# Beef Cattle Carcass Data Interpretation ## Key Takeaways - Carcass data (Hot Carcass Weight, Ribeye Area, Fat Thickness, Marbling Score, Yield Grade, Quality Grade) provide objective metrics reflecting the interplay of genetics, environment, and management, serving as the primary quantitative link between on-farm decisions and end-product value. - Genetic selection for carcass traits is feasible due to moderate heritability (e.g., HCW ~0.40, Marbling ~0.35), enabling producers to utilize Expected Progeny Differences (EPDs) to improve muscling, fatness, and marbling, while balancing with other production traits to avoid antagonisms. - Nutritional management, particularly diet energy density and composition (e.g., forage vs. concentrate), directly influences fat deposition and marbling, with grass-based diets yielding distinct fatty acid profiles (e.g., higher CLA) compared to concentrate-based diets. - Environmental factors such as thermal load, pen density, and flooring significantly impact carcass composition and yield; for instance, heat stress suppresses feed intake and favors fat accretion, while inadequate lying time correlates with lower tenderness. - Integrated record-keeping, linking individual animal identification to carcass data, health events, and feed intake, is critical for identifying specific genetic lines or management groups requiring adjustment, enabling iterative improvement and benchmarking against industry standards. - Failure patterns such as low HCW, reduced marbling with normal weight, or high incidence of dark cutters necessitate root-cause investigation, often requiring consultation with nutritionists, veterinarians, or geneticists to address underlying issues in disease, feeding, or handling. --- Beef cattle carcass data interpretation translates postmortem measurements into actionable feedback for genetic selection, nutritional management, and marketing decisions. Carcass reports provide objective trait values,carcass weight, ribeye area, fat thickness, marbling score, and yield grade,that reflect the combined effects of genotype, environment, and management. Correct interpretation requires understanding the production system in which the animals were raised, the packing plant’s grading protocols, and the statistical context of the data. These records serve as the primary quantitative link between on-farm decisions and end-product value. ## At a Glance | Carcass Trait | Abbreviation | Unit | Primary Use | |---------------|--------------|------|-------------| | Hot carcass weight | HCW | kg (lb) | Feeding endpoint, feed efficiency feedback | | Ribeye area | REA | cm² (in²) | Muscling indicator, yield grade component | | Fat thickness | FT | mm (in) | Carcass fatness, yield and quality grade | | Marbling score | Marb | 0,9 scale | Quality grade, tenderness and palatability proxy | | Yield grade | YG | 1,5 | Carcass cutability, lean-to-fat ratio | | Quality grade | QG | Select/Choice/Premium | Consumer acceptance, price grid | ## System Context and Data Flow ### Packing Plant to Producer Carcass data originate at federally inspected slaughter facilities where trained graders apply USDA standards. Producers receive kill sheets listing each animal’s individual traits alongside group averages. Transmission methods vary,paper reports, electronic portals, or third-party data services. Timeliness influences usefulness, delayed reports reduce the ability to adjust feeding programs for subsequent groups. ### Carcass Trait Definitions - **Hot carcass weight**: Weight of the dressed carcass before chilling, measured in kilograms or pounds. It is the primary metric for determining feeding endpoint and is used in feedyard closeout analysis. - **Ribeye area**: Cross-sectional area of the longissimus dorsi muscle measured at the 12th,13th rib interface. Larger area indicates greater muscling and higher lean yield. - **Fat thickness**: External fat measured at the same rib interface, typically at three-quarters of the distance from the medial side. Thicker fat is associated with higher energy intake and later maturity. - **Marbling score**: Visual assessment of intramuscular fat distribution in the ribeye, scored on a 0,9 scale. Higher scores (e.g., 5,7) correspond to Choice and Prime quality grades. - **Yield grade**: Calculated from HCW, REA, FT, and kidney-pelvic-heart fat percentage (often set at 2.5% if not measured). Grades 1 and 2 indicate high cutability, grades 4 and 5 indicate excess external fat and lower lean yield. - **Quality grade**: Derived from marbling and maturity estimates, applying to C, D, E maturity (young cattle). USDA Select, Choice, Prime are the common grades, Commercial, Utility, Cutter, and Canner occur for older or defective carcasses. ## Planning Decisions ### Genetic Selection Carcass traits vary heritably (e.g., HCW ~0.40, marbling ~0.35, REA ~0.40), enabling within-herd improvement through expected progeny differences (EPDs). Producers selecting sires with favorable carcass EPDs can shift progeny distributions toward heavier muscling, lower fat thickness, and higher marbling. The [Association of a missense mutation in the bovine leptin gene with carcass fat content and leptin mRNA levels](https://api.elsevier.com/content/abstract/scopus_id/0036010957) illustrates a molecular marker that correlates with fat deposition, though application requires validation in specific production contexts. Genetic progress is cumulative but slow, producers should balance carcass goals with maternal and growth traits to avoid antagonisms (e.g., extreme muscling linked to calving