Preweaned Holstein Calves Research Articles

An organic zinc-chelating-peptide GQ-Zn supplementation ameliorates diarrhea through regulate gut microbiota and metabolites in pre-weaning Holstein calves

An organic zinc-chelating-peptide GQ-Zn supplementation ameliorates diarrhea through regulate gut microbiota and metabolites in pre-weaning Holstein calves

Changes in skin temperature and behaviors of preweaning Holstein calves in a hot environment monitored by a multimodal tail-attached device

This study aimed to determine the applicability of a tail-attached device in monitoring animal-based indicators (ABI) associated with changes in environmental conditions in calves through investigating the relationship between sensor-derived ABI and the temperature-humidity index (THI). Furthermore, to identify effective ABI indicative of heat stress status, sensor-derived ABI of calves under differing heat stress levels based on rectal temperature (RT) were compared. The tail-attached device, which is capable of measuring skin temperature (ST), activity intensity, and roll angle along the longitudinal axis of the tail at 3-min intervals, was attached to 99 preweaning female Holstein calves for an average of 4 wk (26.4 ± 6.8 d). After selecting data from mild to hot days (daily average THI of ≥55), physiological (daily maximum tail ST) and behavioral (daily average activity intensity, daily total lying time, and daily total body position change) ABI were computed, and their relationship with the daily average THI was determined using piecewise regression analysis. Additionally, during the hot season, RT of 20 randomly selected tested calves were measured thrice a week (every 2.4 ± 0.5 d), and a comparison was conducted between the ABI of calves with normal RT (<39.5°C) and those with high RT (≥39.5°C), utilizing data from days characterized by potential heat stress (daily average THI of ≥75). During the study, ambient temperature (°C) and relative humidity (%) were recorded every 10 min using an automatic digital data logger, from which the daily average THI was calculated. Piecewise regression analysis identified THI breakpoints of 73.6 for tail ST, 79.1 for average activity intensity, 72.3 for lying time, and 79.1 for position change. All the tested ABI tended to increase as THI increased, and this trend was pronounced in tail ST, activity intensity, and position change after the breakpoint. These 3 ABI were higher in calves with high RT compared with those with normal RT, whereas lying time shared similar values between the RT groups. Overall, these findings suggest that the tail-attached device can simultaneously monitor both physiological and behavioral ABI in calves, and among the ABI, tail ST, activity intensity, and position change are the effective ABI indicative of heat stress status.

Evidence of innate training in bovine γδ T cells following subcutaneous BCG administration.

The Bacillus Calmette Guerin (BCG) vaccine has been shown to induce non-specific protection against diseases other than tuberculosis in vaccinated individuals, attributed to the induction of trained immunity. We have previously demonstrated that BCG administration induces innate immune training in mixed peripheral blood mononuclear cells and monocytes in calves. Gamma Delta (γδ) T cells are non-conventional T cells that exhibit innate and adaptive immune system features. They are in higher proportion in the peripheral blood of cattle than humans or rodents and play an essential role in bovine immune response to pathogens. In the current study, we determined if BCG administration induced innate immune training in bovine γδ T cells. A group of 16 pre-weaned Holstein calves (2-4 d age) were enrolled in the study and randomly assigned to vaccine and control groups (n=8/group). The vaccine group received two doses of 106 colony forming units (CFU) BCG Danish strain subcutaneously, separated by 2 weeks. The control group remained unvaccinated. Gamma delta T cells were purified from peripheral blood using magnetic cell sorting three weeks after receiving the 1st BCG dose. We observed functional changes in the γδ T cells from BCG-treated calves shown by increased IL-6 and TNF-α cytokine production in response to in vitro stimulation with Escherichia coli LPS and PAM3CSK4. ATAC-Seq analysis of 78,278 regions of open chromatin (peaks) revealed that γδ T cells from BCG-treated calves had an altered epigenetic status compared to cells from the control calves. Differentially accessible peaks (DAP) found near the promoters of innate immunity-related genes like Siglec14, Irf4, Ifna2, Lrrfip1, and Tnfrsf10d were 1 to 4-fold more accessible in cells from BCG-treated calves. MOTIF enrichment analysis of the sequences within DAPs, which explores transcription factor binding motifs (TFBM) upstream of regulatory elements, revealed TFBM for Eomes and IRF-5 were among the most enriched transcription factors. GO enrichment analysis of genes proximal to the DAPs showed enrichment of pathways such as regulation of IL-2 production, T-cell receptor signaling pathway, and other immune regulatory pathways. In conclusion, our study shows that subcutaneous BCG administration in pre-weaned calves can induce innate immune memory in the form of trained immunity in γδ T cells. This memory is associated with increased chromatin accessibility of innate immune response-related genes, thereby inducing a functional trained immune response evidenced by increased IL-6 and TNF-α cytokine production.

