Animal Pathology Research Articles

The role of cyanotoxins in human and animal pathology (а review)

Cyanobacteria are the oldest and most widespread form of life on Earth. Many of them produce toxins that are dangerous to humans and animals. The review presents data on the distribution of toxin-producing cyanobacteria, the pathogenesis of the action of toxins on human and animal cells and tissues. A significant consideration is given to the neurotoxic effect of cyanotoxins, which is most common cause of animal death. Cyanotoxins can cause severe damage to the central and peripheral nervous systems, as well as the liver, kidneys, reproductive system and digestive tract. Data on hepatotoxic, nephrotoxic, cardiotoxic, immunotoxic effects of cyanotoxins are presented. Their role in the human brain degenerative diseases is considered. The possible influence of cyanotoxins on carcinogenesis, especially in the liver, large intestine and rectum, is evaluated. The limitations of the existing data on the pathogenicity of cyanobacteria and medical care necessary for cyanotoxin-induced diseases are noted. The necessity for further studies of clinical manifestations of pathological processes caused by cyanotoxins, the development of diagnostic methods and specific therapy of poisoning is discussed.

First report of human Thelazia callipaeda infection in Portugal

The zoonotic parasitic nematode Thelazia callipaeda, also known as the oriental eye worm, is endemic in several European countries, including Portugal. Infections may result in ocular disease in domestic and wild animals as well as humans, with more or less severe manifestations. We report the first human case of ocular thelaziosis by T. callipaeda in Portugal, a country where the parasite had already been found to infect dogs, cats, red foxes, wild rabbits and a beech marten. An 80-year-old patient from east-central Portugal, who had been suffering from tearing for a few years, had whitish filiform fragments removed from the left eye. Polymerase chain reaction of partial cytochrome c oxidase subunit 1 and 18S small subunit rRNA genes followed by bidirectional sequencing and BLAST analysis confirmed T. callipaeda haplotype 1, the only haplotype previously reported in Europe. The endemicity of T. callipaeda in domestic and wild animals in east-central Portugal makes it very likely that infection of the human patient had occurred locally. In east-central and other geographical areas of Portugal, veterinarians and physicians, especially ophthalmologists, should regard T. callipaeda as a cause of ocular pathology in animals and humans.

Environmental Contamination by Echinococcus spp. Eggs as a Risk for Human Health in Educational Farms of Sardinia, Italy.

Cystic Echinococcosis (CE) is a severe zoonosis caused by the larval stage of the tapeworm Echinococcus granulosus. These parasites are naturally transmitted between canid definitive hosts that harbour the adult stage in the intestine, and mainly ungulate intermediate hosts, with larval cysts developing in their internal organs. The close coexistence between dog and sheep with incorrect hygiene management are the most important factors for the persistence of this parasitic pathology. The Educational Farms (EF) are farms and agritourisms suitably equipped to carry out training activities for people interested in farm practices and agricultural processing, in particular student groups. Public attendance of farms represents a new potential risk factor for the zoonoses transmission. Consumption of contaminated food and water in combination with contact or playing with domestic dogs (Canis familiaris) are possible routes of zoonoses human infection. In fact, Echinococcus spp. eggs may persist in the environment up to several months at low temperatures and moist conditions, having the chance of contaminating different matrices and surfaces. The aim of this investigation was to study environmental contamination by parasitic elements as a risk for zoonoses, such as Echinococcus spp. A total of 116 samples (35 of water, 33 of soil, 23 of vegetables, 25 of dog faeces) were collected in 30 EF in Sardinia. Samples were subjected to biomolecular investigation for the research of specific gene sequences of Echinococcus granulosus, Echinococcus multilocularis and Taenia spp. The study allowed to identify eight positive EF due to the presence of Echinococcus granulosus in eight dog faeces samples and one positive EF due to the presence of Taenia spp. in a water sample. The work has allowed to develop and harmonise the diagnostic methods and operating protocols essential for controlling the spread of the CE to create “One Health” intervention plans in high endemic areas through the implementation of SOP (standard operating procedures) for monitoring the pathology in animals, humans and environment.

