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7 most important illnesses that affect the entire dairy herd

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6 de April de 2017 | Postado por Fornari

Learn which are the main diseases that can affect the entire dairy herd, the best way to prevent them and the recommended treatment for each situation:

1. Babesiosis

Babesiosis is an illness that can be caused by the parasites Babesia divergens, Babesia bigemina or Babesia bovis. The last two are responsible for spreading the disease in Brazil. Once inside the system, the parasite reproduces in erythrocytes, leading to red blood cell destruction (for that reason, the animal presents a fierce hemolytic anemia).

In the dairy herd, the infection happens through the vector tick Rhipicephalus micropolus – common species in tropical and subtropical regions. The disease diagnosis can be difficult, since that only 1% of the blood cells tends to be infected and the parasite is intracellular. The symptoms – clearly visibles when the infection is active – include: weight loss, fast heartbeat, high fever, disseminated intravascular coagulation, anemia and, in cows, milking break.

To avoid that the illness spread among the herd, it is important to keep constant track of the animals, including weight variations.

Vitamin complexes, hydration and liver protectors – allied to usage of babesicide, anti-plasmicide or double acting drugs – help in recovering the infected animal. In chronic cases, a blood transfusion with anticoagulants might be necessary.

The most sensitive race to the tick is Bos taurus e the most resistant is Bos indicus.

2. Clostridiosis

This is the term used to call illnesses caused by the anaerobic bacteria from Clostridium genus. These bacteria – usually found in the animal organism, even when it is healthy – that might produce toxins which unchain a series of symptoms that may cause death

Clostridiosis can be classified in four groups:

  • Neurotropic – Botulism and tetanus are in this group
  • Myonecrotizing – Gas gangrene, which is also called malignant edema, is one of the main myonecrotizing illnesses
  • Enteric/Enterotoxemic – Acute haemorrhagic enteritis is an example of enteric clostridiosis.
  • Hepatonecrotic – Liver necrosis is one of the most common diseases of this kind of clostridiosis.

The causes and symptoms may vary, according to the classification of the clostridiosis. In a botulism case, for instance, the animal is infected when consuming contaminated food or water. It is very important that the vet is familiar to the type of clostridiosis that is being treated, to prevent its dissemination among the herd and to heal the infected animals

In general, the prevention is made through vaccines and antibiotics and antitoxins are used (in the botulism and tetanus cases) to treat contaminated animals.

3. Foot-and-mouth Disease

Foot-and-mouth disease is a viral illness (Picornaviridae aphthovirus virus), transmitted through drooling or blood coming from infected animals. It also can be transmitted through water, by birds and by people that stay in contact with the herd (carrying the virus on clothes or hands). The virus is very resistant, remaining active in the pasture, leather or bone narrow after the animal dies.

The main symptoms are lack of appetite, mouth, gum and tongue thrush, fever and injured hooves (which causes locomotion difficulty to the animal).

In Brazil, herd vaccination is mandatory every six months, since the third month of life.

To treat the illness, it is important to look after injuries and heart tonic of the affected animals with medication. It is also fundamental to disinfect the place to prevent further contamination.

4. Brucellosis

Brucellosis is a bovine illness caused by Brucella abortus bacteria. It is also called Malta fever or infectious abortion. The animal infection may occur orally or during birth of infected animals. There is a great rate of contamination through artificial insemination too, when the infected semen is deposited directly in the animal’s womb.

Inside the bovine organism, the bacteria is taken through the bloodstream and infects many tissues.

The main presented symptoms are abortion at the end of gestation and birth of dead or weak calves. The abortion usually happens in the first gestation of the infected cow, being rarer in the subsequent ones. In males, it may occur inflammation of the testicles. Brucellosis can also render the animal infertile.

To control the affliction, it is also important to diagnose it as soon as possible, replace the infected animals and protect the healthy herd with vaccines.

5. Tuberculosis

Tuberculosis is an illness with barely perceptible signs to the pastoralists. The main symptoms are weight loss and coughing. The milk production might be considerably impaired when the animals are affected with tuberculosis. The bacteria responsible for spreading the disease is Mycobacterium bovis.

The infection occurs through the air, by suspended droplets or inhaling contaminated dust. Calves are also infected by drinking milk with the bacteria.There is no treatment or vaccine for this disease. Prevention control against bovine tuberculosis is the best way to protect the entire dairy herd.

6. Mastitis

Mastitis is an illness that affects the mammal glands of the animal. It can be caused, primarily, by Streptococcus and Staphylococcus bacteria and coliforms. Issues on how the milking is made and the lack of hygiene in the environment where the cow is located are the main facilitating factors for herd infection. To prevent the disease, it is needed to observe the processes used to get the milk, to ensure that the equipments are employed as recommended by the vendor and keep the place where the animals stay clean.

Mamitis symptoms include swollen, red-colored and hot udder. The milk can also be affected, getting out more watery or thick, with flakes or clots. Besides, the cow also presents lack of appetite and weight loss. The damages might be huge for the breeder, since the disease also causes a decrease of the milk production.

The symptoms of the clinical mastitis can be seen with naked eye. However, subclinical mastitis, precursor to the clinical mastitis, must be diagnosed through exams as the California Mastitis Test (CMT) and the Somatic Cell Count (SCC).

Once the mastitis is diagnosed, it is important to separate the sick animals and follow the milking order: healthy cows, cows that are healed from mastitis and cows who are being treated from mastitis. The treatment may vary according to the gravity of the situation. In general, milking the sick cow four times a day is needed and, after the last milking, give medications, when necessary.

Cows that are in their resting time, and not producing milk, need to be medicated with special remedies for this phase.

7. Verminosis

Another disease that may affect milk production is verminosis. In some critical cases, it may cause the animal’s death. But the greatest damage is related to decrease of the production. It is important to know that, in 95% of the cases, verminosis manifests itself in a subclinical form, therefore, without apparent symptoms. So, in most of the times, the disease is discovered only when it is in an advanced stage.

To avoid that the illness affect the dairy herd, it is crucial to make a parasite control. To do that, applying vermifuge at the right time is necessary. It is worth of notice that, like every other mentioned disease in this article, the verminosis may vary from one region to another. In Central Brazil, for instance, parasite control must be done in May, July and September – because in May the dry season begins in the area and in September it is possible to reduce the pasture contamination during the rainy season.

Have you ever experienced contact with contaminated animals with any of those illnesses? Share in the comments!


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