# Beef Cow Drylot Management ## Key Takeaways - **Space Allocation and Welfare:** Overcrowding in drylots exacerbates aggression, lameness, and disease transmission; adequate space (e.g., 150-250 sq ft per head for loafing) is critical for resting, rumination, and facilitating welfare observation, aligning with WOAH standards for animal movement. - **Heat Abatement and Nutrition:** Essential shade provision (2.0-2.5 sq m per cow) mitigates heat stress, which depresses feed intake and fertility; conversely, short-term energy restriction in late gestation negatively impacts calf immune response to vaccination. - **Footing and Lameness Prevention:** Maintaining stable, well-drained footing (e.g., gravel/sand over compacted base) is paramount to prevent lameness, a significant welfare concern and cause of culling; slick or wet surfaces increase injury risk. - **Water Quality and Intake:** Continuous access to clean water is critical, with tank capacity and placement designed for peak demand (50-100 L/cow/day, higher in heat); poor water quality, as monitored by NAHMS, depresses consumption and increases disease risk. - **Manure Management and Biosecurity:** Regular manure removal prevents pathogen buildup, fly proliferation, and hoof problems; proper storage and application, guided by FAO waste management principles, are essential for environmental control and biosecurity. - **Daily Welfare Observation and Record Keeping:** Daily visual inspection for signs of illness, injury, lameness, and aggression, particularly during feeding, is the cornerstone of drylot management; systematic record-keeping of BCS, morbidity, and mortality aids in identifying failure patterns and informing veterinary escalation. --- Drylot management of beef cows involves confining cows, often on a bedded or dirt surface, for all or part of the production cycle. Successful drylot operations require deliberate infrastructure design and daily oversight of space, shade, footing, feed delivery, water, manure, and animal welfare. Proper management supports cow health, reproductive efficiency, and calf performance while controlling labor and environmental costs. ## At a Glance | Aspect | Key Considerations | Approved Source | |--------|-------------------|-----------------| | Space | Allocation per cow must account for body size, group size, and climate. Overcrowding increases aggression, lameness, and disease risk. | [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) , welfare standards for confinement | | Shade | Essential for heat abatement in drylotic systems, improves feed intake and reduces morbidity during hot weather. | [Merck Veterinary Manual](https://www.merckvetmanual.com/) , management heat stress | | Footing | Slick or wet surfaces cause injury. Use gravel, sand, or lime to maintain traction and drainage. | [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) , resource,efficient systems | | Feed delivery | Bunk space should allow simultaneous access without bullying. Consistency in timing and ration delivery reduces digestive upset. | [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) , biosecurity feeding practices | | Water | Continuous clean supply is critical. Tank capacity and placement must accommodate peak drinking demand, especially in heat. | [USDA National Animal Health Monitoring System](https://www.aphis.usda.gov/livestock-poultry-disease/nahms) , water quality in confined operations | | Manure | Regular removal prevents pathogen buildup, hoof problems, and fly proliferation. Composting or field spreading requires runoff management. | [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) , waste management guidance | | Welfare observation | Daily visual inspection for injury, illness, lameness, and aggression. Observation during feeding or in alleys yields the best signal. | [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) , routine inspection protocols | ## System Context and Planning Decisions Drylot beef cow production is used in regions where pasture is unavailable, during drought, or as a tool to protect fragile rangeland. The system also supports early weaning of calves, which can reduce dam nutrient demand and improve body condition recovery for subsequent breeding. Research indicates that calf age at weaning affects both cow performance and economic returns in drylot systems. For instance, weaning at 90 versus 180 days modifies cow body condition and the cost of feeding the cow and calf separately. This decision must be integrated with drylot facility planning. Heifer development in drylot demands particular attention because first,calf heifers are at greater risk of inadequate body condition and delayed rebreeding. Short,term energy restriction during late gestation reduces subsequent calf immune response to vaccination, as demonstrated in studies of beef cows. Providing adequate metabolizable protein during development on low,quality forage can alter pregnancy rates and retention of heifers in the herd. Drylot managers must therefore design feed delivery and space to meet the nutritional and social needs of both mature cows