Mycoplasmosis

Mycoplasmosis encompasses a group of infectious diseases caused by bacteria of the genus Mycoplasma, affecting virtually all domestic livestock species including cattle, pigs, poultry, sheep, and goats. These unique microorganisms lack a cell wall, distinguishing them from typical bacteria and conferring natural resistance to beta-lactam antibiotics including penicillins and cephalosporins. Mycoplasma species cause a diverse array of clinical syndromes ranging from respiratory disease and mastitis to arthritis and reproductive disorders, with specific presentations varying by the Mycoplasma species involved and the host animal affected.

In cattle, Mycoplasma bovis represents the most economically significant species, causing pneumonia, mastitis, arthritis, otitis media, and reproductive disorders that collectively result in substantial losses to the dairy and beef industries. Young calves are particularly susceptible to respiratory disease and polyarthritis, while dairy cattle face mastitis that resists conventional treatment and spreads rapidly through milking equipment. Contagious bovine pleuropneumonia, caused by Mycoplasma mycoides subspecies mycoides, remains a devastating reportable disease in regions where it persists, though it has been eradicated from North America, Australia, and most of Europe.

Swine and poultry production systems face their own significant mycoplasma challenges. Mycoplasma hyopneumoniae causes enzootic pneumonia in pigs, a chronic respiratory condition that reduces growth rates and increases susceptibility to secondary infections in intensively managed herds worldwide. In poultry, Mycoplasma gallisepticum and Mycoplasma synoviae cause chronic respiratory disease, infectious synovitis, and egg production losses that impact both commercial and backyard flocks. The economic impact of these mycoplasma infections includes direct losses from mortality, reduced production, and treatment costs, plus indirect losses from decreased feed efficiency and market penalties.

Mycoplasmosis is treatable with appropriate antibiotics, though treatment success varies considerably by species and syndrome. The lack of a cell wall renders mycoplasmas inherently resistant to cell wall-active antibiotics, limiting therapeutic options to macrolides, tetracyclines, and fluoroquinolones. Prevention through biosecurity, testing and removal of carriers, and in some cases vaccination, offers more reliable control than treatment of established infections. Understanding the biology, transmission patterns, and control options for mycoplasma infections enables producers to protect their livestock and minimize economic losses from these challenging pathogens.

Mycoplasmosis is caused by infection with bacteria of the genus Mycoplasma, the smallest free-living organisms capable of self-replication. These bacteria are distinguished from other prokaryotes by their complete lack of a cell wall, instead possessing only a triple-layered cell membrane. This unique characteristic enables them to assume pleomorphic shapes, pass through filters that trap ordinary bacteria, and resist antibiotics targeting cell wall synthesis. Mycoplasmas are fastidious organisms requiring complex growth media for laboratory culture, complicating diagnostic efforts. Different Mycoplasma species demonstrate strong host specificity, with particular species adapted to infect specific animal hosts and tissue types.

The major pathogenic Mycoplasma species vary by host animal and clinical syndrome. In cattle, Mycoplasma bovis predominates as a cause of respiratory disease, mastitis, arthritis, and otitis, while Mycoplasma mycoides subspecies mycoides causes the dreaded contagious bovine pleuropneumonia in affected regions. Pigs are primarily affected by Mycoplasma hyopneumoniae causing enzootic pneumonia and Mycoplasma hyosynoviae causing polyarthritis. Poultry face Mycoplasma gallisepticum and Mycoplasma synoviae as the primary pathogens. Small ruminants are affected by multiple species including Mycoplasma agalactiae causing contagious agalactia and various Mycoplasma mycoides subspecies. Each species produces characteristic clinical syndromes in its adapted host.

Environmental and management factors significantly influence mycoplasma transmission and disease expression. Close confinement in poorly ventilated housing dramatically increases respiratory mycoplasma spread through aerosol transmission. Commingling animals from multiple sources, as occurs in feedlots, auction markets, and show circuits, facilitates introduction and spread. High stocking density increases contact rates and stress, both factors that promote transmission and clinical disease development. Seasonal housing patterns with winter confinement create annual peaks in respiratory mycoplasmosis. In dairy operations, milking procedures can spread Mycoplasma bovis mastitis from infected to uninfected cows through contaminated milking equipment.

