Bovine MSK ICVA Diseases

Actinomycosis

The clinical presentation of Actinomyces infection in cattle can vary depending on the stage of the disease. Classic signs include:

• Firm, non-painful swelling of the mandible or maxilla, commonly referred to as "Lumpy Jaw." This is the most common presentation.

• Bone involvement, with osteomyelitis leading to the characteristic deformity of the jaw.

• Abscesses with draining tracts, which may exude purulent material containing "sulfur granules," a pathognomonic feature. These granules are small yellowish masses of Actinomyces colonies.

• Difficulty eating or dysphagia, due to the mechanical obstruction caused by the enlarging lesion.

• Weight loss, secondary to reduced feed intake.

• Salivation and occasional nasal discharge.

• Foul odor from secondary infection of necrotic tissue.

In advanced stages, the infection may spread beyond the oral cavity to adjacent soft tissues, lymph nodes, or even the thoracic cavity via hematogenous or lymphatic routes, leading to systemic signs such as fever and lethargy.

Actinomycosis

Diagnosing Actinomyces infection requires a combination of clinical observation, cytology, and culture. The diagnostic approach typically includes:

1. Clinical Examination: Observation of the characteristic hard, bony swelling of the jaw with or without draining tracts is often enough to raise suspicion of "Lumpy Jaw."

2. Fine Needle Aspiration (FNA) or Biopsy:

   • Cytology of the exudate or tissue may reveal sulfur granules, which are colonies of Actinomyces surrounded by host neutrophils. These are considered highly suggestive of infection.

   • Gram staining may reveal gram-positive, filamentous bacteria.

3. Bacterial Culture:

   • A definitive diagnosis requires culture of Actinomyces bovis from purulent material or biopsy. However, this can be challenging because Actinomyces species are slow-growing and may require anaerobic culture conditions.

4. Radiography:

   • Radiographs of the jaw can reveal osteolysis, periosteal reaction, and irregular bone remodeling, confirming the presence of osteomyelitis.

5. Histopathology:

   • If a biopsy is performed, histological examination typically reveals chronic pyogranulomatous inflammation, with central necrosis and the presence of bacterial colonies within sulfur granules.

6. PCR and Molecular Diagnostics:

   • In challenging cases, PCR can be used to identify Actinomyces DNA, providing a more rapid diagnosis than traditional culture.

Actinomycosis: T.X

1. Antibiotics:

   • Penicillin is the antibiotic of choice for Actinomyces infections due to its efficacy against gram-positive anaerobes.

   • Oxytetracycline is another option, especially for long-acting formulations, and may be more practical in herd situations.

   • If Actinomyces infection has spread systemically, prolonged antibiotic therapy (often several weeks to months) is necessary.

2. Surgical Debridement:

   • In advanced cases with extensive bone involvement, surgical debridement of necrotic tissue and abscesses may be required. However, this can be challenging due to the location and extent of the lesion.

   • Draining abscesses may help reduce the bacterial load, but care should be taken to prevent secondary infection.

3. Iodide Therapy:

   • Oral or intravenous iodide therapy (such as sodium iodide) has been used as adjunctive therapy to stimulate granuloma resorption. It is administered weekly for several weeks until clinical improvement is seen. However, excessive iodide use can lead to iodism, with symptoms including dandruff, nasal discharge, and diarrhea, so monitoring is essential.

4. Supportive Care:

   • Ensure the animal has easy access to soft feeds to maintain weight while jaw function is compromised. Hydration and nutritional support are also critical to prevent weight loss.

Prevention of Actinomycosis

• Good dental care, including routine examination of the teeth, can help prevent predisposing factors for Actinomyces infection.

• Avoiding rough forage or pastures containing sharp materials can reduce the risk of oral trauma.

• Early intervention in cases of oral wounds or dental disease can prevent the bacteria from gaining access to deeper tissues.

Fracture

1. Lameness: This is often the first and most obvious sign. Lameness can range from mild to non-weight-bearing, depending on the fracture's severity and location.

2. Swelling and Deformity: A fracture often causes localized swelling due to soft tissue trauma. In severe cases, there may be visible deformity of the limb.

3. Crepitus: Upon palpation, an abnormal crunching sensation (crepitus) may be felt, indicating a fracture.

4. Pain and Reluctance to Move: Affected animals often show reluctance to move, stand, or bear weight on the injured limb. They may exhibit signs of discomfort, including vocalizing or an elevated respiratory rate.

5. Non-healing Wounds: Open fractures, in particular, may be accompanied by non-healing wounds, discharge, and the risk of infection.

Fracture:D.X

1. Physical Examination: Initial evaluation includes palpation of the suspected area for swelling, pain, deformity, or crepitus. An assessment of the degree of lameness (e.g., weight-bearing or non-weight-bearing) is crucial.

