First detection of Cupriavidus gilardii in a bovine neonatal diarrhea outbreak.

BACKGROUND: Cupriavidus gilardii is an aerobic, gram-negative, motile, glucose-nonfermenting bacillus, first described in 1999. Typically, it exhibits low pathogenicity in humans, causing opportunistic infections primarily in individuals with compromised immune systems. This bacterium has been also found in various environmental sources such as plants and contaminated soils. Notably, there have been no documented cases of C. gilardii infections in animals. CASE PRESENTATION: This case report outlines a bovine neonatal diarrhea outbreak that occurred in Northern Greece, during which C. gilardii was isolated. Faecal samples from 5-day-old calves were collected and transported to the laboratory for further examination. Bacterial culture and next generation sequencing techniques were employed to confirm the presence of this bacterium in the samples. Following the isolation and identification of C. gilardii from the samples, an autogenous vaccine was produced and administered to the cows within the farm. Subsequent to vaccination, a progressive reduction in calf diarrhea and deaths was observed, leading to their eventual complete resolution. To the best of our knowledge, this represents the first documentation of C. gilardii isolation from cases of bovine neonatal diarrhea. CONCLUSION: This case report presents the first isolation case of C. gilardii from animal samples and more specifically from calf faecal samples. It represents an important observation, providing evidence that this opportunistic human pathogen could contribute to clinical symptoms in animals.

Detection and molecular characterization of major enteric pathogens in calves in central Ethiopia.

BACKGROUND: Calf diarrhea is a major cause of morbidity and mortality in the livestock sector worldwide and it can be caused by multiple infectious agents. In Ethiopia, cattle are the most economically important species within the livestock sector, but at the same time the young animals suffer from high rates of morbidity and mortality due to calf diarrhea. However, studies including both screening and molecular characterization of bovine enteric pathogens are lacking. Therefore, we aimed to both detect and molecularly characterize four of the major enteric pathogens in calf diarrhea, Enterotoxigenic Escherichia coli (E. coli K99 +), Cryptosporidium spp., rotavirus A (RVA), and bovine coronavirus (BCoV) in calves from central Ethiopia. Diarrheic and non-diarrheic calves were included in the study and fecal samples were analyzed with antigen-ELISA and quantitative real-time PCR (qPCR). Positive samples were further characterized by genotyping PCRs. RESULTS: All four pathogens were detected in both diarrheic and non-diarrheic calves using qPCR and further characterization showed the presence of three Cryptosporidium species, C. andersoni, C. bovis and C. ryanae. Furthermore, genotyping of RVA-positive samples found a common bovine genotype G10P[11], as well as a more unusual G-type, G24. To our knowledge this is the first detection of the G24 RVA genotype in Ethiopia as well as in Africa. Lastly, investigation of the spike gene revealed two distinct BCoV strains, one classical BCoV strain and one bovine-like CoV strain. CONCLUSIONS: Our results show that Cryptosporidium spp., E. coli K99 + , RVA and BCoV circulate in calves from central Ethiopia. Furthermore, our findings of the rare RVA G-type G24 and a bovine-like CoV demonstrates the importance of genetic characterization.

Determining lactate concentrations in Korean indigenous calves and evaluating its role as a predictor for acidemia in calf diarrhea.

BACKGROUND: Calf diarrhea leads to high mortality rates and decreases in growth and productivity, causing negative effects on the livestock industry. Lactate is closely associated with metabolic acidosis in diarrheic calves. However, there have been no reports on lactate concentrations in Korean indigenous (Hanwoo) calves, especially those with diarrhea. This study aimed to determine the reference range of L-lactate and D-lactate concentrations in Hanwoo calves and to better understand the utility of lactate as predictive factors for acidemia in diarrheic calves. RESULTS: L-lactate and D-lactate concentrations were measured in healthy (n = 44) and diarrheic (n = 93) calves, and blood gas analysis was performed on diarrheic calves. The reference range in healthy calves was 0.2-2.25 mmol/L for L-lactate and 0.42-1.38 mmol/L for D-lactate. Diarrheic calves had higher concentrations of L-lactate and D-lactate than healthy calves. In diarrheic calves, L-lactate and D-lactate each had weak negative correlation with pH (r = - 0.31 and r = - 0.35). In diarrheic calves with hyper-L-lactatemia, the combined concentrations of L-lactate and D-lactate had moderate correlation with pH (r = - 0.51) and anion gap (r = 0.55). Receiver operating characteristic analysis showed D-lactate had fair predictive performance (AUC = 0.74) for severe acidemia, with an optimal cut-off value of > 1.43 mmol/L. The combined concentrations of L-lactate and D-lactate showed fair predictive performance for predicting acidemia (AUC = 0.74) and severe acidemia (AUC = 0.72), with cut-off values of > 6.05 mmol/L and > 5.95 mmol/L. CONCLUSIONS: The determined reference ranges for L-lactate and D-lactate in Hanwoo calves enable the identification of hyper-L-lactatemia and hyper-D-lactatemia. Diarrheic calves exhibited increased lactate concentrations correlated with acid-base parameters. While the concentrations of L-lactate and D-lactate have limitations as single diagnostic biomarkers for predicting acidemia or severe acidemia, their measurement remains important, and L-lactate has the advantage of being measurable at the point-of-care. Assessing lactate concentrations should be considered by clinicians, especially when used alongside other clinical indicators and diagnostic tests. This approach can improve calf diarrhea management, contributing positively to animal welfare and providing economic benefits to farms.