Risk factors for mycoplasmosis include age, immune status, concurrent infections, and environmental stressors. Young animals, particularly calves in the first few months of life, are highly susceptible to mycoplasma respiratory disease and arthritis. Inadequate colostral immunity increases susceptibility. Concurrent viral infections such as bovine respiratory syncytial virus and bovine viral diarrhea virus damage respiratory defenses, facilitating secondary mycoplasma infection. Transportation stress, dietary changes, weaning, and other management stressors compromise immune function and increase disease risk. Animals with chronic mycoplasma infections serve as reservoirs, shedding organisms and maintaining infection within herds.

The pathophysiology of mycoplasma infections involves colonization of mucosal surfaces followed by local tissue damage and immune evasion. Mycoplasmas attach to respiratory or other epithelial cells using specialized tip structures, resisting clearance by mucociliary mechanisms. They produce various enzymes and toxic metabolites including hydrogen peroxide that directly damage host cells. The organisms evade immune responses through antigenic variation, changing their surface proteins to avoid antibody recognition. This immune evasion enables chronic infection with intermittent shedding that maintains transmission within populations. The inflammatory response to infection causes much of the clinical pathology, with immune-mediated damage contributing to pneumonia, arthritis, and other lesions.

Early warning signs of mycoplasmosis vary by species affected and the clinical syndrome developing. In calves, initial signs of respiratory mycoplasmosis include mild nasal discharge, occasional coughing, and subtle depression or reduced feed intake. These early indicators may be overlooked in group-housed calves until more severe signs develop. Ear drooping or head tilting in young calves may indicate developing otitis media before obvious ear discharge appears. In dairy cattle, the first indication of Mycoplasma bovis mastitis may be unexplained increases in somatic cell count or poor response of clinical mastitis cases to standard antibiotic therapy. Early detection requires heightened awareness and vigilant monitoring, particularly during high-risk periods.

Common symptoms in cattle with mycoplasmosis depend on the body systems involved. Respiratory disease presents with persistent coughing, nasal discharge progressing from serous to mucopurulent, labored breathing, fever, and depression. Mycoplasma bovis pneumonia often becomes chronic, with affected calves showing persistent ill-thrift, poor growth, and recurrent respiratory episodes. Mastitis caused by Mycoplasma bovis typically involves multiple quarters, produces abnormal milk with a characteristic sandy or flaky sediment, and fails to respond to conventional intramammary antibiotic therapy. Arthritis manifests as joint swelling, lameness, reluctance to rise, and stiff gait, commonly affecting the stifle, hock, and carpus. Otitis media causes head tilt, ear droop, purulent ear discharge, and vestibular signs in severe cases.

Swine mycoplasmosis, primarily enzootic pneumonia from Mycoplasma hyopneumoniae, presents with characteristic clinical patterns in affected herds. The classic sign is a chronic, nonproductive cough that becomes most apparent when pigs are disturbed or stressed. Unlike acute bacterial pneumonia, affected pigs typically maintain their appetite and remain relatively alert despite chronic respiratory infection. Growth rates are reduced, and feed conversion efficiency declines. Secondary bacterial infections, particularly with Pasteurella multocida, Actinobacillus pleuropneumoniae, or Streptococcus species, may cause acute exacerbations with fever, depression, and respiratory distress. Mycoplasma hyosynoviae arthritis causes sudden onset lameness affecting multiple joints, typically in growing pigs after weaning.

Poultry mycoplasmosis symptoms depend on the species involved. Mycoplasma gallisepticum causes chronic respiratory disease characterized by nasal discharge, facial swelling, conjunctivitis, snicking and rales, and reduced egg production. Turkeys are particularly susceptible, developing severe sinusitis with marked facial swelling. Mycoplasma synoviae primarily causes infectious synovitis with joint and tendon sheath swelling, lameness, and breast blisters from reluctance to stand. Both organisms can cause significant egg production drops in laying flocks. Air sacculitis detected at processing is a common indicator of mycoplasma infection in broiler flocks and may result in condemnation or downgrading.