2. Imaging:

   • Radiography: X-rays are the gold standard for diagnosing fractures, providing detailed images of the fracture type, location, and any associated complications like bone fragment displacement.

   • Ultrasound: Useful in cases where soft tissue involvement is suspected or if radiographs are unavailable in field settings.

   • Computed Tomography (CT): In complex fractures, especially those involving joints, CT can provide a three-dimensional view, aiding in surgical planning.

3. Bloodwork: To rule out any underlying metabolic or infectious causes, blood tests may be performed. For example, calcium, phosphorus, and vitamin D levels should be assessed if nutritional deficiency is suspected.

4. Microbiological Testing: If osteomyelitis or infection is suspected, a sample from the wound or affected area can be cultured to identify pathogens and guide antibiotic therapy.

Fracture: T.X

1. Conservative Management:

   • Immobilization: For non-displaced or stable fractures, immobilization using splints or casts may be sufficient. Immobilization is crucial to prevent further displacement and allow the callus to form. These are commonly used for lower limb fractures.

   • Pain Management: NSAIDs such as flunixin meglumine or meloxicam are commonly used to control pain and inflammation.

2. Surgical Intervention:

   • Internal Fixation: In more severe fractures, particularly those affecting joints or weight-bearing bones, internal fixation using plates, screws, or intramedullary pins may be necessary to achieve stability and proper alignment.

   • External Fixation: In cases where surgery is not feasible, external fixation devices can be used to stabilize the fracture externally.

3. Open Fractures: These require aggressive management to prevent infection. Antibiotic therapy is initiated, and thorough wound debridement is performed. The wound may need to be covered with sterile dressings, and immobilization or surgical repair follows.

4. Supportive Care: Ensuring proper nutrition, hydration, and management of any underlying conditions (e.g., metabolic disorders) is essential. Stall rest and minimizing movement are key components of recovery.

Causes of Lameness

1. Infectious Causes:

   • Digital Dermatitis (hairy heel warts): Caused by Treponema spp. bacteria, this is an infectious condition that leads to painful lesions on the heel and interdigital spaces. It is highly contagious and can result in severe lameness if not treated promptly.

   • Foot Rot: A bacterial infection caused by Fusobacterium necrophorum and Porphyromonas levii, which enters through damaged skin in the interdigital space, leading to cellulitis and necrosis of tissues. It is common in cattle grazing on wet, muddy, or unsanitary ground.

2. Traumatic or Mechanical Causes:

   • Sole Ulcers: These develop from prolonged pressure on the corium, causing necrosis and ulceration of the sole. This condition is often associated with poor hoof trimming, housing conditions, or improper flooring.

   • White Line Disease: Occurs when the white line, which joins the sole to the hoof wall, weakens and allows foreign material to enter, leading to abscess formation. This can be exacerbated by uneven flooring or rough ground.

   • Laminitis: This systemic condition leads to inflammation of the laminae that support the hoof. It can result from metabolic or nutritional imbalances, such as excess carbohydrate intake or septic conditions like metritis or mastitis. Chronic laminitis can lead to permanent hoof deformities and lameness.

3. Nutritional Imbalances:

   • Laminitis: Subclinical or acute laminitis is commonly associated with excessive feeding of high-energy diets (concentrates) in dairy cattle, which leads to subacute ruminal acidosis (SARA). The acidosis causes inflammation and damage to the laminae of the hoof, resulting in lameness.

4. Congenital or Developmental Causes:

   • Interdigital Hyperplasia: Also known as corns, this condition involves abnormal tissue growth between the toes. It can cause mechanical lameness and predispose cattle to infections like foot rot.

Lameness: C.S

1. Altered Gait: Lameness in cattle is often first noticed as a change in gait, where the animal may limp or favor one leg. Lameness is graded on a 1-to-5 scale, with 1 being normal and 5 indicating severe lameness.

2. Reduced Mobility: Affected animals may show reluctance to walk or rise, exhibit abnormal posture (e.g., arching their back), and may prefer to lie down for prolonged periods.

3. Painful Hoof or Limb: On palpation or during hoof trimming, the affected area will often be tender, swollen, or warm to the touch. Pain can cause weight shifting between limbs.

4. Hoof Abnormalities: Conditions such as sole ulcers, white line disease, or digital dermatitis may present with visible lesions, discharges, or structural changes in the hoof.

5. Weight Loss and Reduced Production: Lameness often leads to decreased feed intake due to pain or inability to access feed, resulting in weight loss, poor body condition, and reduced milk yield in dairy cows.

6. Secondary Infections: In cases of foot rot or severe digital dermatitis, there may be significant swelling, foul-smelling discharge, and deeper tissue involvement if untreated.

