Blackleg & Tetanus in Livestock: Symptoms & Treatment

Blackleg Disease in Livestock

Black leg disease is an acute infectious disease that affects cattle, occasionally sheep, and pigs. Its main characteristic is the rapid development of swellings containing gas in the neck, shoulder, thigh, quarter, and occasionally the trunk.

Causes of Blackleg Disease in Livestock

Black leg disease is caused by Clostridium chauvoei, a Gram-positive, spore-forming, rod-shaped bacterium that produces toxins. The disease is infectious but not contagious, and it occurs when animals consume bacterial spores while grazing.

These spores then enter the intestine and spread throughout the bloodstream, reaching the skeletal muscle where they remain dormant.

The primary outbreaks of the disease typically happen during the wet season. The spores are highly resistant to heat and dryness, but can be eliminated by a 3% formalin solution within 15 minutes.

Transmission of the disease occurs when animals graze on infected pastures where the spores are present in the soil. The spores are ingested and absorbed through the mucosa and can also be found in the spleen.

Furthermore, the disease can also enter the body through wounds caused by castration or docking.

Symptoms of Blackleg Disease

The disease manifests through several symptoms, including lameness, loss of appetite, depression, rapid breathing, fever, and swelling. Often, the first noticeable sign is lameness in the affected leg.

Affected animals display a high fever, depression, anorexia, and limited mobility.

Swelling occurs in the upper part of a limb, which could be the thigh or shoulder.

Upon palpation, the swelling initially feels hot and painful, but it eventually becomes cold and painless.

A distinct crepitating sound arises due to gas formation within the swelling.

The skin covering the affected area appears dry, hard, and dark in color. Gaseous swelling may also occur in other body regions, such as the neck, chest, or flank.

If the disease progresses rapidly, the animal may succumb to toxemia within 24-36 hours, and sometimes death may occur without any visible signs of the disease.

Signs of Blackleg Disease in Animals.

A high fever, anorexia, and a lesion emerge on the limb, resulting in stiffness and swelling caused by edema. However, there is no crepitus. Additionally, the skin covering the affected area darkens, while other regions exhibit noticeable edema.

How Blackleg Disease is Transmitted in Livestock

The transmission source is the spores of the Clostridia bacterium, which exist in the soil and await an opportunity to make contact with an open wound or be consumed by a grazing animal.

When consumed, the bacteria can enter the body through small puncture wounds in the animal's digestive tract.

Postmortem Findings in Blackleg Disease

In cases of blackleg disease in cattle, the carcass is positioned on the affected side, with the limb stiff and extended. Bloating and putrefaction follow soon after. Exudates from the nostrils and anus contain frothy blood stains, and all muscles darken upon exposure to air.

Excess fluid, stained with blood, can be found in all body cavities, and regional lymph nodes become enlarged.

In sheep, a similar pattern of edema is observed, but it is less pronounced and accompanied by less gas formation.

Diagnosis: It is important to review the animal's history and observe its clinical signs. In this particular case, crepitus plays a significant role, and the differential diagnosis should consider Anthrax disease.

Postmortem: Laboratory examination includes the collection of blood and hindquarters muscle samples.

Treatment for Blackleg Disease in Livestock

If early diagnosis is done and rapid treatment is given, good results can be achieved with Penicillin, Chlortetracycline, and oxytetracycline. Anti-toxic serum is also effective, but it is expensive. It is important to always vaccinate your livestock as well.

How to Control Blackleg Disease in Animals

Maintain hygiene by burning carcasses instead of burying them, clearing the area, and treating all traumatic wounds with antibiotics until they heal.

Practice prophylaxis by vaccinating annually in enzootic areas.

For sheep, vaccinating before lambing and docking can be helpful.

Tetanus Disease in Livestock

Tetanus, a non-febrile infectious disease, affects both animals and humans. It is characterized by spasmodic tetany and hyperaesthesia. The disease is caused by Clostridium tetani, a rod-shaped anaerobe.

This anaerobe is capable of forming spores that exhibit remarkable resistance to desiccation and can withstand boiling for up to one hour. These spores can survive in the soil for many years.

The bacteria are commonly found in the environment, particularly in soil, dust, and manure. The disease can infect various animal species as well as humans.

