# Livestock Machinery Ownership vs. Custom Hire: A Cost Comparison Guide ## Key Takeaways - Machinery ownership incurs significant fixed costs including depreciation, interest on capital, insurance, and housing, which must be factored into per-hour operational costs. Variable costs such as fuel, repairs, and tire replacement are directly tied to usage hours. - Custom hire rates encompass all operator costs, including machinery, labor, insurance, and profit, and are typically quoted per acre, ton, bale, or hour. This option avoids upfront capital investment but relinquishes control over timing. - A break-even analysis, calculated as total annual fixed costs divided by the difference between the custom rate per hour and the variable cost per hour, determines the usage threshold at which ownership becomes financially advantageous. - Non-monetary factors such as timeliness sensitivity for critical operations (e.g., feeding, harvesting), quality control requirements, biosecurity risks associated with custom operators, and worker safety considerations are crucial in the ownership versus custom hire decision. - Accurate record-keeping of machinery usage, repair costs, and custom hire expenses is essential for ongoing evaluation, allowing for recalculation of break-even points and informed adjustments to machinery management strategies. --- Livestock farmers face a recurring capital decision: whether to purchase machinery such as tractors, mowers, feeders, and manure spreaders or to hire custom operators for those tasks. This guide compares the full costs of machinery ownership-depreciation, interest, repairs, insurance, and storage-against custom hire rates for common livestock farm operations. It provides a break-even analysis framework so you can evaluate your own operation based on acres, hours of use, and enterprise type. The goal is to help you decide when ownership makes financial sense and when custom hire preserves capital for other farm investments. ## At a Glance: Ownership vs. Custom Hire Decision Table The table below summarizes the key factors that favor ownership or custom hire for typical livestock machinery categories. Use it as a starting point for your own cost analysis. | Machinery Category | Typical Annual Use (Hours) | Ownership Favored When | Custom Hire Favored When | | --- | --- | --- | --- | | Tractor (100+ HP) for haying and feeding | 400-800 | You have consistent forage acreage and multiple attachments, labor is available | Annual use is below 300 hours, you lack skilled operators or repair facilities | | Mower-conditioner or disc mower | 100-300 | You harvest hay from more than 100 acres annually, you want timeliness control | Acreage is under 50 acres, custom rates are competitive in your area | | TMR mixer or feed wagon | 200-600 | You feed more than 50 head of cattle year-round, you need precise ration control | Herd size is small or seasonal, you can contract feed delivery from a neighbor | | Manure spreader | 50-200 | You have consistent manure volume and field access, you want to avoid hauling delays | Manure volume is low or you can use a custom applicator who also provides nutrient management planning | ## Understanding Full Ownership Costs Ownership costs fall into two categories: fixed costs that occur regardless of use and variable costs that change with hours operated. A complete comparison requires accounting for both. ### Fixed Costs Depreciation is the largest fixed cost. It represents the loss in value as the machine ages and accumulates hours. Straight-line depreciation over the expected useful life is a common method. For example, a tractor purchased for USD 80,000 with a salvage value of USD 20,000 after 10 years depreciates USD 6,000 per year. Interest or opportunity cost on the capital tied up in the machine is another fixed cost. If you borrow money, the interest rate on the loan is a direct cost. If you pay cash, the opportunity cost is the return you could have earned by investing that money elsewhere. A typical range for interest cost is 4 to 8 percent of the average investment value per year. Insurance and housing are often overlooked. Insurance premiums for farm machinery vary by value and coverage level. Housing costs include shed or barn space, which can be estimated as a percentage of the machine's value or as a per-square-foot charge. ### Variable Costs Repairs and maintenance increase with hours of use. Older machines generally require more frequent repairs. Fuel and lubricants are direct operating costs that depend on engine size, load, and hours. Tires and belts wear out and need replacement at intervals tied to use. The sum of fixed and variable costs per hour gives the total ownership cost per hour. This figure is the minimum you must recover through the value of the work performed or the custom rate you would otherwise pay. ## Understanding Custom Hire Rates Custom hire rates are the fees charged by operators who perform specific tasks with their own equipment. Rates vary by region, operation type, and market conditions. Common livestock-related custom operations include mowing, raking, baling, hauling hay, mixing feed, and spreading manure. Custom rates are typically quoted per acre, per bale, per ton, or per hour. They include the operator's costs for machinery, fuel, labor, insurance, and profit. When you hire a custom operator, you avoid all