Calf Diarrhea Research Articles

Health-associated changes of the fecal microbiota in dairy heifer calves during the pre-weaning period.

Neonatal calf diarrhea is a multifactorial condition that occurs in early life when calves are particularly susceptible to enteric infection and dysbiosis of the gut microbiome. Good calf health is dependent on successful passive transfer of immunity from the dam through colostrum. There are limited studies on the developing gut microbiota from birth to weaning in calves. Therefore, the objective of this study was to examine the effect of immune status and diarrheal incidence on the development of the fecal microbiota in Jersey (n = 22) and Holstein (n = 29) heifer calves throughout the pre-weaning period. Calves were hand-fed a colostrum volume equivalent to 8.5% of their birthweight, from either the calf's dam (n = 28) or re-heated mixed colostrum (≤2 cows, ≤1d; n = 23) within 2 h of birth. All calves were clinically assessed using a modified Wisconsin-Madison calf health scoring system and rectal temperature at day (d) 0, d7, d21, or disease manifestation (DM) and weaning (d83). Weights were recorded at d0, d21, and d83. Calf blood samples were collected at d7 for the determination of calf serum IgG (sIgG). Fecal samples were obtained at d7, d21/DM [mean d22 (SE 0.70)], and at weaning for 16S rRNA amplicon sequencing of the fecal microbiota. Data were processed in R using DADA2; taxonomy was assigned using the SILVA database and further analyzed using Phyloseq and MaAsLin 2. Significant amplicon sequence variants (ASVs) and calf performance data underwent a Spearman rank-order correlation test. There was no effect (p > 0.05) of colostrum source or calf breed on serum total protein. An effect of calf breed (p < 0.05) was observed on sIgG concentrations such that Holstein calves had 6.49 (SE 2.99) mg/ml higher sIgG than Jersey calves. Colostrum source and calf breed had no effect (p > 0.05) on health status or the alpha diversity of the fecal microbiota. There was a relationship between health status and time interaction (p < 0.001), whereby alpha diversity increased with time; however, diarrheic calves had reduced microbial diversity at DM. No difference (p > 0.05) in beta diversity of the microbiota was detected at d7 or d83. At the genus level, 33 ASVs were associated (adj.p < 0.05) with health status over the pre-weaning period.

A Novel Multiepitope Fusion Antigen as a Vaccine Candidate for the Prevention of Enterotoxigenic E. coli-Induced Calf Diarrhea.

Calf diarrhea caused by enterotoxigenic E. coli (ETEC) poses an enormous economic challenge in the cattle industry. Fimbriae and enterotoxin are crucial virulence factors and vaccine targets of ETEC. Since these proteins have complicated components with large molecular masses, the development of vaccines by directly expressing these potential targets is cumbersome Therefore, this study aimed to develop a multiepitope fusion antigen designated as MEFA by integrating major epitopes of FanC and Fim41a subunits and a toxoid epitope of STa into the F17G framework. The 3D modeling predicted that the MEFA protein displayed the epitopes from these four antigens on its surface, demonstrating the desired structural characteristics. Then, the MEFA protein was subsequently expressed and purified for mouse immunization. Following that, our homemade ELISA showed that the mouse antiserum had a consistent increase in polyclonal antibody levels with the highest titer of 1:217 to MEFA. Furthermore, the western blot assay demonstrated that this anti-MEFA serum could react with all four antigens. Further, this antiserum exhibited inhibition on ETEC adhesion to HCT-8 cells with inhibitory rates of 92.8%, 84.3%, and 87.9% against F17+, F5+, and F41+ ETEC strains, respectively. Additionally, the stimulatory effect of STa toxin on HCT-8 cells was decreased by approximately 75.3% by anti-MEFA serum. This study demonstrates that the MEFA protein would be an antigen candidate for novel subunit vaccines for preventing ETEC-induced diarrhea in cattle.

Use of Immunostimulators in the Prevention of Coronavirus Disease in Calves

Vaccination and passive immunization, disinfection and biosecurity, feeding and feeding, care, hygiene and immune status of animals are essential to prevent BCoV diseases, limit the use of antibacterial drugs and reduce the subsequent emergence of microbial resistance, improve the quality of animal products and animals. Multivalent vaccines are now available to limit the spread of the virus and achieve hyperimmune herd passive immunization in calves, which may protect or reduce the severity of BCoV diarrhea in calves. The importance of passive immunization is noted. An oral live vaccine has also been developed to prevent diarrhea in calves. Studies have also been conducted on the use of intranasal BCoV vaccination in calves against bovine respiratory disease and winter dysentery.