Symptom progression in mycoplasmosis typically follows a chronic pattern with periods of apparent improvement and recurrence. Calves with respiratory mycoplasmosis may show initial improvement with antibiotic treatment only to relapse when therapy is discontinued. Chronic pneumonia leads to permanent lung damage, reduced growth potential, and increased susceptibility to other respiratory pathogens. Mycoplasma mastitis spreads progressively through the herd if not recognized and controlled, with new cases appearing in previously unaffected cows. The chronic nature of mycoplasma infections, with shedding that continues despite apparent clinical recovery, perpetuates transmission within affected herds.

Emergency symptoms requiring immediate attention in mycoplasmosis cases include severe respiratory distress with open-mouth breathing, extended head and neck, and cyanosis indicating life-threatening pneumonia. Recumbent animals unable to rise due to severe polyarthritis require urgent assessment. Calves with marked head tilt and circling from inner ear involvement need prompt treatment to preserve neurological function. In dairy herds, explosive mastitis outbreaks affecting multiple cows simultaneously warrant immediate investigation and aggressive control measures. Any suspicion of contagious bovine pleuropneumonia, a reportable disease, requires immediate notification of regulatory authorities.

Clinical examination provides initial assessment of suspected mycoplasmosis cases and guides sample collection for laboratory confirmation. Physical examination of respiratory cases includes auscultation revealing increased bronchial sounds, wheezes, and crackles in pneumonia cases. Joint swelling, heat, and pain on manipulation characterize arthritis. Otitis media produces purulent discharge from the ear canal with head tilt and sometimes facial paralysis. Mastitis cases show characteristic abnormal milk with sandy sediment and involvement of multiple quarters. The pattern of disease within a herd, including age groups affected, clinical syndromes observed, and response to previous treatments, helps focus diagnostic investigation.

Laboratory diagnosis of mycoplasmosis requires specialized testing due to the fastidious nature of these organisms. Culture remains the gold standard for definitive identification but requires specialized media and extended incubation periods of several weeks. Samples for culture must be collected carefully to avoid contamination and transported appropriately to maintain organism viability. Polymerase chain reaction testing provides more rapid results, detecting mycoplasma DNA directly from clinical samples including nasal swabs, transtracheal washes, milk, joint fluid, and tissues. PCR can identify organisms to the species level, guiding targeted control measures. Serological testing through ELISA detects antibodies indicating exposure but cannot distinguish current from past infection.

Differential diagnosis for mycoplasma infections varies by clinical syndrome. Respiratory mycoplasmosis must be distinguished from viral respiratory diseases including infectious bovine rhinotracheitis, bovine respiratory syncytial virus, and parainfluenza, as well as bacterial pneumonia from Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Mycoplasma mastitis requires differentiation from mastitis caused by other pathogens, with the characteristic poor treatment response and multi-quarter involvement suggesting mycoplasma involvement. Arthritis cases require differentiation from septic arthritis caused by other bacteria, trauma-induced joint problems, and developmental orthopedic diseases. Combined testing for mycoplasma and other likely pathogens provides comprehensive diagnostic information.

Herd-level diagnostics help characterize the extent of mycoplasma infection and guide control strategies. Bulk tank milk culture or PCR testing screens for Mycoplasma bovis shedding in dairy herds, identifying infected herds before clinical mastitis cases appear. Testing of multiple animals within affected groups establishes prevalence and identifies individual carriers. Post-mortem examination of animals that die or are culled allows thorough tissue sampling and lesion characterization. In poultry, serological monitoring through the National Poultry Improvement Plan provides flock-level status information. Strategic sampling programs tailored to the operation and species guide efficient use of diagnostic resources.