Dynamics of oxidative stress and immune responses in neonatal calves during diarrhea.

Oxidative stress is the imbalanced redox status between oxidant production and their scavengers leading to intestinal physiological dysfunction. However, the role of systemic and local oxidative status during neonatal calf diarrhea is not known. This study assessed systemic (serum) and local (fecal) oxidative status when calves either naturally developed diarrhea or naturally recovered. Healthy calves were enrolled in the study at d 18 of age, and their health status was monitored from the enrollment. Based on their enteric health status on d 21 and 28, calves were grouped as continuous diarrhea from d 21 to 28 (n = 14), diarrhea at d 21 but recovered at d 28 (DH group, n = 19), healthy at d 21 but developed diarrhea at d 28 (HD group, n = 15), and healthy throughout the study (HH group, n = 16). Serum and fecal samples were collected at d 21 and 28 from all calves in the morning 2 h after feeding. Dynamics of oxidative stress indicators including reactive oxygen species (ROS), malondialdehyde (MDA), H2O2, 8-hydroxy-2'-deoxyguanosine (8-OHDG), glutathione peroxidase, superoxide dismutase, catalase (CAT), and total antioxidant capacity and inflammatory indicators TNF-α, IL-1ß, IL-4, IL-6, IL-10, and IFN-γ were evaluated using serum samples. In addition, fecal oxidative stress indicators ROS and MDA were measured. Serum ROS, MDA, 8-OHDG, as well as fecal ROS and MDA, were higher, whereas serum CAT and H2O2 were lower in diarrheic calves than those of healthy calves. Serum ROS, MDA, and 8OHDG and fecal ROS and MDA increased in the HD group from d 21 to 28 as they developed diarrhea. In contrast, all these oxidative stress markers decreased in the DH group from d 21 to 28 as they recovered. However, serum H2O2 had an opposite changing trend, which became lower in the HD group and higher in the DH group at d 28. In conclusion, both systemic and local oxidative stress markers and cytokine profiles altered as calves moved from being healthy to having diarrhea or vice versa. Serum ROS, MDA, and 8-OHDG can be used to develop biomarkers to screen calves prone to enteric infections during the preweaning period.

Water, mineral, and blood acid-base balance in calves with naturally occurring diarrhea receiving two alternative oral rehydration solutions or a placebo.

Quantifying the water and mineral losses in feces is essential to determine the optimal composition of oral rehydration solutions (ORS) for diarrheic animals. In a randomized complete block design, this study evaluated water, mineral, and blood acid-base balance of calves with naturally occurring diarrhea receiving ORS or a placebo. On d 0, 45 calves (age: 18 ± 3.2 d; mean ± SD) were selected based on the presence of visual signs of diarrhea, such as dirty tail or wet feces, along with clinical symptoms evaluated by measuring the skin turgor and the degree of enophthalmos. On d 1, calves were divided into blocks of 3 animals based on blood base excess (BE) measured at 0900 h, and within each block, calves were randomly assigned to 1 of 3 treatments (15 calves per treatment) including (1) a hypertonic ORS (HYPER; Na+ = 110 mmol/L; 370 mOsm/kg; strong ion difference [SID] = 60 mEq/L), (2) a hypotonic ORS with low Na+ (HYPO; Na+ = 77 mmol/L; 278 mOsm/kg; SID = 71 mEq/L), and (3) a placebo consisting of lukewarm water with 5 g/L of whey powder (CON). Milk replacer (MR) was fed through teat buckets twice daily at 0630 h and 1700 h in 2 equally sized meals of 2.5 L from d 1 to 3 and of 3.0 L on d 4 and 5. Treatments consisting of 2.0 L lukewarm solutions were administered between milk meals from d 1 to 3 at 1200 h and 2030 h through teat buckets. Refusals of MR and treatments were recorded daily, and blood samples were collected from the jugular vein once daily at arrival in the afternoon of d 0 and at 0900 h from d 1 to 5 after arrival. Urine and feces were collected quantitatively over a 48-h period from 1200 h on d 1 to 1200 h on d 3, and a representative sample of each 24-h period was stored. In addition, the volume of extracellular fluid was evaluated on d 2 by postprandial sampling over a 4-h period relative to the injection of sodium thiosulfate at 1300 h. Total daily fluid intake (MR, treatment, and water) from d 1 to 3 was greater in HYPER (LSM ± SEM; 8.9 ± 0.36 L/d) and HYPO (7.8 ± 0.34 L/d) than in CON (6.6 ± 0.34 L/d). This resulted in a greater water balance (water intake - fluid output in urine and feces) in calves receiving ORS (59.6 ± 6.28 g/kg BW per 24 h vs. 39.6 ± 6.08 g/kg BW per 24 h). Fecal Na+ losses were greater in HYPER than in the other treatments (81 ± 12.0 mg/kg BW per 24 h vs. 24 ± 11.8 mg/kg BW per 24 h). Blood pH was higher in HYPO (7.41 ± 0.016) than CON (7.35 ± 0.016) over the 5 monitoring days, whereas HYPER (7.37 ± 0.017) did not differ with other treatments. In this experimental model, diarrheic calves were likely unable to absorb the high Na+ load from HYPER, resulting in greater Na+ losses in feces, which might have impaired the alkalinizing capacity of HYPER. In contrast, HYPO significantly sustained blood acid-base balance compared with CON, whereas HYPER did not. This suggests that low tonicity ORS with a high SID are more suitable for diarrheic calves.