Phitest for analyzing the homogeneity of single-cell populations.

Single-cell RNA sequencing technologies facilitate the characterization of transcriptomic landscapes in diverse species, tissues and cell types with unprecedented molecular resolution. In order to better understand animal development, physiology, and pathology, unsupervised clustering analysis is often used to identify relevant cell populations. Although considerable progress has been made in terms of clustering algorithms in recent years, it remains challenging to evaluate the quality of the inferred single-cell clusters, which can greatly impact downstream analysis and interpretation. We propose a bioinformatics tool named Phitest to analyze the homogeneity of single-cell populations. Phitest is able to distinguish between homogeneous and heterogeneous cell populations, providing an objective and automatic method to optimize the performance of single-cell clustering analysis. The PhitestR package is freely available on both Github (https://github.com/Vivianstats/PhitestR) and the Comprehensive R Archive Network (CRAN). There is no new genomic data associated with this article. Published data used in the analysis are described in detail in the Supplementary Data. Supplementary data are available at Bioinformatics online.

Prevalence analysis and main criteria for assessing the incidence of eczema for dogs

The article discusses one of the common skin diseases of dogs – eczema, which affects about 9.1% of dogs in the city of Kursk. The proportion of dog's skin diseases in the total morbidity structure of animals with non-infectious (57.7%) and infectious pathologies (42.3%) was 36.3%. The influence of the age of animals on animal pathology was determined: eczematous diseases are more often recorded for the animals aged from one to two years (57.5%), somewhat less often (32.7%) at the age of 2 months to 1 year and in isolated cases (9.8%) over the age of 5. It has been established that inurban climatic conditions the frequency of dog's eczematous lesionsis influenced by the air temperature and the amount of precipitation.A high percentage of dogs affected by eczema (47%) is noted in the fall (mainly in September) – 47% and in the summer months (July-August) – 25%. Eczema was registered slightly less in winter (12%) and spring (16%) periods. The causes of dog's eczema of various origins were determined: 34.3% – liver dysfunction, 28.6% – allergic reaction to food, 25.7% – mechanical irritation, 8.5% – pathogenic effect of entomoses and endoparasitic mites, 2, 9% – allergic reaction to drugs. Weeping eczema was found for 42 animals (70%), "chronic eczema" for 18 dogs (30%). Typical clinical signs of eczema manifestations for dogs were recorded in the following ratios: itching – 100%, exudation – 94.5%, papules – 93.2%. Other clinical manifestations were less common, or were only in the anamnesis (fever – 5%, decreased appetite – 18%, drinking a lot of water – 12%, pain when moving the dog – 8%, loss of activity – 20%). A tendency to eczema was observed in dogs with pronounced skin folds, in older animals and in dogs with a thick undercoat.

Review of Pathology of Wildlife and Zoo Animals

Review of Pathology of Wildlife and Zoo Animals

Adverse renal effects of NLRP3 inflammasome inhibition by MCC950 in an interventional model of diabetic kidney disease.

Activation of nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome has been reported in diabetic complications including diabetic kidney disease (DKD). However, it remains unknown if NLRP3 inhibition is renoprotective in a clinically relevant interventional approach with established DKD. We therefore examined the effect of the NLRP3-specific inhibitor MCC950 in streptozotocin-induced diabetic mice to measure the impact of NLRP3 inhibition on renal inflammation and associated pathology in DKD. We identified an adverse effect of MCC950 on renal pathology in diabetic animals. Indeed, MCC950-treated diabetic animals showed increased renal inflammation and macrophage infiltration in association with enhanced oxidative stress as well as increased mesangial expansion and glomerulosclerosis when compared with vehicle-treated diabetic animals. Inhibition of the inflammasome by MCC950 in diabetic mice led to renal up-regulation of markers of inflammation (Il1β, Il18 and Mcp1), fibrosis (Col1, Col4, Fn1, α-SMA, Ctgf and Tgfβ1) and oxidative stress (Nox2, Nox4 and nitrotyrosine). In addition, enhanced glomerular accumulation of pro-inflammatory CD68 positive cells and pro-oxidant factor nitrotyrosine was identified in the MCC950-treated diabetic compared with vehicle-treated diabetic animals. Collectively, in this interventional model of established DKD, NLRP3 inhibition with MCC950 did not show renoprotective effects in diabetic mice. On the contrary, diabetic mice treated with MCC950 exhibited adverse renal effects particularly enhanced renal inflammation and injury including mesangial expansion and glomerulosclerosis.