Immediate treatment of clinical mycoplasmosis focuses on antimicrobial therapy targeting the causative organism combined with supportive care addressing symptoms and complications. Because mycoplasmas lack cell walls, they are inherently resistant to beta-lactam antibiotics including penicillins and cephalosporins that target cell wall synthesis. Effective antimicrobial classes include macrolides such as tulathromycin, tilmicosin, and tylosin; tetracyclines including oxytetracycline and chlortetracycline; and fluoroquinolones such as enrofloxacin and danofloxacin where approved. Treatment should begin promptly upon clinical recognition, as delays allow disease progression and tissue damage that may become irreversible. Early intervention offers the best chance of clinical improvement.

Antibiotic therapy selection and duration depend on the species affected, clinical syndrome, and regulatory considerations. In cattle with respiratory mycoplasmosis, long-acting macrolides provide sustained tissue concentrations and require fewer treatments than shorter-acting alternatives. Treatment duration typically extends at least five to seven days, with some protocols continuing longer for chronic cases. Mycoplasma bovis mastitis does not respond well to intramammary antibiotics and is generally considered incurable, with treatment decisions focusing on whether to maintain affected cows or cull them to prevent spread. In swine, in-feed or water medications with tetracyclines or macrolides treat affected groups, while injectable antibiotics address individual clinical cases. Poultry treatment involves water-administered antibiotics for flock treatment during outbreaks. All antibiotic use must comply with withdrawal time requirements for food-producing animals.

Supportive care complements antibiotic therapy and may significantly influence outcomes. Anti-inflammatory drugs including meloxicam and flunixin meglumine reduce fever, control pain, and combat inflammation-mediated tissue damage. Calves with severe respiratory distress benefit from bronchodilators and environmental management minimizing dust and ammonia exposure. Adequate hydration through provision of clean water and potentially supplemental fluids supports recovery. Nutritional support maintaining energy intake despite illness prevents additional metabolic stress. Arthritis cases require pain management and may benefit from joint drainage in severe cases. Isolation of affected individuals prevents ongoing transmission to herdmates.

Alternative and adjunctive treatments are sometimes employed alongside conventional therapy. Immunostimulants or immune modulators are marketed for respiratory disease complexes, though evidence for efficacy specifically against mycoplasma is limited. Probiotics and nutritional supplements support overall health during recovery. Some producers use herbal or homeopathic preparations, though scientific validation for mycoplasma infections is lacking. Autogenous vaccines prepared from organisms isolated from the affected herd are used in some operations with endemic problems, providing herd-specific immune stimulation. These approaches should complement rather than replace appropriate antimicrobial therapy for clinical cases.

Herd-level treatment protocols address mycoplasmosis as a population health issue rather than purely an individual animal problem. Mass medication through feed or water can reduce infection pressure during outbreak situations, though prophylactic antimicrobial use faces increasing regulatory and market pressure. Strategic pulse dosing at high-risk times, such as arrival of new cattle to feedlots, may prevent clinical disease development. In dairy herds with Mycoplasma bovis mastitis, treatment protocols must acknowledge the poor cure rates and focus on identification and removal of shedding cows rather than attempted cure. Development of written protocols with veterinary input ensures consistent, appropriate responses to mycoplasma cases.

Treatment decision-making for mycoplasmosis involves balancing therapeutic potential against economic realities and animal welfare considerations. Cure rates for many mycoplasma infections are disappointingly low despite appropriate therapy, particularly for Mycoplasma bovis mastitis and chronic respiratory cases. Animals with severe, chronic, or recurrent disease may warrant culling rather than repeated treatment that is unlikely to succeed. Economic analysis should consider treatment costs, lost production, reduced future performance, and risk of continued shedding. The welfare of chronically affected animals experiencing ongoing pain or respiratory distress must be considered, with humane endpoints established for cases not responding to treatment.