Effect of maternal bovine appeasing substance on health and performance of preweaned dairy calves

This study aimed to evaluate the impacts of a maternal bo­vine appeasing substance (MBAS) administered to preweaned Holstein calves on their health and performance. In total, 410 calves individually allocated were enrolled (Treatment, n = 205; Control, n = 205). Treated calves received a topical application of MBAS to the nuchal skin (2.5 ml) and the skin above the muzzle (2.5 ml) at one day of age and then every 14 days until weaning at 60 days of life. An extra dose was ap­plied when calves were moved from hutches to collective pens at approximately 100 days of age. Calves allocated to the control group did not receive any kind of treatment. MBAS re­duced the incidence of diarrhea (treatment = 58.6% vs control = 70.8%; P = 0.01) as well as mortality risk (treatment = 2.4% vs control = 7.8%; P = 0.02). Furthermore, calves treated with MBAS had greater (P = 0.002) body weight 7 days after calves were moved from the hutches to the collective pens. There­fore, the use of MBAS during the preweaning period appears to be an effective strategy to improve health and growth of dairy calves.

Comparable Evaluation of Nutritional Benefits of Lactobacillus plantarum and Bacillus toyonensis Probiotic Supplementation on Growth, Feed Utilization, Health, and Fecal Microbiota in Pre-Weaning Male Calves.

This study was conducted to investigate the impact of probiotic supplementation using Lactobacillus plantarum DSA 20174 and/or Bacillus toyonensis ATCC 55050 on growth performance, blood parameters, hematological measures, and fecal microbiota in pre-weaning Holstein calves. Thirty-two four-day-old male calves with a similar genetic background, weighing an average of 38.27 ± 0.12 kg, were randomly assigned to four groups. The groups consisted of a control group (CON) without supplementation, a group receiving B. toyonensis (BT) at 3 × 109 cfu/calf/day, a group receiving L. plantarum (LP) at 1 × 1010 cfu/calf/day, and a group receiving a combination of LP and BT (LP + BT) at half the dosage for each. The study found that calves supplemented with LP and LP + BT experienced significant improvements in average daily gain and final body weight compared to the control group. The LP + BT group showed the most positive effects on TDMI, starter intake, and CP intake. RBC counts tended to be higher in the probiotic groups, with the LP + BT group having the highest values. The LP + BT group also had higher total protein, albumin, globulin, and hematocrit concentrations. All probiotic groups showed higher serum IgG concentrations. Probiotic supplementation led to increased total bacterial count and decreased levels of E. coli, salmonella, and clostridium. The LP + BT group had a significant decrease in coliform count, while both LP and LP + BT groups had increased Lactobacillus populations. In conclusion, LP + BT probiotic supplement showed the most beneficial effects on growth, feed efficiency, blood constituents, and modulation of fecal microbiota composition.

