Invited Review: Improved control of Johne's disease in dairy cattle through advancements in diagnostics, testing and management of young stock.

Johne's disease (JD; paratuberculosis) control programs have been regionally implemented across the globe, but few have successfully eradicated the pathogen (Mycobacterium avium ssp. paratuberculosis (MAP)) causing this disease. The limited success may partly be attributed to excluding young stock (calves and replacement heifers or bulls) from testing strategies aimed at identifying MAP-infected cattle. Young stock can shed MAP in feces and can have detectable MAP-specific antibodies in blood, as confirmed in experimentally and naturally infected cattle. Furthermore, MAP transmission causes new infections in young stock. Calves and heifers are often included in JD management strategies on dairy farms but excluded from conventional diagnostic tests due to a presumed lag between infection and detection of MAP shedding and/or MAP-specific serum antibodies. We summarize evidence of MAP shedding early in the course of infection and discuss promising diagnostics, testing and management strategies to support inclusion of young stock in JD control programs. Improvements in fecal Polymerase Chain Reaction, interferon-gamma release assay (IGRA), and enzyme-linked immunosorbent assay (ELISA) enable earlier detection of MAP and specific early immune responses. Studies on IGRA and ELISA have focused on evaluation of new antigens and optimal age of testing. There are new diagnostics, including phage-based tests to detect viable MAP, and gene expression patterns and metabolomics to detect MAP-infected young stock. In addition, refinements in testing and management of calves and heifers may enable reductions in MAP prevalence. We provide recommendations for dairy farmers, researchers, veterinarians, and other stakeholders that may improve JD control programs with an objective to control and potentially eradicate JD. Additionally, we have identified the most pressing gaps in knowledge that currently hamper inclusion of young stock in JD prevention and control programs. In summary, transmission among young stock may cause new MAP infections, and appropriate use of new diagnostic tests, testing and management strategies for young stock may improve the efficacy of JD control programs.

Excretory urography can track down morphological changes in the urinary bladder associated with urachal anomalies in calves for early diagnosis.

OBJECTIVE: To investigate radiographic detection by excretory urography of morphological changes in the urinary bladder associated with urachal anomalies in calves. METHODS: Excretory urography was performed to detect morphological changes in the urinary bladder of 13 calves, of which 6 were nondysuric with swelling of umbilical region and 7 were dysuric without clinical umbilical swelling from November 2022 through April 2024. RESULTS: The urinary bladder was delineated in all 13 calves after excretory urography. The aspect ratios (length:height), which objectively evaluate the shape of the urinary bladder, ranged from 1.08 to 2.43 (1.90 in average) and 1.34 to 11.89 (4.75 in average) in nondysuric and dysuric calves, respectively. The ratios of calves with nondysuric were significantly lower than those of dysuric (P < .05). CONCLUSIONS: Excretory urography could play an important role in evaluating abnormal morphological changes due to urachus anomalies in the urinary bladder of calves. CLINICAL RELEVANCE: Among calves with dysuria, urachal anomaly should be included in the differential diagnosis. Excretory urography is proposed as an alternative option for early diagnosis among calves presenting with dysuria to improve livestock productivity.

Dose titration of intravenously administered gamma-hydroxybutyric acid for sedation in Holstein-Friesian calves.

Gamma-hydroxybutyric acid (GHB) is a short-chain fatty acid that can potentially provide safe, prolonged sedation with minimal cardiorespiratory effects. This preliminary trial, performed in 10 three-week-old male Holstein-Friesian calves, investigated the effects of GHB administered intravenously over 5 min at a dose of 100 (G100, n=2), 150 (G150, n=4) or 200 mg/kg (G200, n=4). Once lateral recumbency was achieved, scores for sedation depth (range: 0 = no sedation to 3 = marked) and response to noxious stimulation (range: 0 = strong to 3 = absent), heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP) and arterial blood gases were monitored every 15 min until sternal recumbency. Times from end of administration to lateral recumbency and return to sternal/standing positions were recorded. Dose G100 resulted in mild sedation and ataxia without decubitus. Doses G150 and G200 respectively resulted in time to lateral recumbency 8 ± 2 and 9 ± 3 min, lasting 189 ± 41 and 283 ± 29 min, while overall median (range) scores for sedation were 3 (1-3) and 3 (2-3) respectively and response to noxious stimulation 0 (0-3) and 0 (0-3) respectively. The mean ± SD for HR was 110 ± 10 and 106 ± 11 bpm respectively; for MAP 87±9 and 94±5 mmHg respectively; and for RR 28 ± 5 and 26 ± 5 bpm respectively. The mean ± SD for arterial partial pressure of oxygen (PaO2) at these two dose rates was 74 ± 6 and 74 ± 2 mmHg respectively, while the arterial partial pressure of carbon dioxide oxygen (PaCO2) was 53 ± 3 and 47 ± 0.8 mmHg respectively. Based on these preliminary results we conclude that GHB has the potential to be used as a long-acting sedative in calves. Further studies are needed to confirm this.

