Content
- 1 What is leptospirosis
- 2 Sources of infection and routes of infection
- 3 Forms of the disease
- 4 Symptoms of leptospirosis in cattle
- 5 Research on leptospirosis in cattle
- 6 Treatment of leptospirosis in cattle
- 7 Pathological changes in leptospirosis in cattle
- 8 Prevention of leptospirosis in cattle
- 9 Conclusion
Leptospirosis in cattle is a fairly common infectious disease. Most often, mass death of animals from leptospirosis results from the lack of proper care and feeding of cows. The disease occurs with various lesions of the internal organs of cattle and poses the greatest danger to young animals and pregnant cows.
What is leptospirosis
Leptospirosis is a contagious disease of humans, wild and domestic animals, and is bacterial in nature. This disease was first noted in 1930 in the North Caucasus in cattle.
The causative agent of bovine leptospirosis is Leptospira
The causative agent of leptospirosis in cattle is Leptospira, pathogenic microorganisms. They have a curved body shape and are unusually active when moving. They live in a humid environment, for example, in soil they can remain viable for about a year. The bacteria get there with the feces of infected cattle. Leptospira does not form spores and dies quickly in the external environment. Exposure to direct sunlight is especially harmful to it.Disinfectants also act on bacteria.
Leptospirosis causes significant damage to the economy of many farms. In addition to the death of young cattle, leptospirosis provokes spontaneous abortions in adults, the birth of still calves, exhaustion of animals, and a significant decrease in milk production. Leptospirosis activity is most often observed during the period when livestock begins grazing on pasture, in the spring. Young animals suffer more from the disease because their immune system has not yet been strengthened.
Sources of infection and routes of infection
One of the symptoms of leptospirosis is yellowness of the mucous membranes
The source of infection is the feces and urine of sick individuals, as well as rodents that carry the bacteria. Transmission factors include contaminated feed and water, soil and animal bedding. As a rule, infection occurs through the nutritional route. In addition, infection is possible:
- aerogenic method;
- sexual;
- intrauterine;
- through open wounds on the skin and mucous membranes.
Outbreaks of infection occur during the warm season. After Leptospira penetrates the bloodstream of cattle, they begin active reproduction. The body of an infected individual, trying to get rid of the pathogen, releases toxins. They are the cause of the malaise. After one animal is infected, the infection is rapidly transmitted to the entire livestock through urine, saliva, and feces. Then the disease becomes epidemiological.
Forms of the disease
Leptospirosis in cattle can occur in the following forms:
- acute;
- chronic;
- subclinical;
- manifest;
- atypical;
- subacid.
Each of these forms of the disease has its own characteristics of manifestation and treatment.
Symptoms of leptospirosis in cattle
Symptoms and treatment of leptospirosis in cattle largely depend on the course and form of the disease. Adults are characterized by an asymptomatic course of the disease. Young animals suffer from the following symptoms:
- increased body temperature;
- development of anemia and jaundice;
- diarrhea;
- atony of the forestomach;
- muscle cramps;
- rapid pulse, shortness of breath;
- dark colored urine;
- loss of appetite;
- conjunctivitis, necrosis of the mucous membranes and skin.
The acute form of the disease causes the death of the animal within 2 days after heart failure or kidney failure. With chronic leptospirosis, the symptoms are not so pronounced, but in the absence of treatment they also lead to the death of cattle.
One of the first symptoms of leptospirosis in cattle that you need to pay attention to is sudden hyperthermia, followed by a decrease in body temperature. In this case, the animal may show aggression.
A pond with dirty water can be a source of infection
The manifest form lasts up to 10 days. Characteristic signs of this form of the disease:
- increased body temperature up to 41.5 °C;
- animal oppression;
- lack of chewing gum;
- yellowness of the skin;
- painful urination;
- diarrhea, stool retention;
- pain in the lumbar region upon palpation;
- abortions of pregnant cows;
- tousled fur;
- tachycardia.
If treatment is not started in a timely manner, livestock mortality reaches 70%.
The chronic form of leptospirosis is characterized by exhaustion, a drop in milk yield and milk fat content, and the development of mastitis.The prognosis is most often favorable, as is the case with the atypical form of the disease, which occurs with mild clinical manifestations.
The subclinical course of leptospirosis in cattle is usually discovered during routine diagnostics.
Research on leptospirosis in cattle
Diagnosis of cattle for leptospirosis involves the use of epizootological data, pathological observations, identification of symptoms and changes in the blood. During hematological examination of infected individuals, the following is noted:
- low red blood cell count;
- increased or decreased hemoglobin levels;
- drop in blood sugar levels;
- leukocytosis;
- increase in bilirubin and proteins in plasma.