Effects of rosemary essential oil as a feed additive on performance, rumen fermentation, and blood parameters in preweaning Holstein calves

The objective of this study was to investigate the effects of rosemary essential oil (REO) supplementation on growth performance, some blood metabolites and rumen fermentation in calves throughout the suckling period. Fourty Holstein calves were randomly divided to four dietary groups. Each group consisted of 10 calves; control with no REO supplementation (CON), supplementation of 500 mg/d REO (REO1), supplementation of 1000 mg/d REO (REO2) and supplementation of 2000 mg/d REO (REO3). REO supplementation quadratically increased (P&lt;0.05) the calf starter (CS) intake, average daily gain (ADG) and feed efficiency. Calves fed REO1 and REO2 had the highest CS intake and ADG. Ruminal ammonia-N concentration was lower (P=0.02) for calves fed REO3 than calves fed REO1, but total volatile fatty acids concentration was higher (P&lt;0.01) for calves fed REO1 compared with calves fed CON and REO3. The concentrations of ghrelin, NEFA and BHBA increased linearly (P&lt;0.05) with increasing levels of REO. Calves fed REO2 and REO3 had the highest concentration of ghrelin. Cholesterol concentration decreased linearly (P&lt;0.01) with increasing REO levels on d 56. Calves fed REO2 and REO3 had the lowest cholesterol concentration. Also, serum IgG concentration was higher (P&lt;0.01) in calves fed REO2 and REO3 compared with calves fed CON on d 28. It was concluded that the addition of different amounts of rosemary essential oil can positively change some rumen and blood metabolites of calves, as well as the supplementation of REO may have a beneficial effect on growth performance by increasing ghrelin.

Subcutaneous Bacillus Calmette-Guérin Administration Induces Innate Training in Monocytes in Preweaned Holstein Calves.

The bacillus Calmette-Guérin (BCG) vaccine, administered to prevent tuberculosis, is a well-studied inducer of trained immunity in human and mouse monocytes. We have previously demonstrated that aerosol BCG administration induces innate training in calves. The current study aimed to determine whether s.c. BCG administration could induce innate training, identify the cell type involved, and determine whether innate training promoted resistance to bovine respiratory syncytial virus (BRSV) infection, a major cause of bovine respiratory disease in preweaned calves. A total of 24 calves were enrolled at 1-3 d of age and blocked by age into two treatment groups (BCG, n = 12; control, n = 12). BCG was given s.c. to preweaned calves. The control calves received PBS. We observed a trained phenotype, demonstrated by enhanced cytokine production in response to invitro stimulation with LPS (TLR-4 agonist) in PBMCs and CD14+ monocytes from the BCG group 2 wk (IL-1β, p = 0.002) and 4 wk (IL-1β, p = 0.005; IL-6, p = 0.013) after BCG administration, respectively. Calves were experimentally infected via aerosol inoculation with BRSV strain 375 at 5 wk after BCG administration and necropsied on day 8 postinfection. There were no differences in disease manifestation between the treatment groups. Restimulation of bronchoalveolar lavage fluid cells isolated on day 8 after BRSV infection revealed enhanced IL-1β (p = 0.014) and IL-6 (p = 0.010) production by the BCG group compared with controls. In conclusion, results from our study show that s.c. administration of the BCG vaccine can induce trained immunity in bovine monocytes and influence cytokine production in the lung environment after BRSV infection.

Differential gene expression in peripheral leukocytes of pre-weaned dairy calves with respiratory disease

Bovine respiratory disease (BRD) is a leading cause of calf morbidity and mortality in both beef and dairy sectors of the United States cattle industry resulting in financial losses and compromised welfare. Differential gene expression (DGE) al­lows detailed insight into individual immune responses and can identify enriched pathways and biomarkers that contrib­ute to disease susceptibility and outcome. Differential expres­sion of genes related to innate immune function has been well documented in both feedlot and post-weaned dairy cattle with experimentally induced or naturally occurring BRD. However, little is known regarding DGE in pre-weaned Holstein calves. Therefore, the aims of this study were to evaluate gene expres­sion in peripheral leukocytes relative to BRD diagnosis, dis­ease progression and age progression in Holstein heifer calves throughout the preweaning period.