and developing heifers. ## Core Management Framework ### Space The area provided per cow in a drylot affects competition, resting time, and cleanliness. Space requirements vary with cow size, ground type, and local climate because more space allows better drainage and reduces mud. Adequate resting area supports rumination and reduces hoof damage. The WOAH Terrestrial Code recommends that housing systems allow animals to lie down, stand up, and turn around without difficulty. In drylots, this translates to a minimum resting area that prevents overcrowding. Overcrowding also undermines welfare observation by making it harder to detect sick or injured animals. Managers should calculate space based on the largest animal in the group and adjust for the surface area used for feeding, watering, and resting. Free,stall or bedded pack systems require different dimensions than open dirt pens. When space is limited, aggression at the feed bunk and waterer increases, and lower,ranked cows may not achieve adequate intake. ### Shade Cows in drylot are exposed to direct sunlight for much of the day. Shade reduces heat load and improves feed efficiency. The Merck Veterinary Manual notes that heat stress depresses feed intake and increases respiration rate, with potential to impair fertility. Shade can be provided by permanent structures, portable shades, or natural tree cover if available. Effective shade covers 2.0 to 2.5 square meters per cow and should be oriented to cast shade during the hottest part of the day. Without shade, cattle seek relief in other ways,standing in water troughs, crowding into corners, or lying in manure which increases disease risk. Shade also influences manure distribution and pen drainage. The position of shade relative to feeders and waterers affects overall pen use. ### Footing Footing material must provide stable traction and drain well. Concrete floors are durable but become hazardous when wet, addition of grooving or rubber matting can improve safety. Dirt surfaces require regular grading and removal of excess moisture to prevent mud entrapment and hoof softening. The FAO notes that suitable bedding or footing reduces lameness, which is a major welfare concern in confinement. Common footing strategies include a base of compacted gravel or limestone topped with sand or fine aggregate, ensuring that the surface does not ball up or freeze into hard clods. Weekly hoof checking for cracks, swelling, or injury becomes part of the welfare observation routine. If footing is not maintained, lameness can increase culling rates and reduce cow longevity. ### Feed Delivery Feed delivery in drylot includes provision of hay, silage, total mixed rations, or free,choice mineral. Bunk space must allow all cows to eat without excessive competition. The USDA APHIS recommends designing feed bunks to minimize soiling and to allow easy cleaning. Bunk height should be appropriate for cow size to avoid neck strain. Feed delivery at a consistent time each day supports digestive health. In research with heifers, early weaning and subsequent drylot feeding altered growth patterns, emphasizing that ration formulation and feeding management directly affect final body weight and reproductive readiness. Avoiding sudden ration changes helps prevent acidosis. The PubMed record on metabolizable protein supply during dormant forage grazing indicates that drylot feeding can complement pasture systems when forage quality is low. ### Water Water is the most essential nutrient. In a drylot, cattle need continuous access to clean water at temperatures that encourage intake. The NAHMS reports that water quality issues in confinement systems can depress consumption and increase the risk of disease. Tanks should be sized to meet peak demand, typically 50 to 100 liters per cow per day in moderate conditions, with higher volume during heat. Waterer placement should be in a well,drained area away from heavy manure accumulation to reduce contamination. Regular scrubbing and disinfection prevent biofilm growth and algae. If pipelines freeze in winter, insulation or heated tanks are necessary. ### Manure Manure accumulates rapidly in drylots and requires systematic removal. The FAO waste management guidance outlines that proper collection and storage prevent environmental contamination and control fly and pathogen loads. Manure can be scraped daily or removed after each group turnover. Deep,bedded systems need to be cleaned out when moisture content rises. Without regular removal, cows lie in wet, ammoniacal conditions, increasing the risk of mastitis, hoof rot, and respiratory irritation. The USDA APHIS notes that drylot design should include drainage slopes and minimal standing water. Manure stockpiles must be covered or placed away from animal areas to avoid runoff into feed or water. ### Welfare Observation Daily welfare observation is the backbone of drylot management. The WOAH Terrestrial Code specifies that stockpersons must be trained to detect early signs of disease, injury, and abnormal behavior. In drylot, cows are concentrated, so contagious diseases such as bovine