# Diagnostic Approach to Weight Loss in Adult Dairy Cows: Parasitism, Nutrition, and Chronic Disease ## Key Takeaways - Weight loss in adult dairy cows necessitates a systematic, sequential diagnostic approach beginning with a detailed history, including parity, lactation stage, and body condition score (BCS) trend, to differentiate physiological early-lactation fat mobilization from pathological wasting. - Paratuberculosis diagnosis is challenging due to *Mycobacterium avium* subsp. *paratuberculosis* (MAP) biology; radiometric fecal culture offers higher sensitivity (54.4%) than conventional culture (45.1%) or DNA probes (33.5%) in subclinical cases, and negative results do not rule out infection. - Fasciolosis diagnosis requires specific fecal sedimentation techniques for *Fasciola hepatica* eggs, but serology often correlates better with production impact than coprology, especially in chronic infections with intermittent egg shedding. - Nutritional assessment mandates ration analysis comparing formulated versus delivered diets for energy, protein, and mineral deficits, alongside evaluation of dry matter intake, feed bunk management, and potential mycotoxin contamination. - Chronic inflammatory diseases, such as subclinical mastitis (indicated by elevated somatic cell counts and milk culture results), can cause weight loss through increased inflammatory demand and reduced feed intake, requiring investigation beyond enteric pathogens. - Diagnostic errors include premature closure on a single positive test (e.g., paratuberculosis ELISA without diarrhea), misattributing weight loss to incidental parasitism, and overlooking chronic inflammatory conditions like mastitis or lameness. --- Weight loss in an adult dairy cow is a common but diagnostically demanding presentation. The differential diagnosis spans infectious enteropathies, parasitic disease, nutritional mismanagement, and chronic organ failure, and the same clinical sign can arise from entirely different pathophysiological mechanisms. This article provides a systematic framework for the practicing veterinarian to investigate weight loss in adult dairy cattle, with emphasis on distinguishing parasitism, nutritional causes, and chronic disease through history, physical examination, targeted laboratory testing, and response-based reasoning. It is written for clinicians who require a structured diagnostic pathway instead of a list of differentials. The approach taken here is deliberately sequential. Early decisions about which tests to run and how to interpret them depend on signalment, stage of lactation, season, and herd-level factors. A cow that is losing weight in early lactation may be in negative energy balance by design, whereas the same body condition score in a dry cow signals pathology. The diagnostic workup must therefore begin before the hands-on examination, with a structured history that establishes the production context. Later sections address the specific diagnostic features of Johne's disease, fasciolosis, nutritional insufficiency, and chronic inflammatory or neoplastic conditions, with attention to the sensitivity and specificity of available tests at different stages of disease. ## At a Glance | Parameter | Clinical Relevance | Diagnostic Consideration | |---|---|---| | Body condition score trend | Rate and timing of loss distinguish physiological from pathological | Serial scoring at dry-off, calving, and mid-lactation | | Fecal consistency | Diarrhea supports enteric disease but is absent in many wasting conditions | Intermittent diarrhea is typical of clinical paratuberculosis | | Stage of lactation | Early-lactation loss may be physiological, loss after peak requires investigation | Compare against expected lactation curve | | Fecal culture or PCR for *Mycobacterium avium* subsp. *paratuberculosis* | Confirms paratuberculosis but has low sensitivity in subclinical infection | Radiometric culture outperforms conventional culture and DNA probe in subclinical cases | | Liver enzyme profile and bile acids | Identifies hepatic disease as a cause of weight loss | Fasciolosis may produce elevated gamma-glutamyl transferase | | Fecal fluke egg count | Confirms patent *Fasciola hepatica* infection but misses immature stages | Serology correlates better with production impact | | Ration analysis | Detects energy, protein, or mineral deficits | Compare formulated versus delivered ration | | Chronic disease screen | Rules out mastitis, lameness, and other production-limiting conditions | Somatic cell count, locomotion score, and milk culture | ## The Pathophysiology of Weight Loss in Adult Dairy Cattle Weight loss reflects a sustained negative balance between energy intake and energy expenditure. In adult dairy cows, the differential diagnosis can be organized by which component of this balance is disrupted. Reduced intake