Dry Liposculpture of the Calves and Ankles-A Novel Technique for Sculpting the Lower Legs.

BACKGROUND: Liposuction of the calves and ankles was historically described as a "taboo" procedure and linked with higher postoperative pain and unpleasing aesthetic results. OBJECTIVES: This study presents a Novel technique for dry liposculpture of the calves and ankles using a tourniquet, as a safe and less painful procedure, which achieves better aesthetic results. METHODS: This single surgeon, retrospective study included 70 women who underwent surgery based on the technique described. Details regarding the surgical outcomes and pain levels were collected, and patients completed 2 years of follow-up. RESULTS: A mean of 1395 cc fat was aspirated from both legs, combined, and the mean duration of surgery was 98 minutes. No major complications were observed, and postoperative pain levels were low. Pre- and post-surgery pictures were evaluated by 8 certified senior plastic surgeons for aesthetic results. DISCUSSION: The findings suggest that dry liposculpture is suitable for reshaping the calves and ankles. CONCLUSIONS: This technique is safe, with precise and satisfactory aesthetic results, low levels of postoperative pain, and may take less time to perform than wet liposuction. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effects of forage feeding to calves on performance, rumen fermentation and nutrient digestibility: A meta-analysis.

The literature on whether or not to feed forage is marked by inconsistencies, largely due to various factors associated with forage inclusion in calf diets. To elucidate these factors, we conducted a 3-level meta-analysis to comprehensively investigate the overall effects of forage provision in young calves. We searched for studies published between 2000 and 2023 in Google Scholar, ScienceDirect, and X-Mol. Moderator analyses were performed to evaluate the effects of different forage sources, forage provision methods, starter forms, milk levels and forage levels on the heterogeneity of growth performance, rumen fermentation and nutrient digestibility outcomes in studies feeding forage to calves. Mixed-effect model was used to predict the relationship between forage level and performance. Funnel plot and Egger's test were used to determine publication bias. A total of 86 treatment comparisons from 36 articles were included in the final data set. The weighted mean difference (WMD) was used to evaluate the effect size, and the statistical heterogeneity of the effect size was estimated using Cochrane's Q test. The results showed that forage supplementation improved growth performance, structural growth, and development of rumen fermentation in calves. However, moderator analyses revealed that several factors, including forage source, feeding method, physical form of starter, milk feeding level and forage feeding level might contribute considerably to variability, resulting in significant heterogeneity in the effects of forage provision in calves. Larger effect sizes were found for oat hay (OH) supplementation rather than alfalfa hay (AH) or straw, feeding forage as a free-choice (FC) compared with a total mixed ration (TMR; defined as a mixture of calf starter and forage), especially when forage was fed as a FC resulting in higher total dry matter intake (TDMI) and body barrel. Forage supplementation was more effective in boosting calf growth in calves provided ground starter than in calves fed pelleted and textured starter. Greater effects were shown for AH supplementation than OH or straw in improving rumen fermentation parameters. Furthermore, compared with the preweaning period, the effect of providing forage on calves was more noticeable in the postweaning period. The results of the mixed-effects model analysis indicated that calves can be efficiently fed 12% of dry matter as forage during the preweaning period to support their growth and development. Meanwhile, 9% of dry matter might be the optimal level for feeding OH and straw to preweaning calves. More studies are essential to explore how different levels of AH dietary supplementation affects calves during the preweaning period, to improve the consistency and accuracy of the dose-response curve predictions. Overall, growth performance and rumen fermentation of dairy calves were affected by forage inclusion. Moreover, forage source, feeding method, physical form of starter, milk feeding level, and forage level are essential factors that result in different degrees of effect on the calf's performance and rumen fermentation.

Opportunities for Laboratory Testing to Inform Antimicrobial Use for Bovine Respiratory Disease: Application of Information Quality Value Stream Maps in Commercial Feedlots.

BACKGROUND/OBJECTIVES: The implementation of information quality value stream maps (IQ-VSMs) in food animal production systems can increase our understanding of the opportunities and challenges when using laboratory testing for antimicrobial resistance (AMR) to support antimicrobial stewardship (AMS). Our objectives were to (1) explore the implementation of information quality value stream mapping as a continuous improvement tool to inform decisions for bovine respiratory disease (BRD) management and AMS and (2) apply the information quality dimensions to identified Kaizen opportunities for the integration of laboratory data into BRD management systems to assess the appropriateness of BRD treatment plans in western Canadian feedlot production. METHODS: A 'Current State' IQ-VSM outlined the processes, available information, information processing steps, and control decisions contributing to BRD management and treatment in commercial western Canadian feedlots, recognizing that laboratory BRD pathogens and AMR data are typically not part of BRD management. RESULTS: The 'Future State' IQ-VSM incorporated Kaizen opportunities for improvement, including (i) the strategic collection of respiratory samples from representative samples of calves for laboratory analysis, regardless of clinical BRD status, (ii) compilation of laboratory data at the pen and feedlot levels, and (iii) analysis of pen- and feedlot-level laboratory data to inform the veterinarian's assessment of the appropriateness of current BRD treatment plans. CONCLUSIONS: The IQ-VSMs provided a valuable framework to visualize the integration of BRD pathogen and AMR laboratory data to support AMS and address any potential future testing requirements.