Recovery timeline for mycoplasmosis varies substantially based on the clinical syndrome, infection severity, and promptness of treatment initiation. Acute respiratory cases caught early and treated aggressively may show clinical improvement within forty-eight to seventy-two hours, with resolution of fever, improved appetite, and decreased respiratory effort. However, complete recovery of lung function may take weeks, and permanent damage from severe pneumonia is common. Mycoplasma arthritis in calves typically requires weeks of treatment before joint swelling resolves, with some cases never fully recovering joint function. Mycoplasma mastitis in dairy cattle rarely achieves bacteriological cure regardless of treatment approach, making recovery in the traditional sense essentially impossible.

Post-treatment care and monitoring are essential for evaluating treatment success and detecting relapses. Animals that have received treatment for respiratory mycoplasmosis should be observed closely for at least two weeks following completion of therapy, watching for recurrence of clinical signs. Calves recovering from pneumonia may benefit from continued low-stress management including adequate nutrition, comfortable housing, and avoidance of unnecessary handling. Joint fluid analysis can document resolution of septic arthritis, though this is rarely practical outside valuable individual animals. Dairy cows treated for mastitis require repeated culture or PCR testing to confirm elimination or identify persistent shedding that warrants culling.

Prognosis factors for mycoplasma infections depend on the syndrome involved, timing of intervention, and individual animal factors. Early treatment of respiratory disease before extensive lung consolidation develops carries a reasonable prognosis for clinical recovery, though subtle performance impacts may persist. Chronic pneumonia cases with extensive lung damage have guarded prognosis for return to normal production. Mycoplasma bovis mastitis carries a poor prognosis for bacteriological cure, with most affected cows remaining persistently infected and serving as sources of transmission. Arthritis prognosis depends on the joints affected and severity of involvement, with mild cases often recovering well while severe polyarthritis may cause permanent lameness. Otitis media prognosis includes potential for chronic vestibular deficits.

Return to production considerations for recovered mycoplasmosis cases must account for ongoing performance impacts and transmission risks. Cattle that recover from respiratory mycoplasmosis may have reduced lung capacity affecting subsequent respiratory disease risk and growth potential. Their value as breeding or replacement animals may be diminished. Dairy cows with mycoplasma mastitis history, even if not currently shedding, present ongoing risk of relapse and transmission. Culling recovered shedders is often the most practical approach to protecting herd health. In poultry, recovered flocks may face marketing restrictions or requirements for mycoplasma-free certification.

Vaccination against mycoplasma infections is available for some species and syndromes, though efficacy varies and vaccines do not provide complete protection. Commercial Mycoplasma bovis vaccines for cattle have shown inconsistent results in field trials, with some studies demonstrating reduced disease severity while others show minimal benefit. Autogenous vaccines prepared from isolates obtained from the affected herd may provide more targeted protection. In swine, Mycoplasma hyopneumoniae vaccines are widely used and have proven effective at reducing clinical disease, lung lesions at slaughter, and performance impacts, though they do not prevent infection. Poultry vaccines against Mycoplasma gallisepticum are available in live attenuated and inactivated forms, used primarily in layer and breeder flocks. Vaccination timing, administration route, and product selection should follow veterinary guidance.

Biosecurity measures form the foundation of mycoplasmosis prevention, particularly for operations free of specific mycoplasma species. Maintaining closed herds or flocks with minimal introductions dramatically reduces introduction risk. When purchases are necessary, sourcing from mycoplasma-free or low-prevalence sources and testing new arrivals before introduction provides protection. Quarantine of new arrivals for at least thirty days with testing near the end of quarantine enables detection of shedding animals before they contact the resident herd. In poultry, purchasing chicks and poults from mycoplasma-free sources certified through the National Poultry Improvement Plan prevents vertical transmission from infected parent flocks.

Nutritional management supports resistance to mycoplasma infections by maintaining optimal immune function. Adequate colostrum intake by newborn calves, kids, and lambs provides passive immunity and supports gastrointestinal development. Meeting all nutrient requirements throughout life, with particular attention to transition periods and stress events, supports immune competence. Trace minerals including zinc, copper, and selenium play important roles in immune cell function. Mycotoxin contamination of feeds can impair immunity and may increase susceptibility to respiratory infections. While nutrition alone cannot prevent mycoplasma infection in exposed animals, optimal nutritional status contributes to disease resistance.