arises from anorexia, dental disease, or pain, reduced absorption follows damage to the intestinal mucosa, increased losses occur through protein-losing enteropathy, parasitism, or chronic inflammation, and increased demand accompanies lactation, pregnancy, or neoplasia. Most chronic wasting diseases affect more than one of these pathways simultaneously, which is why a single test rarely provides the diagnosis. The chronic granulomatous enteritis of paratuberculosis illustrates this principle. Infection with *Mycobacterium avium* subsp. *paratuberculosis* produces progressive thickening of the intestinal wall, particularly the ileum, with resulting malabsorption and protein loss. The subclinical form of the disease causes progressive weight loss, reduced milk production, and lower slaughter value before the onset of clinical signs such as chronic diarrhea and emaciation. The long incubation period, often several years, means that clinical disease typically appears in cows aged two to five years, and the diagnosis is frequently made only after the cow has already been culled for poor production. The pathophysiology explains the diagnostic challenge: because the intestinal lesion develops gradually, fecal shedding of the organizm is intermittent and often absent in early infection. Fasciolosis operates through a different mechanism. The migratory stages of *Fasciola hepatica* damage hepatic parenchyma as immature flukes traverse the liver, and adult flukes in the bile ducts cause chronic cholangitis and fibrosis. The resulting impairment of hepatic function reduces appetite, alters protein metabolism, and contributes to weight loss that may be subtle in early infection. Unlike paratuberculosis, the production impact of fasciolosis has been quantified in modern systems, with diagnostic test results correlated with intensity of infection and associated losses in carcass weight and milk yield. ## Distinguishing Physiological from Pathological Weight Loss The first diagnostic decision is whether the weight loss is appropriate for the cow's stage of lactation. Dairy cows in early lactation routinely mobilize body fat to support milk production when energy intake cannot match output. A body condition score loss of 0.5 to 1.0 units on a five-point scale during the first 60 days in milk is expected. Weight loss that continues beyond peak lactation, that occurs in dry cows, or that exceeds this magnitude warrants investigation. The history should establish the parity, calving date, current milk production, and body condition score trajectory. A cow that has lost condition despite adequate intake and normal fecal consistency points toward a chronic disease process instead of a nutritional deficit. Conversely, a cow on a poorly formulated ration may lose weight without any identifiable infectious or parasitic cause. The ration analysis should compare the formulated diet with what is actually delivered, including forage quality, dry matter intake, and the energy and protein density of the total mixed ration. Nutritional causes of weight loss are often herd-level problems, so the clinician should ask whether other cows in the same group are affected. ## Paratuberculosis: Diagnostic Testing and Interpretation Paratuberculosis is the most important infectious cause of chronic weight loss in adult dairy cattle in many regions. The diagnosis is complicated by the biology of the infection. Fecal culture has been the reference standard, but its sensitivity depends on the stage of disease and the culture method. In a study of subclinically infected dairy cattle, radiometric fecal culture detected 54.4% of infected animals, conventional culture on Herrold's egg yolk medium detected 45.1%, and a commercial DNA probe detected only 33.5%. Among animals that were fecal shedders, the sensitivities improved to 89.2%, 73.8%, and 55.0%, respectively. Herd prevalence significantly affected the sensitivity of all three tests. These figures have practical implications. A negative fecal test does not rule out paratuberculosis, particularly in a cow with early or subclinical infection. Serological tests, typically ELISA, detect antibody but have lower sensitivity in early disease and can produce false positives in herds with cross-reacting environmental mycobacteria. The clinician should interpret test results in the context of the cow's clinical signs, the herd's infection status, and the pretest probability based on age and history. In a cow with chronic diarrhea and weight loss, a positive fecal culture or PCR is confirmatory. In a cow with weight loss alone, the diagnostic pathway may require repeated testing over several months or the use of multiple test modalities. ## The Diagnostic Sequence: History, Herd Data, and Physical Examination The investigation begins before the chute. A complete dietary history must include the