difficulty). ### Feeding and Management Diet composition and energy density drive fat deposition and marbling development. Forages and concentrates produce different fatty acid profiles: [Fatty acid composition, including conjugated linoleic acid, of intramuscular fat from steers offered grazed grass, grass silage, or concentrate-based diets](https://api.elsevier.com/content/abstract/scopus_id/0034331723) demonstrates that grass-based diets yield higher concentrations of conjugated linoleic acid and different ratios of saturated to unsaturated fat. Management decisions,implant strategy, days on feed, bunk management,interact with genetics to produce the final carcass. [Influence of monensin on the performance of cattle](https://api.elsevier.com/content/abstract/scopus_id/0021445254) notes that ionophores improve feed efficiency but may affect fat distribution, practitioners must monitor carcass data for unintended shifts in yield or quality grade. ## Core Management Framework ### Record Integration Carcass data hold the most value when linked to individual animal records: birth date, sire, dam, weaning weight, feed intake, and treatment history. Without those links, producers can only observe herd averages and cannot identify which genetic lines or management groups require change. Integration requires unique animal identification (ear tag or RFID) that survives slaughter and appears on the kill sheet. Data systems range from simple spreadsheets to commercial herd-management software, the essential requirement is the ability to sort, filter, and compare carcass outcomes across management groups, years, or sires. ### Benchmarking Isolated carcass reports reveal little about performance. Producers must compare their data against industry standards, packer grid specifications, or historical farm averages. The [Consumer thresholds for establishing the value of beef tenderness](https://api.elsevier.com/content/abstract/scopus_id/0035748267) shows that tenderness,a trait rarely measured in routine grading,directly influences consumer satisfaction and willingness to pay. Carcass marbling is an imperfect proxy, producers targeting high-value markets may need to incorporate tenderness testing or use genetic markers linked to calpain/calpastatin. Benchmarking also requires recognizing that carcass merit varies with season, cattle type (steer, heifer, dairy-beef), and market channel. Repeated poor performance in a specific trait warrants consultation with a livestock extension specialist or beef quality assurance advisor. ## Facilities and Environment Carcass composition and yield reflect ante-mortem conditions. Housing systems influence muscle deposition and fat partitioning through thermal load, space allowance, and flooring. In confinement, pen density beyond recommended limits elevates stress hormones, reducing glycogen reserves and increasing the risk of dark-cutting carcasses. The [Merck Veterinary Manual](https://www.merckvetmanual.com/) emphasizes that chronic heat stress suppresses feed intake and alters endocrine function, favoring fat accretion over lean growth,a shift detectable in ribeye area and backfat measurements. Conversely, excessive cold exposure elevates maintenance energy requirements, potentially depressing average daily gain and marbling development. Mud depth and wet pens compound these effects by increasing energy expenditure for locomotion and reducing lying time, which correlates with lower tenderness scores observed at slaughter. Shade provision and water access modify these outcomes. The [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) guidelines note that evaporative cooling can mitigate heat load, but facility design must ensure uniform air movement to avoid microenvironments that promote respiratory disease. Respiratory disease during the finishing phase reduces carcass weight and quality grade due to decreased feed efficiency and increased trim losses from lung adhesions. Ventilation audits using CO₂ and ammonia thresholds, as per [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) recommendations, should be part of routine monitoring. ## Nutrition and Water Dietary energy density directly modulates carcass fatness. High-concentrate rations accelerate marbling deposition but, if introduced abruptly, can cause ruminal acidosis and liver abscesses, which lower dressing percentage and cause liver condemnation. The inclusion of ionophores such as monensin improves feed conversion and reduces the incidence of subacute acidosis in some production systems, though responses vary with basal diet composition ([Scopus 0021445254](https://api.elsevier.com/content/abstract/scopus_id/0021445254)). Ruminant nutritionists should adjust energy levels relative to genetic potential, overly aggressive feeding in moderate-framed cattle produces excessive external fat without proportionate increases in intramuscular lipid. Forage-based systems yield carcasses with distinct fatty acid profiles. Feeding grazed grass or grass silage increases conjugated linoleic acid (CLA) and n-3 fatty acids in intramuscular fat compared to concentrate-based diets ([Scopus 0034331723](https://api.elsevier.com/content/abstract/scopus_id/0034331723)). This differential affects human health perception but also influences shelf life and flavor. Packers may apply discounts when unsaturated fat levels exceed thresholds for oxidative stability. Producers targeting niche markets must document feeding history consistently to verify claims. Water quality is a secondary but non-negligible factor. High sulfate or nitrate levels depress