Effect of prophylactic use of tulathromycin on gut bacterial populations, inflammatory profile and diarrhea in newborn Holstein calves

Waste milk consumption in dairy calves: Effects on innate immunity and inflammatory profile

Waste milk (WM) is commonly used in calf feeding to reduce rearing costs; however, its effects on the innate immune response remain unexplored. Therefore, this study aimed to evaluate the effects of WM on the innate immune response and inflammatory profile of pre-weaned dairy calves. Thirty male Holstein calves were assigned to receive pasteurized waste milk (PWM), saleable milk (SM), and WM (n = 10 in each group). Blood samples were collected on D7, D21, D35, D49, and D63 (days of life) to assess the white blood cell (WBC) count, phagocytic activity of polymorphonuclear cells (PMN), and nitric oxide (NO) production by monocyte-derived macrophages, in addition to the measurement of oxidative stress biomarkers and haptoglobin concentration. A trend towards a higher occurrence of respiratory disease was detected in calves that received WM, followed by PWM. A group effect (P = 0.00) was observed in absolute monocyte values, with higher values found in the WM group. Only the TBARS concentration showed a group × time interaction among all oxidative stress biomarkers, with the highest mean found in calves receiving WM, followed by those receiving PWM and SM. Elevated TBARS concentrations indicated higher lipid peroxidation, which may have resulted from the accumulation of reactive oxygen species (ROS) due to immune challenges from ingesting pathogens present in WM. Haptoglobin concentration was unaffected. WM promoted lipid peroxidation and antioxidant enzyme activity, suggesting a pro-inflammatory effect. The time-effects of PMN phagocytosis reflected the development of the immune system in neonatal calves, which is consistent with previous studies.

Progression of the faecal microbiome in preweaning dairy calves that develop cryptosporidiosis

BACKGROUND

Cryptosporidiosis is a diarrheal disease that commonly affects calves under 6 weeks old. The causative agent, Cryptosporidium parvum, has been associated with the abundance of specific taxa in the faecal microbiome during active infection. However, the long-term impact of these microbiome shifts, and potential effects on calf growth and health have not yet been explored in depth.

METHODS

Three hundred and forty-six (346) calves from three dairy farms had one faecal swab collected during the first week of life (W1). Thereafter, sampled calves were monitored for diarrhoeal disease and those that suffered a diarrhoea event were tested for C. parvum by lateral flow testing (LFT). Calves that experienced diarrhoea and tested positive for C. parvum by LFT were assigned to the Cryptosporidium-positive (Cp+) group (n = 32). Matched healthy (H) controls with no history of diarrhoea were selected from the remaining cohort (n = 33). The selected subset of calves (n = 65) was observed until weaning, collecting a faecal swab, at approximately Week 5 (W5) and Week 10 (W10) after birth, resulting in a total of 191 samples (W1; n = 65, W5; n = 64, W10; n = 62). 16S rRNA gene amplicon sequencing was performed on all extracted samples.

RESULTS

Analysis of the longitudinal microbiome showed significant changes in the microbial diversity and composition across all three time-points. Whilst Firmicutes were elevated in the Cp+ group at W5 compared to the H group, no other significant differences were detected between H and Cp+ groups. Whilst the core microbiota showed some taxa were exclusive to each group, the role of these taxa in health and disease has yet to be determined. Antibiotics were also found to have an impact on the relative abundance of some taxa. Though healthy calves received a significantly higher body condition score than Cp+ calves at W5, the difference did not reach significance at W10, suggesting that Cp+ calves may catch up to their healthy counterparts once the infection has resolved.

CONCLUSIONS

The findings of this study illustrated the changes in the microbial diversity and composition during the preweaning period in dairy calves. The results also indicated that the faecal microbiome is not predictive of cryptosporidiosis and implied that cryptosporidiosis doesn't cause long-term gut dysbiosis. This study furthered our understanding of the parasite-microbiome relationship and its impact on the bovine host.