PREVALENCE OF ROTAVIRUS AND CORONAVIRUS ORIGIN DISEASES BY AGE GROUPS AMONG CALVES IN THE NORTH-WEST REGION OF AZERBAIJAN

The purpose of the study was to identify the prevalence of diarrhea caused by rotavirus and coronavirus in newborn calves located in the North-West region of the republic using rapid testing. The study was conducted among 45 heads of calves of local races and crosses in 20 farms of the Ismailli, Gabala, and Zagatala districts. In 14 heads of calves out of 45 calves (35.5%), pathogens were not identified, and in 31 heads of calves pathogens were identified in single or mixed cases. The identified pathogens among them were distributed as follows: rotavirus in 22 calves (48.9%), coronavirus in 3 calves (6.7%), in 8 calves – (Cryptosporodium parvum) 17.8%), in 5 calves – Giardia (11.1%) and another 5 calves had E. coli K99 (11.1%). The results of the study show that the causes of diarrhea in calves in the North-West region of the republic, among other pathogens, include rotavirus and coronavirus infections, and it is important that this be taken into account when carrying out treatment and preventive measures

Impact of Limosilactobacillus fermentum probiotic treatment on gut microbiota composition in sahiwal calves with rotavirus diarrhea: A 16S metagenomic analysis study”

BackgroundDiarrhea poses a major threat to bovine calves leading to mortality and economic losses. Among the causes of calf diarrhea, bovine rotavirus is a major etiological agent and may result in dysbiosis of gut microbiota. The current study was designed to investigate the effect of probiotic Limosilactobacillus fermentum (Accession No.OR504458) on the microbial composition of rotavirus-infected calves using 16S metagenomic analysis technique. Screening of rotavirus infection in calves below one month of age was done through clinical signs and Reverse Transcriptase PCR. The healthy calves (n = 10) were taken as control while the infected calves (n = 10) before treatment was designated as diarrheal group were treated with Probiotic for 5 days. All the calves were screened for the presence of rotavirus infection on each day and fecal scoring was done to assess the fecal consistency. Infected calves after treatment were designated as recovered group. Fecal samples from healthy, recovered and diarrheal (infected calves before sampling) were processed for DNA extraction while four samples from each group were processed for 16S metagenomic analysis using Illumina sequencing technique and analyzed via QIIME 2.ResultsThe results show that Firmicutes were more abundant in the healthy and recovered group than in the diarrheal group. At the same time Proteobacteria was higher in abundance in the diarrheal group. Order Oscillospirales dominated healthy and recovered calves and Enterobacterials dominated the diarrheal group. Alpha diversity indices show that diversity indices based on richness were higher in the healthy group and lower in the diarrheal group while a mixed pattern of clustering between diarrheal and recovered groups samples in PCA plots based on beta diversity indices was observed.ConclusionIt is concluded that probiotic Limosilactobacillus Fermentum N-30 ameliorate the dysbiosis caused by rotavirus diarrhea and may be used to prevent diarrhea in pre-weaned calves after further exploration.

Development and application of one-step multiplex Real-Time PCR for detection of three main pathogens associated with bovine neonatal diarrhea.

Neonatal calf diarrhea (NCD) is one of the most common diseases in calves, causing huge economic and productivity losses to the bovine industry worldwide. The main pathogens include bovine rotavirus (BRV), bovine coronavirus (BCoV), and Enterotoxigenic Escherichia coli (ETEC) K99. Since multiple infectious agents can be involved in calf diarrhea, detecting each causative agent by traditional methods is laborious and expensive. In this study, we developed a one-step multiplex Real-Time PCR assay to simultaneously detect BRV, BCoV, and E. coli K99+. The assay performance on field samples was evaluated on 1100 rectal swabs of diseased cattle with diarrhea symptoms and compared with the conventional gel-based RT-PCR assay detect BRV, BCoV, and E. coli K99+. The established assay could specifically detect the target pathogens without cross-reactivity with other pathogens. A single real-time PCR can detect ~1 copy/µL for each pathogen, and multiplex real-time PCR has a detection limit of 10 copies/µL. Reproducibility as measured by standard deviation and coefficient of variation were desirable. The triple real-time PCR method established in this study was compared with gel-based PT-PCR. Both methods are reasonably consistent, while the real-time PCR assay was more sensitive and could rapidly distinguish these three pathogens in one tube. Analysis of surveillance data showed that BRV and BCoV are major enteric viral pathogens accounting for calves' diarrhea in China. The established assay has excellent specificity and sensitivity and was suitable for clinical application. The robustness and high-throughput performance of the developed assay make it a powerful tool in diagnostic applications and calf diarrhea research. ​.

