In calves, the immune system has not yet strengthened, the body is susceptible to negative factors and is susceptible to diseases. One of the most common pathologies is cryptosporidiosis, which occurs in calves with varying degrees of severity. The disease affects not only cattle, but also pets and humans. The infection multiplies on the mucous tissues of the digestive tract, invades the lungs, and in the absence of proper treatment causes the death of the animal.
Concept of illness
Cryptosporidiosis is an infectious pathology that occurs in calves in acute and subacute forms, caused by protozoan pathogenic microorganisms - coccidia, belonging to the Cryptosporidium family. The infection invades the tissues of the stomach and intestines, which disrupts the function of digestion and absorption. Sometimes coccidia spread to the respiratory system and negatively affect the immune system.
The first to be affected by infection are the intestinal mucous tissues. Moreover, the damage can be extensive, covering almost the entire organ. Due to a decrease in the absorption capacity of intestinal tissues, diarrhea begins. Intestinal villi swell and atrophy, and the number of mucus-producing goblet cells decreases. In the intestines, the synthesis of enzymes is significantly reduced, and the concentration of sugars in the villi decreases.
Pathogens
The causative agents of cryptosporidiosis are coccidia of the Cryptosporidium family - round or oval microorganisms. The parasite cell is translucent, its membrane is almost transparent. Representatives of the family are smaller than other coccidia, but almost do not react to antimicrobial drugs. Cryptosporidium develops in the host tissues within 3-6 days, and goes through 3 life stages:
- Sporogony is multiple division of a fertilized cell - oocysts, with a diameter of 3-7 microns. As a result, sporozoites are formed - mononuclear cells.
- Merogony is the fragmented development of a fertilized egg in which there is no female nucleus.
- Gametogony – sexual reproduction.
The oocyst shell is dense and thin.The first is immune to external negative influences and ensures cell viability for 1.5 years. Oocysts with a thin membrane, although more sensitive, are weakly released from the body and partially remain, provoking a second wave of the disease. Since coccidia are immune to antiseptic drugs and temperature fluctuations, they actively reproduce both in the barn and outdoors. There are no farms where cryptosporidiosis pathogens cannot be detected.
In 1 kg of cow manure, laboratory analysis can detect more than 1 million oocysts.
Methods of infection
Calves become infected through the nutritional route, that is, the infection enters the digestive tract when swallowing contaminated food or drink. Less commonly, infection occurs through contact of the animal’s mucous membranes with equipment and care products.
Cryptosporidiosis carriers are not only sick individuals, but also humans. For example, an infection can be brought into a barn by a farm worker on his boots. Rodents living in barns often become carriers of cryptosporidiosis.
Symptoms of cryptosporidiosis
Having penetrated the calf’s body, cryptosporidium begins to actively multiply, causing inflammation of the intestines and respiratory organs. Incubation lasts from 3 to 6 days. Symptoms of cryptosporidiosis appear in calves 6-9 days after birth, and recovery occurs after about 2 weeks. Cryptosporidiosis occurs with varying intensity, depending on the animal’s immunity, conditions of detention and quality of care. The disease in calves is not chronic, only acute and subacute, that is, the pet either dies or survives.
The likelihood of death of a sick animal increases when cryptosporidiosis is complicated by eimeriosis, salmonellosis, and clostridiosis.
The table lists the forms of cryptosporidiosis and typical symptoms.
| Flow form | Symptomatics |
| light | lethargy, weak appetite, mild diarrhea with liquid or viscous fecal matter without mucous inclusions - symptoms are observed for several days, the calf recovers |
| average | weakness, poor appetite, dehydration, profuse and persistent diarrhea with watery-mucous fecal matter - symptoms last 6-8 days, the calf recovers with proper care and treatment |
| heavy | The calf is lying down, cannot get up, has no appetite, and the body is dehydrated. The abdomen is painful, profuse diarrhea with watery-mucous feces, which may contain blood streaks, the eyeballs become dull and sunken. The mucous membranes take on a blue tint, body temperature rises to 40-41 °C, tachycardia, convulsions, loss of muscle sensitivity are noted; in the absence of competent and timely treatment, the infection affects the lungs, the calf dies |
Diagnosis of pathology
For diagnosis, feces from a sick calf are taken. For pathological examination, fecal matter from the rectum is used. The diagnostic method used is a native smear. The dried fecal smear is fixed with methyl alcohol and stained with carbol fuchsin. The oocysts turn red, and sporozoites are visible inside each cell under a microscope. The surrounding substrate takes on a green color.
You can also use Giemsa solution for staining - mixed azure, eosin and methylene blue. Oocysts under a microscope appear as slightly bluish-pink colored cells. Inside the cell, light blue elongated and slightly curved sporozoites are visible.
How to treat cryptosporidiosis in cattle
There are no effective medications.Treatment of cryptosporidiosis in calves involves the use of drugs:
- "Amprolium";
- "Sulfadimezin";
- "Norsulfazole";
- "Paromomycin";
- "Chemococcid".
The first four drugs do not destroy the infection, but only slow down the formation of oocysts in the calf’s body. And the last medicine on the list accelerates the development of immunity in the animal’s body. The listed drugs should be used simultaneously with a course of immunostimulants. Abroad, these drugs are classified as unlicensed. Our farmers use them at their own peril and risk.
Halofuginone lactate
The only licensed medicine is halofuginone lactate. The drug is sold in liquid form. It has a depressing effect on the stage of sporogony and merogony during the propagation of the pathogen. Halofuginone lactate is suitable for both the prevention and treatment of cryptosporidiosis. As a prophylactic agent, the drug is used 2 days after the calf is born. For therapeutic purposes, the drug is used immediately after the onset of symptoms of cryptosporidiosis.
Halofuginone lactate does not destroy the infection, but weakens diarrhea and inhibits oocyst division. Dose – 0.1 mg per 1 kg of calf body weight. But it must be taken into account that the concentration of the active substance in the composition of drugs from different manufacturers is not the same. Therefore, to determine the dosage, you should read the instructions. The drug is given to the calf every day for a week, added to the milk. Do not give the medicine to weakened pets, or when diarrhea lasts more than a day.
Adjuvant therapy
To increase the effectiveness of the medications used, the sick calf is put on a therapeutic diet. Droppers are placed to administer solutions that normalize the water-salt balance in the body.They give the calf decoctions that coat the walls of the diseased intestine, reducing inflammation.
Use of probiotics
Probiotics have no effect against coccidia. They are necessary to restore intestinal microflora, ruined by the proliferation of pathogenic microorganisms and the use of drugs. Probiotics are dissolved in warm water and given to the calf to drink instead of one meal.
Prevention of the problem
A vaccine against cryptosporidiosis has not been developed. Therefore, it is impossible to protect calves. Oocysts are tenacious and actively reproduce, so even prevention is difficult. The main preventive measures are maintaining cleanliness in the barn, quality feeding and strengthening the immunity of calves. The bedding is changed regularly. The barn is disinfected using a solution of hydrogen peroxide and 10% formaldehyde. Oocysts die at temperatures below -20 °C and above +60 °C. Therefore, thermal disinfection can be carried out: steam, boiling water, fire.
Farm workers should periodically have their stool tested for the presence of coccidia. You should buy young stock only from trusted sellers who keep livestock in proper conditions. A sick calf is immediately separated from the herd.