Genome characterization of a Turkish bovine rotavirus field isolate by shotgun metagenomics.

A bovine rotavirus (BRV) isolate from Kirsehir was isolated from feces of a neonatal calf with diarrhea, identified, and sequenced by shotgun sequencing. Its genotype constellation is G10-P[5]-I2-R2-C2-M2-A3-N2-T6-E2-H3. The structural genes and the non-structural genes NSP1, NSP3, and NSP4 of the Kirsehir isolate were similar in sequence to those of BRVs identified in Turkey. However, VP2, NSP2, NSP4, and NSP5/6 showed similarity to those of rotaviruses from different animal hosts. These findings not only expand our current understanding of the diversity of rotaviruses but also contribute to our understanding of the evolution of rotaviruses at both the national and global levels and reinforce the significance of conducting further research on rotaviruses in Turkey.

Blood metabolomics reveals the therapeutic effect of Pueraria polysaccharide on calf diarrhea.

BACKGROUND: Neonatal calf diarrhea (NCD) is typically treated with antibiotics, while long-term application of antibiotics induces drug resistance and antibiotic residues, ultimately decreasing feed efficiency. Pueraria polysaccharide (PPL) is a versatile antimicrobial, immunomodulatory, and antioxidative compound. This study aimed to compare the therapeutic efficacy of different doses of PPL (0.2, 0.4, 0.8 g/kg body weight (BW)) and explore the effect of plasma metabolites in diarrheal calves by the best dose of PPL. RESULTS: PPL could effectively improve the daily weight gain, fecal score, and dehydration score, and the dosage of 0.4 g/kg BW could reach curative efficacy against calf diarrhea (with effective rates 100.00%). Metabolomic analysis suggested that diarrhea mainly affect the levels of taurocholate, DL-lactate, LysoPCs, and intestinal flora-related metabolites, trimethylamine N-oxide; however, PPL improved liver function and intestinal barrier integrity by modulating the levels of DL-lactate, LysoPC (18:0/0:0) and bilirubin, which eventually attenuated neonatal calf diarrhea. It also suggested that the therapeutic effect of PPL is related to those differential metabolites in diarrheal calves. CONCLUSIONS: The results showed that 0.4 g/kg BW PPL could restore the clinical score of diarrhea calves by improving the blood indexes, biochemical indexes, and blood metabolites. And it is a potential medicine for the treatment of calf diarrhea.

Investigation of hemogram, oxidative stress, and some inflammatory marker levels in neonatal calves with escherichia coli and coronavirus diarrhea.

Calf diarrhea is the most common disease affecting calves in the neonatal period resulting in economic losses. Although predisposing factors play a role in the etiology of the disease, in most cases, different pathogens are involved in the development of the infection. In this study, hemogram data, glutathione and malondialdehyde levels were examined to determine lipid peroxidation and glutathione levels in E. coli- and coronavirus-infected calves. Serum amyloid A and calprotectin levels were also analyzed to determine inflammatory status. The study included a total of 45 female Montofon calves aged 0-1 week, including the E. coli group (15 calves), the coronavirus group (15 calves), and the control group (15 calves). Analysis revealed that total leukocyte, neutrophil, lymphocyte, malondialdehyde, serum amyloid A, and calprotectin levels increased in the coronavirus-infected calves compared with the E. coli group and the control group. In contrast, the levels of glutathione, one of the antioxidant markers, decreased. In conclusion, the main findings related to the determination of inflammation and oxidative status were characterized by the presence of E. coli and coronavirus diarrhea, and it is suggested that future studies may be guided by the fact that inflammatory conditions are higher in viral disease than in bacterial infection.

Characterization of fecal branched-chain fatty acid profiles and their associations with fecal microbiota in diarrheic and healthy dairy calves.