Fecal microbiota of diarrheic calves: Before, during, and after recovering from disease

BACKGROUND

It is unknown if gastrointestinal dysbiosis in diarrheic calves causes disease or is a consequence of the disease.

OBJECTIVES

Describe the fecal microbiota of calves before, during, and after recovering from diarrhea.

ANIMALS

Fifteen female Holstein calves of 0 to 21 days old from a single farm. Seven calves remained healthy throughout the study, and 8 developed diarrhea on Day 14.

METHODS

Longitudinal cohort study. Microbiota composition was characterized by amplifying the V4 region of the 16S rRNA gene.

RESULTS

Diversity (Shannon index) increased with age in healthy and diarrheic calves from Day 3 to 21, but diarrheic calves had a lower diversity on the day diarrhea was first observed (Day 14). By Day 21, diversity increased in calves that recovered from diarrhea and was not significantly different from that of their healthy counterparts (P > .05). Weighted UniFrac distance showed significant differences in the fecal microbiota between diarrheic and healthy calves at Day 14 of age (PERMANOVA, P < .05), but not before or after diarrhea (PERMANOVA, P > .05). Lactobacillus, Clostridium Sensu Stricto 1, and Collinsella were differentially abundant on Day 10 in calves that developed diarrhea on Day 14 (P < .05).

CONCLUSION AND CLINICAL IMPORTANCE

The fecal microbiota of healthy and diarrheic calves evolved similarly during the first 10 days of age but differed significantly on the day of onset of diarrhea. Enriching Lactobacillus, Clostridium Sensu Stricto 1, and Collinsella before diarrhea onset could have been contributed to the development of diarrhea.

Moringa oleifera leaf polysaccharide regulates fecal microbiota and colonic transcriptome in calves

This study investigated the effects of Moringa oleifera polysaccharide on growth performance indicators, serum biochemical indicators, immune organ indicators, colonic morphology, colonic microbiomics and colonic transcriptomics in newborn calves. 21 newborn calves were randomly divided into three groups of 7 calves per treatment group: control group (no Moringa oleifera polysaccharide addition); low-dose group (Moringa oleifera polysaccharide 0.5 g/kg); and high-dose group (Moringa oleifera polysaccharide 1 g/kg). This trial used gavage to feed MOP to calves. The test lasted 8 weeks. Calves were humanely electroshocked on the last day of the trial and slaughtered afterwards. Thymus, spleen, blood and colonic contents were collected for further testing. The results of this trial showed that MOP significantly increased the body weight of newborn calves and reduced the rate of calf diarrhea, thus promoting calf growth. Fecal scores showed a linear decrease with the addition of MOP. In terms of serum biochemistry, feeding MOP significantly increased serum ALB levels in a linear fashion. In terms of serum antioxidants, feeding MOP linearly increased CAT and T-AOC levels and decreased MDA concentrations, and in terms of serum immunity, feeding MOP linearly increased IgA, IgG, and IgM levels. At the same time, MOP regulated the abundance of Firmicutes and Bacteroidetes in the intestinal tract of calves, which reduced the occurrence of diarrhea. In addition, moringa polysaccharide could regulate genes related to inflammatory signaling pathways such as MAPK signaling pathway, TGF-beta signaling pathway, PI3K-Akt signaling pathway and TNF signaling pathway in calves' intestine to reduce the occurrence of intestinal inflammation. In conclusion, MOP can be used as a novel ruminant additive for the prevention of enteritis in calves.

Evaluation of the Metabolic Relationship between Cows and Calves by Monitoring Calf Health and Cow Automatic Milking System and Metabolic Parameters