current ration formulation, feed analysis results, dry matter intake estimates, feeding management, and any recent ration changes. Ask specifically about forage sources, mycotoxin risk, feed spoilage, and whether the affected cows are grouped with fresh or high-producing animals where competition may limit intake. The history should also cover anthelmintic and flukicide protocols, vaccination status, biosecurity practices, and whether replacement animals are purchased or home-raised. Regional disease prevalence matters: paratuberculosis reporting varies substantially by geography, with survey data from England and Wales showing the highest farm-level prevalence in southern regions, and Canadian reviews emphasizing the role of herd-level risk factors in disease spread ([clinical stages and prevalence of Johne's disease in Canadian dairy herds](https://pubmed.ncbi.nlm.nih.gov/17017652/), [prevalence and distribution of clinical Johne's disease in English dairy herds](https://pubmed.ncbi.nlm.nih.gov/9787418/)). Herd-level data often outperforms individual examination for prioritizing differentials. Review monthly milk recording data for the affected cows. A cow losing body condition while maintaining milk yield suggests an energy deficit, whereas a cow with falling milk and progressive weight loss points toward chronic infection or parasitism. Compare the affected animals to herdmates of similar parity and days in milk. If multiple cows are affected, nutritional or management causes rise in priority. A single thin cow in an otherwise healthy herd shifts attention toward individual disease. Physical examination should be systematic and complete. Record body condition score, rectal temperature, heart rate, respiratory rate, and rumen fill. Assess hydration status, mucous membrane color, and the presence of submandibular or brisket edema. Auscult the thorax and abdomen. Palpate the udder for fibrosis or asymmetry. Examine the feet, as chronic lameness can reduce time at the feed bunk. Rectal examination should assess rumen size and tone, abomasal position, and the character of the feces. Fecal consistency ranges from normal to pasty to watery, and the distinction matters: profuse watery diarrhea with weight loss in an adult cow strongly suggests paratuberculosis, whereas intermittent soft feces may reflect parasitism or nutritional causes. The physical examination also determines which ancillary tests are indicated. A cow with tachycardia, tachypnoea, and fever requires a different workup than an afebrile cow with normal vital parameters. The examination findings should be recorded in a standard format that allows comparison on recheck, including body condition score, body weight if scales are available, and a fecal consistency score. ## Fecal Analysis: Parasitology and Paratuberculosis Testing Fecal examination is the first laboratory step in most cases. Quantitative fecal egg counts using the McMaster technique identify gastrointestinal nematode burdens. In adult dairy cows, however, egg counts correlate poorly with total worm burden, and low counts do not exclude significant parasitism. Liver fluke diagnosis requires a separate sedimentation technique, as fluke eggs are dense and do not float reliably in standard flotation solutions. Coprological methods for *Fasciola hepatica* have improved considerably, but sensitivity remains imperfect, particularly in chronic infections with intermittent egg shedding ([advances in coprological and serological diagnosis of bovine fasciolosis](https://pubmed.ncbi.nlm.nih.gov/24229764/)). Paratuberculosis testing requires a deliberate strategy because no single test is adequate. Fecal culture has historically been the reference standard, but its sensitivity in subclinical infection is limited. In one evaluation of subclinically infected cattle, radiometric culture detected 54.4% of infected animals, conventional culture 45.1%, and a commercial DNA probe 33.5%, with herd prevalence significantly affecting test performance ([sensitivity of fecal culture and DNA probe for paratuberculosis diagnosis](https://pubmed.ncbi.nlm.nih.gov/1591658/)). These figures underscore that a negative test result does not rule out infection, especially in early or low-shedding cases. PCR on fecal samples offers faster turnaround than culture but shares similar sensitivity limitations. Serology with ELISA detects antibody but performs poorly in the early subclinical phase. For clinical cases with chronic diarrhea and weight loss, fecal PCR or culture is the test of choice, and a positive result in a clinically affected cow is diagnostic. | Test | Target | Best Use | Interpretation Caveats | |------|--------|----------|------------------------| | Fecal egg count (McMaster) | Nematode eggs | Screening for gastrointestinal parasitism | Low counts do not exclude disease in adults | | Fecal