ownership costs but you give up control over timing and may have to wait during peak seasons. To compare custom hire with ownership, you need the custom rate for each operation you would otherwise perform with your own machine. Local USDA National Agricultural Statistics Service reports or state extension service surveys provide typical rates for your area. The USDA Economic Research Service provides farm economy data that includes information on input costs and custom rate trends. ## Break-Even Analysis: When Ownership Pays Break-even analysis answers the question: How many hours or acres must I use a machine each year for ownership to be cheaper than custom hire? The formula is: Break-even hours per year = Total annual fixed costs / (Custom rate per hour - Variable cost per hour) For example, suppose a tractor has annual fixed costs of USD 8,000 (depreciation, interest, insurance, housing). The variable cost per hour is USD 15 (fuel, repairs, tires). The custom rate for tractor work is USD 45 per hour. Break-even hours = USD 8,000 / (USD 45 - USD 15) = USD 8,000 / USD 30 = 267 hours per year If you expect to use the tractor more than 267 hours per year, ownership is cheaper per hour. If you expect less than 267 hours, custom hire is cheaper. This calculation must be done for each machine or operation. The break-even point shifts if custom rates rise or fall, if your fixed costs change, or if your variable costs differ from the estimate. ## Practical Steps for Evaluating Your Operation Follow these steps to assess whether ownership or custom hire makes sense for your livestock farm. ### Step 1: List All Machinery Operations Write down every powered task on your farm: mowing, raking, tedding, baling, hauling hay, mixing feed, feeding, spreading manure, hauling water, moving livestock, and any tillage or planting. Include the estimated hours per year for each task. ### Step 2: Gather Cost Data Collect the following for each machine you already own or are considering purchasing: - Purchase price or current market value - Expected useful life in years - Salvage value at end of life - Loan interest rate or opportunity cost rate - Annual insurance premium - Annual housing cost - Fuel consumption per hour - Repair and maintenance history or estimates - Tire and belt replacement intervals and costs For custom hire, obtain current rates from local custom operators, extension service reports, or USDA NASS surveys. ### Step 3: Calculate Ownership Cost Per Hour Use the following method: Annual depreciation = (Purchase price - Salvage value) / Useful life in years Average investment value = (Purchase price + Salvage value) / 2 Annual interest cost = Average investment value x Interest rate Total annual fixed costs = Depreciation + Interest + Insurance + Housing Variable cost per hour = Fuel cost per hour + Repair cost per hour + Tire cost per hour Total ownership cost per hour = (Total annual fixed costs / Annual hours) + Variable cost per hour ### Step 4: Compare to Custom Rate If your total ownership cost per hour is lower than the custom rate for that operation, ownership is cost-effective at your current hours. If it is higher, custom hire is cheaper. ### Step 5: Perform Break-Even Analysis Use the break-even formula from the previous section. If your actual hours are above the break-even point, ownership is justified. If below, consider custom hire or sharing machinery with a neighbor. ## Records and Measurements for Informed Decisions Accurate records are essential for comparing ownership and custom hire costs. Without them, you are guessing. ### Machinery Cost Records Maintain a log for each machine that includes: - Purchase date and price - Annual hours of use - Fuel consumption per hour - Repair costs by date and component - Insurance premiums - Housing costs This data allows you to calculate your actual ownership cost per hour instead of relying on estimates. Over several years, you can identify trends such as rising repair costs as the machine ages. ### Custom Hire Records For each custom operation, record: - Date and task performed - Acres, tons, bales, or hours - Rate charged - Operator name and contact - Timeliness issues or delays Compare these records to your ownership cost calculations. If custom rates rise faster than your ownership costs, the break-even point shifts in favor of ownership. ### Enterprise Records Link machinery costs to specific livestock enterprises. For example, track the cost of haying equipment against the value of hay fed to beef cows or dairy heifers. This helps you see whether machinery costs are justified by the returns from the livestock enterprise. ## Common Failure Patterns in Machinery Decisions Farmers often make mistakes when comparing ownership and custom hire. Recognizing these patterns can help you avoid them. ### Underestimating Fixed Costs Depreciation and interest are real costs even if you do not write a check for them each month. Farmers who ignore these costs often believe their machinery is cheaper than it actually is. A tractor that is paid off still has an opportunity cost if it could be sold and the proceeds invested. ### Overestimating Annual Use Many farmers buy a machine expecting to use it 500 hours per year but end up using it 200 hours. The fixed costs are spread over fewer hours, making the cost per hour much higher than anticipated. Be conservative