intake and can interact with rumen fermentation to reduce feed efficiency. The [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) resources advise annual water testing, particularly during drought when total dissolved solids concentrate. Inadequate water availability during transport and lairage,addressed in WOAH transport standards,contributes to glycogen depletion and carcass pH elevation, especially in excitable animals. ## Production-Stage Decisions Weaning strategy influences subsequent carcass endpoints. Early weaning onto high-energy diets can accelerate marbling formation but may compromise frame development if nutrient imbalances occur. Backgrounding programs that manage growth rate to target a moderate body condition score at the start of finishing reduce the incidence of overly fat or underfinished carcasses. Implant and beta-agonist use alter composition: implants improve lean gain but can depress marbling scores if used excessively or for prolonged periods. Veterinary oversight, supported by [USDA National Animal Health Monitoring System](https://www.aphis.usda.gov/livestock-poultry-disease/nahms) data, is essential to calibrate withdrawal periods and avoid illegal residues that cause [food safety](/knowledge/bacteria/livestock-bacteria/cooking-chicken-bacteria-prevention) recalls. Health management decisions during the finishing phase have direct carcass consequences. Bovine respiratory disease (BRD) reduces average daily gain and results in lighter, lower-grading carcasses with greater incidence of lung lesions. The [PubMed record 42426588](https://pubmed.ncbi.nlm.nih.gov/42426588/) outlines methodologies for assessing BRD impact on carcass characteristics, emphasizing that early detection and treatment improve outcomes. Leptin polymorphisms have been associated with carcass fat content and leptin mRNA expression ([Scopus 0036010957](https://api.elsevier.com/content/abstract/scopus_id/0036010957)), but these markers are not yet validated for routine selection. Producers should consult geneticists before incorporating such tests into replacement decisions. ## Records Integrated records linking feed conversion ratios, health events, and final carcass data enable iterative improvement. Standardized data collection at harvest,including hot carcass weight, ribeye area, backfat thickness, marbling score, and yield grade,must be paired with individual or lot identification. [USDA APHIS](https://www.aphis.usda.gov/livestock-poultry-disease) provides templates for recording injection sites, which remain a major cause of trim losses. Discrepancies between live weight and carcass weight exceeding 62% dressing percentage indicate low fill, high gut content, or excessive shrink, warranting review of lairage time and watering regimes. Electronic capture of kill sheet data allows producers to identify trends: seasonality in marbling scores, implant response variability, or pen-level differences in ribeye area. Failure to integrate feed records with carcass outcomes is a common gap, for example, a shift to lower-cost byproducts may reduce energy density and depress marbling before visible changes in body condition appear. Monthly reconciliation of feed delivery logs with carcass data, using tolerance bands defined by the nutritionist, aids early detection. ## Welfare Handling practices before slaughter directly affect meat quality. Electric prod use, excessive noise, and poor facility design cause acute stress and panic, leading to glycogen depletion and high ultimate pH (>5.8), producing dark, firm, and dry (DFD) beef. The [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) outlines pre-slaughter handling standards, including stockperson training and facility maintenance. Lameness, often from foot rot or sole abscesses, reduces feed intake and increases cortisol levels,both detrimental to carcass yield and tenderness. Veterinarians should audit lameness prevalence at each production stage. Transportation distance, stocking density, and weather conditions interact to affect welfare outcomes. Mortalities during transport are concentrated in heat-stressed, fatigued animals. Post-mortem inspection data on bruising rates and fracture incidence serve as leading indicators. The [PubMed record 42325666](https://pubmed.ncbi.nlm.nih.gov/42325666/) describes relationships between handling stressors and carcass bruising, operators should train personnel in low-stress handling techniques. ## Worker and [Food Safety](/knowledge/bacteria/livestock-bacteria/cooking-chicken-bacteria-prevention) Foodborne pathogens present a hazard that carcass data can partly monitor. *Escherichia coli* O157:H7 has been isolated from cattle feces and carcasses ([Scopus 0027715142](https://api.elsevier.com/content/abstract/scopus_id/0027715142)). Carcass contamination often originates from hide transfer during slaughter. Pre-harvest interventions,such as vaccination, feed additives, and water acidification,require verification through microbiological testing integrated with plant records. The [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) site provides surveillance data for pathogens relevant to beef safety. Injection-site lesions are a worker safety issue during fabrication (needle-stick risk) and a food quality defect. Records of product type, route, anatomical location, and withdrawal time should be maintained. The Merck Veterinary Manual emphasizes that antibiotic residues, though rare, are detected through slaughter plant sampling programs. When a violation occurs, professional escalation to the herd veterinarian is necessary