With this study, we investigated the relationship between a cow's and calf's metabolic state, and its effect on health status. To achieve this, 20 calves of primiparous and 20 calves of multiparous cows were selected. The calves were monitored for 30 days and scored for signs of disease, as described in McQuirk (2008); according to score, they were divided into healthier calves; the Low calf score group (LCS, 5-8), Medium calf score group (MCS, 9-12) and High calf score group (HCS, 14-17); or calves most prone to disease. Their mothers were monitored for the same period with a Lely Astronaut 3 herd management system (Lely, Maassluis, The Netherlands) for rumination time, milk yield, milk fat, protein, lactose concentrations and milk fat to protein ratio. Both cows and calves were sampled for blood, and concentrations of glucose with β-hydroxybutyrate were registered. The results indicate that primiparous cows had a 16% higher blood glucose concentration (3.03 mmol/L SE = 0.093) compared with multiparous cows (2.61 mmol/L, SE = 0.102) (p < 0.01), but no difference in calf glucose was recorded. Β-hydroxybutyrate levels did not differ significantly between cows and calves by parity group. Rumination time was longest in the HCS group at 550.79 min/d. and was 16% longer compared with the LCS group (461.94 min/d.; p < 0.001) and 8% longer compared with the MCS group (505.56 min/d.; p < 0.001). The MCS group rumination time mean was statistically significantly higher compared with the LCS group by 8% (p < 0.001). Milk yield was also highest in the HCS group (44.8 kg/d.): 19% higher compared with the MCS group (36.31 kg/d., p < 0.001) and 13% higher than the LCS group (38.83 kg/d., p < 0.001). There was also a significant difference between the MCS and LCS groups of 6% (p < 0.001). The HCS group had the highest milk fat concentration (4.47%): it was 4% higher compared with the LCS group (4.28%, p < 0.001) and 5% higher than the MCS group (4.25%, p < 0.001). Milk fat to protein ratio was highest in the HCS group (1.21) and was 7% higher than in the MCS group (1.12, p < 0.001) and 8% higher than in the LCS group (1.11, p < 0.001). The LCS group was determined to have the highest concentration of milk lactose (4.66%). It was 1% higher compared with the MCS group (4.62%, p < 0.001) and 1.07% higher than the HCS group (4.61%, p < 0.001). We can conclude that parity did not affect calf health status and that cows of the HCS group showed symptoms of negative energy balance expressed through higher milk yield, higher milk fat concentration and higher milk fat to protein ratio, with lower milk lactose concentration. Further and more thorough research is needed to evaluate the relationship between pregnant cows and calves.

Effects of supplementation with Saccharomyces cerevisiae products on dairy calves: A meta-analysis

Saccharomyces cerevisiae products (SCP) have the potential to promote the growth and development of the gastrointestinal tract and immunity in young livestock animals. However, the effects of SCP supplementation on calves are inconsistent among the reported studies in the literature. Hence, we performed a meta-analysis to comprehensively assess the effects of SCP on the growth performance, ruminal fermentation parameters, nutrients digestibility, ruminal histological morphology, serum immune response, and fecal pathogen colony counts in calves. We searched the Web of Science, ScienceDirect, PubMed, and China National Knowledge Infrastructure for relevant studies published up to October 1, 2021. After screening against a set of criteria, the data of 36 studies were included in our meta-analysis (2,126 calves in total). We evaluated the quality of the data using sensitivity analysis and assessed publication bias. Our meta-analysis revealed several important findings. First, SCP supplementation increased the ruminal short-chain fatty acid concentration, ruminal papilla height, and fiber digestibility, pointing toward stimulation of the development of the rumen in calves. Second, SCP supplementation increased the serum concentrations of total protein, IgA, and IgG but decreased fecal pathogen colony counts, suggesting that SCP could help calves to promote immunity (especially maintaining circulating concentrations of immunoglobulins in preweaning calves) and resistance to pathogens. Third, a subgroup analysis between preweaning and postweaning calves showed that SCP increased average daily gain and dry matter intake preweaning but not postweaning, suggesting that SCP is better supplemented to preweaning calves to achieve the best results. Forth, based on the dose-response curve, 24 to 25 g/d might be the optimal dose range of SCP supplementation (into starter feed) preweaning to achieve the best overall effect, meanwhile, we need more studies to improve the consistency and accuracy of the dose-response curve prediction. Overall, SCP supplementation improved growth performance, rumen development, and immunocompetence in calves, particularly in preweaning calves.