Bovine Coronavirus Prevalence and Risk Factors in Calves on Dairy Farms in Europe.

This study evaluated prevalence and risk factors in health, management, and biosecurity of bovine coronavirus (BCoV) in neonatal and weaned dairy calves on 125 dairy farms in Europe. Nasal and fecal swabs from neonatal calves, weaned calves, and fresh cows were analyzed for BCoV using RT-PCR, and blood and bulk milk samples were collected for BCoV antibody levels using ELISA. Multiple logistic regression models with random effects of herds were used to evaluate the herd health status, husbandry, management, and biosecurity associated with BCoV shedding (nasal and/or fecal PCR positive samples) in neonatal and weaned calves. BCoV was detected in 80% of herds and in 24% of neonatal calves, 23% of weaned calves, and 5% of fresh cows. The biosecurity scored on 109 dairies with Biocheck.Ugent was, on average, 60% (external score 71%, internal score 47%), and there was no clear association between various biosecurity measures on BCoV shedding in calves. Dry cow vaccination against BCoV reduced shedding in neonatal calves, whereas it was linked to increased shedding in weaned calves in these farms. Several husbandry factors, including nutrition (transition milk feeding and milk feeding levels) and management (group housing and weaning age), were associated with BCoV shedding in calves.

Combining Transcriptomics and Proteomics to Screen Candidate Genes Related to Bovine Birth Weight.

The placenta is a vital organ in bovine reproduction, crucial for blood supply, nutrient transport, and embryonic development. It plays an essential role in the intrauterine growth of calves. However, the molecular mechanisms governing placental function in calves remain inadequately understood. METHODS: We established transcriptome and proteome databases for low-birth-weight (LB) and high-birth-weight (HB) calf placentae, identifying key genes and proteins associated with birth weight through bioinformatics analyses that included functional enrichment and protein-protein interactions (PPIs). Both mRNA and protein levels were validated. RESULTS: A total of 1494 differentially expressed genes (DEGs) and 294 differentially expressed proteins (DEPs) were identified when comparing the LB group to the HB group. Furthermore, we identified 53 genes and proteins exhibiting significant co-expression across both transcriptomic and proteomic datasets; among these, 40 were co-upregulated, 8 co-downregulated, while 5 displayed upregulation at the protein level despite downregulation at the mRNA level. Functional enrichment analyses (GO and KEGG) and protein-protein interaction (PPI) analysis indicate that, at the transcriptional level, the primary factor contributing to differences in calf birth weight is that the placenta of the high-birth-weight (HB) group provides more nutrients to the fetus, characterized by enhanced nutrient transport (SLC2A1 and SLC2A11), energy metabolism (ACSL1, MICALL2, PAG2, COL14A1, and ELOVL5), and lipid synthesis (ELOVL5 and ELOVL7). In contrast, the placenta of the low-birth-weight (LB) group prioritizes cell proliferation (PAK1 and ITGA3) and angiogenesis. At the protein level, while the placentae from the HB group exhibit efficient energy production and lipid synthesis, they also demonstrate reduced immunity to various diseases such as systemic lupus erythematosus and bacterial dysentery. Conversely, the LB group placentae excel in regulating critical biological processes, including cell migration, proliferation, differentiation, apoptosis, and signal transduction; they also display higher disease immunity markers (COL6A1, TNC CD36, CD81, Igh-1a, and IGHG) compared to those of the HB group placentae. Co-expression analysis further suggests that increases in calf birth weight can be attributed to both high-efficiency energy production and lipid synthesis within the HB group placentae (ELOVL5, ELOVL7, and ACSL1), alongside cholesterol biosynthesis and metabolic pathways involving CYP11A1 and CYP17A1. CONCLUSION: We propose that ELOVL5, ELOVL7, ACSL1, CYP11A1, and CYP17A1 serve as potential protein biomarkers for regulating calf birth weight through the modulation of the fatty acid metabolism, lipid synthesis, and cholesterol levels.

Dry-ageing impacts on meat quality, oxidative stability, and release of free amino acids in striploins from dairy crossbred yearling and 2-year-old steers.