to audit treatment protocols and ensure compliance. ## Failure Patterns Common carcass data patterns signaling management failures include: - Low hot carcass weight relative to pen average: Due to chronic disease, insufficient energy intake, or excessive shipping shrink. - Reduced marbling with normal weight: Suggests genetic limitation, early implant use, or insufficient days on feed. - High backfat but low ribeye area: Indicates overconditioning from overfeeding energy to cattle with limited frame or muscle capacity. - Increased liver abscesses (>15% in a pen): Associated with high-concentrate rations and inadequate bunk management, the [PubMed record 42353521](https://pubmed.ncbi.nlm.nih.gov/42353521/) discusses risk factors. - High incidence of dark cutters (>5% in a lot): Points to handling stress, mixing unfamiliar animals, long lairage without water, or excitable temperament. Each failure pattern requires root-cause investigation. Escalation to a nutritionist, veterinarian, or geneticist is warranted when patterns persist across multiple loads. ## Practical Monitoring Producers should establish baseline values for key carcass endpoints. Ultrasound scanning of live cattle before harvest,either at farm level or at the feedlot,provides real-time feedback on backfat and ribeye area, enabling culling decisions before shipment. The [FAO](https://www.fao.org/animal-production/en/) resources describe ultrasound technique limitations: operator skill affects accuracy, and scanning cannot fully predict marbling. Tenderness is the most variable quality attribute. Consumer thresholds for tenderness acceptance have been documented ([Scopus 0035748267](https://api.elsevier.com/content/abstract/scopus_id/0035748267)), but no commercial instrument can reliably predict tenderness from live measurements. Aging protocols, electrical stimulation, and genetic selection (e.g., calpain-calpastatin system) require coordination among producer, processor, and retailer. Their effectiveness is monitored through Warner-Bratzler shear force values or taste panel data, which should be reviewed periodically with a meat scientist. Integrating production records with carcass data is the cornerstone of improvement. When anomalies arise,a sudden drop in yield grade, a spike in liver abscesses,the response should involve rechecking feed batch analyses, verifying health event logs, and consulting the plant’s quality assurance department. Professional associations and extension services offer benchmarking databases, though individual herd comparisons require adjustment for genetics, days on feed, and marketing endpoint. Ultimately, interpreting carcass reports requires contextual knowledge of facilities, nutrition, health management, and animal handling. Routine review by the herd veterinarian and nutritionist, combined with objective monitoring using the sources cited, reduces the variability that erodes profit and quality. Integrating carcass data with health records allows producers to detect subclinical conditions that affect both animal welfare and product quality. Health observation should include routine assessment of mobility, body condition, and feed intake across the finishing phase, as these parameters often correlate with intermediate carcass outcomes. For example, lameness due to foot rot or joint infection reduces gain and increases the likelihood of carcass condemnation at slaughter. The [Merck Veterinary Manual](https://www.merckvetmanual.com/) describes such conditions and their antemortem signs. Producers should document each animal's health events and treatments in a manner that permits retrospective linkage to individual carcass reports. This record integration enables identification of recurring problems, such as liver abscesses that lower yield grade and necessitate offal disposal, or injection-site lesions that damage high-value cuts. Biosecurity measures extend directly to carcass quality. Pathogen carriage in the gastrointestinal tract, particularly *Escherichia coli* O157, can lead to hide and carcass contamination at processing. A study on cattle as a possible source of verocytotoxin-producing *E. coli* O157 infections in man (Scopus record 0027715142) underscores the importance of pre-harvest interventions. Maintaining clean, dry pens, providing clean water, and minimizing fecal-oral transmission reduce pathogen shedding. Biosecurity protocols should follow the [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) for transport and lairage to limit stress-induced shedding and cross-contamination. Diagnostic and veterinary escalation is warranted when carcass data reveal unexpected patterns. For example, a sudden increase in dark-cutting carcasses (high ultimate pH) suggests chronic stress or glycogen depletion before slaughter. Veterinarians should investigate handling practices, transport duration, weather extremes, and group mixing. Similarly, elevated trim losses due to bruises necessitate a review of facility design, pen stocking density, and employee training. The [USDA Animal and Plant Health Inspection Service (APHIS) Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) program provides guidelines for reportable conditions that might first appear as abnormal carcass findings, such as abscesses, pneumonia lesions, or neoplasms. Each diagnosis should be communicated to the processing plant's veterinarian and, when appropriate, to the [USDA National Animal Health Monitoring System](https://www.aphis.usda.gov/livestock-poultry-disease/nahms) for regional trend surveillance. Uncertainty is inherent in interpreting