Important Cattle Diseases


What are the common and important cattle diseases? Information on the cattle diseases, symptoms and treatment methods.

Cattle Diseases

Cattle are subject to a wide variety of infectious and nutritional diseases that can cause serious economic losses. The most important of the diseases that commonly affect cattle are discussed below.

Cattle Diseases

Foot-and-Mouth Disease. This is a highly infectious disease that is one of the most dreaded of all livestock diseases. It is caused by a virus and it affects hogs and sheep as well as cattle. The main symptom of the disease is blisters in the mouth and on the feet. The animals may also become lame. The disease causes a severe loss in meat and milk production and sometimes even death.

The first outbreak of foot-and-mouth disease in the United States occurred in 1870. There have been eight other outbreaks in the United States, the last in 1929. In all but two of the outbreaks, this disease was wiped out within a few months. However, nearly two years of quarantining, destruction of infected and exposed herds, and cleaning and disinfection of premises were necessary to stamp out the infections found in 1914 and 1924.

The disease continues to exist in Africa, Asia, Europe, and South America, and only the utmost vigilance by agents of the U.S. Department of Agriculture keeps it from invading the United States. Cattle, swine, sheep and goats, and the fresh, chilled, or frozen meats of these animals cannot be imported unless they are from countries free from the disease.

In addition to preventing the importation of infected animals, the U.S. Department of Agriculture operates a foot-and-mouth disease research laboratory on an island off the eastern coast. This laboratory is working on new and more effective means of controlling the disease if a new. outbreak should occur.

Mastitis. This is the most costly of all cattle diseases. It is particularly serious in dairy herds because it affects the udder and sharply reduces milk production. Mastitis may be caused by several bacteria, including Streptococcus agalactiae, Micrococcus pyogines, and Escherichia coli. Nearly 20% of cows have mastitis at least once a year.

Mastitis exists in two forms, acute and chronic. In both forms of mastitis, the mammary cells are replaced with fibrous tissue, and in advanced cases the udder becomes useless. In acute mastitis the infected quarter of the udder is hot, tense, hard, and tender. Milk secretion stops almost completely. Fever, dullness, and loss of appetite may also occur.

Chronic mastitis is not so easily recognized. Inflammation and infection of the udder usually involve only a small portion of the milk-secreting tissue. The udder may appear normal, but flakes or clots may appear in the milk. The butterfat and protein content of the milk is usually reduced, and the salt content increases.

Calf Scours. The most destructive disease of calves is calf scours. The typical symptom is diarrhea. The most fatal form of the disease appears at birth or within 6 to 72 hours after birth. The calf may be found dead or cold, weak, and dying. Sometimes, however, newborn calves may have mild diarrhea for 10 to 30 days and then recover with little assistance. However, most calves that have scours become unthrifty, grow slowly, and are highly susceptible to pneumonia.

A variety of organisms can cause scours. The disease occurs more frequently in large herds than in very small herds of one or two cows. Calf pens, calving stalls, barnyards, trucks, and other facilities may be contaminated by the infectious agents. Lack of .Vitamin A in the cow’s diet may reduce the resistance of the calf to scours, and what are known as noninfectious scours may be caused by improper feeding.

Pneumonia. The symptoms of pneumonia include dullness, coughing, rapid breathing, high temperature, and a nasal discharge. A complete or partial loss of appetite may also occur. Death may result in a few hours or days if treatment is not successful. Pneumonia may affect both cows and calves. In mature cattle it is often a secondary infection that invades the animal after another disease has weakened it. The organisms that cause pneumonia can usually be combated with the proper antibiotics; but if treatment is to be most effective it must be started early.

Screwworm. Screwworm flies lay their eggs in the wounds of cattle. The eggs hatch in 12 to 24 hours, and the tiny maggots feed in the living flesh. Infested animals usually die unless they are treated promptly. On the range prompt treatment of infested cattle has been difficult, costly, and often impossible.

The successful war against screwworm is probably one of the more spectacular accomplishments in cattle protection in recent years. To control these ravaging insects, scientists developed a procedure which prevents the females from reproducing. Male flies are reared in large numbers in a laboratory and then sterilized by exposure to gamma rays from radioactive cobalt. The sterile males are released from airplanes over the screwworm infested areas. Wild females, once mated to a sterile male, do not mate again and therefore cannot reproduce.

As a result of a campaign begun in 1957, in which many billions of sterile flies were produced and released, screwworms have been eradicated in the southeastern United States and in most of the Southwest.

Brucellosis. Brucellosis is a cattle disease that may infect humans. It is caused by the bacteria, Brucella abertus. The disease is commonly known as Bang’s disease and as undulant fever, and in cattle it may also be known as infectious abortion because it causes cows to lose their calves before the normal time for birth. The infection may spread rapidly through a herd and from one herd to another. The birth of weak calves and other abnormal occurrences during birth may result from brucellosis infection. No effective treatment for cattle infected with brucellosis has been found.

Since 1934 there has been a nationwide program for the control and eradication of brucellosis in the United States. Infected animals are slaughtered and many healthy animals, mostly calves, are vaccinated. During the early years of the campaign, the infection rate was above 6% of all cattle tested, but by 1965 annual losses from this disease had been reduced by 75%.