Another obvious sign of leptospirosis is the detection of antibodies to the pathogen in a fifth of the entire cattle population. This will require a bacteriological analysis of cow urine. In addition, the diagnosis should be differentiated from listeriosis, chlamydia, piroplasmosis and brucellosis.
The final diagnosis is made after all the necessary studies (microscopy, histology, serological tests). Leptospirosis is diagnosed only after culture isolation. Thus, the diagnosis of leptospirosis in cattle should be comprehensive.
Treatment of leptospirosis in cattle
Livestock vaccination
First of all, it is necessary to isolate sick individuals from the herd in a separate room and create comfortable conditions for them. To combat leptospirosis in cattle, an injection of anti-leptospirosis serum is performed.Antibiotic therapy and symptomatic treatment of leptospirosis in cows will also be required.
Serum against bovine leptospirosis is administered subcutaneously in a dosage of 50-120 ml for adults and 20-60 ml for calves. The injection should be repeated after 2 days. Antibiotics include streptomycin, tetracycline or biomycin. The drugs are used for 4-5 days twice a day. To eliminate hypoglycemia, glucose solution is administered intravenously. To normalize gastrointestinal function, Glauber's salt is prescribed. Taking caffeine and methenamine gives good results. If there is damage to the oral mucosa, you need to rinse with a solution of manganese.
The instructions for bovine leptospirosis provide for the inspection of all animals in the herd if at least one sick individual is detected. Next, the entire livestock is divided into 2 halves: in one, animals with clinical signs of the disease, which are treated according to the scheme, and also hopeless cows, subject to culling. Healthy cattle from the second half undergo mandatory immunization.
Pathological changes in leptospirosis in cattle
The corpse is emaciated, dry, dull fur with bald patches. When opening the corpse of an animal, the following changes are observed:
- yellow tint of the skin, mucous membranes and internal organs;
- necrotic lesions and edema;
- accumulation of exudate mixed with pus and blood in the abdominal cavity and thoracic region.
Changes in the animal's liver
Leptospirosis especially affects the liver of a cow (photo). It is significantly increased in volume, the edges are somewhat rounded.In this case, the color of the organ is yellow, hemorrhages and foci of necrosis are visible under the membrane. The cow's kidneys are also subject to changes. At autopsy, pinpoint hemorrhages and exudate are noticeable. The bladder is greatly distended and filled with urine. The gall bladder is filled with brown or dark green contents.
Samples and tests taken from the organs of the corpse show changes as a result of the invasion.
Prevention of leptospirosis in cattle
One of the most effective measures to prevent disease among livestock is timely vaccination. For this purpose, a polyvalent vaccine against bovine leptospirosis is used, which prevents the development of the disease in unfavorable farms. It includes various cultures of infectious agents inactivated by artificial means. The drug, entering the cow’s body, leads to the development of stable immunity for a long period. After a certain time, repeated vaccination will be required. The frequency of the procedure depends on the age of the animal.
In addition, veterinary rules on animal leptospirosis provide for compliance with sanitary and hygienic rules when breeding cattle on farms. Farm owners are obliged to:
- carry out regular inspection of individuals in the herd;
- feed with high-quality proven food and drink with clean water;
- change the litter on time;
- fight rodents on the farm;
- carry out daily cleaning of the barn and disinfection once a month;
- grazing livestock in areas with clean water;
- carry out routine diagnostics of the herd;
- declare cattle quarantine if leptospirosis is suspected and when new animals are imported.
It is also recommended to examine the fetus during a miscarriage in a cow for the presence of bacteria.
When quarantine is introduced on a farm, the movement of livestock within and outside the territory is prohibited, animals are not used for breeding during this period, products from the farm are not sold, and grazing is prohibited. The barn and surrounding areas and premises should be disinfected and deratized. Milk from infected cows is boiled and used only on the farm. Milk from healthy individuals can be used without restrictions. Quarantine is lifted only after all necessary measures and negative tests.
Polyvalent vaccine
Conclusion
Leptospirosis in cattle is a complex infectious disease that affects all organs of the animal. It is also quite dangerous for humans, therefore, if a sick individual is detected in the herd, you will need to take all necessary precautions to prevent further spread of the infection in the herd and among the personnel on the farm. It is worth noting that if strict preventive measures are followed, infection can be avoided.
Is it possible to dissect the corpse of a cow if it is vaccinated against leptospirosis?