Evaluation of serum concentrations of total protein and gamma-globulin as an indicator of serum immunoglobulin G concentration in dairy calves

The aim of this study was to evaluate precision of estimating serum immunoglobulin G (IgG) concentration from total protein (TP) or gamma-globulin (γGLB) concentration as an alternative approach, and to compare morbidity of pre-weaned dairy calves differing in serum γGLB concentration. In trial 1, blood was sampled from 129 Holstein calves in the first week after birth, and serum concentrations of TP, γGLB, and IgG were measured. Spearman's correlation coefficient (rs) between serum IgG and TP concentrations was 0.89, and rs between serum IgG and γGLB concentrations was 0.96. Absolute residual (observed – predicted) serum IgG concentrations were smaller when estimated by serum γGLB concentration than by serum TP concentration, and differences in the absolute residuals were smaller for calves fed colostrum replacer (1.68 vs. 4.29 g/L) than those fed whole colostrum (2.41 vs. 3.48 g/L). In trial 2, blood was sampled from 740 Holstein heifer calves during the first week of age, and serum γGLB concentration was measured. The calves were divided into 4 categories based on their serum γGLB concentration; ≥ 1.0 g/dL (Excellent), 0.7 ≤ γGLB <1.0 g/dL (Good), 0.4 ≤ γGLB <0.7 g/dL (Fair) and <0.4 g/dL (Poor). Morbidity for diarrhea and respiratory disease in pre-weaned dairy calves was determined for the first 28 and 56 d of age, and compared among the 4 categories based on serum γGLB concentration. Calves with serum γGLB concentration higher than 0.7 g/dL (Good and Excellent) had less diarrhea during the first 28 d of age than those with lower serum γGLB concentration (Fair and Poor). Calves with serum γGLB concentration higher than 1.0 g/dL (Excellent) had less respiratory diseases for the first 56 d of age than those with lower serum γGLB concentration (Good, Fair, and Poor). These results suggest that serum IgG concentration can be estimated more precisely from concentration of γGLB than TP particularly for calves fed colostrum replacer, and that γGLB concentrations in the first week of age are associated with morbidity of calves. Transfer of passive immunity in dairy calves can be assessed effectively by serum γGLB concentration.

Comprehensive genetic analysis of the first near-complete genome of bovine coronavirus and partial genome of bovine rotavirus in Türkiye through metagenomics.

Obtaining the complete or near-complete genome sequence of pathogens is becoming increasingly crucial for epidemiology, virology, clinical science and practice. This study aimed to detect viruses and conduct genetic characterization of genomes using metagenomics in order to identify the viral agents responsible for a calf's diarrhoea. The findings showed that bovine coronavirus (BCoV) and bovine rotavirus (BRV) are the primary viral agents responsible for the calf's diarrhoea. The current study successfully obtained the first-ever near-complete genome sequence of a bovine coronavirus (BCoV) from Türkiye. The G+C content was 36.31% and the genetic analysis revealed that the Turkish BCoV strain is closely related to respiratory BCoV strains from France and Ireland, with high nucleotide sequence and amino acid identity and similarity. In the present study, analysis of the S protein of the Turkish BCoV strain revealed the presence of 13 amino acid insertions, one of which was found to be shared with the French respiratory BCoV. The study also identified a BRV strain through metagenomic analysis and detected multiple mutations within the structural and non-structural proteins of the BRV strain, suggesting that the BRV Kirikkale strain may serve as an ancestor for reassortants with interspecies transmission, especially involving rotaviruses that infect rabbits and giraffes.

Management of bacterial neonatal diarrhea in calves

Diseases such as neonatal diarrhea are common in poorly managed herds and can cause major losses in any cattle breeding system in the world, especially in intensive systems, accounting for 2% of herd losses. As soon as the calf is born, it is exposed to numerous factors, such as agents, the host and the environment, which together can favor the onset of this disease because, due to the reproductive characteristics of the female bovine, there is no transfer of transplacental immunity to the newborn.