This study determined the impacts of dry-ageing on meat quality, oxidative stability, and release of free amino acids (FAAs) in striploins from dairy-crossbred yearlings and 2-year-old steers (n = 12 each group) over 21 days of in-bag dry-ageing. Dry-ageing increased weight losses, with higher % drying rates in yearling meat during dry-ageing, likely due to the smaller loin size and lower intramuscular fat content (P < 0.05). Yearling meat showed greater (P < 0.05) decreases in moisture content, but both meats reached similar moisture levels by day 21. pH values increased with dry-ageing with variations at different ageing times. Dry-ageing reduced a*, b*, and chroma while increasing L* and hue angles on day 21 (P < 0.05), likely due to dehydration and lipid oxidation (higher TBARS, P < 0.05) after 14 days, especially in yearling meat. The decreased levels (P < 0.05) of some monounsaturated fatty acids and conjugated linoleic acid cis-9, trans-11 were likely linked with lipid oxidation. Total levels of FAAs and essential amino acids increased significantly, especially within the first 7 days, with distinct patterns between the two meats. Dry-aged yearling meat contained more FAAs associated with sweat taste (e.g., glutamine and glycine) and fewer FAAs associated with bitter taste (e.g., phenylalanine and tyrosine). Carnosine levels varied and significantly increased after 21 days. Dry-ageing demonstrated distinct effects on dehydration, lipid oxidation, and release of FAAs in meat from yearlings compared with 2-year-old steers, which can be tailored to develop high-quality beef products with unique flavours.

Effects of Partial Replacement of Corn Grains With Mango Seed Kernel on Nutrient Digestibility, Blood Metabolites and Rumen Parameters of Growing Calves.

Fruit by-products are a sustainable and cost-effective alternative to traditional grain feed for livestock. One of the most important by-products is mango seed kernel (MSK), which can be used as a valuable energy source for feeding growing calves in the tropical and subtropical productive regions of the world. This study investigated the effect of replacing corn grains (CGs) with MSK on intake, nutrient digestibility, blood metabolites and rumen parameters. Eighteen growing male Friesian calves (200 ± 6.55 kg of body weight and 9-11 months old) were randomly assigned to three treatment groups. Three concentrate feed mixtures were formulated such that MSK replaced CG at 0%, 25% and 50%. Dry matter intake was unaffected, whereas dry matter, organic matter and fibre digestibility increased linearly (p < 0.05) with increased inclusion of MSK. Ruminal pH (p = 0.053) and total volatile fatty acid (VFA) concentration (p = 0.041) increased linearly. There was a linear decrease in cholesterol (p = 0.029) and AST (p = 0.028) levels in the blood of calves. In conclusion, this study demonstrated the positive effect of replacing 50% of CG with MSK on rumen parameters, including a higher ruminal pH and total VFA concentration, alongside higher nutrient digestibility. The dietary inclusion of mango seed can serve as a valuable and sustainable dietary component for growing calves.

Effects of propolis extract administration on immune parameters, faecal consistency scores, and growth performance of Holstein-Friesian calves.

The purpose of the study was to investigate the effect of Ethanolic Extract of Propolis (EEP) administration on immune parameters, faecal consistency scores, growth performance, and feed efficiency of Holstein Friesian calves. A total of 24 calves were divided into two different groups, control (n = 12) and EEP (n = 12). Both groups consisted of 6 male and 6 female calves. The calves were fed milk amounting to 10% of their birth weight each day until they reached 60 days of age. Additionally, they were given starter feed and dry hay once a day. Calves assigned to the EEP group received 4 ml of EEP daily. Use of EEP increased (P < 0.05) the serum IgG and IgM levels at 2 months of age compared to the control group. EEP also showed efficacy (P < 0.01) in reducing faecal consistency in calves throughout the study. The levels of IL-1ß, IL-6, TNF-α and NF-κB expression in calves treated with EEP were lower (P < 0.05) throughout the EEP application period. On the other hand, IGF-1 mRNA transcript levels were (P < 0.01) higher in EEP group calves than in the control group. Furthermore, EEP-fed calves consumed less dry matter for 1 kg of live weight gain during the weaning-4 months (P < 0.01) and birth-4 months (P < 0.05) periods. These results indicate that EEP supplementation, through its immunostimulatory effects, plays a crucial role in the control of neonatal calf diarrhoea. Growth and development as well as IGF-1, which stimulates growth in almost all somatic cells, was also significantly increased by EEP supplementation. The combined effect of the rich bioactive compounds found in EEP appears to have a significant impact on health and well-being, resulting in improved early life performance in dairy calves.

Whole genome sequence analysis reveals high genomic diversity and potential host-driven adaptations among multidrug-resistant Escherichia coli from pre-weaned dairy calves.

