and finishing pigs, but it must be managed carefully. Limit it to 20 to 30 percent of the ration dry matter, test it for salt and mycotoxins, and make sure it is free of packaging material. Introduce it gradually and provide plenty of clean water.

What is the biggest risk with feeding distillers grains to cattle?

The biggest risk is sulfur toxicity, which can cause polioencephalomalacia, a brain condition that can be fatal. Keep the total sulfur content of the ration below 0.4 percent of dry matter for cattle on high-concentrate diets and below 0.3 percent for cattle on high-forage diets. Test both the feed and the water for sulfur.

How do I prevent urinary calculi in wethers fed soybean hulls?

Urinary calculi are caused by an imbalance of calcium and phosphorus in the ration. Soybean hulls are low in calcium and high in phosphorus, so add limestone or another calcium source to bring the calcium to phosphorus ratio to at least 2 to 1. Provide free access to clean water and consider adding ammonium chloride to the ration.

Do I need to test every load of byproduct feed?

Ideally, yes. Byproduct feeds vary from load to load, and the variation can be significant. At a minimum, test each new source and test monthly if you are feeding a byproduct on an ongoing basis. Test more frequently if the byproduct is variable or if you are feeding it to young or breeding animals.

What should I do if my animals refuse to eat a byproduct feed?

First, check the feed for spoilage, mold, or off-odors. If the feed is spoiled, remove it immediately. If the feed looks good, the issue may be palatability or a sudden change in the ration. Mix the byproduct with more palatable feeds, introduce it more gradually, or reduce the inclusion rate. If the problem persists, consult your veterinarian or extension agent.

Related Farming Guides

This section will be populated with links to related farming guides on livestock nutrition, feed management, and farm economics. Check back for updates or explore the site for more articles on practical livestock management.

Related Clinical & Scientific Guides

• Animal Welfare Audits: Building a Useful Farm Program
• Total Mixed Ration (TMR) for Dairy: Mixing and Feeding Management
• Feed Additives for Livestock: Probiotics, Enzymes, and More

References

• USDA Farm Management
• FAO Farm Management
• FAO Animal Production and Health
• WOAH (World Organisation for Animal Health)

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