Cause Of Death In Calves Research Articles

WITHDRAWN: First report of Toxocara vitulorum infection in a dairy calf in Tennessee

The ascarid nematode, Toxocara vitulorum is a destructive parasite of ruminants with a world-wide distribution that causes mortality in calves, especially those with poor nutrition. Reports of Toxocara vitulorum are scarce in the continental United States and Canada. A single gravid female T. vitulorum was discovered on the necropsy of a 2.5-month-old mini jersey calf from a dairy farm in Sparta, TN. Genetic analysis of the 18S and COI genes revealed a 100 % match to T. vitulorum samples isolated from beef calves in Iowa and a 96.73 % match to T. vitulorum isolated from a yak in Austria, respectively. Although perforation of the small intestine was seen in the calf and is the typical cause of death in calves with high burdens of this worm, it is unknown if this single nematode infection contributed to the cause of death in this case. The source of the infection in this calf also remains unknown. Fecal centrifugal flotations on the rest of the herd (n = 8) did not produce any T. vitulorum eggs, even in the 2 calves that were under 6 months old on the farm. We were unable to obtain milk to test for T. vitulorum larvae from the calf's mother. This is the first report of T. vitulorum in dairy calves in the US and the first report of this parasite in Tennessee. Given the devastation caused by this parasite in cattle and bison herds in other countries, further studies to determine the prevalence and pathogenicity of this parasite in the US are vital to prevent spread of this parasite to other vulnerable species and to prevent economic losses in the animal industry.

Detection of calf abnormal respiratory behavior based on frame difference and improved YOLOv5 method

Bovine respiratory disease (BRD) is the leading cause of death in calves. Abnormal respiratory behavior (ARB) is one of the prevalent clinical signs of BRD in calves, manifesting as tachypnea and visible chest and abdominal respiration. This paper proposed a calf ARB detection method based on frame difference (FD) and improved YOLOv5 to increase detection efficiency and achieve automatic detection. A total of 1400 video segments, each lasting about 30 s, were collected from 10 calves with ARB and 40 with normal respiratory behavior (NRB). First, a squeeze-and-excitation (SE) model was added to the YOLOv5 network to realize key feature extraction of the calf head and trunk. Next, the model was trained and tested using 5520 images obtained after You Only Cut Once (YOCO) image enhancement. Next, FD was used to obtain the shaking pixels and determine the proportion of trunk shake (PTS) for each frame of the calf image. Then, 1250 video segments were divided into 3 s video units. Finally, 2500 ARB and 2500 NRB 3 s video units were manually selected for the calf ARB detection set. The maximum, minimum, mean, variance and standard deviation of PTS within each 3 s video unit were extracted as feature values and input to support vector machine (SVM). The results showed that the improved YOLOv5 network achieved high mAP50 of 98.2% and mAP50:95of 92.6%, which was 0.9% and 2.3% higher than the baseline YOLOv5. Meanwhile, ARB could be detected with an accuracy of 96.80%, a sensitivity of 95.20%, a specificity of 98.40%, and a precision of 98.35% after 5-fold cross-validation. The results indicated that the proposed method could effectively detect calf trunk and head and be used for calf ARB detection, providing a technical reference for calf ARB detection.

Ultrasonographic diagnosis of clinical and subclinical bovine respiratory disease in Holstein calves.

Background and Aim:Bovine respiratory disease (BRD) is the main cause of death in calves, and early BRD diagnosis saves lives. This study aimed to diagnose clinical and subclinical BRD in calves by assessing some biochemical alterations and ultrasonography (USG).Materials and Methods:Fifty-four Holstein dairy calves in Al-Sharqiyah Province, Egypt, were used in the study. They were divided into three groups. The first control group consisted of 10 clinically healthy calves. The second group consisted of 34 calves suffering from clinical lower respiratory tract disorders. The third group consisted of 10 subclinical BRD-affected calves. Ultrasonographic examinations of chest and thoracic ultrasound scoring were performed once per 2 weeks for each calf. Blood samples were collected for serum separation to measure albumin (ALB), total protein (TP), ALB, globulin, and haptoglobin (HP).Results:The USG revealed small consolidation areas within an aerated lung lobe, a hypoechoic parenchyma of the entire distal lung lobe, and a hypoechoic-circumscribed structure surrounded by an echogenic wall appeared within the lung tissue in calves that suffered from lobular pneumonia, lobar pneumonia, and lung abscess, respectively. However, subclinical cases showed a small consolidation area in the cranial aspects of the right cranial lung lobe. The ultrasound lung score (ULS) was greater in clinical than in subclinical cases. The BRD-affected calves recorded significant increases in serum TP, globulin, and HP. Meanwhile, serum ALB decreased significantly.Conclusion:Thoracic ultrasound had a reliable tool in the BRD diagnosis, especially in the early prediction of subclinical cases in newborn calves. In addition, the ULS appeared to be a better classifier than the clinical respiratory score (CRS) for BRD diagnosis. On the other side, it was found that regression models were very useful in assessing the prediction of biochemical blood parameters based on the ULS and CRS in diseased cases.