respiratory disease or pinkeye can spread quickly. Observation is best performed when cows are standing at the feed bunk or waterer. Managers check for separation from group, lowered head, droopy ears, labored breathing, nasal or ocular discharge, lameness, and signs of bullying. Records of cull rates, treatment incidence, and body condition score provide objective data to adjust space, shade, or feed. ## Facility Design and Environmental Factors A successful drylot requires deliberate planning for space allocation, shade provision, footing durability, and manure management. Space allowance influences cow comfort, social dynamics, and productive performance. Insufficient area increases aggression and competition at feed bunks and waterers, whereas generous space reduces stress but raises infrastructure cost. The [Merck Veterinary Manual](https://www.merckvetmanual.com/) emphasizes that beef cows in confinement need at least 150 to 250 square feet per head for loafing areas, with additional space for feeding and watering zones. Shade is critical in warm climates because cattle with limited access to relief from solar radiation experience elevated body temperature, reduced feed intake, and compromised fertility. Permanent shade structures oriented north-south allow solar movement and can reduce heat load. Portable shades, though less durable, permit rotation to avoid manure buildup underneath. Footing in a drylot directly affects injury risk and hygiene. Concrete aprons around bunks and waterers facilitate cleaning but must have a textured surface or grooves to prevent slipping, especially when wet. Dirt or clay pads require periodic re-grading to remove depressions that hold moisture and manure slurry, which predispose cows to foot rot and lameness. The [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) guidance recommends bedding with straw or sand in heavy-use areas to improve drainage and provide cushioning. **Manure management** must be planned from the outset. Drylots generate high nutrient loads that, if unmanaged, contaminate runoff, attract flies, and degrade air quality. Regular scraping and stockpiling, combined with a nutrient management plan that considers field application rates, are standard practices. Composting or stacking manure in a lined area reduces pathogen load and odor, as outlined in [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) resources. Sloped lots (2% to 4% grade) allow water to drain away from animal resting areas, minimizing mud and the associated increased risk of mastitis and neonatal scours. Feed delivery in a drylot should prioritize consistency in timing, nutrient composition, and bunk access. Cows fed a total mixed ration (TMR) benefit from a diet that meets energy, protein, mineral, and vitamin requirements without sorting. Bunk space of at least 24 to 30 inches per cow minimizes competition and ensures subordinate animals do not lose condition. Water availability is equally critical. Beef cows in confinement consume 10 to 20 gallons per day, with higher intakes during lactation and hot weather. Trough capacity and flow rate must accommodate peak demand, inadequate water reduces feed intake and depresses milk production. The [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) notes that water quality should be tested regularly for microbial contamination, salinity, and nitrates, especially when using alternative sources such as wells or recycled water from manure lagoons. A single waterer per pen may be insufficient, placing two water sources at opposite ends of the lot reduces fighting and ensures all animals can drink without excessive dominance. ## Production Stage Decisions Calving and weaning management are central to drylot success. Controlled studies have examined the effect of weaning age on cow and calf performance and subsequent economic returns. An [Elsevier abstract](https://api.elsevier.com/content/abstract/scopus_id/0034204383) (2000) on spring,calving beef cows reports that early weaning (around 120 days) reduces feed demand on the cow and improves body condition score going into winter, but may increase costs for feeding the calf separately. Later weaning (200 days) allows higher calf weights at sale but stresses the cow if forage is limited. Producers must weigh condition, feed availability, and market timing. The reproductive performance of beef heifers is also sensitive to weaning management, a later study ([Elsevier 2014](https://api.elsevier.com/content/abstract/scopus_id/84904988783)) found that heifers weaned at a lighter weight and then managed on drylot diets had lower pregnancy rates if not provided adequate metabolizable protein. That finding aligns with research on protein supplementation during winter grazing ([Elsevier 2013](https://api.elsevier.com/content/abstract/scopus_id/84882592768)) that shows metabolizable protein supply during heifer development influences both pregnancy and subsequent in,herd retention rate. Energy restriction during late gestation has documented immunological consequences. Research detailed in an [Elsevier