sedimentation | Fluke eggs | Suspected fasciolosis | Intermittent shedding causes false negatives | | Fecal PCR | *M. avium* subsp. *paratuberculosis* DNA | Clinical suspect with diarrhea | Negative result does not rule out infection | | Fecal culture | Viable *M. avium* subsp. *paratuberculosis* | Confirmation, strain typing | Slow turnaround, sensitivity limited in subclinical cases | | Serum ELISA | Anti-*M. avium* subsp. *paratuberculosis* antibody | Herd screening, late subclinical infection | Poor sensitivity in early infection | ## Blood Biochemistry and Hematology Serum biochemistry provides information about organ function, protein status, and energy balance. A minimum database includes total protein, albumin, globulins, and a liver enzyme panel. Hypoalbuminaemia with weight loss suggests protein-losing enteropathy, which occurs in paratuberculosis and severe parasitism, or chronic liver disease. Hyperglobulinaemia accompanies chronic inflammation or infection. Beta-hydroxybutyrate and non-esterified fatty acids assess energy balance in early lactation, though their utility diminishes in cows that are months into lactation. Liver enzymes and bile acids identify hepatic pathology, and urea and creatinine evaluate renal function. Hematology may reveal anemia, which can accompany chronic parasitism or malnutrition, though hematological changes are often nonspecific. The timing of sampling matters. Blood for energy metabolites should be collected before feeding to standardize results. Serum for antibody testing should be collected before any treatment that might affect immune function. If the herd has a known paratuberculosis problem, serology results should be interpreted in light of the herd's infection status, as herd prevalence affects test performance ([sensitivity of fecal culture and DNA probe for paratuberculosis diagnosis](https://pubmed.ncbi.nlm.nih.gov/1591658/)). ## Feed Analysis and Nutritional Assessment Feed analysis is mandatory when more than one cow is affected or when the ration has changed recently. Submit representative samples of all forages, concentrates, and total mixed ration for proximate analysis, including dry matter, crude protein, neutral detergent fiber, starch, and minerals. Compare the analyzed values to the ration formulation. Common failures include forages with lower energy density than assumed, excessive neutral detergent fiber limiting intake, and mineral imbalances. Evaluate dry matter intake records if available, and consider whether feed bunk management, stocking density, or water availability limits consumption. Mycotoxin screening is indicated when feed quality is suspect, particularly with mouldy silage or grain. The clinical picture of mycotoxin exposure is often vague, with reduced intake, decreased production, and ill-thrift. The diagnosis requires feed testing and exclusion of other causes, as clinical signs are not pathognomonic. ## Decision Points and Documentation The diagnostic sequence is iterative. If initial testing does not identify a cause, reassess the history and examination findings before proceeding to more invasive or expensive tests. A negative paratuberculosis test in a cow with classic signs should prompt repeat testing after several weeks, as shedding is intermittent. Similarly, a single negative fecal fluke examination does not exclude fasciolosis, and repeat sampling or serology may be warranted in endemic areas ([advances in coprological and serological diagnosis of bovine fasciolosis](https://pubmed.ncbi.nlm.nih.gov/24229764/)). Document all findings in the medical record, including the history, examination findings, test results, and the reasoning behind the diagnostic plan. Record body condition score and body weight at each visit. Photographs of the cow and feces can be useful for tracking progression. The record should state the working differential list, the tests performed, and the interpretation of each result. This documentation supports future decision-making and provides a basis for herd-level recommendations if a contagious cause is confirmed. ## Recognized Complications and Early Detection The principal failure mode in the weight loss workup is premature closure: attributing cachexia to the first positive test result without reconciling it against the full clinical picture. Paratuberculosis ELISA results illustrate this risk. The subclinical form produces progressive weight loss and reduced milk production before diarrhea appears, and available tests generate many false negatives and some false positives in subclinically infected animals [Johne's disease in Canada Part I: clinical symptoms, pathophysiology, diagnosis, and prevalence in dairy herds](https://pubmed.ncbi.nlm.nih.gov/17017652/). A positive ELISA in a cow with normal fecal consistency, no herd history of the disease, and a low within-herd