Lameness: D.X

1. Physical Examination:

   • Observe the animal’s gait and posture. A lameness scoring system can help assess the severity of lameness.

   • Palpate the limbs and hooves for swelling, heat, or tenderness.

   • Examine the hooves for visible lesions, abscesses, or hoof deformities. Hoof trimming may be necessary to reveal hidden conditions such as sole ulcers or white line disease.

2. Hoof Testing:

   • Using hoof testers, apply pressure to various parts of the hoof to identify areas of pain, particularly when white line disease, sole ulcers, or abscesses are suspected.

3. Laboratory Testing:

   • In cases of suspected infectious lameness (e.g., foot rot or digital dermatitis), collect samples from lesions for bacterial culture to confirm the diagnosis and determine the appropriate antibiotic treatment.

4. Radiography:

   • In severe cases where bone involvement is suspected, radiographs may be useful for diagnosing osteomyelitis or joint involvement.

5. Blood Tests:

   • For systemic conditions like laminitis, blood tests can help identify metabolic or nutritional imbalances, such as acidosis or mineral deficiencies.

Lameness:T.X

1. Infectious Causes:

   • Digital Dermatitis: Topical antibiotic sprays (e.g., tetracycline) and footbaths containing copper sulfate or formalin are commonly used to treat and control outbreaks. Herd-wide footbaths can help reduce the spread of infection.

   • Foot Rot: Systemic antibiotics (e.g., penicillin, oxytetracycline, or ceftiofur) are used to treat the bacterial infection. Cleaning and debriding the interdigital area, followed by foot baths, can also promote healing.

2. Traumatic/Mechanical Causes:

   • Sole Ulcers: Corrective hoof trimming is essential to redistribute weight away from the affected area. A hoof block can be applied to the unaffected claw to reduce pressure. Pain relief using non-steroidal anti-inflammatory drugs (NSAIDs) such as meloxicam is often indicated.

   • White Line Disease: Drainage and debridement of abscesses, followed by appropriate hoof trimming, are necessary. If infection has spread, antibiotics may be required.

   • Laminitis: Address the underlying metabolic cause (e.g., correct ruminal acidosis), provide pain relief with NSAIDs, and use proper hoof trimming techniques to prevent further complications.

3. Nutritional Management:

   • Adjust the diet to prevent metabolic diseases like laminitis. Ensuring proper fiber-to-concentrate ratios and supplementing with biotin, zinc, and other essential minerals can improve hoof quality.

4. Surgical Interventions:

   • In cases of severe infection or non-responsive abscesses, surgical debridement or amputation of the affected digit may be necessary.

5. Supportive Care:

   • For cattle with severe lameness, providing a soft, dry resting area can reduce pressure on affected limbs. Weight-bearing on the affected limb should be minimized, and nutritional support is crucial to prevent weight loss.

Hallmark Clinical Signs and Diagnosis

The hallmark signs of lameness in cattle include altered gait, weight shifting, and reluctance to move or rise. Specific conditions have unique clinical features:

• Digital Dermatitis: Painful lesions in the heel area with moist, foul-smelling discharge.

• Foot Rot: Swollen, warm foot with a foul odor, and necrosis between the claws.

• Sole Ulcers: Visible ulceration on the sole, often accompanied by pain and reluctance to bear weight.

• White Line Disease: Abscess or separation at the white line, often with discharge and severe pain.

Definitive diagnosis involves visual inspection, palpation, and appropriate testing such as radiography or bacterial culture.

Lameness: Prevention

1. Hoof Care: Regular hoof trimming (typically every 6-12 months) is essential for maintaining hoof health and preventing conditions like sole ulcers and white line disease. Preventive foot baths can reduce the incidence of infectious diseases like digital dermatitis and foot rot.

2. Improving Housing and Flooring: Providing soft, dry bedding, minimizing the time cattle spend on hard, rough surfaces, and ensuring proper drainage in outdoor environments can prevent hoof trauma and infection.

3. Nutritional Management: Balancing the diet with appropriate levels of fiber, minerals (e.g., zinc, copper, and biotin), and vitamins can improve hoof integrity. Reducing the risk of ruminal acidosis through proper feed management is crucial in preventing laminitis.

4. Biosecurity: Isolate and treat infected animals promptly to prevent the spread of infectious causes like digital dermatitis. Maintain proper hygiene in high-traffic areas such as milking parlors.

Myopathy (White Muscle Disease)

White Muscle Disease is primarily a nutritional deficiency disorder stemming from inadequate dietary selenium or vitamin E. Selenium plays a crucial role in antioxidant defense systems as a cofactor for the enzyme glutathione peroxidase, which helps detoxify harmful free radicals produced during cellular respiration. Vitamin E functions synergistically as an antioxidant, protecting cell membranes from oxidative damage.