Identification of major protozoal enteropathogens causing calf diarrhea in dairy farms in and around Holeta Town, Oromia Special Zone, Ethiopia

Calf diarrhea can be caused by a variety of pathogens, including bacteria, viruses, protozoa, and intestinal parasites. Giardia, Eimeria, and Cryptosporidium are the most significant protozoan parasites and are all individually and ollectively infectious. A case-series study was carried out in and around Holeta dairy farms, Oromia Special Zone, Ethiopia, from November 2017 to April 2018 to identify the main protozoan enteropathogens from diarrheic calves. Samples were purposely collected from three dairy farms: Serkalem Dairy Farm (SDF), Holeta Agricultural Research Centre (HARC), and Ada Berga Agricultural Research Centre (ABARC). A total of 93 fecal samples were taken from diarrheic calves of up to 4 months of age. Protozoan enteropathogens were identified using flotation and modified Ziehl Neelsen staining methods. Cryptosporidium, Eimeria, and Giardia were detected in 44 (47.3%), 50 (53.8%), and 34 (36.6%) of the diarrheic fecal samples examined, respectively. The findings indicated that there were 17 (18.27%) cases of Cryptosporidium, Eimeria, and Giardia as mixed infections, 16 (17.2%) cases of Cryptosporidium and Eimeria, 5 (5.4%) cases of Cryptosporidium and Giardia, and 4 (4.3%) cases of Eimeria and Giardia, compared to 13 (13.97%), 6 (6.45%), and 5 (5.4%) cases of Cryptosporidium, Eimeria and Giardia as single infections, respectively. The selected farms had significant prevalence levels of three common protozoa: Eimeria, Giardia, and Cryptosporidium. Further molecular research is required to identify the species and genotype levels of protozoal enteropathogens and related risk factors.

Association of passive immunity and genetic composition, health, and performance of tropical dairy calves

This retrospective cohort study aimed to identify risk factors for the failure of transfer of passive immunity (FPI) in preweaned dairy calves, explore its associations with morbidity, mortality, genetics, and determine a standardized cut-off point for FPI. Analyzing data from 6011 calves, factors such as sire predicted transmitted ability for milk (PTA), birth season, retained placenta (RP), total serum protein concentration (TSP), morbidity (neonatal calf diarrhea - NCD, bovine respiratory disease - BRD, tick-borne disease - TBD), mortality, and average daily weight gain (ADG) were considered. The calves were categorized into predominantly Gyr (PG) and predominantly Holstein (PH) genetic composition groups. Multivariate mixed logistic regression revealed optimal TSP cut-off points for predicting morbidity (7.6 g/dL) and mortality (6.9 g/dL). PH calves exhibited 1.35 times higher odds of FPI and 1.48 times greater odds of disease. Calves from multiparous cows and those born to dams with RP had increased FPI odds. Disease prevalence was 53%, with 41% NCD, 18% BRD, and 10% TBD. Season, parity, PTA, and birth weight were associated with disease odds, though FPI was not a reliable predictor. The mortality percentage was 6%, with PH calves and those with a positive PTA having higher odds. The ADG was 0.64 kg, and FPI-affected calves gained less weight. The study compared and identified various risk factors that potentially impact calf immunity. However, the use of a standardized cut-off point for FPI assessment was not effective in predicting morbidity and mortality at this specific farm.

Bovine neonatal enteric immunity: a key consideration in the prevention of calf diarrhoea

The mucosa is the largest component of the immune system, providing a first line of defence against most pathogens encountered. Although the mucosa is located in all areas where there are mucosal surfaces (such as the respiratory and urogenital tracts), the clinical importance of diarrhoea in calf veterinary practice means the gastrointestinal mucosa is of particular interest. Taking steps to promote good health of the gastrointestinal mucosa can enhance gastrointestinal mucosal immunity and aid prevention of calf diarrhoea, the leading cause of mortality and morbidity in calves under 1 month old.