in your use estimates. ### Ignoring Repair Costs on Older Machines As machines age, repair costs can escalate rapidly. A machine that was cost-effective at 10 years old may become a money loser at 15 years old. Track repair costs annually and recalculate your break-even point. ### Failing to Account for Labor Custom hire rates include labor. Ownership costs do not include the value of your own labor or the labor of family members. If you value your labor at a market rate, add it to the ownership cost per hour for a fair comparison. ### Buying for a Single Task A machine that is used for only one task, such as a specialized feeder or a manure spreader, has a narrow cost recovery window. If that task can be custom hired at a reasonable rate, ownership is hard to justify unless the machine is used many hours per year. ## Welfare and Safety Context Machinery decisions affect animal welfare and worker safety in ways that go beyond cost. ### Animal Welfare Considerations Timeliness of feeding and bedding operations directly affects animal welfare. If you own your feeder or mixer, you control the schedule. If you rely on a custom operator, you may face delays during bad weather or when the operator is busy with other clients. Delays in feeding can cause stress, reduced feed intake, and health problems in livestock. Similarly, manure spreading must be done when fields are accessible and conditions are right. A custom operator may not be available at the optimal time, leading to manure storage overflow or application on wet soils that cause compaction and runoff. The USDA National Agricultural Library provides resources on animal health and welfare that include the importance of consistent feeding schedules and clean living conditions. Owning your equipment can help you meet these welfare standards more reliably. ### Worker Safety Machinery ownership requires you to train operators, maintain safety guards, and follow safe operating procedures. Tractors, mowers, and mixers pose risks of rollovers, entanglement, and crushing injuries. Custom operators are responsible for their own safety training and equipment maintenance, which shifts some liability away from you. However, you still have a duty to provide a safe workplace if you employ workers who operate your machinery. The USDA Agricultural Research Service conducts research on animal production and protection that includes worker safety in livestock operations. ### Biosecurity Custom operators move between farms, which creates a biosecurity risk. They can carry pathogens on tires, boots, and equipment. If you own your machinery, you control cleaning and disinfection protocols. If you hire custom operators, you must verify that they follow biosecurity practices between farms. The U.S. Food and Drug Administration provides animal and veterinary resources that address disease prevention. Consider biosecurity as a non-monetary factor in the ownership versus custom hire decision. ## Limitations of the Comparison The ownership versus custom hire comparison has limitations that you should understand. ### Market Variability Custom rates change with fuel prices, labor availability, and demand for services. A rate that is favorable today may be unfavorable next year. Ownership costs are more predictable once you own the machine, but they are also subject to changes in repair costs and fuel prices. ### Quality Differences Custom operators may not perform work to your standards. They may mow at the wrong height, bale at the wrong moisture, or mix feed inconsistently. If quality is critical to your livestock operation, ownership gives you control. ### Availability During Peak Seasons In many regions, custom operators are booked solid during haying and harvest seasons. If you cannot get a custom operator when you need one, you may lose forage quality or delay feeding. Ownership ensures you have equipment when you need it. ### Tax Implications Machinery ownership offers depreciation deductions and potential Section 179 expensing under U.S. tax law. Custom hire payments are fully deductible as operating expenses. Consult a tax professional to understand how each option affects your tax liability. ### Financing Constraints Purchasing machinery requires capital or credit. If you have limited access to financing, custom hire allows you to preserve capital for other farm needs such as livestock purchases, facility improvements, or land acquisition. ## Professional Escalation Criteria Some situations warrant consulting a professional before making a machinery decision. ### When to Consult an Accountant or Tax Advisor - You are considering a large machinery purchase that would significantly affect your tax situation - You need to understand the tax implications of Section 179 expensing versus bonus depreciation - You are comparing the tax treatment of ownership versus custom hire for your specific business structure ### When to Consult a Farm Business Management Specialist - You are unsure how to allocate machinery costs across multiple enterprises - You need help developing a whole-farm budget that includes machinery costs - You are considering a partnership or cooperative arrangement for machinery sharing ### When to Consult a Lender - You need financing for a machinery purchase and want to understand the terms - You are considering refinancing existing machinery debt - You want