Blackleg, tetanus and white muscle disease are three deadly conditions for calves.
“These three diseases result in compromised muscle function in calves and are not seen often, but when you do see them, it tends to affect more than one calf,” said Werner Debertin of New Brunswick’s provincial veterinary services.
“All three are lethal if they are not addressed and they are easily prevented with vaccinating or mineral supplementation,” he said in a recent Beef Cattle Research Council webinar about animal health.
Clostridial myositis, also known as blackleg, is fatal because muscles are infected by the bacteria Clostridium chauvoei, which grow in a low oxygen environment. The bacteria form spores in the soil and can last for decades. They are ingested by the animal, absorbed through the intestinal wall and move through the blood stream.
“It often follows an environmental disturbance in the pasture or field,” Debertin said.
The spores may be stirred up after a heavy rain or dry period when animals grazed closely to the ground.
It affects deeper muscles as well as the heart and diaphragm.
Cattle of all ages can be affected, but it most often hits healthy, fast-growing animals six to 24 months old. It is often seen on pasture in summer and fall when cattle are discovered dead. Death occurs within 12 to 48 hours.
The animal develops dark, dry muscles, and Crepitus occurs, in which bubbles form in the muscle.
“If you poke the hide of the animal with your fingers, it feels like you are breaking bubble wrap,” he said.
Lameness and soreness are the main symptoms. High fever, lethargy, crepitus and reluctance to move are other symptoms, but diagnosis is often determined during a post mortem.
Penicillin can be used on all of an infected animal’s siblings for treatment and prevention. They should be treated for up to 14 days, but it is not always successful.
Multivalent clostridial vaccines that include tetanus should be given to calves three months and older and boostered two to three weeks later.
Vaccinate cows four to eight weeks before calving so that they can pass immunity through the colostrum to the calves, especially in areas where blackleg is known to occur.
This disease is related to the blackleg bacteria. It is soil borne, and spores enters the body through a wound. It can affect animals of all ages.
Neurotoxins are produced and irritate the nerves supplying muscles. The muscles then go into spasms.
“The severity continues until animals are no longer able to breathe due to involvement of the diaphragm and dehydration because of the inability to swallow,” Debertin said.
Tetanus is often associated with surgical castration or injuries to the birth canal during a hard calving.
Mild signs are observed at first: the animal seems anxious, is stiff when walking, its third eyelid droops, it develops a sawhorse stance and has a water pump tail that is extended. These symptoms are followed by death.
The disease could be treated with penicillin if caught early enough. The wound needs to be debrided. Place the animal in a quiet place with deep bedding and good footing on the floor. A tetanus antitoxin at 15,000 units or more could be given.
Vaccination is effective against tetanus.
“If you are going to use elastrators in calves, it is a good idea to vaccinate your cows four to eight weeks before calving so they pass immunity through the colostrum,” he said.
Give the vaccine to bull calves two to four weeks before banding and provide a booster when the procedure is done.
Selenium deficiency in parts of Western Canada can cause white muscle disease.
Selenium and vitamin E given together prevents oxidative damage to muscles and builds a good functioning immune system.
“Often you will have vaccine failures due to a deficiency in selenium,” Debertin said.
The disease damages muscle cells that are replaced with scar tissue.
There are two forms of the disease.
The first is a congenital type in which animals are born with a deficiency because dams didn’t receive enough mineral supplement. It may occur in bunches of animals.
The disease affects the heart and causes respiratory distress because the animals do not circulate the blood properly. Calves may have a hard time getting up.
“If you see this, it does have a poor prognosis,” he said.
Late term abortions can happen in which the fetus dies because of heart failure.
The delayed form occurs in calves up to seven to nine months old. It corresponds to more activity among the animals, and the skeletal and heart muscles may be affected.
If the heart is involved, heart failure can occur and the animal may die suddenly.
Calves should receive an injection at birth or any time they are processed or handled when they are being vaccinated before sale time. Cows should also receive 200 to 500 IU of vitamin E daily during the last 60 days before calving.
Selenium deficiency can cause reduced disease resistance and retained placentas.
Deficiency symptoms reveal calves that tend to lay around and may lack an aggressive suckling ability or be chronically stiff. There is soreness, an arched back and weakness.
Consult a nutritionist or veterinarian if selenium deficiency is suspected.