Branched-chain fatty acids (BCFA) have recently been reported to play a role in human gut health during early life. However, little information is available on the fecal BCFA profiles in young ruminants and whether they are associated with the development of neonatal calf diarrhea. The objectives of this study were to (1) characterize BCFA profiles in feces collected from young calves, (2) compare the fecal BCFA composition between diarrheic and nondiarrheic dairy calves, and (3) explore the potential relationships between BCFA and microbiota in the feces. A total of 32 male Holstein dairy calves (13 ± 3 d old) with the same diet management were grouped as diarrheic (n = 16) or healthy (n = 16) based on fecal score (determined by liquid fecal consistency with some solid particles); diarrhea cases were defined as fecal score ≥2 for at least 2 d. Fecal samples were collected on the seventh day after calf arrival, and the fecal BCFA and microbial profiles were assessed using gas chromatograph and amplicon sequencing, respectively. In total, 7 BCFA were detected in the feces of all dairy calves; however, the concentrations of fecal BCFA differed between diarrheic and nondiarrheic calves. Specifically, the concentrations of iso-C16:0, iso-C17:0, anteiso-C17:0, and total even-chain BCFA were significantly higher in the feces of diarrheic calves. When the associations between BCFA and bacteria were studied, the relative abundance of Eggerthella was positively correlated with the concentrations of iso-C16:0 (ρ = 0.67), iso-17:0 (ρ = 0.77), anteiso-C17:0 (ρ = 0.73), and iso-C18:0 (ρ = 0.65), whereas the relative abundance of Subdoligranulum was positively correlated with the concentrations of iso-C14:0 (ρ = 0.62), iso-C15:0 (ρ = 0.78), and anteiso-C15:0 (ρ = 0.63). Use of random forest algorithm showed that BCFA such as anteiso-C15:0, iso-C16:0, iso-C17:0, iso-C18:0, and total even-chain BCFA could be used as biomarkers to differentiate diarrheic calves from healthy ones. Our findings generated fundamental knowledge on the potential roles of BCFA in neonatal calf gut health. Follow-up studies with larger animal populations are warranted to validate the feasibility of using BCFA as indicators of health status in neonatal calves.

A new passive immune strategy based on IgY antibodies as a key element to control neonatal calf diarrhea in dairy farms.

BACKGROUND: Neonatal diarrhea remains one of the main causes of morbi-mortality in dairy calves under artificial rearing. It is often caused by infectious agents of viral, bacterial, or parasitic origin. Cows vaccination and colostrum intake by calves during the first 6 h of life are critical strategies to prevent severe diarrhea but these are still insufficient. Here we report the field evaluation of a product based on IgY antibodies against group A rotavirus (RVA), coronavirus (CoV), enterotoxigenic Escherichia coli, and Salmonella sp. This product, named IgY DNT, has been designed as a complementary passive immunization strategy to prevent neonatal calf diarrhea. The quality of the product depends on the titers of specific IgY antibodies to each antigen evaluated by ELISA. In the case of the viral antigens, ELISA antibody (Ab) titers are correlated with protection against infection in calves experimentally challenged with RVA and CoV (Bok M, et al., Passive immunity to control bovine coronavirus diarrhea in a dairy herd in Argentina, 2017), (Vega C, et al., Vet Immunol Immunopathol, 142:156-69, 2011), (Vega C, et al., Res Vet Sci, 103:1-10, 2015). To evaluate the efficiency in dairy farms, thirty newborn Holstein calves were randomly assigned to IgY DNT or control groups and treatment initiated after colostrum intake and gut closure. Calves in the IgY DNT group received 20 g of the oral passive treatment in 2 L of milk twice a day during the first 2 weeks of life. Animals were followed until 3 weeks of age and diarrhea due to natural exposure to infectious agents was recorded during all the experimental time. RESULTS: Results demonstrate that the oral administration of IgY DNT during the first 2 weeks of life to newborn calves caused a delay in diarrhea onset and significantly reduced its severity and duration compared with untreated calves. Animals treated with IgY DNT showed a trend towards a delay in RVA infection with significantly shorter duration and virus shedding compared to control calves. CONCLUSIONS: This indicates that IgY DNT is an effective product to complement current preventive strategies against neonatal calf diarrhea in dairy farms. Furthermore, to our knowledge, this is the only biological product available for the prevention of virus-associated neonatal calf diarrhea.

Short communication: Hypernatremia in diarrheic calves associated with oral electrolyte administration in water and milk replacer in absence of access to water.