Evaluation of tributyrin supplementation in milk replacer on diarrhoea occurrence in preweaning Holstein calves

Neonatal calf diarrhoea is one of the most important health challenges in cattle herds causing substantial economic losses and antimicrobial use. Due to the raising problem of antimicrobial resistance, effective alternatives are urgently required, in line with European policies. The aim of this study was to evaluate the effect of tributyrin supplementation in milk replacer on diarrhoea, performance and metabolic status in preweaning Holstein calves. Twelve newborn calves, after colostrum administration, were randomly allotted in two experimental groups for 42 days: control (CTRL) fed milk replacer, tributyrin (TRIB) fed milk replacer supplemented with 0.3% of liquid tributyrin on milk powder weight. Calves BW was recorded on a weekly basis from day 7 to day 42, and feed intake was recorded daily to calculate zootechnical performance. Faecal consistency was assessed daily through the faecal score (0–3 scale; considering diarrhoea moderate = 2 and severe = 3). Faecal samples were collected weekly from rectal ampulla for microbiological analysis by plate counting method evaluating the number of total bacteria, lactic acid bacteria and coliform bacteria. On day 0 and day 42, individual blood samples were collected from jugular vein for metabolic profile analysis. Serum samples of day 42 were also evaluated for the antioxidant barrier using a colorimetric test, while glucagon-like peptide 2 and diamine oxidase concentrations were measured through immunoenzymatic assays. Tributyrin supplementation did not influence the zootechnical performance of calves over 42 days of trial. Diarrhoea frequency was significantly lower in TRIB compared to CTRL group (27.91 and 38.37%; P < 0.01) considering the whole experimental period. In particular, the major effect was observed for moderate diarrhoea in TRIB group that showed a significantly reduced frequency compared to CTRL (P < 0.01) thus suggesting a preventive effect of tributyrin. Faecal total bacterial, lactic acid and coliform bacteria counts did not show differences between groups. Urea serum concentrations tended to be lower in TRIB compared to CTRL, indicating an efficient utilisation of dietary protein. Antioxidant barrier and glucagon-like peptide 2 were comparable between CTRL and TRIB on day 42. Diamine oxidase concentrations were significantly decreased in TRIB compared to CTRL group after 42 days of trial (P < 0.01), suggesting a higher gut epithelial integrity probably due to lower diarrhoea frequency and the nourish effect of tributyrin on enterocytes. In conclusion, tributyrin could be considered as a valuable bioactive feed additive to decrease the neonatal diarrhoea occurrence and support intestinal integrity in preweaning calves.

Effects of milk-derived bioactive peptide VPP on diarrhea of pre-weaning calves.

A well-known milk-derived bioactive tripeptide, VPP (Val-Pro-Pro) has good anti-inflammatory, anti-hypertension, and anti-hydrolysis properties. However, whether VPP can alleviate calf intestinal inflammation is unclear. In this experiment, the effects of VPP on growth, diarrhea incidence, serum biochemical indices, short-chain fatty acids, and fecal microorganisms were examined in pre-weaning Holstein calves. Eighteen calves with similar birth date, body weight, and genetic background were randomly assigned equally to two groups (n = 9). The control group was given 50 mL of phosphate buffer saline before morning feeding, whereas the VPP group received 50 mL of VPP solution (100 mg/kg body weight/d). The study lasted for 17 days, with the first 3 days used for adaptation. Initial and final body weights were determined, and daily dry matter intake and fecal score were recorded throughout the study. Serum hormone levels and antioxidant and immune indices were measured on day 14. Fecal microorganisms were collected on days 0, 7, and 14, and 16S rDNA sequencing was performed. Oral administration of VPP did not significantly affect calf average daily feed intake and body weight, but the growth rate in body weight was significantly higher in the VPP group than in the control group on day 7 (P < 0.05). Compared with the control, VPP significantly decreased serum TNF-α and IL-6 contents (P < 0.05), and concentrations of nitric oxide and IL-1β also decreased but not significantly (0.05 < P < 0.1). After seven days of VPP, relative abundances of g_Lachnoclostridium, uncultured_bacterium_, and g_Streptococcus in fecal samples increased significantly (P < 0.05). Compared with the control, VPP significantly increased concentrations of the fecal short-chain fatty acids n-butyric acid and isovaleric acid (P < 0.05). In conclusion, VPP can relieve intestinal inflammation and alleviate the degree of diarrhea in pre-weaning calves.