Food-producing animals such as dairy cattle are potential reservoirs of antimicrobial resistance (AMR), with multidrug-resistant (MDR) organisms such as Escherichia coli observed in higher frequency in young calves compared to older cattle. In this study, we characterized the genomes of enteric MDR E. coli from pre-weaned dairy calves with and without diarrhea and evaluated the influence of host-level factors on genomic composition. Whole genome sequence comparative analysis of E. coli (n = 43) revealed substantial genomic diversity that primarily clustered by sequence type and was minimally driven by calf diarrheal disease status (healthy, diarrheic, or recovered), antimicrobial exposure, and dietary zinc supplementation. Diverse AMR genes (ARGs)-including extended-spectrum beta-lactamase genes and quinolone resistance determinants-were identified (n = 40), with unique sets of ARGs co-occurring in gene clusters with large AMR plasmids IncA/C2 and IncFIB(AP001918). Zinc supplementation was not significantly associated with the selection of individual ARGs in E. coli, however analysis of ARG and metal resistance gene pairs identified positive associations between certain aminoglycoside, beta-lactam, sulfonamide, and trimethoprim ARGs with acid, tellurium and mercury resistance genes. Although E. coli in this study lacked the typical virulence factors of diarrheagenic strains, virulence genes overlapping with those in major pathotypes were identified. Among the 103 virulence genes detected, the highest abundance and diversity of genes corresponded to iron acquisition (siderophores and heme uptake). Our findings indicate that the host-level factors evaluated in this study were not key drivers of genomic variability, but that certain accessory genes in enteric MDR E. coli may be enriched. Collectively, this work provides insight into the genomic diversity and host-microbe interface of MDR E. coli from pre-weaned dairy calves.

Calf immunization protocols with low-virulence isolates of Anaplasma marginale: Analysis of post-inoculation effects and protection against natural challenge.

Bovine anaplasmosis is endemic and is of fundamental importance worldwide. Therefore, measures for controlling and preventing clinical diseases are warranted to ensure the reduction of associated economic losses. The objective of the present study was to assess the post-inoculation effects and protection conferred by three different protocols of inoculation of low-virulence live strains of Anaplasma marginale (UFMG1 and UFMG3) in field-challenged cattle. Sixty-eight Holstein calves with an average age of 17 days were randomly divided into four groups. The groups received two subcutaneous administrations spaced 40 days apart, at a dosage of 2 × 106 infected erythrocytes of the following A. marginale strains: G1 (UFMG1 + UFMG1); G2 (UFMG3 + UFMG3); G3 (UFMG1 + UFMG3); and G4 (control). Every two days, the animals were evaluated for rectal temperature, Packed Cell Volume (PCV), and blood smears. Blood samples were collected prior to inoculation, before the field challenge, and after the challenge period, nPCR and IFAT techniques were performed. There were no significant differences in rickettsemia levels, reduction in PCV, or antibody detection among the different inoculation strategies. Forty days after the second inoculation, 90 %, 84.6 %, and 90.9 % of the animals in G1, G2, and G3, respectively, tested positive using nPCR. After inoculation, the group G2, which received the UFMG3 inoculum, had a higher frequency of treatment (odds ratio of 6.7; 1.198-38.018 CI; p = 0.03), while groups G1 and G3 demonstrated similar treatment frequencies compared to the control. During the natural challenge phase, 13.3 % of animals in group G1 required treatment (odds ratio of 0.108; 0.018-0.635 CI; p = 0.014) compared to 58.8 % of the control group. Considering the results collectively, the protocol using the UFMG1 strain (G1) stands out for its potential to be safe and induce some degree of immunization against A. marginale, reducing the incidence of clinical disease and the need for treatment during natural challenge.

Effect of various flavors in starter diets on growth, behavior, and blood parameters of Holstein calves.

This study investigated the effect of adding various flavors to calf starter concentrates on the performance, behavior, and blood parameters of Holstein dairy calves. The hypothesis was that an optimal flavor enhancer would increase starter intake, improve growth performance, and possibly enable earlier weaning without adverse physiological effects. In Experiment 1, a cafeteria test was conducted with 80 pre-weaned calves to evaluate four synthetic flavor enhancers (salty, sweet, sour, bitter) at levels of 3.3, 6.6, and 9.9 g/kg dry matter (DM), and a control without a flavor enhancer. Experiment 2 tested higher levels (9.9, 19.8, 29.7 g/kg DM) of the sweet flavor enhancer sodium saccharin in a single cafeteria test with 20 calves. Experiment 3 compared three sweet flavor enhancers (sodium saccharin, stevia, sucralose) at 9.9 g/kg DM in another cafeteria test with 20 calves. After selecting sodium saccharin at 9.9 g/kg DM as the optimal flavor enhancer, Experiment 4 was conducted with 40 calves divided into a treatment group receiving the flavored starter and a control group without flavor. In Experiment 1, sodium saccharin at 9.9 g/kg DM resulted in the highest dry matter intake (DMI) of 347 g/d, significantly higher than the control (173 g/d). Experiment 2 revealed a quadratic effect with DMI peaking at 9.9 g/kg DM sodium saccharin (201.0 g/d) and declining at higher levels. Experiment 3 confirmed that sodium saccharin outperformed other sweet flavor enhancers, increasing DMI to 350 g/d compared to 251 g/d for the control. In Experiment 4, calves fed the starter concentrate with 9.9 g/kg DM sodium saccharin showed significantly higher DMI (1749 g/d), average daily gain (ADG; 730 g/d), and feed conversion ratio (FCR; 2.05) compared to the control group (DMI 1470 g/d, ADG 650 g/d, FCR 2.36). Furthermore, calves in the flavored treatment were weaned earlier (59 days) than the control group (64 days). Behavioral observations showed that the sweet flavor treatment increased the time spent on solid feed intake, rumination, and standing behavior. Calves fed the flavored starter had lower levels of cholesterol, triglycerides, and blood urea nitrogen, suggesting improved nutrient utilization. Overall, the results demonstrated the potential benefits of incorporating sodium saccharin as a sweet flavor enhancer in calf starter concentrates, leading to improved feed intake, growth performance, feed efficiency, final body weight (FBW), and behavioral patterns during the critical pre-weaning and post-weaning periods.