Imaging coordinates in lithiasis bladder pathology in companion animals

The pathology of urinary bladder lithiasis is a common condition in veterinary medical practice with a high incidence and hematuric expression that is dominant in the clinical-paraclinical ensemble, therefore, we considered it appropriate to allocate a broad description in the content of this article.

Smart 3D meat inspection

Meat inspection is an important part of education for every veterinary student. However, traditional teaching methods require the sacrifice of living animals, and are thus considered expensive, inadequate and inhumane. Development of novel technologies has provided opportunities for new, improved ways of education. Smart 3D Meat Inspection (S3DMI) is an elearning tool that allows veterinary medicine students to acquire required skills using virtual 3D models of animal organs and carcasses. These models can be manipulated and “cut” just like real organs, allowing students to learn this essential skill without the need for animal carcasses. Students are allowed to practice any part of meat inspection as many times necessary, at their own pace, without time, place or resources limitations. This type of education is considered superior to traditional methods. There is no need for sacrification of animals for educational purposes and the cost of education is greatly reduced, while the educational quality is uninterrupted. Models developed for S3DMI can also be adjusted for courses like animal anatomy and pathology, which also require the use of real animal cadavers. S3DMI is still in its developmental stages, but it has a great potential to minimalize the need for animal sacrifice in the education of future veterinarians, while ensuring the quality improvement.

Natural and experimental salinomycin poisoning associated with the use of florfenicol in pigs

ABSTRACT: This study describes the spontaneous and experimental salinomycin poisoning associated with the use of florfenicol and warns about the effects of the administration of antibiotics to animals that receive ionophores in the feed as growth promoters. A batch with 1,200 finishing pigs fed a diet containing 30ppm of salinomycin received florfenicol (60ppm via feed) to control respiratory diseases. Twenty-seven pigs had difficulty walking, tip-toe walking, muscle tremors, and anorexia seven days after the start of treatment. Twenty-two animals died, 10 recovered, and two were sent to the Laboratory of Animal Pathology of CAV-UDESC to be necropsied. The experimental reproduction of the disease was carried out to clarify the possible influence of florfenicol on salinomycin poisoning using 12 pigs divided into four groups with three animals each, treated for 16 days with diets containing no additives (Group 1), 50ppm of salinomycin (Group 2), 40ppm of florfenicol (Group 3), and 50ppm of salinomycin and 40ppm of florfenicol (Group 4). Only animals in Group 4 became ill. The clinical disease was reproduced from the ingestion of 24.67mg/kg/LW of salinomycin and 19.74mg/kg/LW of florfenicol. Both natural and experimental salinomycin poisoning associated with the use of florfenicol caused a condition of myopathy characterized in histology by hyaline degeneration and floccular necrosis of skeletal fibers, with macrophage infiltrate, associated with the figures of regeneration in skeletal muscles and multifocal areas of the proliferation of fibroblasts, being more intense in the longissimus dorsi and semimembranosus muscles. Therefore, florfenicol can cause the accumulation of ionophore salinomycin in the animal organism, resulting in a condition of toxic myopathy.