Management practices reducing stress and pathogen exposure lower mycoplasmosis risk across all livestock species. Adequate ventilation in housing facilities reduces airborne mycoplasma concentration and supports respiratory health. Avoiding overcrowding decreases both stress and transmission opportunity. Age-segregated rearing limits transmission from older carrier animals to susceptible young stock. All-in, all-out management with thorough cleaning between groups reduces pathogen carryover in swine and poultry operations. Minimizing commingling with animals of unknown health status at sales, shows, and common grazing reduces exposure to new strains. Proper milking procedures and equipment maintenance prevent mycoplasma spread in dairy operations.

Testing and surveillance programs enable early detection of mycoplasma introduction and guide control efforts. Regular bulk tank testing in dairy herds detects Mycoplasma bovis shedding before clinical mastitis cases accumulate. Testing of calves with respiratory disease or arthritis identifies mycoplasma involvement, informing both treatment decisions and herd-level control measures. Serological monitoring through Dairy Herd Improvement Association testing can identify positive herds. Poultry operations maintain mycoplasma-free status through regular serological testing and immediate investigation of positive results. Post-mortem surveillance through slaughter plant inspection and targeted necropsy examination provides additional detection opportunity.

Daily management and monitoring for mycoplasmosis prevention integrate with routine animal husbandry across all livestock species. Observing animals at least once daily allows detection of early illness signs including depression, reduced feed intake, coughing, lameness, or abnormal behavior that might indicate developing infection. In dairy operations, individual cow monitoring through milking data analysis can detect production drops and elevated somatic cell counts suggesting mastitis. Calf health checks should include assessment for respiratory signs, joint swelling, and ear abnormalities. Training all farm personnel to recognize potential mycoplasma signs and report promptly enables early intervention that may prevent severe disease and limit transmission.

Housing and environmental management significantly influence respiratory mycoplasmosis risk by affecting pathogen concentration and respiratory tract defenses. Ventilation systems should provide adequate air exchange without creating cold drafts that stress animals. Target parameters include maintenance of air quality with ammonia below ten parts per million and dust minimized through bedding and manure management. Appropriate stocking density prevents overcrowding that increases both pathogen transmission and stress. Temperature management within the thermoneutral zone for each species reduces respiratory challenge. Calf housing designs that minimize nose-to-nose contact between young calves reduce Mycoplasma bovis transmission during the high-risk early life period.

Herd health programs should incorporate mycoplasmosis surveillance and control as appropriate for the species and operation type. Written protocols developed with veterinary input establish consistent approaches to prevention, detection, treatment, and culling decisions. Vaccination schedules, where vaccines are utilized, should specify products, timing, and administration procedures. Diagnostic testing triggers and sampling protocols guide investigation of suspect cases. Treatment protocols ensure appropriate antimicrobial selection, dosing, and duration. Culling criteria establish when animals should be removed rather than treated. Regular review of program effectiveness through assessment of disease incidence, treatment outcomes, and surveillance results enables continuous improvement.

Record keeping supports evidence-based mycoplasmosis management decisions. Individual animal health records documenting clinical signs, diagnostic results, treatments, and outcomes guide decisions about individual animals and reveal herd-level patterns. Production data including growth rates, milk yield, and feed conversion may reflect subclinical disease impacts. Mortality and culling records categorized by cause identify ongoing mycoplasma problems requiring additional intervention. Diagnostic laboratory results tracked over time show trends in mycoplasma prevalence and species involved. Many operations utilize herd management software to integrate health, production, and diagnostic data for comprehensive analysis.

Economic considerations drive many mycoplasmosis management decisions, from prevention investments to individual treatment choices. The cost of enhanced biosecurity, vaccination programs, and diagnostic testing must be weighed against expected returns in reduced disease losses. Treatment costs including medications, veterinary services, and labor should be compared against the expected improvement in animal value or production. Chronic carrier animals may be economically salvageable as market animals while representing ongoing biosecurity risks as breeding stock. Calculating the total cost of mycoplasma infections including direct losses, reduced performance, and indirect impacts helps justify prevention investments and supports informed management decisions.