prevalence should prompt confirmatory testing instead of a culling decision. A second failure mode is misattributing weight loss to parasitism when fluke or worm burdens are incidental. Coprological and serological methods for Fasciola hepatica have improved substantially, and test results correlate with intensity of infection and production losses [Recent advances in the diagnosis, impact on production and prediction of Fasciola hepatica in cattle](https://pubmed.ncbi.nlm.nih.gov/24229764/). However, a positive fecal sample does not prove causation in an individual cow. The discriminating question is whether the magnitude of the burden explains the magnitude of the loss. A third failure mode is overlooking chronic inflammatory disease. Mastitis, particularly the subclinical form, is a common production-limiting disease with complex causation [Application of Metabolomics in Diagnosis of Cow Mastitis: A Review](https://pubmed.ncbi.nlm.nih.gov/34692813/). A cow with chronic subclinical mastitis and elevated somatic cell count may lose condition through inflammatory demand and reduced feed intake, even when the udder appears normal on palpation. The somatic cell count and milk culture should be reviewed before the workup is closed. | Observation | Likely cause | Discriminating check | |---|---|---| | Positive paratuberculosis ELISA, normal feces, low herd prevalence | False positive or subclinical infection | Repeat ELISA with fecal PCR or culture, interpret with herd prevalence | | Positive fecal fluke count, single cow affected | Incidental parasitism | Compare burden to herd pattern, assess response to targeted treatment | | Weight loss with elevated somatic cell count | Chronic subclinical mastitis | Milk culture and individual cow somatic cell count history | | Weight loss with normal feces, normal parasitology, normal biochemistry | Early paratuberculosis or chronic disease | Serial body condition scoring over 4 to 8 weeks, re-examine | ## Common Diagnostic Errors and Corrective Action The most frequent error in students and less experienced clinicians is treating the physical examination as a formality. Weight loss in adult dairy cows demands a structured examination that includes body condition scoring, rumen fill assessment, rectal examination, and auscultation of the thorax and abdomen. The second error is collecting blood and feces before taking a complete history. Herd-level data on milk production, culling rates, and previous disease events often narrow the differential more efficiently than any single laboratory test. A third error is overinterpreting a single negative test. Fecal culture for Mycobacterium avium subspecies paratuberculosis has limited sensitivity in subclinical infection, among infected cattle, conventional culture detected only 45.1% of cases in one evaluation [Evaluation of conventional and radiometric fecal culture and a commercial DNA probe for diagnosis of Mycobacterium paratuberculosis infections in cattle](https://pubmed.ncbi.nlm.nih.gov/1591658/). A negative culture does not exclude infection. The corrective action is to combine tests with different biological bases, such as ELISA with fecal PCR, and to interpret results in light of the animal's stage of disease. The fourth error is failing to revisit the diagnosis. Weight loss workups often require serial assessments. A cow that continues to lose condition despite negative initial testing should be re-examined, not discharged. ## Limitations of the Evidence and Divergent Expert Opinion The evidence base for several diagnostic decisions in this workup is limited. Test performance characteriztics for paratuberculosis diagnostics vary with herd prevalence, as demonstrated in the evaluation of fecal culture and DNA probe methods [Evaluation of conventional and radiometric fecal culture and a commercial DNA probe for diagnosis of Mycobacterium paratuberculosis infections in cattle](https://pubmed.ncbi.nlm.nih.gov/1591658/). Published sensitivity figures may not transfer directly to a given herd, and expert opinion differs on whether ELISA or PCR should be the primary screening test in low-prevalence herds. For fasciolosis, the correlation between diagnostic test results and production losses is established, but the predictive value of a single fecal sample in an individual cow remains contested [Recent advances in the diagnosis, impact on production and prediction of Fasciola hepatica in cattle](https://pubmed.ncbi.nlm.nih.gov/24229764/). Some authorities advocate serology as the more reliable indicator of exposure, while others prefer coprology for current burden. Both positions have merit, and the choice should reflect the herd's fluke risk period and the question being asked. ## Referral, Specialist Consultation, and Regulatory Reporting Referral is warranted when the workup reaches its limits. A cow that