A randomized trial on the effects of heat stress abatement on environmental conditions and growth, feed efficiency, and concentration of metabolites of pre-weaned female Holstein calves

Heat abatement strategies for pre-weaned calves are seldom adopted. Our objectives were to determine the effects of adding fans to barns on environmental conditions and growth, feed efficiency, concentration of metabolites and health of pre-weaned female Holstein calves. Calves born from July 15th to 30th of 2019 were eligible for enrollment. At birth (d 0), calves were assigned randomly to: SH (n = 125) – hutch under a barn with no cooling, SHF (n = 101) – hutch under a barn cooled through fans. Body weight (BW) and wither-height were measured at birth and d 68. Calves were evaluated thrice weekly (0700–1000 h) using the Calf Health Scoring Chart (UW-Madison). A sub-sample of hutches (SH = 26, SHF = 25) was evaluated for air velocity and temperature at 1000 and 1600 h thrice weekly and calves housed in these hutches were evaluated for rectal temperature (RT) at 1600 h and respiratory rate (RR) at 1000 and 1600 h. Calves were fed a liquid diet twice a day (d 2–18 = 5.56 L/d; d 19–49 = 7.58 L/d; d 50–56 = 3.84 L/d; d 57–63 = 1.64 L/d) and starter ad libitum starting on d 14. A sub-sample of calves (SH = 56, SHF = 44) had intakes of liquid feed and starter measured daily, BW and wither-height measured weekly from birth to d 68, and blood sampled on d 1, 14, 28, 42, 49, 52, 56, 58, 63 and 65 for the measurement of fatty acids, β-hydroxybutyrate, and glucose concentrations. The SHF treatment increased air velocity by 0.8 m/sec and reduced air temperature by 0.3 ºC. The SHF treatment reduced RT (38.70 ± 0.03 vs. 38.78 ± 0.02 °C) and the percentage of calves with hyperthermia (RT ≥ 39.2 °C; 20.6 ± 1.9 vs. 30.2 ± 2.0%) at 1000 h. Treatment did not affect feed efficiency (SH = 0.53 ± 0.01, SHF = 0.53 ± 0.01 g of BW gained/g of dry matter intake), nor did it affect BW (SH = 81.6 ± 0.7, SHF = 82.9 ± 0.8 kg) and wither-height (SH = 89.5 ± 0.3, SHF = 90.1 ± 0.3 cm) on d 68. Concentrations of metabolites were not affected by treatment. Cooling the environment through fans reduced RT and the risk of hyperthermia at 1000 h but it did not affect performance of pre-weaned Holstein calves.

Early detection of disease onset through changes in appearance of pre-weaning calves.

The onset of diseases in pre-weaning calves can lead to changes in their appearance, which can aid early disease detection. This study measured the changes in appearance that led to disease onset in 66 pre-weaning Holstein calves. The appearance scores of the calves were recorded for 7 days before the onset of digestive or respiratory diseases. Appearance features (ear position, head position, topline curve, hair coat length, hair coat gloss, eye opening, and sunken eyes) were recorded using video camera images and scored from 0 (healthy) to 2 (poor). Among the calves with respiratory diseases, the proportion of calves with a score of 0 for ear position decreased linearly over time (p = 0.0437). Among the calves with digestive diseases, the proportion of calves with a score of 2 for hair coat length increased linearly over time (p = 0.0197). Among the calves with both respiratory and digestive diseases, the proportion of calves with scores of 1 for the topline curve and 2 for eye opening increased linearly over time (p = 0.0191). Therefore, early signs of disease manifest as different appearance features depending on the type of disease before its onset.