A major goal in treatment of calves with diarrhea is to restore hydration and to correct metabolic acidosis. This can be achieved by the administration of oral electrolyte solutions (OES). However, the composition of OES products and the administration protocols in practice vary widely, which can potentially compromise the efficacy and safety of these treatments. In particular, administration of OES in milk replacer (MR) and the absence of water supply in young calves are not unusual and these conditions could compromise calf health. In this light, the objective of this study was to evaluate the efficacy and safety of OES administered in MR and in water without access to water. Forty-five male Holstein calves (16.6 ± 1.6 d of age and 45.4 ± 2.2 kg at arrival) were purchased from a collection center located in the Netherlands. After arrival, calves went through an adaptation period of 4 d. Calves that developed diarrhea within 6 d after the end of the adaptation period were enrolled in the study, and the remaining calves were sold after being weaned. Upon morning detection of abnormal fecal scores (d 1 starting point), calves were blocked based on initial BW. Within each block, calves were randomly assigned to 1 of 2 treatments, including a control consisting of a small dose of whey (CON; n = 12) and an OES treatment (OES; n = 14). Treatments were blinded to the farm staff by randomly assigning a letter to each treatment. Treatments were simultaneously administered for 4 d in MR (2.5 L at 0800 and 1730 h) and in water (3 L at 1300 and 2200 h). Calves had no supplemental access to plain water. Blood samples were taken at 0600 h for 4 d, and fecal scores (0 = normal; 1 = watery feces) were assessed daily at 0900 h for 15 consecutive days. Additionally, skin turgor and degree of enophthalmos were assessed at 1000 h from d 1 to 4 using a 3-level scoring system. Calves fed OES had a higher prevalence of diarrhea on d 3, 4, and 5 as well as higher prevalence of delayed skin turgor and increased degree of enophthalmos over the 4 monitoring days. Diarrhea duration was longer in calves receiving OES than in calves receiving CON (4.2 d vs. 2.1 d, respectively). The OES treatment resulted in hypernatremia (serum Na+ >145 mmol/L) within 48 h after the first OES administration. Hypernatremia was linked with higher serum Cl- and urea concentrations and thus higher serum osmolarity in OES calves compared with CON calves. Administered under these conditions, OES resulted in various degrees of hypernatremia and a delayed recovery from diarrhea, thus defeating the purpose of OES administration.

First report of group A rotavirus and bovine coronavirus associated with neonatal calf diarrhea in the northwest of Argentina.

Group A rotavirus (RVA) and bovine coronavirus (BCoV) are the two main viral enteropathogens associated with neonatal calf diarrhea. The aim of the present survey was to investigate the epidemiology and the role of RVA and BCoV in the presentation of dairy and beef calf diarrhea in Lerma Valley of Salta province, within the Northwest region of Argentina. Stool samples of calves with or without diarrhea younger than 2 months of age were collected from 19 dairy farms and 20 beef farms between the years 2014 and 2016. Stool samples were screened for RVA and BCoV detection by ELISA. Heminested multiplex RT-PCR was used for RVA typing and RT-PCR to confirm BCoV. Positive samples were submitted to sequencing analysis. Bovine RVA and BCoV were circulating in 63% (12/19) and 10.52% (2/19) of the dairy farms, respectively, where 9.5% (46/484) of the calves were positives to RVA and 0.4% (2/484) to BCoV. In beef herds, RVA was detected in 40% (8/20) of the farms and in 6.75% (21/311) of the calves, without positives cases of BCoV. Molecular analysis showed that in dairy farms, G6P[11] and G10P[11] were the prevalent RVA strains, while in beef farms, G10P[11] was the prevalent. The main finding was the detection for the first time of a G15P[11] causing diarrhea in beef calves of Argentina that represents a new alert to be consider for future vaccine updates. Analysis of detected BCoV showed that it is related to the other circulating strains of Argentina.

Molecular surveillance of viral pathogens associated with diarrhea in pre-weaned Korean native calves.

Calf diarrhea causes severe economic losses in the cattle industry worldwide. This study investigated the prevalence of bovine coronavirus (BCoV), bovine norovirus (BNoV), bovine group A rotavirus (BoRVA), and bovine torovirus (BToV) in calves aged ≤ 60 days, regardless of diarrhea, across nine different regions in the Republic of Korea (ROK) and reported associations between these viruses and diarrhea. Fecal samples were collected rectally from 689 calves: normal (n = 360) and diarrheic (n = 329). BNoV (84/689, 12.2%) was the most prevalent regardless of diarrhea, followed by BCoV (37/689, 5.4%), BToV (15/689, 2.2%), and BoRVA (13/689, 1.9%). Although BCoV (P = 0.032) and BoRVA (P = 0.007) were significantly associated with diarrhea in pre-weaned calves, BNoV and BToV showed no association. Infection by the four pathogens had no relationship with calf age; BoRVA was detected only in calves aged < 30 days, but this finding was not statistically significant. Phylogenetic analysis revealed that BCoV isolates obtained in this study were distinct from the other known BCoVs, and all BNoV isolates belonged to GIII.2 genotype; genetic variations in BNoVs are present in the ROK. BoRVA isolates distributed in the ROK were assigned to G6P[5]. Within the P[5] genotype, our isolates were divided into two lineages: P[5]-III and P[5]-VIII. P[5]- VIII lineage was dominant in pre-weaned Korean native calves. Our BToV isolates were more closely related to a European isolate, B145, than to Japanese isolates. Here, BNoV was frequently identified in calves, suggesting its non-significant contribution to calf diarrhea, whereas BCoV and BoRVA were responsible for calf diarrhea in the ROK. Consequently, our results highlight the importance of rapid diagnosis against these viruses in calf diarrhea.

A multisite, randomized field trial to evaluate the influence of lactoferrin on the morbidity and mortality of dairy calves with diarrhea.