continues to lose weight despite a negative or equivocal diagnostic workup should be referred to a veterinary teaching hospital or a specialist in bovine internal medicine for advanced imaging, laparotomy, or intestinal biopsy. Laboratory involvement is appropriate when specialised testing is required, such as mycobacterial culture, histopathology, or mass spectrometry-based metabolic profiling. Regulatory reporting obligations vary by jurisdiction. Paratuberculosis is a notifiable or controlled disease in some regions, and international standards for trade-related disease control may apply [WOAH terrestrial animal health standards](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/). Practitioners should consult their national veterinary authority and the [USDA APHIS livestock and poultry disease information](https://www.aphis.usda.gov/livestock-poultry-disease) or the equivalent agency in their country to confirm local requirements before concluding a case. ## Frequently Asked Questions ### How Should I Prioritize Testing When the Client Has a Limited Diagnostic Budget? Begin with the lowest-cost, highest-yield steps: a complete history, body condition scoring of the affected cow against herdmates, and fecal examination for parasite eggs and fluke eggs. These tests frequently identify treatable causes before expensive biochemistry is needed. If paratuberculosis is suspected, pooled or individual fecal PCR or culture can be justified because the herd-level implications are substantial. [Johne's disease control programs in Canada](https://pubmed.ncbi.nlm.nih.gov/17017652/) emphasize that test interpretation is challenging in subclinical infection, so a single negative result should not close the investigation. Reserve serum biochemistry and liver biopsy for cases where nutritional or metabolic disease remains plausible after parasitology is ruled out. Discuss the cost of a missed diagnosis against the cost of testing, and document the agreed plan. ### What Can I Do When Fecal Culture or PCR for Paratuberculosis Is Not Readily Available? Serology is the practical alternative when culture or PCR is unavailable. Enzyme-linked immunosorbent assay (ELISA) is widely accessible and detects antibodies, but sensitivity in subclinically infected cows is limited. [Comparative evaluation of fecal culture and DNA probe methods](https://pubmed.ncbi.nlm.nih.gov/1591658/) showed that no single test detects all infected animals, and sensitivity is influenced by herd prevalence. Interpret a positive ELISA in a cow with compatible signs as supportive evidence. A negative ELISA does not exclude infection, particularly in early or low-shedding cows. Repeat serology after three to six months if clinical suspicion remains high. Submit fecal samples to a regional laboratory when the service becomes available, and use histopathology on ileocaecal lymph node or ileum samples from culled suspect cows to confirm the diagnosis retrospectively. ### How Does the Diagnostic Approach Differ in Beef Suckler Cows Compared with Dairy Cows? Lactation is absent in suckler cows, so milk yield cannot serve as an early indicator of weight loss. The dry cow's energy demand is lower, meaning nutritional causes often present later and with more profound emaciation. Parasite exposure patterns differ because suckler calves and cows often share pasture, increasing pasture contamination. [Bovine fasciolosis epidemiology and production impact](https://pubmed.ncbi.nlm.nih.gov/24229764/) describes regional variation in fluke risk, so seasonal and geographical history is essential. Paratuberculosis remains a key differential, but the economic threshold for testing is different because replacement costs and calving intervals dominate. Examine the calf as well as the cow, since poor calf growth may be the first clue to maternal disease. The physical examination and fecal testing sequence is otherwise unchanged. ### What Records Should I Keep During a Chronic Weight Loss Investigation? Record body condition score, body weight if scales are available, and a photograph of the cow at first examination. Document fecal consistency, appetite, milk production, and rectal temperature at each visit. Keep a timeline of test submissions, laboratory results, and treatments administered, including dates and product names. Note the cow's parity, calving date, and herd-level parameters such as average days in milk and bulk tank somatic cell count. [USDA APHIS animal health information](https://www.aphis.usda.gov/livestock-poultry-disease) and [AVMA practice resources](https://www.avma.org/resources-tools) provide guidance on record systems that support herd-level analysis. These records allow you to distinguish progressive weight loss from cyclical variation and provide defensible documentation if regulatory reporting becomes necessary. ### How Should I Explain