Male Holstein calves fed a milk replacer and pelleted calf starter containing a botanical extract or a direct fed microbial (DFM) alone or in combination.

Botanical extracts (BE; Apex, Adisseo, North America, Atlanta, GA) are known to enhance DMI and gut health, while direct fed microbials (DFM), such as a lactobacillus acidophilus fermentation product (EX: Excel; Pacer Technology, Inc., Murtaugh, ID), has demonstrated improved gut health and growth performance when fed to growing neonatal Holstein calves. The hypothesis was this combination may be synergistic to neonatal calf growth performance and intestinal health. Eighty 2-5-d old Holstein bull calves were blocked by BW and randomly assigned to 1 of 4 treatments arranged using a randomized complete block design. Treatments were: 1) Control: no additives; 2) BE added at 496 mg/kg to the calf starter (CS); 3) EX added to the CS at 2.50 g/kg with EX added to the milk replacer (MR) at 5 g/d; and 4) BE&EX: BE and EX added to CS at same rates and added EX to MR. Calves received 0.283 kg MR in 1.9 L fed 2 x/d for the first 14 d, then increased to 0.42 kg in 2.84 L fed 2x/d through d 35, followed by 0.42 kg MR in 2.84 L fed 1x/d through d 42, followed by weaning. The CS was a 25% CP DM basis mini-pellet and the MR was a 22:20 (CP:fat) fed 2x/d at 0630 and 1800 h along with free choice water. Weaning occurred after d 49 of the 70-d experiment. Calves fed CS EX alone demonstrated greater BW gain compared with calves fed BE&EX with calves fed Control and BE being intermediate and similar (63.9, 63.5, 65.0, and 59.7 kg for Control, BE, EX, and BE&EX, respectively). Total DMI (MR+CS) was lower for calves fed BE&EX compared with calves fed the remaining treatments (116.5, 114.2, 116.4, and 104.9 kg). The feeding of a BE in combination with EX (DFM) to neonatal calves reduced BW during wk 8, 9, and 10 and reduced 0-70 d ADG (874.7, 870.0, 889.7, and 817.6 g/d) compared with calves fed the remaining treatments. Calves fed BE&EX demonstrated the lowest calf starter intake during wk 4 through 10 compared with calves fed the other treatments. The study average calf starter intake for calves fed Control and EX was greater compared with calves fed BE&EX with calves fed BE being similar and intermediate. Calves fed EX and BE&EX demonstrated greater total d of fecal scour score = 1 (5.4, 5.7, 8.0 and 8.3 d) compared with calves fed Control and BE. Gains in frame measurements of hip height, hip width, withers height, and body length were similar while calves fed BE&EX demonstrated lower heart girth gains (19.2, 18.3, 19.7 and 17.6 cm) during the milk feeding phase (0 - 7 wk) compared with calves fed Control and EX, with calves fed BE being similar and intermediate. It is not known why this study demonstrated an antagonism between BE and EX in growth performance and feed intake but further research is needed to identify the mechanism of action.

Effects of Bacillus subtilis on Growth Performance, Metabolic Profile, and Health Status in Dairy Calves.