Diarrhea is one of the most common causes of antimicrobial use and mortality in young calves. To reduce antimicrobial use and resistance on dairy farms, research on alternative therapies for calf diarrhea is necessary. Our laboratory previously conducted a randomized clinical trial investigating the effectiveness of lactoferrin, an iron-binding protein found in colostrum, as a treatment for calf diarrhea. The trial showed significantly reduced calf mortality in diarrheic calves that were administered lactoferrin. Thus, the objective of this study was to corroborate the results of our prior clinical trial across multiple farms and to investigate the effect of lactoferrin on the morbidity and mortality of preweaned calves with naturally occurring cases of diarrhea. This randomized field trial was conducted on 5 commercial dairy farms in Ohio. In total, 485 calves (≤21 d of age) were enrolled at first diarrhea diagnosis (fecal score ≥2 defined as loose to watery) and randomly assigned to receive an oral dose of lactoferrin (3 g of lactoferrin powder dissolved in 30 mL of water) or 30 mL of water (control) once daily for 3 consecutive days. Health assessments were conducted on the day of diarrhea diagnosis (d 0) and 1, 2, 3, 7, 14, 21, 28, and 35 d following diagnosis. Producer records of disease treatment and mortality were collected 120 d following diagnosis. A Poisson regression model was used to test differences between treatments in disease frequency through 35 d post-diarrhea diagnosis and the incidence risk of treatment and mortality risk 120 d post-diarrhea diagnosis; the model controlled for calf age at enrollment, farm, and treatment. Median calf age at enrollment was 11 d and ranged from 1 to 26 d of age. At study enrollment, 51.3% (123/240) and 52.2% (128/245) of calves in the control and lactoferrin treatment groups, respectively, were diagnosed with severe diarrhea (fecal score = 3). The frequency of disease (diarrhea, dehydration, depression, signs of respiratory disease) through 35 d following diarrhea diagnosis was not significantly different for calves in the lactoferrin and control groups. Overall mortality risk for enrolled calves was 9.9%, and 10.7% (22/243) and 9.1% (26/242) of calves in the lactoferrin and control groups, respectively, died or were culled in the 120 d following diarrhea diagnosis. The relative risk of death or culling did not differ between treatment groups, however. Therefore, as performed in this study, lactoferrin as a treatment for calf diarrhea was not beneficial.

Short communication: Investigation of antibiotic alternatives to improve health and growth of veal calves.

The inherent disease susceptibility of veal calves results in frequent antimicrobial use. Improvements in antimicrobial stewardship necessitate alternative therapies to improve calf health and growth, while reducing the need for antimicrobials important to human health. This study investigated the effect of 2 alternative therapies, lactoferrin (an iron-binding protein found in colostrum) and cinnamaldehyde (an essential oil of the cinnamon plant) on growth, disease incidence, and mortality risk in special-fed veal calves. On the day of arrival to the growing facility (3 to 7 d of age), calves (n = 80 per treatment) were randomized to 1 of 3 treatments: (1) control (no supplement), (2) lactoferrin (1 g/d in milk replacer for 7 d), or (3) cinnamaldehyde (1 g/d in milk replacer for 21 d). Body weight was measured on the day of arrival (d 0), 21, and 42 d postarrival. Health assessments were performed twice weekly through 21 d, and mortality records were obtained through 6 wk postarrival. A repeated-measures ANOVA was used to compare growth between treatment groups, and a Poisson regression model (PROC GENMOD, SAS v. 9.4, SAS Institute Inc., Cary, NC) was used to test differences between groups in the incidence of diarrhea (fecal score ≥2 with and without depression and temperature) and disease through 3 wk postarrival. Body weight and average daily gain were similar between treatments. Neither lactoferrin nor cinnamaldehyde had an effect on diarrhea incidence. However, the risk of navel inflammation was significantly lower for calves that received cinnamaldehyde compared with calves in the control group. Mortality through 6 wk postarrival was low, with 4, 1, and 0 deaths from the control, lactoferrin, and cinnamaldehyde treatment groups, respectively. Additional research is needed to investigate various doses of these alternative therapies on calf health and growth, in addition to different routes of administration.

Health benefits of orally administered anti-IL-10 antibody in milk-fed dairy calves.