to evaluate how a machinery purchase would affect your debt-to-asset ratio ### When to Consult an Extension Engineer or Agronomist - You are choosing between different machinery types or sizes for your operation - You need advice on matching machinery to your forage or manure management system - You want to evaluate the environmental impact of manure spreading equipment versus custom application ## A Practical Decision Framework for Ownership vs. Custom Hire Beyond the break-even analysis, livestock farmers need a structured method to evaluate machinery decisions under real-world constraints. The following framework incorporates risk assessment, operational priorities, and financial thresholds to guide your choice. ### The Five-Factor Decision Matrix Use this matrix to score each machinery decision across five factors. Rate each factor from 1 (strongly favors custom hire) to 5 (strongly favors ownership). Add the scores to determine the overall recommendation. **Factor 1: Annual Use Intensity** - 1 point: Less than 100 hours per year - 2 points: 100 to 200 hours - 3 points: 200 to 350 hours - 4 points: 350 to 500 hours - 5 points: More than 500 hours This factor directly reflects your break-even analysis. Machines used below the break-even point score low. Machines used well above it score high. **Factor 2: Timeliness Sensitivity** - 1 point: Task can be delayed 2 weeks without significant loss - 2 points: Task can be delayed 1 week - 3 points: Task should be completed within 3 to 4 days of optimal window - 4 points: Task should be completed within 1 to 2 days - 5 points: Task must be completed within 24 hours of optimal window Feeding livestock, harvesting hay at peak quality, and spreading manure before storage overflow are examples of high timeliness sensitivity. The USDA National Agricultural Library provides resources on animal health and welfare that emphasize consistent feeding schedules and clean living conditions. If delays cause animal stress or health problems, ownership becomes more valuable. **Factor 3: Quality Control Requirements** - 1 point: Quality standards are flexible and custom operators consistently meet them - 2 points: Quality standards are moderate but most custom operators are acceptable - 3 points: Quality standards are important and you need to verify operator performance - 4 points: Quality standards are high and few operators meet them consistently - 5 points: Quality standards are critical and only you can achieve them For example, if you need precise ration mixing for dairy cows to maintain milk production, ownership of a TMR mixer may score higher than custom feed delivery. The FAO Animal Production and Health resources address the importance of feed quality in livestock productivity. **Factor 4: Biosecurity Risk** - 1 point: Custom operators follow strict biosecurity protocols and you trust their practices - 2 points: Operators have reasonable biosecurity but you have some concerns - 3 points: Biosecurity is moderately important and you can manage risks with cleaning protocols - 4 points: Biosecurity is important and you prefer to control equipment access - 5 points: Biosecurity is critical and you cannot accept any cross-farm contamination risk The U.S. Food and Drug Administration provides animal and veterinary resources that address disease prevention. If your herd has high health status or you are in a disease control area, ownership may be necessary. **Factor 5: Capital Availability and Tax Position** - 1 point: Capital is very limited and borrowing costs are high - 2 points: Capital is limited but you have some financing options - 3 points: Capital is adequate and you can consider either option - 4 points: Capital is available and you can benefit from depreciation deductions - 5 points: Capital is abundant and tax benefits of ownership are significant The USDA Economic Research Service provides farm economy data that includes information on input costs and capital trends. Consult a tax advisor to understand how Section 179 expensing or bonus depreciation applies to your situation. **Interpreting the Total Score** - 5 to 10 points: Strongly favors custom hire - 11 to 15 points: Custom hire likely preferred, but verify with break-even analysis - 16 to 20 points: Ownership likely preferred, but verify with break-even analysis - 21 to 25 points: Strongly favors ownership This matrix does not replace the break-even calculation. It adds qualitative factors that affect the true cost of each option. ### A Record System for Ongoing Evaluation To make informed decisions year after year, implement a simple record system that tracks actual costs and usage. **Machinery Cost Ledger** Create a spreadsheet or notebook with one page per machine. Record the following annually: - Machine identification and year - Purchase price or current insured value - Hours used this year - Cumulative hours - Fuel consumed in gallons and cost - Repair costs by category: engine, transmission, hydraulics, tires, belts, other - Insurance premium - Housing cost - Labor hours for operation and maintenance At the end of each year, calculate your actual ownership cost per hour using the method described in the existing article. Compare this to the custom rate for the same task. If your actual cost exceeds the custom rate for two consecutive years, consider selling the machine and switching to custom