Mouse Norovirus Uses Host Metabolites to Enhance Receptor Binding and Evade Immune Recognition

Noroviruses are the major cause of epidemic gastroenteritis in humans, causing ~20 million cases annually, resulting in more than 70,000 hospitalizations and 570-800 deaths in the United States alone. The T=3 icosahedral calicivirus capsid is composed of viral protein 1 (VP1) with three major domains: the N-terminus (N), shell (S), and C-terminal protruding (P) domains. The S domain forms a shell around the viral RNA genome, while the P domains dimerize to form protrusions on the capsid surface. The P domain is subdivided into P1 and P2 subdomains, with the latter containing the binding sites for cellular receptors and neutralizing antibodies. Mouse norovirus (MNV) is a widely used system for study of norovirus biology since we have a cell culture system, reverse genetic tools, and small animal model to eventually correlate structural information to whole animal pathology Mouse norovirus is a surprisingly dynamic virus that switches between receptor and antibody binding structures depending upon the in-vivo environment. In the circulation, the P domain floats above the shell by more than 15Å and the P domain loops (A’B’/E’F’) at the very tip are splayed apart in an ‘open’ conformation that antibodies learn to recognize. Upon ingestion, the low pH environment with high metal and bile salt concentrations in the alimentary canal each independently trigger the P domains to rotate 90° and contract by 15 Å onto the capsid surface. This hides any epitopes at base of the P domain. During this reversible collapse, the two P domains within the dimer rotate about each other and the A’B’/E’F’ loops adopt the ‘closed’ conformation. This opens the receptor binding site while burying the epitopes at the tip of the P domain. Therefore, rather than only depending on escape mutations to block antibody binding, MNV aggressively uses host conditions to remodel itself to enhance receptor binding while blocking antibody recognition. This review will describe the structural processes and biological consequences of the virus responding to activating host cues in the gut while these same triggers bury the epitopes presented in the circulation. This is an aggressive and unique mode of immune escape that has been subsequently shown in other viruses such as COVID-19. Therefore, a deeper understanding of the dynamic processes of virus capsids will improve vaccine design by understanding how to present the epitope conformations at the site of infection rather than what is presented to the immune system.

Activity of Galidesivir in a Hamster Model of SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) has claimed the lives of millions of people worldwide since it first emerged. The impact of the COVID-19 pandemic on public health and the global economy has highlighted the medical need for the development of broadly acting interventions against emerging viral threats. Galidesivir is a broad-spectrum antiviral compound with demonstrated in vitro and in vivo efficacy against several RNA viruses of public health concern, including those causing yellow fever, Ebola, Marburg, and Rift Valley fever. In vitro studies have shown that the antiviral activity of galidesivir also extends to coronaviruses. Herein, we describe the efficacy of galidesivir in the Syrian golden hamster model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Treatment with galidesivir reduced lung pathology in infected animals compared with untreated controls when treatment was initiated 24 h prior to infection. These results add to the evidence of the applicability of galidesivir as a potential medical intervention for a range of acute viral illnesses, including coronaviruses.

Optimization of coprological studies in animals with the use of homeopathic Nux vomica 6CH