All breeds within each susceptible livestock species can be affected by mycoplasmosis, with management factors generally more important than breed-specific susceptibility. In cattle, both dairy and beef breeds experience Mycoplasma bovis infections, though the clinical syndromes and management contexts differ. Holstein calves raised in intensive calf-rearing systems face high respiratory mycoplasmosis risk due to early separation from dams, commingling of calves from multiple sources, and stressful early life conditions. Beef calves raised on cow-calf operations may experience different mycoplasma exposure patterns associated with weaning and shipping stress. No breed demonstrates marked resistance to mycoplasma infection, though individual variation in disease expression occurs.

Production system type significantly influences mycoplasmosis patterns and management approaches. Dairy operations face particular challenges with Mycoplasma bovis mastitis due to the transmission opportunities provided by milking equipment and the impact of infected milk on calf health when fed unpasteurized. Feedlot cattle assembled from diverse sources face high respiratory mycoplasmosis risk from commingling stress and pathogen mixing. Swine operations using continuous flow production experience endemic Mycoplasma hyopneumoniae circulation, while all-in, all-out systems may break transmission cycles. Commercial poultry integrations maintain mycoplasma control through certified clean breeding stock and biosecurity, while backyard flocks with less rigorous control often harbor infection. Understanding these production system differences guides targeted prevention strategies.

Genetic approaches to mycoplasmosis control remain limited compared to other livestock diseases. Research has identified some genetic variation in susceptibility to mycoplasma infection and disease severity, suggesting potential for selection. However, practical genetic tools for mycoplasma resistance are not currently available for commercial application. Selection for general immune competence and disease resistance may provide indirect benefit against mycoplasma infections. In poultry, some commercial genetics companies have incorporated mycoplasma resistance traits into their selection programs. Breed associations and genetic improvement organizations continue to explore incorporation of disease resistance traits, including those relevant to mycoplasmosis, into breeding value calculations.

Commonly co-occurring conditions with mycoplasmosis reflect the immunosuppressive effects of infection and the tendency for mycoplasma to complicate other disease processes. In cattle, Mycoplasma bovis frequently co-infects with other respiratory pathogens including Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni in the bovine respiratory disease complex. Viral infections including bovine viral diarrhea, infectious bovine rhinotracheitis, and bovine respiratory syncytial virus damage respiratory defenses and predispose to secondary mycoplasma infection. In swine, Mycoplasma hyopneumoniae serves as a primary pathogen that facilitates secondary bacterial pneumonia. Poultry mycoplasmosis commonly occurs alongside viral respiratory infections and may complicate diagnosis and treatment.

Conditions with similar clinical presentations require differentiation during diagnostic workup. Respiratory disease from mycoplasma must be distinguished from purely viral pneumonia, other bacterial pneumonias, and lungworm infection. Mycoplasma mastitis shares some characteristics with mastitis from other causes but typically shows distinctive features including multi-quarter involvement and treatment failure. Mycoplasma arthritis in calves requires differentiation from other septic arthritis causes, traumatic joint injury, and developmental conditions. In poultry, infectious coryza, aspergillosis, and nutritional deficiencies may produce respiratory and facial signs resembling mycoplasmosis. Comprehensive diagnostic testing enables accurate diagnosis and targeted treatment.

Complications and sequelae of mycoplasmosis significantly impact long-term animal health and productivity. Chronic respiratory mycoplasmosis causes permanent lung damage including bronchiectasis, pulmonary fibrosis, and reduced functional lung capacity that increases susceptibility to subsequent respiratory challenges. Arthritis may result in chronic lameness, joint deformity, and reduced mobility affecting grazing ability and breeding soundness. Otitis media can cause permanent vestibular deficits and facial nerve paralysis. Mycoplasma mastitis results in quarter loss and chronic shedding that threatens herd health. These long-term consequences often make culling the most appropriate management decision for severely affected animals.