abstract](https://api.elsevier.com/content/abstract/scopus_id/84975796941) (2016) demonstrates that short,term maternal energy restriction in late gestation decreases post,weaning humoral immune response to vaccination in the calf. Therefore, drylot rations for gestating cows should be formulated to meet, not restrict, energy and protein needs during the last trimester. Calving date of first,calf heifers also affects lifetime efficiency. An [Elsevier abstract](https://api.elsevier.com/content/abstract/scopus_id/0025455773) (1990) suggests that heifers calving earlier in the season produce heavier calves at weaning and show improved rebreeding performance, but this requires earlier initiation of improved nutrition. In a drylot system, this means adjusting the ration for spring,calving heifers to support both fetal growth and their own continued development. ## Records and Welfare Observation Systematic record keeping underpins drylot management decisions. Individual cow identification , via ear tags, electronic identification (EID), or neck bands , permits tracking of reproductive events, health treatments, body condition scores (BCS), and weaning weights. Monthly BCS assessment for all cows, or at critical periods (pre,calving, pre,breeding, weaning), allows early detection of nutritional shortfalls. Records of feed intake, water consumption, and mortality are instrumental for troubleshooting failure patterns. The [USDA National Animal Health Monitoring System](https://www.aphis.usda.gov/livestock-poultry-disease/nahms) provides standardized protocols for data collection on beef operations, including drylots, and emphasizes the importance of recording morbidity and mortality by cause. Welfare observation in the drylot should be integrated into daily routines. Lamentess prevalence, lying times, cleanliness scores, and social interaction are practical indicators. The [Merck Veterinary Manual](https://www.merckvetmanual.com/) counsels that cattle in confinement must be inspected at least once daily, with attention to respiratory signs, ocular discharge, diarrhea, and injuries. Restraint facilities (squeeze chutes, headgates) should be well,maintained to minimize distress during handling. Areas where cows congregate , such as under shade or around waterers , are high,risk zones for bullying and should be monitored. **Worker safety** is directly linked to facility design: slip,resistant flooring, properly functioning gates, and non,slam latches reduce the risk of human injury. Education on cattle flight zones and low,stress handling methods, as advocated by [WOAH](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/), protects both workers and animals. [Food safety](/knowledge/bacteria/livestock-bacteria/cooking-chicken-bacteria-prevention) considerations apply primarily if cull cows enter the food chain, therefore, proper withdrawal times for vaccines and therapeutic drugs must be recorded and verified. Manure contamination of water sources and feed bunks can introduce pathogen loads, feed should be delivered in troughs or bunks that are elevated and cleaned regularly. ## Failure Patterns and Practical Monitoring Common failure patterns in beef cow drylots include chronic lameness, poor reproductive performance, and respiratory disease outbreaks. Lameness often stems from inadequate footing, overstocked pens, or infrequent scraping. If lameness exceeds 5% of animals in any pen, immediate investigation of surface conditions, bedding depth, and stocking density is warranted. Poor reproductive rates (low conception or extended calving intervals) usually trace to nutrition , either energy deficiency or protein imbalance , but also can reflect heat stress, inadequate bunk space, or water limitation. Respiratory disease in adult cows is less common than in feeder calves, but overcrowding and dusty conditions during dry periods can provoke bronchopneumonia. Monitoring average daily water intake and noting any decline can flag illness before clinical signs are obvious. Practical monitoring in the drylot relies on repeated standardized assessments. Weekly pen checks for manure consistency, tail head cleanliness, and coat condition provide early signals. [Body condition scoring](/knowledge/animal-farming/farm-management/body-condition-scoring-a-tool-for-feed-management) every two to three weeks during the transition period (weaning to calving) helps match ration density to cow needs. Feed samples should be sent for nutrient analysis at least once per batch change, because drylot rations often contain by,products (distillers grains, corn gluten feed, silages) with variable composition. Water quality tests for total dissolved solids, sulfate, and coliform bacteria are recommended quarterly. When a failure pattern emerges , such as a sudden drop in weaning weights across a group , the producer should review records of weaning age, dam BCS, and feed composition. If feed,related, consulting a nutritionist familiar with drylot beef cow systems is advisable before making large,scale ration adjustments. Professional veterinary input is also necessary for any unexplained increase in