140 High-resolution characterization of the gut microbiota of neonatal dairy calves using full-length 16S rRNA gene amplicon sequencing

Abstract The gut microbiota has a crucial role in preventing pathogen colonization and training the immune system. An imbalanced gut microbiota tends to induce calf diarrhea, which can lead to dehydration and metabolic acidosis. Therefore, it is urgent to identify critical factors that influence the establishment of gut microbiota in the early stages of development in dairy calves. Most previous research relied on short-read-based partial 16S rRNA gene amplicon sequencing to study calf microbiota, which has limited taxonomic resolution. The aim of our study is to obtain a species-level characterization of calf gut microbiota using long-read based full-length 16S rRNA gene amplicon sequencing and investigate the factors that affect the gut microbiota composition in the early stages of development in dairy calves. We collected fecal samples from the recto-anal junction of 25 Holstein-Angus crossed calves at d 4 and d 14 after birth. The calves were raised in individual outdoor hutches from birth and fed milk replacer twice daily. The gut microbiota was analyzed using full-length 16S rRNA gene amplicon sequencing on an Oxford Nanopore sequencer. The results revealed that the gut microbial diversity measured by Chao 1 (P &amp;lt; 0.001) and Shannon index (P &amp;lt; 0.001) significantly increased from d 4 to d 14. We identified 15 and 36 core bacterial species (prevalence ≥ 80%) in d 4 and d 14 gut microbiota, respectively, and both stages share 7 bacterial species: Bacteroides fragilis, Butyricicoccus pulicaecorum, Enterocloster bolteae, Escherichia coli, Lachnoclostridium sp YL32, Rumiococcus gnavus and Streptococcus equinus. The calf gut microbiota was dominated by Bacteroides fragilis (18%), Escherichia coli (13%), Ruminococcus gnavus (10%) and Butyricicoccus pulicaecorum (6%) species on d 4, and Megamonas rupellensis (18%) and Fusobacterium varium (6%) species (relative abundance &amp;gt; 5%) on d 14. Notably, we found a significant impact of hutch location on the composition of gut microbiota, particularly on d 4, but the impact was reduced on d 14. Moreover, there were 4 dystocia calves among the 25 calves, which had a significantly lower Shannon index (P = 0.046) compared with 4 paired normal calves of similar age and sex, and location balanced. In conclusion, this study provides a species-level resolution of gut microbiota for neonatal dairy calves and indicates a potential impact of dystocia on early microbiota development. Additionally, calf microbiota composition is influenced by environmental factors, likely the soil microbiota where hutches were located, with a more substantial effect on the microbiota at an earlier age.

The first complete genome sequence and genetic evolution analysis of bovine norovirus in Xinjiang, China

Abstract Introduction Viruses are among the main pathogens causing diarrhoea in calves. The current study found that bovine norovirus (BNoV) is one of the principal viruses causing diarrhoea in calves in Xinjiang, China. Material and Methods A total of 974 calf faecal samples from six regions in Xinjiang were tested for BNoV using reverse-transcriptase PCR. The genomic characteristics of BNoV and the genetic evolution of the VP1 gene, protein three-dimensional structure characteristics and amino acid variation were analysed using bioinformatics methods. Results Epidemiological survey results showed that the infection rate of BNoV was 19.82%, and all samples tested positive in five regions. The results of the genetic evolution analysis showed that BNoV strains from Tacheng of northern Xinjiang and Kashgar of southern Xinjiang both belonged to the GIII.2 genotype of BNoV but were not on the same cluster of evolutionary branches. Additionally, the amino acid variation of the VP1 protein was not observed to significantly affect its spatial structure. Conclusion This study is the first to report the genetic characteristics of the BNoV complete genome sequence in Xinjiang and provides a scientific basis for BNoV vaccine development and pathogenesis research.

Enterobacteria Isolated From Diarrheic Calves and their Phenotypic Resistance Pattern

Abstract Diarrhea is a prevalent and economically impactful ailment in cattle herds, resulting in substantial losses attributed to mortality, treatment expenses, and impaired calf growth. The aim of this study was to establish data about the occurrence of the main bacterial agents involved in diarrhea in dairy calves in the state of Maranhão, as well as to determine the most effective and/or resistant antibiotics, establishing a foundation for treatment and prevention protocols. The samples were collected with rectal swabs and initially cultivated on sheep blood agar (5%) and MacConkey agar and later on Salmonella-Shigella agar and eosin-methylene blue agar. Gram staining, biochemical tests, and antibiograms were performed on the obtained colonies. Ten municipalities were studied, with 230 calves evaluated from ten dairy farms. A total of 21 animals exhibited clinical signs of diarrhea, representing a frequency of 9.13%. The frequency of positive farms was 35%, and in 50% of municipalities. Bacteria isolated belonged to the Enterobacteriaceae family, with 71.4% Escherichia coli, 14.3% Enterobacter sp., 9.5% Proteus sp. and 4.8% Klebsiella sp. On the antibiogram, the bacteria that showed the highest resistance levels were those of the Proteus genus, followed by Enterobacter sp. and E. coli. The bacteria found are relevant for both animal and human health due to their zoonotic potential and serve as a public health alert since the isolates in this study showed in vitro resistance to several antibiotics, which predisposes them to the emergence of multidrug-resistant bacteria.