single-animal carcass data. Carcass weight and fat thickness are influenced by the animal's genetic potential, health history, and recent diet, but also by random variation such as gut fill variation and the exact site of measurement. Producers should compare individual data against pen-level averages and rolling herd benchmarks instead of absolute thresholds. For traits related to eating quality, such as tenderness, consumer thresholds (Scopus record 0035748267) indicate that only extreme deviations (e.g., very high shear force values) reliably predict rejection. Therefore, culling decisions based solely on a one-time carcass record should be made with caution and in consultation with a geneticist or extension specialist. Nutritional factors further complicate interpretation, monensin supplementation (Scopus record 0021445254) can alter feed efficiency and thereby affect carcass fat deposition differently depending on the basal diet. The fatty acid composition of intramuscular fat, including conjugated linoleic acid, changes with forage versus concentrate feeding (Scopus record 0034331723), which may influence both perceived marbling and consumer acceptance but is not routinely measured. Sustainability objectives intersect with carcass data interpretation. Carcass weight and fat content determine the total edible product and the feed inputs required. Reducing fat trim while maintaining palatability improves the environmental footprint per kilogram of retail meat. The [FAO Animal Production and Health](https://www.fao.org/animal-production/en/) resources highlight that efficient lean tissue accretion, tracked through yield grade and ribeye area, reduces greenhouse gas emissions per unit of protein. Herd-level carcass data can also inform culling of dams with poor maternal or growth traits, accelerating genetic progress toward more sustainable production systems. ## Frequently Asked Questions **1. How often should I review carcass data for my herd?** Review each lot of cattle within two weeks of receiving the kill sheet from the processor. Compare individual records to the pen average and to historical herd benchmarks. Quarterly aggregation of data across multiple lots provides more robust signals for genetic and management decisions. **2. What does a high yield grade (Yield Grade 4 or 5) imply for health?** A high yield grade usually indicates excessive external fat, which can be a marker for overfeeding or genetic predisposition. It may also correlate with increased incidence of liver abscesses and higher metabolic disorders such as acidosis. Check processing plant remarks for liver condemnation reports. **3. Can carcass data identify animals that were sick before slaughter?** Indirectly. Dark-cutting carcasses (pH above 5.8) suggest prolonged stress or glycogen depletion from illness, transportation, or mixing. Lung lesions, abscesses, or joint infections at slaughter confirm prior disease. Correlation of such findings with feedlot health records is essential. **4. What is the value of tracking marbling score across different sire groups?** Marbling score (USDA Quality Grade) is moderately heritable and influenced by nutrition. Comparing progeny of different sires fed the same ration reveals genetic differences in intramuscular fat deposition. This information aids selection decisions and can be paired with feeding program adjustments (Scopus record 0034331723). **5. How do I know if a carcass defect is due to genetics or management?** Recurrence across multiple progeny of the same bull suggests a genetic component, a single occurrence or temporal cluster points toward management or environmental causes. Submit data to a breed association or genetic evaluation program for more precise partitioning. **6. What records should I keep to make carcass data useful?** Individual animal identification (EID or tattoo), birth date, weaning weight, finishing ration details, days on feed, health treatments with dates, and slaughter date. Link all records to the kill sheet animal number. A relational database or simple spreadsheet with these fields is sufficient. **7. Are there zoonotic risks associated with handling carcass data reports?** Carcass reports themselves pose no direct [zoonotic risk](/knowledge/parasites/pet-parasites/zoonotic-risk-humans-get-parasites-from-pets), but the slaughter environment and tissues may carry pathogens. The [USDA APHIS Livestock and Poultry Disease](https://www.aphis.usda.gov/livestock-poultry-disease) resource outlines biosafety for individuals who visit processing plants. Always follow facility protocols for protective clothing. **8. How should I handle a carcass with a suspect foreign substance or abnormal growth?** Isolate the lot's carcass report and contact the processing plant's quality assurance team immediately. The plant may retain samples. Inform your herd veterinarian, as such findings could represent a food safety issue or a reportable condition under [WOAH Terrestrial Animal Health Code](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/). Do not commingle affected carcass data with routine records until cleared. **Educational veterinary notice:** This material is intended for informational and educational purposes. Individual herd health and carcass quality decisions should involve a licensed veterinarian who can interpret findings in the context of herd-specific risk factors, local disease prevalence, and regulatory obligations. Always consult a veterinarian for diagnosis, treatment, and biosecurity planning. ## 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.