Transmission of Tetanus Disease in Livestock

The bacteria enter animals through deep traumatic wounds, during parturition, or due to management procedures. Wounds become contaminated with microorganisms from the soil, feces, and dirt-contaminated nails.

When these contaminated wounds heal, they create optimal anaerobic conditions for toxin production. Clostridium tetani can remain dormant in the wound until it heals and may also be found in the intestines of healthy animals, eventually being spread to the soil through feces.

In the event of a wound infection, the toxin travels along peripheral nerves to the brain, causing an exaggerated response to stimuli.

Symptoms of Tetanus Disease

1. Painful muscle spasms and stiff, immovable muscles (muscle rigidity) in the jaw.
2. Muscles around the lips are tense, sometimes resulting in a constant grin.
3. Neck muscles experience painful spasms and rigidity.
4. Difficulty swallowing and rigid abdominal muscles.
5. The incubation period can range from 1 to 2 weeks, although it can be as short as 3 days in young animals. However, the infection may remain dormant for several months.
6. The disease progression is characterized by increasing stiffness and muscle rigidity, starting from the head.
7. The animal is unable to chew, with erect, stiff, and immobile ears, as well as a protruding third eyelid.
8. Dilated nostrils and rigid jaw muscles lead to lockjaw.
9. Walking becomes difficult, and the animal turns without flexing its body.
10. The muscles are hard to the touch, and flatulence and tympany (abdominal bloating) are noticeable.
11. Opisthotonus, an abnormal posture where the animal arches its back, may also be observed. Additionally, the animal exhibits an exaggerated reaction to minor stimuli, resulting in muscular spasms. Animals that fall remain with rigid muscles.
12. In prolonged cases, the spasms may subside, allowing the animal to move slightly.
13. In severe cases, the temperature may rise, leading to death at 42℃.
14. A distinguishing feature is a temporary recovery, followed by final spasms and death. Postmortem findings are challenging.

Differential Diagnosis: Strychnine poisoning - spasms are more pronounced, with longer and more relaxed periods between them, leading to an earlier occurrence of death.

Treatment of Tetanus Disease in Livestock

There is a greater likelihood of recovery in cattle compared to horses or sheep.

The goal is to eliminate microorganisms, neutralize circulating toxins, and relax muscles to restore respiration until all toxins are eliminated.

For horses, it is advisable to administer anti-toxin/milil injections.

Wounds should also receive appropriate treatment.

In the case of microorganisms, Penicillin is administered. Muscle relaxants like Chlorpromazine are given daily at a dosage of 0.2mg/kg for 1-2 weeks.

How to Control Tetanus Disease in Livestock

The treatment for generalized tetanus involves the administration of intravenous antitoxin, antibiotics, wound debridement, sedation, or muscle relaxation. Additionally, nursing care such as feeding, maintaining hydration, and preventing soiling is provided.

To prevent tetanus, it is crucial to maintain proper hygiene and cleanliness during castration and other surgical procedures. Wounds must be kept free from contamination.

In areas where tetanus is common, active immunity can be achieved by administering toxoids in three doses spaced 1-2 months apart. Solid immunity is attained after 8 months.

Annual vaccination is also recommended, and both toxoid and antitoxin can be administered together.

Spasm refers to muscle contraction, while convulsions are spasms that affect the entire body. Toxoid is a toxin that has been rendered harmless through physical or chemical means, but it still retains its antigenic properties. On the other hand, antitoxin neutralizes the harmful effects of the toxin.

Conclusion

In conclusion, blackleg disease and tetanus pose significant threats to livestock health and can have devastating consequences if not properly managed. Blackleg disease, caused by Clostridium chauvoei, spreads through bacterial spores ingested from infected pastures or through wounds. Swift diagnosis and treatment, including the use of antibiotics and vaccination, can help control the disease.

Similarly, tetanus, caused by Clostridium tetani, enters animals through deep wounds and can lead to painful muscle spasms and rigidity. Preventive measures such as proper wound care, vaccination, and maintaining hygiene are essential in controlling tetanus.

To protect livestock from these diseases, it is crucial to prioritize hygiene, implement proper wound management, and consider regular vaccinations. Vaccination is a key preventive measure that helps build immunity against blackleg disease and tetanus. Additionally, maintaining clean environments, properly disposing of carcasses, and treating wounds with antibiotics are effective strategies to minimize the risk of infection.