This study focused on assessing whether the inclusion of probiotics (B. subtilis) as feed additives during the preweaning stage can enhance the body weight and metabolic condition of neonatal calves. A total of 50 Holstein calves, all born on the same farm, were randomly divided into two homogeneous treatment groups after birth. The calves in the control group (CG) were fed a milk replacer (n = 25) (13 females and 12 males) and those in the B. subtilis-supplement-treated group (TG), (n = 25) (13 females and 12 males) were fed a milk replacer with 7.5 mL/calf/day of B. subtilis probiotic (complied with the manufacturer's guidelines). The probiotic was administered 24 h post-birth, signifying the start of the experimental period. It took one month to collect the animals. Body weight was measured at birth for all animals. A local veterinarian, working on the farm, conducted daily health checks of the calves, recording health parameters and any antibiotic treatments. Blood samples were collected from each calf at birth and 30, 60, and 90 days by puncturing the jugular vein using 10 mL evacuated serum tubes before morning feeding. Significant differences in body weight were observed between the CG and the TG at 30, 60, and 90 days of age. At 30 days, the TG had a 4.11% higher average body weight than the CG (54.38 kg vs. 52.71 kg). At 60 days, the TG's average weight was 3.75% higher (79.21 kg vs. 76.34 kg), and at 90 days, the TG had a 2.91% higher average weight (112.87 kg vs. 109.67 kg). At 30 days of age, the TG showed significantly lower AST activity, with a 41.12% decrease compared to the CG (51.02 IU/L vs. 72.00 IU/L). Conversely, GGT activity was significantly higher in the TG by 64.68% (40.64 IU/L vs. 14.35 IU/L). Phosphorus concentration at 30 days was also significantly higher in the TG by 9.36% (3.27 mmol/L vs. 2.99 mmol/L). Additionally, the TG had a significantly lower total protein concentration, with a 21.63% decrease at 30 days (46.32 g/L vs. 56.34 g/L) and a 20.28% decrease at 60 days (48.32 g/L vs. 58.12 g/L) compared to the CG. These findings indicate that dairy calves given conventional milk replacer along with a daily dose of 7.5 mL of B. subtilis probiotic experienced enhanced growth performance and a more favourable metabolic profile during the first 90 days of their lives.

Comparative Study of the Healing Process of Disbudding Wounds in Calves Using Bepanthene® or an Antibiotic Spray.

The process of disbudding female calves is a common procedure in many dairy farms, avoiding injuries caused by horns and reducing feed bunk space requirements. The most common method for disbudding calves is by the use of a cautery iron, responsible for destroying the horn-generating tissue. After the procedure, wounds may be treated with an antibiotic-based spray. Nowadays, antimicrobial resistance is a worldwide concern in both human and veterinary medicine, highlighting the need to invest in the monitoring of antimicrobial use and in the development of alternative treatments in favour of One Health. The goal of this study is to promote a reduction in the use of antibiotics in farm animals by investigating an alternative treatment for disbudding wounds. Bepanthene® (dexpanthenol, a derivative of pantothenic acid, a component of the B vitamin complex) is a plausible option, since it is widely used in human medicine for the treatment of skin irritations and burns. The comparison of the healing process of disbudding wounds treated with Bepanthene® or a chlortetracycline-based spray was achieved through the presentation of a randomly-ordered sequence of images of the lesions to a panel of convenience-selected and blinded-to-treatment evaluators, composed of seven veterinarian practitioners, five veterinary medicine students, and five human medical field nurses. In order to classify the lesions, the panel applied an adapted format of a validated healing scale (Bates-Jensen Wound Assessment Tool), incorporating seven parameters of evaluation, culminating in the values used for statistical analyses. In the practitioners' evaluation, a statistically significant effect for the factors of time and treatment in favour of Bepanthene® was found for the parameters "Edges", "Necrotic Tissue Type", and "Skin Colour Surrounding Wound", indicating that Bepanthene® is superior to the spray when considering these parameters of healing. The assessment by the veterinary students showed a significant effect for the factors of time and treatment for the parameters "Necrotic Tissue Type", in favour of the Bepanthene®, and "Granulation Tissue", in favour of the antibiotic spray, demonstrating no clear benefit for either treatment. Lastly, the evaluation performed by nurses showed a significant effect for the factors of time and treatment, in favour of the Bepanthene®, for the parameters "Necrotic Tissue Type" and "Skin Colour Surrounding Wound", leading to the conclusion that Bepanthene® is associated with better and faster healing when compared to the spray. Overall, these findings lead us to suggest that Bepanthene® presents a better healing index compared to a chlortetracycline-based spray, allowing it to be safely used as a substitute to an antimicrobial agent.

Pharmacokinetic Pattern of Menbutone in Calves after Single Intravenous and Intramuscular Administration.

Menbutone is a choleretic agent currently used in Europe to treat digestive disorders in livestock and dogs. Pharmacokinetic parameters were established in 4-month Holstein calves after intravenous (IV) and intramuscular (IM) administration. The drug was administered to 12 animals (10 mg/kg) for both IV and IM routes following a crossover design. Plasma samples were collected at various time points over 24 h and analyzed by reverse-phase high-performance liquid chromatography with a photodiode-array detector, following a method validated according to European Medicines Agency guidelines. Pharmacokinetic parameters were calculated using compartmental and non-compartmental methods. Menbutone followed a two-compartment open model after IV injection, with a total clearance (Cl) of 71.9 ± 13.5 mL/h/kg, an elimination half-life (t½ß) of 4.53 ± 2.45 h, and a volume of distribution at steady-state (Vss) of 310.4 ± 106.4 mL/kg. Non-compartmental elimination half-life (t½λ) was 4.2 ± 1.1 h. After IM administration, drug pharmacokinetics was best described by a one-compartment open model. The peak plasma concentration (Cmax) was 15.1 ± 4.3 µg/mL; the time to reach Cmax (tmax), 1.66 ± 0.55 h; and the mean absorption time (MAT), 2.50 ± 1.42 h. Absorption was high, with a fraction of the dose absorbed (F) of 83.5 ± 22.4%. Menbutone was rapidly eliminated from plasma for both routes of administration, with a fast and high IM bioavailability.