morbidity, mortality, or poor pregnancy rates, as these may indicate underlying disease or management error beyond routine correction. ## Health Observation and Daily Monitoring Regular health observation is the foundation of disease prevention in drylot systems. Each pen should be inspected at least once daily, preferably at the same time, with attention to individual cow demeanor, gait, body condition, and feeding behavior. Cows that isolate, fail to rise for feed delivery, or exhibit labored respiration, nasal discharge, or diarrhea warrant immediate closer evaluation. The Merck Veterinary Manual emphasizes that early detection of illness reduces treatment costs and improves outcomes. Observational records should include pen-level indicators such as leftover feed, water trough cleanliness, and manure consistency. For drylot operations, the reduced space and high animal density mean that subtle signs of disease can escalate quickly, therefore, stockmen must be trained to recognize deviations from normal and to escalate concerns to a veterinarian. The USDA National Animal Health Monitoring System (NAHMS) provides guidance on standardized health assessments in beef cattle, noting that systematic observation can identify emerging health problems before they become widespread. Nutritional stressors, such as the short-term energy restriction in late gestation that decreases postweaning calf humoral immune response (PubMed 84975796941), underscore the interplay between drylot diet and immunity. Health observation must integrate nutritional history and environmental conditions. ## Biosecurity Protocols Biosecurity in the drylot aims to prevent introduction and spread of infectious agents. Essential measures include controlling visitor access, having dedicated footwear and clothing for personnel, and maintaining a clear line between clean and contaminated areas. The WOAH Terrestrial Animal Health Code recommends that operations establish a biosecurity plan tailored to their disease risk profile, including protocols for new animal introductions, isolation of sick animals, and proper disposal of mortalities. For drylots, shared equipment (loaders, feed trucks) can transfer pathogens between pens, cleaning and disinfection between uses is prudent. Manure management also has a biosecurity dimension: accumulated waste can harbor bacteria and parasites, so pen cleaning schedules should prevent excessive buildup. The USDA APHIS Livestock and Poultry Disease resources provide guidelines on disease surveillance and reporting, emphasizing that biosecurity is most effective when implemented consistently and reviewed annually with a veterinarian. Uncertainty exists regarding the optimal frequency of pen cleaning because pathogen survival varies with climate and manure depth, professional veterinary input is needed to tailor protocols to local conditions. ## Diagnostic and Veterinary Escalation When a cow shows signs of disease, prompt diagnostic workup is critical. This may include assessment of rectal temperature, respiratory rate, rumen motility, and evaluation of fecal samples or blood work. The Merck Veterinary Manual details common differentials for respiratory disease, lameness, and digestive disorders in confined beef cattle. Farm personnel should be able to perform basic health assessments and administer treatments under a veterinary-client-patient relationship (VCPR). For conditions that do not respond to first-line therapy, or when multiple animals in a pen become ill, veterinary escalation is necessary. The veterinarian may conduct necropsy, submit samples to a diagnostic laboratory, and revise prevention strategies. Uncertainty in diagnosis arises when clinical signs are ambiguous or when multiple agents are involved, professional interpretation of laboratory results is essential. The PubMed record 42114127 on weaning age effects highlights that management decisions (such as weaning age) influence later health outcomes, so historical management records should accompany diagnostic workups. Escalation also applies to reproductive issues: if pregnancy rates decline or calving difficulty increases, veterinary investigation of nutrition, genetics, and facility design is warranted. ## Uncertainties in Drylot Management Drylot systems introduce several uncertainties that require ongoing evaluation. The optimal space allowance per cow is not universally defined because it depends on climate, pen surface, and group dynamics. Research on group size and social stress shows variable effects on productivity and health. Similarly, the ideal frequency of manure removal is context-dependent: too frequent removal may disrupt the beneficial microbial environment of bedding (if used), while infrequent removal increases pathogen loads. Nutritional requirements in drylots differ from pasture systems due to reduced exercise and altered energy expenditure, precise formulation of total mixed rations must account for these factors. The effect of continuous confinement on hoof health and lameness remains incompletely understood, and preventive hoof trimming protocols are not