When selenium or vitamin E levels are insufficient, oxidative stress increases, resulting in the peroxidation of cell membranes and leading to the degeneration of muscle fibers. This damage predominantly affects both skeletal and cardiac muscles, manifesting as muscle necrosis, which, on gross pathology, often appears as pale streaks—hence the term "white muscle disease."

Myopathy (White Muscle Disease):C.S Acute Cardiac form

This form primarily affects the heart muscle and is often seen in calves during the first few weeks of life. It can lead to sudden death without preceding signs or present with acute cardiovascular failure.

• Clinical signs include:

  • Tachycardia and arrhythmias

  • Respiratory distress (due to heart failure)

  • Cyanosis and weakness

  • Recumbency and sudden death

The hallmark sign in post-mortem examinations is myocardial necrosis, often found in the left ventricle and septum.

Myopathy (White Muscle Disease):C.S Skeletal Muscle form

The skeletal muscle form is more commonly seen in calves between a few weeks to months old. It can result in significant morbidity but is generally less acutely fatal than the cardiac form.

• Clinical signs include:

  • Stiffness and reluctance to move

  • Weakness and recumbency

  • Muscle tremors and atrophy

  • Difficulty standing (due to degeneration of large muscle groups like the quadriceps, neck, and back)

  • Swollen, firm, painful muscles

  • Decreased suckling ability in young calves, leading to weight loss

In severe cases, secondary complications such as aspiration pneumonia may arise due to the weakened muscles involved in swallowing.

Myopathy (White Muscle Disease):D.X

1. Serum Selenium and Vitamin E Levels:

   1. The most definitive diagnostic test is the measurement of serum selenium and whole blood glutathione peroxidase activity.

      1. Affected animals typically have low levels of selenium and/or vitamin E.

   2. Normal serum selenium levels are typically > 0.08 ppm, with levels below 0.05 ppm often diagnostic for deficiency.

   3. Serum vitamin E

      1. Levels below 1 µg/ml considered deficient.

2. Muscle Enzymes:

   1. Elevated levels of (CK) and (AST) in the blood are indicative of muscle damage

3. Gross Pathology and Histopathology:

   1. On necropsy, affected muscles exhibit characteristic pale streaks of necrotic muscle fibers, particularly in the skeletal and cardiac muscles.

   2. Histopathology will reveal multifocal degeneration, necrosis, and mineralization of the muscle fibers, confirming the diagnosis of nutritional myodegeneration.

Myopathy (White Muscle Disease):T.X

1. Injectable Selenium and Vitamin E:

   1. sodium selenite combined with vitamin E (as found in products like Bo-Se or Mu-Se)

2. Oral Supplementation:In Herds with ongoing deficiencies

   1. Oral selenium supplements can be administered in the form of mineral blocks, drenches, or as feed additives.

   2. Vitamin E can also be supplemented orally through high-quality forages or synthetic forms.

3. Supportive Care:In severe cases, supportive care is critical.

   1. Fluid therapy

   2. Anti-inflammatory drugs

   3. Physical therapy in mildly affected animals to encourage muscle regeneration

Prevention is the most effective strategy against White Muscle Disease. The following measures should be implemented in areas where selenium deficiency is common:

1. Selenium and Vitamin E Supplementation in Feed: Regular inclusion of selenium in trace mineral supplements or feed formulations can prevent deficiencies.

   • The FDA-approved maximum level for selenium supplementation is 0.3 ppm in total dietary intake.

2. Soil Testing: In regions where selenium-deficient soils are known, routine soil testing is recommended to determine the need for supplementation.

3. Parenteral Supplementation: In high-risk regions, routine administration of injectable selenium and vitamin E to pregnant cows and calves soon after birth can prevent the onset of clinical disease.

Osteoarthritis:C.S

1. Lameness + Reduced range of motion

2. Crepitus + Muscle atrophy

3. Reluctance to rise or walk + Altered gate

Osteoarthritis:D.X

1. Exam

2. Lameness score

3. Rads

4. U/S

5. Synovial fluid analysis

Osteoarthritis:T.X

Conservative Management

1. Rest

2. Weight management

3. Environment modifications

Pharm

1. NSAIDs

2. Steroids

3. Chondroprotectants (Hyaluronic etc)

4. Joint injections

SX

Supportive care: PT, Laser

Umbilical Hernia:C.S

1. Palpable mass

   1. Often reducible

   2. Incarceration: Intestines are trapped

2. Abscessation

   1. If infection

3. Poor growth

Umbilical Hernia:D.X

1. Palpation

2. U/S

3. Differentiate from abscess

4. Rads

Umbilical Hernia:T.X

Small hernias (<5cm)

1. Spontaneously resolve in young

2. Belly bands or hernia belts

If Large or complicated

1. Surgery