High-Risk Cattle Management and Stocker Calf Health: Modulation of the Bovine Respiratory Microbiome from a Systems Perspective

Bovine respiratory disease (BRD) affects animals in all segments of the North American beef industry. The segmented nature of the beef industry results in the marketing of cattle that are considered to be at high risk of developing BRD. The microbiota is the complex microbial ecosystem that exists in and on the body of all animals. The respiratory tract has its unique microbiota that is shaped by many factors. Stress reduction, appropriate nutritional management, strategic use of vaccines, and antimicrobial administration targeted to the highest risk individuals have the potential to stabilize an inherently unstable microbial population and enhance calf health.

Impact of Antibiotic Therapies on Resistance Genes Dynamic and Composition of the Animal Gut Microbiota

Antibiotics are major disruptors of the gastrointestinal microbiota, depleting bacterial species beneficial for the host health and favoring the emergence of potential pathogens. Furthermore, the intestine is a reactor of antibiotic resistance emergence, and the presence of antibiotics exacerbates the selection of resistant bacteria that can disseminate in the environment and propagate to further hosts. We reviewed studies analyzing the effect of antibiotics on the intestinal microbiota and antibiotic resistance conducted on animals, focusing on the main food-producing and companion animals. Irrespective of antibiotic classes and animal hosts, therapeutic dosage decreased species diversity and richness favoring the bloom of potential enteropathogens and the selection of antibiotic resistance. These negative effects of antibiotic therapies seem ineluctable but often were mitigated when an antibiotic was administered by parenteral route. Sub-therapeutic dosages caused the augmentation of taxa involved in sugar metabolism, suggesting a link with weight gain. This result should not be interpreted positively, considering that parallel information on antibiotic resistance selection was rarely reported and selection of antibiotic resistance is known to occur also at low antibiotic concentration. However, studies on the effect of antibiotics as growth promoters put the basis for understanding the gut microbiota composition and function in this situation. This knowledge could inspire alternative strategies to antibiotics, such as probiotics, for improving animal performance. This review encompasses the analysis of the main animal hosts and all antibiotic classes, and highlights the future challenges and gaps of knowledge that should be filled. Further studies are necessary for elucidating pharmacodynamics in animals in order to improve therapy duration, antibiotic dosages, and administration routes for mitigating negative effects of antibiotic therapies. Furthermore, this review highlights that studies on aminoglycosides are almost inexistent, and they should be increased, considering that aminoglycosides are the first most commonly used antibiotic family in companion animals. Harmonization of experimental procedures is necessary in this research field. In fact, current studies are based on different experimental set-up varying for antibiotic dosage, regimen, administration, and downstream microbiota analysis. In the future, shotgun metagenomics coupled with long-reads sequencing should become a standard experimental approach enabling to gather comprehensive knowledge on GIM in terms of composition and taxonomic functions, and of ARGs. Decorticating GIM in animals will unveil revolutionary strategies for medication and improvement of animals' health status, with positive consequences on global health.

The Antibiotic Treatment of Calf Diarrhea in Four European Countries: A Survey

Neonatal calves are commonly affected by diarrhea caused by different pathogens, but not always bacteria. Yet, antibiotics are routinely used as a treatment to an unknown extent. It was our goal to survey antibiotic use for the treatment of neonatal calf diarrhea in different countries and to identify influencing factors. A total of 873 farmers and veterinarians in Austria, Belgium, Portugal, and Scotland participated in a voluntary online survey. The data were analyzed using classification and regression tree analyses and chi² tests. Overall, 52.5% of the participants stated that they use antibiotics when treating neonatal calf diarrhea. Of those, 27% use them always, and 45% use highest priority critically important antibiotics. The most important factor differentiating antibiotic use practices was the country the participants were from, which could be due to regulatory differences between the countries. All antibiotic products stated were licensed for use in cattle, but several were not licensed for the treatment of diarrhea in calves. Our study shows that there is an urgent need for more scientific evidence to define best practices for the treatment of neonatal calf diarrhea. Furthermore, consensual criteria for antibiotic therapy must be defined, and targeted training for farmers and veterinarians must be provided.