standardized. These uncertainties underscore the value of maintaining detailed records and consulting with Extension specialists and veterinarians to adapt best practices to individual operations. Acknowledging uncertainty also reinforces the importance of not over,extrapolating results from one study or region to another. ## Sustainability Considerations Drylot operations can be managed sustainably by reducing land degradation, improving nutrient recycling, and minimizing environmental emissions. Confined feeding concentrates manure nutrients, making them easier to collect, store, and apply to cropland at agronomic rates. The FAO Animal Production and Health guides emphasize integrated nutrient management planning to avoid water pollution. Because drylots require less land per animal unit than pasture, they can spare land for conservation or crop production. However, sustainability also encompasses animal welfare and social acceptance, therefore, drylot managers should provide adequate shade, windbreaks, and bedding to meet behavioral needs. The PubMed record 84882592768 on metabolizable protein supply during heifer development shows that precise nutrition can improve lifetime efficiency, which contributes to environmental sustainability by reducing the number of replacement heifers needed. Economic sustainability depends on feed costs, waste disposal costs, and market premiums for high-health cattle. Regular review of these factors with a team including nutritionists and veterinarians helps balance productivity with long-term stewardship. ## Frequently Asked Questions **1. How often should I check cows in a drylot for signs of illness?** At least once daily during the same time each day, with extra checks after weather extremes or changes in feed delivery. **2. What is the minimum space recommendation per beef cow in a drylot?** Recommendations vary, but pens should provide enough room for all cows to lie down simultaneously without overcrowding, consult your veterinarian for site,specific guidance. **3. Should I quarantine new cows before adding them to an established drylot group?** Yes. A minimum 30,day quarantine, with observation and diagnostic testing as advised by your veterinarian, reduces disease introduction. **4. How can I tell if my cows are under heat stress in a drylot?** Look for panting, drooling, excessive standing in shade, reduced feed intake, and increased water consumption. Provide shade and ventilation. **5. What types of footing are best for drylot pens to prevent lameness?** Sloped concrete with proper drainage or compacted aggregate are common, surface should be non,abrasive and well,drained. **6. How should I dispose of mortalities in a drylot?** Follow local regulations and the WOAH Terrestrial Animal Health Code, options include rendering, incineration, or properly permitted composting under veterinary oversight. **7. Can I use drylot management for pregnant heifers?** Yes, but heifers require additional space, careful nutritional management, and close observation for calving ease. **8. What is the most important health observation to make daily?** A consistent behavior check: cows that do not rise to eat or drink, or that separate themselves from the group, are early signals of disease. ## Educational Veterinary Notice This information is for educational purposes and does not replace a veterinary-patient relationship. Each drylot operation has unique risk factors, management decisions should be made in consultation with a licensed veterinarian who is familiar with the herd’s history and local disease patterns. ## Related Farming Guides - [Beef Cattle Farming Forage Reproduction Calving Health Signals And Herd Management](/knowledge/animal-farming/beef-cattle/beef-cattle-farming-forage-reproduction-calving-health-signals-and-herd-management) - [Beef Cattle Body Condition Scoring](/knowledge/animal-farming/beef-cattle/beef-cattle-body-condition-scoring) - [Calving Management For Beef Herds](/knowledge/animal-farming/beef-cattle/calving-management-for-beef-herds) - [Rotational Grazing For Beef Cattle](/knowledge/animal-farming/beef-cattle/rotational-grazing-for-beef-cattle) - [Beef Herd Biosecurity Plan](/knowledge/animal-farming/beef-cattle/beef-herd-biosecurity-plan) ## Related Clinical & Scientific Guides * [Cattle Head Gate Selection and Adjustment](/knowledge/animal-farming/beef-cattle/cattle-head-gate-selection-and-adjustment) * [Beef Cattle Handling Facility Flow](/knowledge/animal-farming/beef-cattle/beef-cattle-handling-facility-flow) * [Beef Cattle Maternity Pen Design: Comfort and Monitoring](/knowledge/animal-farming/beef-cattle/beef-cattle-maternity-pen-design-comfort-monitoring) ## References and Further Reading - [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) - [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) - [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) - [Merck Veterinary Manual](https://www.merckvetmanual.com/) - [USDA National Animal Health Monitoring System](https://www.aphis.usda.gov/livestock-poultry-disease/nahms) > This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.