Impacts of Reducing Protein Content in Milk Replacer on Growth Performance and Health of Young Calves.

Simple SummaryThe appropriate protein percentages in calf milk replacer (MR) is a key factor in determining the optimal growth of young calves. We hypothesized that elevated MR feeding with a lower protein content may not negatively affect the performance, metabolic traits, and health of the calves. The question on is: how much protein is required by calves in order to achieve an intended growth rate? In the present study, the average daily gain was similar between both groups fed MR of 19% and 22% protein, although crude protein intake was reduced in the group fed MR of 19% protein. Even though the mean dry matter content in the feces of group fed MR of 19% protein was partly lower, the incidence of diarrhea was not greater in this group. Both groups fed MR of 19% and 22% protein had very great serum insulin-like growth factor 1 (IGF-1) concentrations. This confirms that both groups, i.e., also the animals fed with a crude protein-reduced MR, were adequately supplied with nutrients. Furthermore, the lower serum urea concentration in the 22% protein in MR calves indicates that they probably had a greater body protein accretion and the proportion of amino acids for energy supply was lower than in the 19% protein in MR calves. Thus, the urea content in the blood serum indicated that a higher protein intake during the pre-transition period is feasible with a higher protein content in the MR.In the present study, a drinking amount of 10 L of milk replacer (MR) was allowed to dairy calves in order to approach the natural drinking behavior. The question is: how much protein is required by calves in order to achieve an intended growth rate? For this reason, sixty-eight pre-weaned Holstein calves were divided into two groups and fed with 10 L/d of MR containing either 22% protein (MR22) or 19% protein (MR19) at an almost comparable energy intake. Effects on performance, metabolic status, and health were compared. Feed intake, growth performance, and health status were monitored during the pre-transition, transition, and postweaning phase (until 157 d of age). Total feed intake, and intake of MR, body weight (BW), and average daily gain (ADG) were not significantly different between MR22 and MR19 during the entire experimental period (p > 0.05). At d 42, calves in MR19 group showed greater serum levels of growth hormone (16.2 vs. 22.2 ng/mL; p = 0.02), insulin-like growth factor 1 (262 vs. 291 ng/mL; p = 0.03), and urea (2.86 vs. 3.04 mmol/L; p < 0.01). The results of the present study suggested that when high amounts of MR are provided, the protein content in MR can be reduced to 19% without any adverse effects on growth performance as well as on health status of dairy calves.

Induction of leaky gut by repeated intramuscular injections of indomethacin to preweaning Holstein calves

This study was designed to develop a protocol for repeated intramuscular indomethacin injections to replicate leaky-gut-like symptoms in male Holstein calves to model and study the detrimental effects of leaky gut on gut tissue function and inflammatory response. A generalized randomized block design was used to evaluate how repeated indomethacin intramuscular injections affected the development of leaky gut in 18 male Holstein calves. Animals were enrolled at 3 ± 1 d of life, and after 21 d of adaptation, they were randomly assigned to 1 of 3 treatments consisting of intramuscular saline or indomethacin injections every 12 h for 48 h: (1) control (CTL), saline injection, (2) low intramuscular indomethacin (INDO-L) dosed at 1.2 mg/kg of body weight (BW), and (3) high intramuscular indomethacin (INDO-H) dosed at 2.4 mg/kg of BW. During the challenge, milk intake, starter intake, fecal scores, and rectal temperature were measured daily, and BW was measured at the beginning and at the end of the challenge. Plasma samples were used to measure the recovery of markers of intestinal permeability before and after the challenge by dosing lactulose, d-mannitol, and chromium-EDTA. In addition, several cytokines were measured in plasma during the challenge. Calves were dissected at the end of the challenge to obtain tissue and digesta samples from the gastrointestinal tract and liver. No treatment differences were observed for starter and milk intakes, fecal scores, BW, and rectal temperature. The difference in marker concentrations between pre and post challenges was higher for INDO calves compared with CTL calves in the case of lactulose and chromium-EDTA. In addition, chemokine ligand 2 and 4 and IL-6 were higher for INDO-H calves compared with CTL. Both doses of indomethacin resulted in reductions in villus length and surface area in the distal jejunum and ileum and reductions in crypt depth and width in the colon. We showed that repeated indomethacin injections over a 48-h period induced leaky-gut-like symptoms in a region-specific manner, affecting mainly the distal section of the intestine. This outcome was characterized by histomorphological changes in the distal jejunum, ileum, and colon and by increased gut permeability. Interestingly, changes in liver morphology and immune function also occurred, possibly due to the increased translocation of foreign antigens breaching the epithelial cell wall. The leaky gut challenge model described here could be used to improve understanding of the pathogenesis of intestinal disorders in cattle and provide a reliable alternative for testing feed additives with intestinal health benefits.