a Working Diagnosis of Paratuberculosis to a Producer Who Has Not Seen Diarrhea? Explain that diarrhea is a late sign and that many infected cows lose condition and milk production for months before fecal consistency changes. [Clinical signs of Johne's disease in Canadian dairy herds](https://pubmed.ncbi.nlm.nih.gov/17017652/) describe the subclinical form as progressive weight loss with reduced milk production and premature culling. Emphasize that the cow may look normal to the untrained eye while already shedding bacteria. Use the test results to show that infection is present even without diarrhea. Discuss the herd-level implications, including the risk to young stock and the need for biosecurity review. Be honest about test limitations and the possibility of false negatives. Offer to review calf-rearing practices and purchase policies, since these are the main routes of herd introduction and spread. ### When Should I Suspect a Cause Outside the Parasitic, Nutritional, and Chronic Disease Categories? If the standard workup is unrewarding, reconsider the history for access to toxins, including lead, ionophores, or plants. Examine the cow for dental disease, particularly in older animals, and for evidence of chronic pain from lameness or abdominal adhesions. [MSD Veterinary Manual clinical resources](https://www.msdvetmanual.com/) list neoplastic conditions such as lymphoma as causes of adult cow wasting. Perform a rectal examination to assess for abdominal masses, and consider thoracic auscultation for evidence of metastasis. If the cow is febrile or has an elevated somatic cell count, pursue mastitis or metritis as a chronic drain on condition. Refer the case for ultrasonography or exploratory laparotomy when the cow is valuable and the diagnosis remains obscure. Document the negative findings carefully, as they support a presumptive diagnosis of a non-infectious, non-nutritional process. ## Related Clinical & Scientific Guides * [Rumen Health Assessment in Dairy Cows: Clinical and Subclinical Indicators](/knowledge/veterinary-medicine/food-animal-medicine/rumen-health-assessment-dairy-cows-clinical-subclinical-indicators) * [Mastitis Control Programs in Dairy Herds: Monitoring and Prevention](/knowledge/veterinary-medicine/food-animal-medicine/mastitis-control-programs-dairy-herds-monitoring-prevention) * [Swine Nutrition and Health: Feed-Related Disease Diagnosis](/knowledge/veterinary-medicine/food-animal-medicine/swine-nutrition-health-feed-related-disease-diagnosis) ## References and Further Reading - [Johne's disease in Canada Part I: clinical symptoms, pathophysiology, diagnosis, and prevalence in dairy herds.](https://pubmed.ncbi.nlm.nih.gov/17017652/). 2006. - [Recent advances in the diagnosis, impact on production and prediction of Fasciola hepatica in cattle.](https://pubmed.ncbi.nlm.nih.gov/24229764/). 2014. - [Application of Metabolomics in Diagnosis of Cow Mastitis: A Review.](https://pubmed.ncbi.nlm.nih.gov/34692813/). 2021. - [Evaluation of conventional and radiometric fecal culture and a commercial DNA probe for diagnosis of Mycobacterium paratuberculosis infections in cattle.](https://pubmed.ncbi.nlm.nih.gov/1591658/). 1992. - [Multi-Platform Detection of Small Ruminant Lentivirus Antibodies and Provirus as Biomarkers of Production Losses.](https://pubmed.ncbi.nlm.nih.gov/32426375/). 2020. - [Prevalence, incidence and geographical distribution of Johne's disease in cattle in England and the Welsh borders.](https://pubmed.ncbi.nlm.nih.gov/9787418/). 1998. - [USDA APHIS Animal Health Information](https://www.aphis.usda.gov/livestock-poultry-disease). USDA APHIS. - [FAO Animal Production and Health](https://www.fao.org/animal-production/en/). FAO. - [MSD Veterinary Manual, Professional Edition](https://www.msdvetmanual.com/). MSD Veterinary Manual. ## Related Articles - [Dairy Cow Nutrition: Diagnostic Approach to Metabolic Disorders](/knowledge/veterinary-medicine/food-animal-medicine/dairy-cow-nutrition-diagnostic-approach-metabolic-disorders) - [Diagnostic Approach to Mastitis in Dairy Cows: Pathogen Identification and Herd Patterns](/knowledge/veterinary-medicine/food-animal-medicine/diagnostic-approach-mastitis-dairy-cows-pathogen-identification) - [Dairy Calf Health: Diagnostic Approach to Neonatal Diarrhea](/knowledge/veterinary-medicine/food-animal-medicine/dairy-calf-health-diagnostic-approach-neonatal-diarrhea) - [Diagnostic Approach to Lameness in Dairy Cattle: Lesion Localization](/knowledge/veterinary-medicine/food-animal-medicine/diagnostic-approach-lameness-dairy-cattle-lesion-localization) - [Diagnostic Workup for Poor Growth in Beef Calves: Distinguishing Parasitism from Nutrition](/knowledge/veterinary-medicine/food-animal-medicine/diagnostic-workup-poor-growth-beef-calves-parasitism-nutrition) > This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.