The primary objective of this randomized controlled trial was to determine whether anti-IL-10 egg yolk antibodies fed upon arrival to a calf ranch would lower the prevalence of Cryptosporidium parvum shedding in naturally challenged preweaned dairy calves. The secondary objectives included measuring the effect of anti-IL-10 antibodies on calf health, performance, and shedding of less common diarrheal pathogens. A total of 133 calves, enrolled at 24 to 72 h of age, received a daily dose of 0.96 g of egg yolk powder with anti-IL-10 antibodies (MAB, n = 71) or without anti-IL-10 antibodies (MEP, n = 62) split between 2 feedings for the first 11 d on feed at a calf ranch. Daily health evaluations were completed for 15 d after arrival and on d 56. Digital weights were collected at enrollment and d 56, and hipometer weights were collected at enrollment and d 7 and 56. Packed cell volume and serum total protein concentration were measured at enrollment and on d 7 and 14. Fecal pH was measured at enrollment and on d 5 and 14, and fecal pathogen (C. parvum, coronavirus, rotavirus, and Salmonella spp.) shedding was assessed at d 5 and 14. Continuous outcomes were compared between groups using a Student's t-test or Wilcoxon rank sum test. Fecal pathogen shedding at d 14, respiratory disease at d 56, and antibiotic usage were compared using relative risk (RR) and chi-squared test. Fecal pH (median and interquartile range) on d 14 was 6.65 (6.39-6.99) and 6.52 (5.97-6.81) for MAB and MEP, respectively. On d 56, the risk of respiratory disease was lower for MAB compared with MEP (RR = 0.40; confidence interval = 0.16-0.99). The risk for antibiotic treatment was lower for MAB- compared with MEP-treated calves (RR = 0.38; confidence interval = 0.17-0.88). The risk of shedding rotavirus was higher in MAB (RR = 1.38; confidence interval = 1.10-1.81) calves. After multivariable analyses, hipometer weights (least squares means ± standard error) were 1.7 ± 0.8 kg greater on d 56 in MAB compared with MEP; however, ADG was 0.04 ± 0.02 kg/d lower in MAB calves. Total health score, diarrhea days, average respiratory score, packed cell volume, and serum total protein were not affected by feeding anti-IL-10 egg antibodies. In summary, feeding anti-IL-10 antibodies was associated with increased fecal pH, reduced risk of respiratory disease later in the preweaning period, and decreased antibiotic usage despite higher rotavirus infection. These findings might be associated with improved mucosal immunity, enhanced host defenses, or reduced susceptibility and warrant further investigation.

[The significance of cryptosporidiosis for the health of calves in Switzerland]. / Die Bedeutung der Cryptosporidiose für die Kälbergesundheit in der Schweiz.

INTRODUCTION: Diarrhea in calves is one of the most important cattle diseases in Switzerland. The diagnosis and treatment of calf diarrhea represent a major challenge. Single-celled Cryptosporidium parasites are the most prevalent causative agents of calf diarrhea besides rotavirus in the first weeks of life, and are responsible for about 50% of diarrheal cases. Cryptosporidium parvum has been described as a cause of diarrhea in one to three weeks old calves since the 1970s. Oral ingestion of persistent environmental oocysts results in severe diarrhea lasting four to six days and shedding of large numbers of infectious oocysts. A tiny amount of 10 oocysts is already sufficient to cause disease. Detailed knowledge about the epidemiology and virulence of the different C. parvum strains is still lacking. In addition, current diagnostic tests cannot reliably distinguish between non-pathogenic (e.g. C. bovis) and pathogenic Cryptosporidium species. Until now, no effective therapeutic drug or vaccine against calf cryptosporidiosis has been found. Water-borne epidemics and the zoonotic potential of Cryptosporidium in immunodeficient patients are of great medical importance. The increasing number of cryptosporidiosis cases associated with high infant mortality in less industrialized and impoverished regions (including South-East Asia and sub-Saharan Africa) has intensified the research in recent years. The recent discoveries of new therapeutics against C. parvum may benefit calf medicine in the near future. This review article reports on these new developments, highlights calf cryptosporidiosis in Switzerland and draws attention to a new research project.

INTRODUCTION: La diarrhée chez les veaux est l'une des maladies du bétail les plus courantes en Suisse. Le diagnostic de la cause et le traitement de la diarrhée des veaux représentent un défi majeur. En Suisse, les cryptosporidies sont, avec les rotavirus, l'agent causal le plus fréquent de diarrhée du veau dans les premières semaines et elles sont responsables d'environ 50% des cas. Le parasite unicellulaire Cryptosporidium parvum a été décrit depuis les années 1970 comme un agent de diarrhée chez les veaux d'une à trois semaines. Après ingestion orale d'oocystes persistants dans l'environnement, il se produit après quelques jours une diarrhée sévère de quatre à six jours avec excrétion massive d'oocystes déjà infectieux. Même quelques oocystes persistants dans l'environnement peuvent être pathogènes. Du point de vue épidémiologique, il existe encore de grandes lacunes dans la connaissance de la variabilité suspectée dans la virulence de diverses souches de C. parvum. En outre, des espèces non pathogènes (entre autres Cryptosporidium bovis) peuvent être présentes chez les veaux, qui ne se distinguent pas de C. parvum avec les tests diagnostiques actuels. Jusqu'à présent, aucun médicament efficace sur le plan thérapeutique et aucun vaccin contre la cryptosporidiose du veau n'ont été trouvés. En médecine humaine, les épidémies transmises par l'eau (en particulier aux États-Unis) et l'importance zoonotique des cryptosporidies comme pathogènes opportunistes chez les personnes immunodéficientes jouent un rôle de premier plan. La forte morbidité de la cryptosporidiose associée à une forte mortalité infantile dans les régions les moins industrialisées et les plus pauvres (entre autres en Asie du Sud-Est et en Afrique subsaharienne) ont relancé la recherche sur ces parasites au cours des dernières années. En particulier, la découverte de nouveaux médicaments contre C. parvum est susceptible de bénéficier à la médecine du veau dans un proche avenir. Cet article de synthèse fait le point sur ces nouveaux développements mais surtout sur la cryptosporidiose du veau en Suisse et attire l'attention sur un nouveau projet de recherche.