Effect of Astragalus membranaceus Root on the Serum Metabolome of Preweaning Dairy Calves

The effect of the Astragalus membranaceus root (AMR) on the serum metabolic profiles of preweaning calf were investigated in this study. Sixteen preweaning Holstein calves were randomly allocated into two groups with eight calves per group, and offered a control basal diet (CON group) or supplemented with 20 g superfine powder of AMR (AMR group) for 14 day. Serum samples were collected from calves on day 0, 7 and 14. Serum albumin, globulin, total protein, glucose, reduced glutathione and superoxide dismutase were evaluated. Serum metabolic profiling was analyzed using ultra-high-performance liquid chromatography–time-of-flight mass spectrometry. The results demonstrated that there were no significantly difference of total protein, glucose, reduced glutathione and superoxide dismutase between the CON group and AMR group (p &gt; 0.05), while within the CON group and AMR group, serum glucose showed a continuous upward trend from 0 day to 14 day (p &lt; 0.001). Untargeted metabolomics analysis found the metabolism of preweaning calf was considerably changed during growth, mainly including amino acid metabolism and carbohydrate metabolism and showed an increasing in protein synthesis and gluconeogenesis. 19 differential metabolites have been screened after supplementing AMR for 14 day, nine of which were up-regulated, including ornithine, L-pyroglutamic acid, L-proline and D-proline, and 10 down-regulated, containing L-kynurenine, 5-hydroxyindoleacetate, linoleic acid and 4-pyridoxic acid. Pathway analysis found these metabolites mainly participated in three primary pathways: arginine and proline metabolism, tryptophan metabolism and glutathione metabolism (p &lt; 0.05), while linoleic acid metabolism and vitamin B6 metabolism were also enriched (0.1 &lt; p &lt; 0.05). Such metabolic changes reflected the enhancement of the antioxidant and anti-inflammatory capacity of preweaning calves.

Moringa oleifera leaf meal as a feed supplement for dairy calves

The study evaluated the effects of supplements of Moringa oleifera leaf meal (MOLM) on blood biochemistry and growth of pre-weaned Holstein calves (n = 48). Four-day-old calves were blocked (based on order of birth and birth weight) and randomly allocated to three dietary treatments, namely M0: unsupplemented control, M30: supplemented with 8.33 g MOLM /100 kg bodyweight (BW), and M60: supplemented with 16.66 g MOLM /100 kg BW. The experiment ended when the calves were 42 days old. The MOLM was diluted in the milk of the morning feeding session. Feed intake, faecal score, and body temperature were recorded daily. Bodyweight and body measurements were taken weekly, and blood samples were collected at the same time. Starter dry matter intake (DMI) for the M60 group was higher than for M0 group with a significant week effect. Calves in M60 had higher final bodyweight and body measurements than M0 and M30. Similar trends were observed for superoxide dismutase (SOD), catalase (CAT), and serum antioxidant activity (SAOA). Immunoglobulin G (Ig) levels increased with the age of calves in both M30 and M60 groups, with the increase being progressively larger with the level of MOLM supplementation. Calves in the M60 group had fewer days of diarrhoea. Supplementation of MOLM supplied secondary metabolites and nutrients that improved feed utilization and later stimulated growth, increased enzymatic antioxidants, and reduced diarrhoeal incidence in pre-weaned calves. Dilution of MOLM by as little as 16.66 g/100 kg BW in the milk for dairy calves can be recommended.