Effects of Pathogenic Escherichia coli Infection on the Flora Composition, Function, and Content of Short-Chain Fatty Acids in Calf Feces.

Simple SummaryCalf diarrhea caused by bacteria usually begins to occur 2–3 d after birth. The main pathogenic bacteria are Escherichia coli, Campylobacter, Salmonella, and Clostridium perfringens. Pathogenic E. coli is the main bacterium that causes diarrhea in calves. It invades the body of calves and releases enteric toxins that cause diarrhea. The incidence of calf diarrhea caused by pathogenic E. coli O1 can reach 60–70%, even as high as 90–100% in large-scale calf farms, and the mortality rate can reach over 50%. Therefore, the prevention and treatment of calf diarrhea are extremely important. We established a calf diarrhea model by artificially intervening in the colonization of intestinal microbial flora and studied the influence of pathogenic E. coli on the composition, function, and short-chain fatty acid content of calf feces. Our research shows that pathogenic E. coli O1 can significantly reduce the abundance and diversity of calf intestinal microflora, increase harmful bacteria, reduce the colonization of beneficial bacteria, and reduce the short-chain fatty acid content in feces.Calf diarrhea caused by pathogenic Escherichia coli is a major cause of death in calves, with a mortality rate of over 50%. It is crucial to understand the pathogenesis and development of calf diarrhea for its prevention and treatment. We aimed to study the effect of pathogenic E. coli on the flora composition, function, and short-chain fatty acid (SCFA) content of calf feces using a calf diarrhea model. Sixty-four newborn Holstein calves (40–43 kg) were divided into a normal group (NG; n = 32) and a test group (TG; n = 32). At the beginning of the experiment, the TG were orally administered pathogenic E. coli O1 (2.5 × 1011 CFU/mL, 100 mL) to establish a calf diarrhea model, and the NG were orally administered the same amount of physiological saline solution. The calves of the two groups were subjected to the same feeding and management. Fresh feces samples were collected at different time points and subjected to 16S rRNA high-throughput sequencing and gas chromatography–mass spectrometry to determine the fecal microbial composition and SCFA content. Pathogenic E. coli O1 significantly altered microbiotas composition in the feces of calves, increasing the relative abundance of Proteobacteria and decreasing that of Firmicutes. It also led to a significant increase in the relative abundance of Escherichia-Shigella and a decrease in Lactobacillus, as well as significantly decreased SCFA content. Therefore, we postulate that pathogenic E. coli induces calf diarrhea by causing intestinal florae imbalance and reducing the content of SCFA.

Direct evidence of the preventive effect of milk replacer–based probiotic feeding in calves against severe diarrhea

Diarrhea is a major cause of death in calves and this is linked directly to economic loss in the cattle industry. Fermented milk replacer (FMR) has been used widely in clinical settings for calf feeding to improve its health and growth. However, the protective efficacy of FMR on calf diarrhea remains unclear. In this study, we verified the preventive effects of FMR feeding on calf diarrhea using an experimental infection model of bovine rotavirus (BRV) in newborn calves and a field study in dairy farms with calf diarrhea. In addition, we evaluated the protective efficacy of lactic acid bacteria-supplemented milk replacer (LAB-MR) in an experimental infection model. In the experimental infection, calves fed FMR or high-concentrated LAB-MR had diarrhea, but the water content of feces was lower and more stable than that of calves fed normal milk replacer. The amount of milk intake also decreased temporarily, but recovered immediately in the FMR– and LAB-MR–fed calves. As compared with the control calves, FMR– or LAB-MR–fed calves showed less severe or reduced histopathological lesions of enteritis in the intestinal mucosa. In a field study using dairy calves, FMR feeding significantly reduced the incidence of enteritis, mortality from enteritis, duration of a series of treatment for enteritis, number of consultations, and cost of medical care for the disease. These results suggest that feeding milk replacer–based probiotics to calves reduces the severity of diarrhea and tissue damage to the intestinal tract caused by BRV infection and provides significant clinical benefits to the prevention and treatment of calf diarrhea.