hire. **Custom Hire Log** For each custom operation, record: - Date and task - Operator name and contact - Acres, tons, bales, or hours - Rate charged - Total cost - Timeliness rating: on time, slightly delayed, significantly delayed - Quality rating: excellent, acceptable, poor - Biosecurity concerns noted Review this log annually. If you consistently experience delays or quality issues, the non-monetary costs of custom hire may justify ownership even if the break-even analysis favors custom hire. **Enterprise Cost Allocation** Link machinery costs to specific livestock enterprises. For example, if you own a hay mower, allocate its costs to the beef cow or dairy enterprise that consumes the hay. This helps you see whether the machinery investment is justified by the returns from that enterprise. The USDA Agricultural Research Service conducts research on animal production and protection that includes enterprise analysis. ### Troubleshooting Common Decision Errors Even with good records, farmers make predictable mistakes. Use these troubleshooting steps to check your reasoning. **Error 1: Ignoring the Time Value of Money** A dollar spent today is worth more than a dollar spent next year. When comparing a large machinery purchase to annual custom hire payments, discount future costs to present value. Use a discount rate equal to your borrowing cost or opportunity cost of capital. A farm business management specialist can help with this calculation. **Error 2: Comparing Average Costs Instead of Marginal Costs** When you already own a machine, the decision to use it for an additional task should be based on marginal cost, not average cost. The marginal cost is the variable cost per hour plus any additional wear and tear. If the custom rate exceeds your marginal cost, using your own machine is cheaper even if your average cost is higher. However, this logic only applies to short-term decisions. For long-term planning, use full average costs. **Error 3: Overlooking Storage and Maintenance Time** Ownership requires time for cleaning, storing, and maintaining machinery. This time has an opportunity cost if you could be doing other farm work. Estimate the hours spent on machinery care and value them at your labor rate. Add this to the ownership cost. **Error 4: Assuming Custom Rates Stay Constant** Custom rates can rise sharply when fuel prices increase or when labor becomes scarce. Build a sensitivity analysis into your decision. Ask: If custom rates increase by 20 percent, does the break-even point change enough to favor ownership? If rates decrease by 20 percent, does custom hire become more attractive? The USDA Economic Research Service provides farm economy data that includes trends in input costs. ### Professional Escalation Criteria Some machinery decisions require professional input beyond your own analysis. **When to Consult a Farm Business Management Specialist** - You are considering a machinery purchase that would increase your debt-to-asset ratio above 40 percent - You need help developing a multi-year capital budget that includes machinery replacement - You are evaluating a partnership or cooperative machinery sharing arrangement - You want to perform a discounted cash flow analysis comparing ownership and custom hire **When to Consult an Extension Engineer** - You are choosing between different machinery sizes or types for your operation - You need advice on matching machinery capacity to your forage or manure system - You want to evaluate fuel efficiency or emissions of different machinery options **When to Consult a Tax Advisor** - You are considering a large purchase that would trigger Section 179 or bonus depreciation limits - You need to understand how machinery trade-ins affect your tax basis - You are comparing the tax treatment of leasing versus purchasing **When to Consult a Lender** - You need financing and want to understand loan terms and interest rates - You are considering refinancing existing machinery debt - You want to evaluate how a machinery purchase would affect your operating line of credit ### Welfare and Safety Context Revisited The decision framework must account for animal welfare and worker safety, which are not captured in financial calculations alone. **Animal Welfare** Timeliness of feeding, bedding, and manure removal directly affects animal health. The USDA National Agricultural Library provides resources on animal health and welfare that emphasize the importance of consistent routines. If custom hire delays compromise welfare, ownership may be necessary even if the financial analysis is marginal. **Worker Safety** Machinery ownership requires you to train operators, maintain safety equipment, and follow safe operating procedures. The USDA Agricultural Research Service conducts research on animal production and protection that includes worker safety. If you lack the time or expertise to maintain machinery safely, custom hire may reduce risk. **Biosecurity** Custom operators moving between farms create disease transmission risk. The U.S. Food and Drug Administration provides animal and veterinary resources that address disease prevention. If your herd is in a high-health-status program or you are in a disease control area, ownership may be the only acceptable option. ### Limitations of the Decision Framework This framework has limitations. It does not account for personal