Passive immunity to control Bovine coronavirus diarrhea in a dairy herd in Argentina.

Bovine coronavirus (BCoV) is a viral enteric pathogen associated with calf diarrhea worldwide being, in Argentina, mostly detected in dairy husbandry systems. The aim of the present work was to study if maternal IgG1 antibodies (Abs) to BCoV acquired by colostrum intake modulate the development of BCoV infection in calves reared in a dairy farm in Argentina. Thirty Holstein calves were monitored during their first 60 days of age. Animals were classified into two groups depending on their initial BCoV IgG1 Ab titers. The "failure of passive transfer" (FPT) group had significantly lower IgG1 Abs to BCoV than the "acceptable passive transfer" (APT) group of calves (log10 1.98 vs. 3.38 respectively) (p<0.0001). These differences were also observed when the total protein levels in both groups were compared (p=0.0081). Moreover, 71% (5/7) of calves from the FPT group showed IgG1 seroconversion to BCoV compared to 29.4% (5/17) of animals from the APT group. Regarding viral circulation, BCoV was detected in 10% (3/30) of all calves and BCoV IgG1 Ab seroconversion was detected in 42% of the total animals showing that almost half of the calves were infected with BCoV. In conclusion, calves with high titers of specific BCoV IgG1 (≥1024) were mostly protected against viral infection, while animals with low titers of IgG1 (<1024) were mostly infected with BCoV. IgG1 Abs from colostrum origin are critical for prevention of BCoV infection.

Lactoferrin reduces mortality in preweaned calves with diarrhea.

Calf diarrhea is the most common reason for mortality and antimicrobial therapy in preweaned calves on dairy farms in the United States. Conventional and organic livestock producers require alternative therapies for calf diarrhea to reduce the necessity of conventional antimicrobials. Alternatives administered for mild cases or early in the disease course may be useful to mitigate disease progression and reduce the likelihood of septicemia and negative sequelae. Lactoferrin is a bioactive protein naturally found in colostrum that has been shown to prevent septicemia in high-risk infants. Among organic producers, garlic extract is widely used for the treatment of disease and perceived to be efficacious. The objectives of the study were to determine the effectiveness of lactoferrin and garlic extract to reduce mortality and culling, improve weight gain, and reduce the duration of disease in preweaned calves with the first diagnosis of diarrhea. In total, 628 calves with diarrhea from a single commercial dairy were enrolled in a blinded, randomized field trial. Calves diagnosed with diarrhea (fecal score ≥3), were randomized to 3 consecutive days of oral garlic extract, lactoferrin, or water (control). Calves were clinically evaluated for up to 10 d. Body weight was measured at enrollment and 10 d later. For calves receiving garlic extract, the risk of death or culling was not significantly different than calves in the control group; however, calves that received lactoferrin had approximately half the risk of death or culling in the 120 d following diagnosis. Additionally, the relative risk of death or culling in the 60 d following diagnosis was significantly lower for the subset of calves with severe diarrhea at enrollment. Neither garlic nor lactoferrin had a significant effect on disease duration or average weight gain during the 10-d period. Lactoferrin significantly reduced mortality and culling when administered to preweaned calves with the first diagnosis of diarrhea; however, additional studies conducted across multiple farms are necessary to corroborate the observed reduction in mortality and culling. If the results are confirmed, lactoferrin may become an important tool to improve treatment outcomes and reduce the necessity of antimicrobials.

Longitudinal study of bovine rotavirus group A in newborn calves from vaccinated and unvaccinated dairy herds.

Reports of rotavirus excretion in calves usually result from cross-sectional studies, and in face of the conflicting results regarding protection of calves born to vaccinated dams against diarrhea, the aim of the present study was to evaluate rotavirus excretion in dairy calves born to vaccinated or unvaccinated dams, to identify the genotypes of bovine rotavirus group A (RVA) strains isolated from these animals as well as to investigate characteristics of the disease in naturally occurring circumstances throughout the first month of life. Five hundred fifty-two fecal samples were taken from 56 calves, 28 from each farm and, in the vaccinated herd, 11/281 samples (3.91%) taken from six different calves tested positive for RVA while in the unvaccinated herd, 3/271 samples (1.11%) taken from 3 different calves tested positive. The genotyping of the VP7 genes showed 91.2% nucleotide sequence identity to G6 genotype (NCDV strain), and for the VP4 gene, strains from the vaccinated herd were 96.6% related to B223 strain, while strains from the unvaccinated herd were 88% related to P[5] genotype (UK strain). Genotypes found in this study were G6P[11] in the vaccinated herd and G6P[5] in the unvaccinated herd. All calves infected with rotavirus presented an episode of diarrhea in the first month of life, and the discrepancy between the genotypes found in the commercial vaccine (G6P[1] and G10P[11]) and the rotavirus strains circulating in both vaccinated and unvaccinated herds show the importance of keeping constant surveillance in order to avoid potential causes of vaccination failure.