36 Preweaning causes of morbidity and mortality

Abstract Prior to weaning, beef calves are susceptible to a variety of traumatic, infectious, parasitic, nutritional, and metabolic diseases. Calves less than three weeks of age are particularly vulnerable to weather-related factors that may induce hypo- or hyperthermia, predation and other forms of physical injury, and metabolic diseases often related to starvation. The most common infectious cause of death in calves less than three weeks of age is diarrhea due to a variety of viral, bacterial, and protozoal infections. The leading cause of death in calves from 3 weeks of age to weaning is pneumonia, although parasitism and nutritional deficiencies are common causes of impaired productivity at that age. Both neonatal calf diarrhea and calf pneumonia can be explained in part by age-related susceptibility due to loss, or failure to acquire, maternal immunity from colostrum. The waning of passively-acquired maternal immunity, in the gut in the case of neonatal calf diarrhea, or systemically in the case of pneumonia, prior to the onset of a strong acquired immunity creates an age-related window of susceptibility for these two important infectious diseases of calves prior to weaning. Most pathogens associated with diarrhea or pneumonia are endemic to most cattle herds. The adult cow herd serves as the reservoir of these agents from one year to the next. Between birth and weaning, pathogens are primarily transmitted between calves by direct contact or through contaminated environmental surfaces. The incidence of both neonatal calf diarrhea and calf pneumonia are affected by population dynamics that create opportunities for effective contacts. The system of management either creates or averts the relative opportunities for all forms of calf-hood diseases, and the design of beef cattle production systems that favor disease prevention remains an important scientific endeavor.

Blackleg (Clostridium chauvoei infection) in beef calves

Blackleg (Clostridium chauvoei infection) has long been recognized as a cause of death in calves grazing summer pastures. Clinical signs are not often observed in affected calves due to the peracute nature of the disease, but may include fever, lameness, and swelling and crepitation over large muscle groups, followed by collapse and death. Typical gross and histopathologic lesions in these muscle groups are well-described and include gelatinous, gassy subcutaneous changes, along with well-defined muscle necrosis. Areas of necrosis can also be present in myocardium, diaphragm, and tongue, among other sites. Primary gross lesions consisted of pleuritis and pericarditis in animals examined in this report. More typical blackleg lesions were found in some but not all calves, including necrosis in thigh and abdominal muscles, dark discoloration of diaphragm muscle, and histologic evidence of necrotic myocarditis. Practitioners finding these lesions in animals found dead on pasture should consider C. chauvoei infection as the diagnosis regardless of whether muscle necrosis lesions are present.

Comparison Between Intraperitoneal and Intravenous Fluid Administration in Moderately Dehydrated Calves on a California Calf Ranch

Several California calf ranches have utilized intraperitoneal (IP) administration of electrolyte solutions to dehydrated calves with favorable clinical response in most patients. Calf ranch records were inadequate, however, to evaluate medium and long term effects of IP treatment, and comparison with IV administration was not made. Objectives of this study were to: 1) compare weight gain to 28 days post-treatment, 2) compare rates of survival to 60 days post-treatment, 3) evaluate pathologic changes to peritoneal surfaces and 4) determine primary cause of death in calves treated with fluids administered by IV or IP routes.
 Fifty-five male, Holstein calves, 1 to 16 days of age were used in this trial. Study calves were randomly assigned to treatment with a commercial electrolyte solution by the intravenous route (IV, N=27) or the intraperitoneal (IP, N=28) route of administration. Calves were weighed on day 28 posttreatment and monitored daily for 60 days after treatment. All study calves that died during this period were submitted for a complete post-mortem evaluation.
 Weight increase at 28 days post-treatment was .9 kg greater in the IV group, and four more IV treated calves survived to 60 days post-treatment as compared to IP treated calves. Statistical analysis of weight gains and survival rate showed no difference between treatments. Gross and histopathologic changes to the peritoneum at necropsy were similar between IV and IP treated calves. Some differences in the primary cause of death were noted between groups.
 In conclusion, this study showed no significant differences in weight gain to 28 days post-treatment, in survival to 60 days post-treatment, and in changes to the peritoneum in calves treated with fluids by either intravenous or intraperitoneal routes.

Sudden death of calves by experimental infection with Strongyloides papillosus. IV. Electrocardiographic and pneumographic observations at critical moments of the disease

Electrocardiographic and pneumographic observations at critical moments were carried out on five calves that died suddenly following experimental infections with Strongyloides papillosus. Time which elapsed during these critical moments was calculated from the time of observation of ventricular flutter (VF) to the appearance of accelerated respiration and cessation of respiration. The beginning of accelerated respiration ranged from −19 to 41 s after VF. Time (minutes:seconds) of cessation of respiration ranged from 2:10 to 3:50 after VF. The results of the experiment suggested sudden cardiac death as the cause of death in calves following infection with Strongyloides papillosus.