The first commercially approved efficacious cryptosporidium vaccine protecting New-Born calves from severe diarrhea

Neonatal calf diarrhea (NCD) is an important cause of morbidity and mortality in calves. Four major pathogens, including Enterotoxigenic Escherichia coli (ETEC), bovine rotavirus (BRV), bovine coronavirus (BCV), and Cryptosporidium spp., are associated with NCD, with Cryptosporidium parvum (C. parvum) recognized as a major contributor. Despite various treatment options available, there is no effective vaccine for bovine cryptosporidiosis yet. In this study, recombinantly expressed C. parvum gp40 was evaluated as a candidate vaccine in pregnant animals. The vaccine was administered to pregnant cows during the last trimester of their pregnancy resulting in highly statistically significantly increased anti-gp40 antibody titers. The resulting anti-gp40 antibodies were transmitted to the calves via colostrum. Both suckling (n = 29; test:14, control:15) and non-suckling (n = 16; 8 per group) calves were challenged with live C. parvum oocysts. The calves that received the colostrum from gp40 vaccinated cows showed a highly statistically significant improvement in health (p < 0.0001), reduced incidence (p < 0.0001), and duration of severe diarrhea (p < 0.001) and increased weight gain in suckling calves (p < 0.0001). This study demonstrates that immune bovine colostrum, induced by immunization of late-gestation cows with C. parvum gp40, provided substantial protection to calves against cryptosporidiosis. These findings suggest that the gp40 vaccine has potential for preventing outbreaks of neonatal diarrhea associated with cryptosporidiosis in calves, thereby improving animal welfare and performance.

Neonatal Calf Diarrhea and Gastrointestinal Microbiota: Etiologic Agents and Microbiota Manipulation for Treatment and Prevention of Diarrhea.

Neonatal calf diarrhea is the leading cause of neonatal morbidity and mortality globally. The changes associated with the gastrointestinal microbiota in neonatal calves experiencing diarrhea and its etiology are not fully understood or completely defined in the literature. Several studies have demonstrated that the fecal microbiota of calves that experience diarrhea substantially deviates from that of healthy age-matched calves. However, one key question remains: whether the changes observed in the bacterial communities (also known as dysbiosis) are a predisposing factor for, or the consequence of, gastrointestinal inflammation caused by the pathogens associated with calf diarrhea. The first objective of this literature review is to present the current information regarding the changes in the fecal microbiota of diarrheic calves and the impact of the pathogens associated with diarrhea on fecal microbiota. Modulation of the gastrointestinal microbiota using pre- and probiotics, colostrum feeding, and fecal microbiota transplantation (FMT) has been used to treat and prevent gastrointestinal diseases in humans and dogs. Although information regarding the use of probiotics for the prevention of diarrhea is available in cattle, little information is available regarding the use of these strategies for treating calf diarrhea and the use of prebiotics or FMT to prevent diarrhea. The second objective of this literature review is to summarize the current knowledge regarding the impact of prebiotics, probiotics, synbiotics, colostrum feeding, and FMT for the treatment and prevention of calf diarrhea.

Exploring genetic polymorphisms and transcript levels of antioxidant and metabolic markers for prediction and monitoring diarrhea in Holstein dairy calves

ABSTRACT The objective of this study was to investigate the genetic polymorphisms and transcript levels of antioxidant and metabolic markers for diarrhea monitoring in Holstein dairy calves. For DNA and RNA extraction, blood samples were taken from 100 female calves (50 with diarrhea and 50 appearing healthy). DNA sequencing and real time PCR for and metabolic genes were performed to identify genetic variants linked to diarrhea susceptibility. Results revealed that there were nucleotide sequence variations in the investigated genes between healthy and diarrheal calves. Keap1, HMOX1, CMPK2, ASPG, FPGT, TNNI3 K, and LPCAT1 were considerably more highly expressed in diarrheic calves than resistant ones. The Nrf2, PRDX2, and PRDX6 genes, however, produced a different pattern. This study provides a practical control strategy to lessen newborn diarrhea in Holstein dairy calves and emphasizes the significance of nucleotide variations along with antioxidant and metabolic gene expression patterns as proxy markers of diarrhea susceptibility/resistance.