Background: Etiology of various gastrointestinal dysfunctions varies from infections and infestations to consequences of emotional stress and errors in animals’ nutrition. Taking this variability of etiology and pathogenesis into account, a lot depends not only on completeness of homeopathic history taking but also on the quality of laboratory studies. In our experience, coprology studies are especially complicated when persistent gastrointestinal disorders were preceded by massive use of allopathic remedies. This sometimes necessitates repeated examinations. That is why our interest in having reliable results and early detection of latent indigestion made us look for non-invasive methods which could be easy to use in animals but at the same time could reveal latent gastrointestinal pathology in animals. Aims: The study was aimed to determine the effect of a homeopathic medication Nux Vomica 6CH on detection of latent gastrointestinal pathology in small domestic animals. Method: Coprology studies were performed simultaneously with the use of sedimentation method and Fulleborn method (modification of Scherbovich). Infestations were diagnosed and characteristics of patient digestion were recorded. Feces test detected: 1. Presence of endoparasites (helminths, protozoa and yeast-like structures); 2. State of intestinal microflora (presence of different species and their balance with each other); 3. Degree of food absorbency (presence or lack of undigested protein, carbohydrates and fat); 4. Presence of inedible inclusions; 5. Presence of cells (lymphocytes, erythrocytes, intestinal epithelium, tumor fragments). If animal feces tests were non-informative, then all medications (except vitally important) were discontinued and Nux Vomica 6CH twice a day twenty minutes prior to food intake was prescribed for 6 days (4 globules dissolved in 10 ml of water). Results: 4500 coprology tests were performed during 3 years in cats and dogs. About 10% of the total number of examined animals (449 patients) produced very little information about the state of gastrointestinal systems at the first examination. When these cases were analyzed, the following reasons were found: long-term use of strong drugs, significant weakening of body immune system. As a result diagnostic tests were of very little value. These animals were treated by Nux Vomica 6CH for 6 days and then repeated feces test was performed. This produced a more informative picture of the state of gastrointestinal system and enabled to determine etiology and pathogenesis of the animal condition and prescribe necessary treatment. Conclusion. In such a way, Nux Vomica 6CH homeopathic remedy promoted effective optimization of coprology studies in animals. The suggested scheme of use for Nux Vomica 6CH significantly improves feces test quality. This in turn reduces time needed to choose strategy and tactics of treatment of small domestic animals with different chronic diseases.

Histomorphological evaluation of osteoclast cell count in femur bone of mice induced by anastrazole and protective effect of olive oil.

Objective: The objective of this study is to find out protective effect of olive oil to prevent bone loss by decreasing osteoclast count in patient receiving Anastrazole. Study Design: Experimental study. Setting: Pakistan Council for Scientific and Industrial Research (PCSIR) Animal House, Peshawar and Pathology Lab KGMC Peshawar. Period: March 2019 to December 2019. Material & Methods: Sixty female albino mice 6-8 weeks of age were selected for this experimental study and Aromatase inhibitor drug Anastrazole was given alone and in combination with olive oil once daily for 30 successive days. Femur bone samples were collected and stained with Eosin and Hematoxylin for histomorphological evaluation of osteoclast cell count in three all three groups i.e. control group, those receiving Anastrazole alone and those given Anastrazole and olive oil in combination. Results: The mean weight of all experimental female albino mice before study was 30.77- 33.05 grams and after the study was 30.84- 21.31 grams. Control group 1 which was given normal diet showed increased weight of mice with less osteoclast cell count as compared to experimental groups (2 and 3). In group 2 (Drugged) which was given Anastrazole, weight of were lesser than control group 1 and group 3(Anastrazole + olive oil), while, osteoclast score was greater than group 1(control) and group 3 (Anastrazole + olive oil). Group3 (Drugged+ Olive oil) showed greater weight of mice than group 2 (Anastrazole) but, lesser than control group 1. Osteoclast score was greater than control group but lesser than group 2 (Anastrazole). Conclusion: The results showed positive and protective effects of olive oil against Anastrazole induced bone loss in female albino mice.

Antiaging diets: Separating fact from fiction.

Caloric restriction has been known for nearly a century to extend life span and delay age-associated pathology in laboratory animals. More recently, alternative “antiaging” diet modalities have been described that provide new mechanistic insights and potential clinical applications. These include intermittent fasting, fasting-mimicking diets, ketogenic diets, time-restricted feeding, protein restriction, and dietary restriction of specific amino acids. Despite mainstream popularization of some of these diets, many questions remain about their efficacy outside of a laboratory setting. Studies of these interventions support at least partially overlapping mechanisms of action and provide insights into what appear to be highly conserved mechanisms of biological aging.