Milk Fever. A nutritional disease of high-producing dairy cows, milk fever occurs occasionally during calving but most often in the first few days after calving when the cow is coming into full production of milk. The condition is produced by a rapid lowering of calcium, or lime, in the blood. The symptoms are paralysis, inability to rise, and partial or total loss of consciousness. Despite the name of the disease, fever is not a usual symptom.

This ailment used to cause rapid death in as many as 90% of the cows affected. Fortunately, with modern methods of treatment, only a few dairy cattle now die from the disease.

Treatment for milk fever consists of injecting a calcium-glucose solution into the blood system. To counteract a common lack of blood sugar in affected cows, dextrose is often added to the solution. Immediately after treatment the cow brightens up and usually makes a good recovery in 1 or 2 hours. No effective methods of prevention are known.

Ketosis. Another nutritional disease, ketosis most often occurs in the early months of lactation. During this period of peak milk production, it is difficult to feed high-producing cows enough to meet their needs. When a deficiency is prolonged, ketosis may occur. It also occurs occasionally in cows that are not lactating and even in steers.

The more obvious symptoms of ketosis involve the nervous reactions of the animal. The cattle may be excitable, may stagger and sway when they walk, or may be listless. During the early stages of the disease, the cattle also develop a peculiar aroma on their breaths which experienced dairymen learn to detect. The aroma comes from the abnormal amounts of ketone bodies formed in the blood because of a metabolic abnormality. These ketone bodies are volatile and are excreted from the lungs as well as in the urine. Milk production usually drops markedly in cows affected with ketosis. Ketosis can be treated by injections of glucose and feeding of drugs.

Pinkeye. Pinkeye, also known as infectious keratitis, affects the eyelids of cattle. The linings of the lids become red and congested. The eyes are closed, and the animals show evidence of pain, especially in bright sunlight. They usually lose weight because they cannot see to graze. Some animals may become permanently blind.

Pinkeye is most commonly seen in the summer. The infection is usually introduced into uninfected herds by newly purchased animals that are either infected or have been exposed to infection while in transit. It may also be transmitted by flies and gnats.

Anaplasmosis. Anaplasmosis is an infectious disease caused by a protozoa (Anaplasma morginale) that infects the red blood cells and causes anemia. The disease is transmitted by bloodsucking insects such as mosquitoes, horseflies, and ticks. It occurs in the northern areas, but it is especially troublesome in warmer climates.

The severity and duration of the disease vary greatly. Symptoms may be so mild as to go unnoticed by the casual observer. In severe cases the animal usually becomes thin, and the pulse and breathing rate increase. As the disease progresses, there is drooling from the mouth, discharge of mucus from the nostrils, and increasing weakness. The disease is most severe in mature cattle, and as many as 50% of the affected animals have died in some outbreaks.

Certain antibiotics can suppress the multiplication of the protozoa and can rid carrier animals of infection, and they are often used to treat the disease. Blood transfusions are also useful in many cases, but, to be effective, 2 to 3 gallons (7.5 to 11 liters) of whole blood must be injected into the sick animal.

Bloat. This is a digestive disorder in which the cattle’s paunch and reticulum are swollen by stomach gases. The disease can kill cattle in a few hours. Its occurrence has increased rapidly after 1930, probably as a result of new feeding practices—particularly the increased use of alfalfa and other legumes for feed.

Tuberculosis. Tuberculosis was once widely prevalent in the United States. In 1917 the disease was found in 40% to 80% of the cattle in some of the badly infected areas, and a campaign against the disease was started. By 1940, the incidence had been reduced to less than 0.5% in the United States, in Puerto Rico, and in the Virgin Islands, and in 1965 the incidence in the United States was down to 0.08%.

The tubercle bacilli causing cattle tuberculosis are not the same as the bacteria causing human tuberculosis. However, humans are slightly susceptible to the cattle disease, and therefore, the control of cattle tuberculosis is beneficial to the human population as well as to the cattle industry.

Tick Fever. Another serious cattle disease in the early days of the United States was tick fever. This costly disease probably entered the country as early as the 17th century by way of the West Indies and Mexico. Trailherds from Texas carried the pestilence and cause of death to cattle into Indian territory, Missouri, Kansas, and Arkansas. Farmers suspected that the tick was the carrier of this disease, and researchers found the protozoan parasite (Babesia bigemina) that was the cause of the disease and confirmed that the tick (Boophilus annulatus) was the carrier of the parasite. This research not only opened the way to eradicating tick fever but also showed the way for revealing the causes of human diseases such as malaria, yellow fever, typhus, bubonic plague, and Rocky Mountain spotted fever. Today tick fever is no longer a significant disease of cattle in this country.

Pleuropneumonia. Pleuropneumonia was one of the first serious diseases to affect cattle in the United States. A highly contagious disease, it was introduced into the United States by a cow from a British ship in 1843. Forty years later an extensive campaign to combat the disease began, and 5 years later the disease had been eradicated from the United States at a cost of $1.5 million. However, constant vigilance is necessary to prevent the disease from reentering the country since it does still exist throughout a large part of the world. Many governments have active campaigns to eradicate the very costly disease.

Pleuropneumonia is caused by a virus, Asterococcus mycoides. Known in Germany as “lung plague,” this disease causes an inflammation of the lungs and the lining of the thoracic cavity. Animals affected with pleuropneumonia often develop high fevers, lose weight, and drop in milk production. Many of them die.


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