Effect of Age on the Pharmacokinetics of Marbofloxacin Following Intravenous Administration in Calves.

The aim of this study was to compare the pharmacokinetics of marbofloxacin after intravenous (IV) administration of a single dose of 10 mg/kg to calves of different ages. The study was carried on 1- (n = 6), 2- (n = 6), and 4-month-old (n = 6) Montofon calves. Plasma concentrations of marbofloxacin were measured using HPLC, and pharmacokinetic data were calculated by non-compartmental analysis. The elimination half-life (t1/2ʎz), volume of distribution at steady state (Vdss), total clearance (ClT), and area under the concentration-versus time curve (AUC0-∞) values of marbofloxacin in 1-month-old calves were 10.62 h, 1.03 L/kg, 0.08 L/h/kg, and 127.90 h*µg/mL, respectively. While the t1/2ʎz (from 10.62 to 3.36 h) and AUC0-∞ (from 127.90 to 47.35 h*µg/mL) decreased in parallel with the age of the calves, ClT (from 0.08 to 0.21 L/h/kg) increased. The Vdss of marbofloxacin was higher in 1- and 2-month-old calves compared to 4-month-old calves. After IV administration of marbofloxacin at a dose of 10 mg/kg, an ƒAUC0-24/MIC90 ratio of ≥ 125 was obtained for bacteria with MIC90 values of ≤ 0.60, ≤ 0.39 and ≤ 0.27 µg/mL in 1-, 2-, and 4-month-old calves, respectively. These results show that the antibacterial effect of marbofloxacin, which has concentration-dependent activity, decreases due to age-related pharmacokinetic changes and that the 10 mg/kg dose should be reviewed according to the MIC90 value of the bacteria.

Investigating the regulatory effect of Shen Qi Bu Qi powder on the gastrointestinal flora and serum metabolites in calves.

Object: To investigate the effects of Shen Qi Bu Qi Powder (SQBQP) on the average daily gain, blood indexes, gastrointestinal microflora, and serum metabolites of calves. Methods: A total of 105 calves were randomly assigned to three groups (n = 35 per group): the control group (C, fed with a basal diet for 21 days) and two treatment groups (SQBQP-L and SQBQP-H, fed with the basal diet supplemented with 15 and 30 g/kg of SQBQP), respectively for 21 days. The active components of SQBQP were identified using LC-MS/MS. Serum digestive enzymes and antioxidant indices were determined by ELISA kits and biochemical kits, respectively. Serum differential metabolites were analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), while flora in rumen fluid and fecal were analyzed by 16S rDNA sequencing. Further correlation analysis of gastrointestinal flora and serum metabolites of SQBQP-H and C groups were performed with Spearman's correlation. Results: The principal active components of SQBQP mainly includes polysaccharides, flavonoids, and organic acids. Compared to the control group (C), calves in the SQBQP-H (high dose) and SQBQP-L (low dose) groups showed a significant increase in serum amylase (AMS) levels (P<0.001), while lipase content significantly decreased (P<0.05). Additionally, the average daily gain, T-AOC, and cellulase content of calves in the SQBQP-H group significantly increased (P<0.05). Proteobacteria and Succinivibrio in the rumen flora of the SQBQP-H group was significantly lower than that of the C group (P<0.05). The relative abundance of Proteobacteria, Actinobacteria, Candidatus_Saccharibacteria, Deinococcus_Thermus, Cyanobacteria, and Succinivibrio in the SQBQP-H group was significantly increased (P<0.05), while the relative abundance of Tenericutes and Oscillibacter was significantly decreased (P<0.05). Serum metabolomics analysis revealed 20 differential metabolites, mainly enriched in amino acid biosynthesis, ß-alanine metabolism, tyrosine, and tryptophan biosynthesis metabolic pathways (P<0.05). Correlation analysis results showed that Butyrivibrio in rumen flora and Oscillibacter_valericigenes in intestinal flora were significantly positively correlated with average daily gain, serum biochemical indexes, and differential metabolite (-)-Epigallocatechin (R>0.58, P<0.05). Conclusion: SQBQP can promote calves weight gain and enhance health by modulating gastrointestinal flora and metabolic processes in the body.