The Cystostomy Operation with A New Catheter for Cats: A Case Report

The findings contained in this paper were reached through studying a case of a urinary tract obstruction. These results were used for the evaluation of an innovative veterinary catheter for cystostomy that we have developed for cats. The study was carried out at the research facility in the Department of Surgery, obstetrics and pathology of small animals in Kazan State Academy of Veterinary Medicine named after N.E. Bauman. The subject was a one-year-old male cat suffering from a urinary obstruction. The important symptoms were the lack of urination and hematuria. Diagnosis of the disease was made based on anamnesis and clinical examinations. As complementary tests, ultrasonography besides urine and blood analyses were also done. The confirmed case of obstructive urolithiasis was managed by surgery. The animal was observed over 14 days after the operation. The interpretation of the data resulting from the analysis and the follow-up of the animal's general condition revealed interesting results concerning the absence of postoperative complications and the effectiveness of the new catheter.

Highly lethal Vibrio parahaemolyticus strains cause acute mortality in Penaeus vannamei post-larvae

A new lethal disease, commonly known as the “glass post-larval disease”, occurs in many shrimp hatcheries in China since late 2019. This disease affects 6– 12-day-old post-larvae of Penaeus vannamei and leads to over 90% mortality within 24– 48 h after the first sign of abnormal individuals. The typical gross clinical signs include an empty digestive tract and pale or colorless hepatopancreas, which result in a translucent look of diseased animals. Here, by applying per os infection study, we show that the “glass post-larval disease” is caused by an infectious agent. Three highly lethal Vibrio parahaemolyticus strains, vp-HL-201910, vp-HL-202005, and vp-HL-202006 are isolated from naturally infected post-larvae collected from different farms. They are very closely related to each other since their 16S rRNA and thermolabile hemolysin genes are identical. These strains reproduce the same pathology in experimental animals and can be successfully re-isolated. The normal structure of hepatopancreas tubule and midgut epithelium is seriously damaged by the representative strain vp-HL-202005. A comparison study suggests that vp-HL-202005 is ~1000 times more virulent than the strain causing acute hepatopancreatic necrosis disease. Moreover, the bacteria-free sonicate supernatant of vp-HL-202005 induces the same symptom in post-larvae shrimp, which strongly suggests that the pathology is caused by a bacterial toxin(s). These findings demonstrate that the “glass post-larvae disease” is caused by a specific type of highly lethal V. parahaemolyticus. Thus, we rename it “highly lethal Vibrio disease” (HLVD). HLVD is a serious threat to shrimp aquaculture.

Tomographic Imaging and Correlation to Quantify Vascular and Inflammatory Changes in an Experimental Spinal Cord Injury.

Spinal cord injury (SCI) is a devastating condition causing the loss of sensory and motor functions. SCI pathology is multifaceted, encompassing inflammation, scarring, neuronal damage, and vascular and tissue remodeling. The dynamics of SCI rapidly transform from acute, sub-acute, and chronic phases. The rapidly changing environment necessitates the real-time monitoring of disease severity. Therefore, in this study, we used the IVIS spectrum, a noninvasive fluorescence imaging modality, to monitor the disease pathology in live animals. We used near-infrared fluorescence imaging agents including Angiosense 750 EX, a probe that detects vascular changes, and Cat B 680 FAST, a probe that detects inflammation at various day points post injury (DPI), that is, DPI-1, DPI-14, and DPI-28. We quantified the pathophysiological changes after SCI using IVIS in live animals. As a result, we observed distinct differences in the disease progression between injured and sham mice. Moreover, live imaging showed a good correlation with behavioral studies, protein expression, and immunohistological analysis. Hence, the goal of this study was to introduce a new optical imaging modality that offers a determination of disease severity and the advantage of accelerated imaging of the correlated biomarkers in a real-time and dynamic manner. This study concluded that Cat B 680 Fast and Angiosense 750 EX could be used to assess the disease severity after SCI. Furthermore, our study suggests that the noninvasive fluorescence optical imaging modality offers a unique approach in monitoring neuroinflammatory diseases in live animals.

Serological investigation and genotyping of Mycobacterium avium subsp. paratuberculosis in sheep and goats in Inner Mongolia, China.