preference, family labor availability, or the satisfaction of owning and operating your own machinery. It assumes you have accurate cost data and realistic use estimates. It does not predict future custom rate changes or repair cost spikes. Use it as a guide, not a rule. Revisit your decision annually as conditions change. ## Frequently Asked Questions ### How do I calculate depreciation for my farm machinery? Depreciation is the loss in value over time. The straight-line method divides the purchase price minus salvage value by the expected useful life in years. For example, a machine bought for USD 50,000 with a salvage value of USD 10,000 after 10 years depreciates USD 4,000 per year. Consult IRS Publication 225 or your tax advisor for tax depreciation methods. ### What is the average custom rate for hay mowing in my area? Custom rates vary by region and are published by state extension services and USDA National Agricultural Statistics Service. Contact your local extension office or search for the most recent custom rate survey for your state. Rates are typically quoted per acre and include the operator's machinery, fuel, labor, and profit. ### How many hours per year should I use a tractor to justify ownership? The break-even point depends on your fixed costs and the custom rate. A typical break-even for a 100 HP tractor might be 250 to 350 hours per year. Calculate your own break-even using the formula: total annual fixed costs divided by (custom rate per hour minus variable cost per hour). ### Can I share machinery with a neighbor to reduce costs? Machinery sharing can reduce fixed costs for both parties. Formalize the arrangement with a written agreement that covers cost sharing, scheduling, maintenance responsibilities, and liability. Consult a farm business management specialist for guidance on structuring the agreement. ### What records should I keep for machinery cost analysis? Keep a log for each machine with purchase date and price, annual hours, fuel consumption, repair costs, insurance premiums, and housing costs. Also record custom hire rates and usage for comparison. These records allow you to calculate actual ownership costs and update your break-even analysis annually. ### How do I account for my own labor when comparing ownership and custom hire? Value your labor at the wage you would pay a hired worker to operate the machinery. Add this cost to the variable cost per hour for ownership. Custom hire rates already include labor, so this adjustment makes the comparison fair. ### What are the biosecurity risks of hiring custom operators? Custom operators can carry pathogens on tires, boots, and equipment between farms. Ask operators about their cleaning and disinfection protocols. Consider requiring a written biosecurity plan before allowing them on your farm. The U.S. Food and Drug Administration provides animal and veterinary resources that address disease prevention. ### Should I buy a used machine or a new one for my livestock operation? Used machines have lower purchase prices and depreciation but higher repair costs. New machines have higher fixed costs but lower variable costs and greater reliability. Run the break-even analysis for both options using realistic repair cost estimates. A well-maintained used machine may be more cost-effective if you can afford the repair risk. ## Related Farming Guides - [Livestock Farm Record Keeping System](/knowledge/animal-farming/farm-management/livestock-farm-record-keeping-system) - [Beekeeping Enterprise Budget Startup Costs And Profitability Analysis](/knowledge/animal-farming/apiculture/beekeeping-enterprise-budget-startup-costs-and-profitability-analysis) - [Livestock Nutrition And Feed Management A Cross Species Decision Framework](/knowledge/animal-farming/farm-management/livestock-nutrition-and-feed-management-a-cross-species-decision-framework) - [Farm Health Intelligence Observation Records Biosecurity Diagnostics And Veterinary Escalation](/knowledge/animal-farming/farm-management/farm-health-intelligence-observation-records-biosecurity-diagnostics-and-veterinary-escalation) - [Farm Odor And Neighbor Communication Plan](/knowledge/animal-farming/farm-management/farm-odor-and-neighbor-communication-plan) ## Related Clinical & Scientific Guides * [Animal Welfare Audits: Building a Useful Farm Program](/knowledge/animal-farming/farm-management/animal-welfare-audits-building-a-useful-farm-program) * [Total Mixed Ration (TMR) for Dairy: Mixing and Feeding Management](/knowledge/animal-farming/farm-management/total-mixed-ration-dairy-mixing-feeding) * [Feed Additives for Livestock: Probiotics, Enzymes, and More](/knowledge/animal-farming/farm-management/feed-additives-livestock-probiotics-enzymes) ## References and Further Reading - [www.ers.usda.gov](https://www.ers.usda.gov/topics/farm-economy) - [www.nrcs.usda.gov](https://www.nrcs.usda.gov/) - [FAO Animal Production and Health](https://www.fao.org/animal-production/en) - [Animal Health and Welfare](https://www.nal.usda.gov/animal-health-and-welfare). USDA National Agricultural Library. - [Animal Production and Protection](https://www.ars.usda.gov/animal-production-and-protection). USDA Agricultural Research Service. - [Animal and Veterinary Resources](https://www.fda.gov/animal-veterinary). U.S. Food and Drug Administration. > This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.