Differential Microbial Composition and Interkingdom Interactions in the Intestinal Microbiota of Holstein and German Simmental × Holstein Cross F1 Calves: A Comprehensive Analysis of Bacterial and Fungal Diversity.

Calf intestines are colonized by rich and complex microbial communities, playing a crucial role in animal physiology, metabolism, nutrition, and immune function. In this study, we provide insight into the composition of fecal microbial bacteria and fungi, respectively, as well as the cross-kingdom interactions. We investigated the intestinal microbiota of different breeds of calves by characterizing the bacterial and fungal communities in the rectal feces of Holstein calves and German Simmental × Holstein cross F1 generation (GXH) using 16S rRNA and ITS amplicon sequencing techniques. PICRUSt2 (version 2.2.0) were used to determine microbial diversity and function and explore the reasons why Holstein calves are more susceptible to diarrhea. The results revealed no significant difference in the diversity of fecal microbiota among the groups (p > 0.05). We identified Firmicutes, Bacteroidetes, and Proteobacteria as the dominant bacterial phyla in the fecal bacterial communities of the two breeds of calves. Ascomycota and Basidiomycota play important roles in the fungal community but differ in relative abundance. Bacteroides was the dominant genus at the group level for calf fecal microbiota in both breeds. The relative abundance of Prevotella, Escherichia-Shigella, Peptostreptococcus, and Butyricicoccus was higher in Holstein calves, and the relative abundance of Faecalibacterium, Megamonas, Butyricicoccus, and Alloprevotella was lower than GXH group. Aspergillus and Cladosporium were the dominating genera of fecal fungi in both groups of calves. LEfSe analysis revealed 33 different bacteria and 23 different fungi between the two groups, with more differential strains found in GXH. In addition, the feces fungi-bacteria interkingdom interactions varied among breeds. Thus, the composition and structure of bacterial and fungal communities in calf feces varied by breed, indicating a potential association between breed and microbial communities. We also found differences in the network between bacterial-fungal kingdoms. We explain the reasons for Holstein calves being more prone to diarrhea. This indicated that breed makes differences in calf diarrhea rates by influencing gut microbial composition and interactions.

Sodium acetate and sodium butyrate attenuate diarrhea in yak calves by regulating gut microbiota and metabolites

Diarrhea is a severe issue in calves that causes fertility problems and economic issues worldwide. Sodium acetate/sodium butyrate (SA/SB) alleviates diarrhea in mice; however, little information is available about the preventive effect of SA/SB on diarrheic yak calves living on the Tibet plateau. Yak calves (n = 19) of age ≥4 months and weight 37 ± 2 Kg were randomly divided into control (C, n = 10) and supplement groups (S, n = 9). Yaks belonging to the supplement group were given sodium butyrate (10 g/kg) and sodium acetate (5 g/kg) for 28 days, along with normal feed, seasonal grasses, pasture, and water. The blood and fecal samples from yak calves were collected for assessment of antioxidant capacity, inflammatory cytokines, microbiome, and short-chain fatty acids (SCFAs) concentration analysis. Results of this study revealed that a lower diarrhea rate, higher weight, and net weight gain were recorded in yaks belonging to group S supplemented with SA/SB. Similarly, increased antioxidant capacity with higher levels of T-AOC, SOD, and GSH-px and decreased inflammatory reactions by decreasing both TNF-α and IL-1β concentrations were recorded in yaks of group S. The concentration of SCFAs was significantly higher (p < 0.05) in yaks from group S than group C. Microbiome analysis revealed that 8 phyla and 54 genera were significantly different (p < 0.05) in both yak groups, with increased probiotics (Akkermansia, Oscillospira), SCFAs producing genera (Oscillospira, ASF356, Anaerosporobacter and Phascolarctobacterium), and decreased inflammatory related genus (Flavonifractor, Fournierella) and harmful bacteria (Oscillibacter, Achromobacter) in group S. In conclusion, the results demonstrated that SA and SB could decrease diarrhea rates in yak calves on the plateau via increasing antioxidant ability and SCFAs, while decreasing inflammatory responses in yaks by moderating gut microbiota. The current results provide new insights for the prevention and treatment of diarrhea in yaks.