Paratuberculosis a contagious and chronic disease in domestic and wild ruminants, is caused by Mycobacterium avium subspecies paratuberculosis (MAP). Typical clinical signs include intractable diarrhea, progressive emaciation, proliferative enteropathy, and mesenteric lymphadenitis. Paratuberculosis is endemic to many parts of the world and responsible for considerable economic losses. In this study, different types of paratuberculosis and MAP in sheep and goats were investigated in Inner Mongolia, a northern province in China contiguous with two countries and eight other provinces. A total of 4434 serum samples were collected from six cities in the western, central, and eastern regions of Inner Mongolia and analyzed using the ELISA test. In addition, tissue samples were collected from seven animals that were suspected to be infected with MAP. Finally, these tissues samples were analyzed by histopathological examination followed by polymerase chain reaction (PCR), IS1311 PCR-restriction enzyme analysis (PCR-REA), and a sequence analysis of five genes. Among all 4434 ruminant serum samples collected from the six cities in the western, central, and eastern regions of Inner Mongolia, 7.60% (337/4434) measured positive for the MAP antibody. The proportions of positive MAP antibody results for serum samples collected in the western, central, and eastern regions were 5.10% (105/2058), 6.63% (85/1282), and 13.44% (147/1094), respectively. For the seven suspected infected animals selected from the herd with the highest rate of positivity, the gross pathology and histopathology of the necropsied animals were found to be consistent with the pathological features of paratuberculosis. The PCR analysis further confirmed the diagnosis of paratuberculosis. The rest of the results demonstrated that herds of sheep and goats in Inner Mongolia were infected with both MAP type II and type III. To the best of our knowledge, this is the first study of the two subtypes of MAP strains in sheep and goats in Inner Mongolia.

PREVALENCE AND ETIOLOGICAL FACTORS CAUSING THE RETENTION OF THE PLACENTA IN COWS

Among the main reasons for the retention of the membranes, weakening of the contractile function of the uterus, as well as fusion of caruncles with cotyledons as a result of inflammatory processes arising in them. At the same time, hemodynamic disorders and hypotonia of the uterus, according, noticeably prevail over the rest. The reason for the retention of the membranes, should be considered the blood circulation in the maternal part of the placenta, due to the high concentration of unbound heparin in it and the low concentration of ascorbic acid. Hyperkinesia, allocated by a number of authors animals, in all likelihood, does not play such a big role. Purpose. To study the prevalence and etiological factors responsible for the retention of membranes in cows. Materials and methods. For the period from 2015 to 2021, in the herds of cows belonging to the Krasnodarskoe EF and the Kuban EF and were under supervision, 194 cases of pathogenic process due to the retention of membranes in cows. The number of dairy cows in the herd in different years ranged from 795 to 845, and averaged 830 heads. Of these, in 2015, the retention of membranes was registered in 22 cows (2.65%), in 2016 in 19 (2.29%), in 2017 in 32 (3.86%), in 2018 in 35 (4 , 2%), in 2019 for 29 (3.5%), in 2020 for 26 (3.02%) and in 2021 for 31 cows (3.73%). The research results were subjected to mathematical processing using standard statistical analysis programs for the IBM PC. The reliability of the results was determined by the parametric Student’s test. Results. The results of processing the obtained data indicate that from the second half of April to August, the rate of retention of membranes in cows, in relation to the average annual, increases markedly and reaches 12.35% of all calving cows. Meanwhile, many studies carried out in the conditions of farms and complexes indicate that in the warm season, the pathology of childbirth associated with the retention of the membranes is significantly reduced. In this regard, we made an attempt to analyze the conditions of keeping, feeding and insemination of cows prior to the development of this pathology in animals in training and experimental farms. Conclusion. Analyzing the etiological factors that determine the retention of the membranes in cows of educational and experimental farms, it can be concluded that the development of this pathology of the birth period in cows is in close connection with the state of the fodder base in farms and with the presence of helminth infestation in animals. A regularity was revealed between the presence of traumatic foreign objects in the cows’ net, causing traumatic reticulitis, and the subsequent occurrence of chronic placentitis in them, leading to the retention of the membranes.