Assessing the effects of experimental bacterial challenge with Pasteurella multocida and ampicillin on the respiratory microbiota of pre-weaned Holstein calves

The association between changes in the respiratory microbiota and Bovine Respiratory Disease (BRD) in dairy calves is not well understood. We investigated characteristics of the nasopharyngeal (NP) microbiota associated with BRD following Pasteurella multocida infection. We also evaluated the effect of ampicillin on the respiratory microbiota. Calves (n = 30) were inoculated with P. multocida and randomly allocated into an antibiotic group (AMP; n = 17) or placebo group (PLAC; n = 11) when lung lesions developed. Deep NP swabs (DNPS) were collected before and after challenge. Monitoring was performed daily until euthanasia at day 14. Swabs and tissue samples were collected for analysis. The V4 hypervariable region of the 16 S rRNA gene was amplified and sequenced on an Illumina MiSeq. Increased species abundance in the pre-challenge DNPS was associated with a decrease in cumulative respiratory disease over 14 days post-infection. While NP beta diversity was affected by infection, antibiotic therapy showed no effect on the alpha and beta diversity nor the relative abundance (RA) of genera in the NP tonsil, lymph node and lung microbiota. Antibiotic therapy was associated with an increased RA of NP Pasteurella spp. and a decreased RA of NP Prevotella spp. Common taxa among all samples included GIT-associated bacteria, which suggests a possible link between the GIT microbiota and respiratory microbiota in dairy calves.

Effects of sodium humate and glutamine on growth performance, diarrhoea incidence, blood parameters, and faecal microflora of pre-weaned calves.

This study aimed to evaluate the effects of administration of sodium humate (HNa) and glutamine (Gln) on growth performance, diarrhoea incidence, serum parameters, and faecal microflora of pre-weaned Holstein calves. In a 57-day experiment, 28 healthy newborn female calves were randomly allocated to four treatment groups: (1) CON (control); (2) HNa (basal diet + 5% HNa); (3) Gln (basal diet + 1% Gln); and (4) HNa + Gln (basal diet + 5% HNa + 1% Gln). The calves in the CON group were fed with basal diet. HNa and Gln were alone or together mixed with milk (Days 1-20) or milk replacer (Days 21-57) and orally administered to each calf. The results indicated that calves combined supplemented with HNa and Gln had a higher average daily gainat 0-21 days, 21-57 days, and 0-57 days, and starter intake at 21-57 days and 0-57 days (p < 0.05). Compared with the CON group, calves in HNa, Gln, and HNa + Gln groups showed lower faecal scores and diarrhoea incidence at 0-21 days and 0-57 days (p < 0.05). Combined administration of HNa and Gln increased the concentration of IgG and IgA, activities of glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) but decreased the concentration of diamine oxidase (DAO), D-lactic acid (D-lac), TNF-α, and malondialdehyde (MDA) in the serum of calves compared with the CON group throughout the entire period (p < 0.05). Furthermore, the abundances of Bifidobacterium and Lactobacillus were increased but the Escherichia coli was decreased in faecal grab samples of HNa + Gln group calves in comparison with the CON group (p < 0.05). In conclusion, combined administration of HNa and Gln effectively improved the growth performance, antioxidant and immune status, and intestinal beneficial bacteria, and further reduced the diarrhoea incidence of the pre-weaned calves.

Dietary supplementation of free or two fat-coated sodium butyrate with varying release times on gastrointestinal development and tight junctions in preweaning Holstein calves

The aim of this study was to determine the effects of free and two fat-coated sodium butyrate (SB) on performance, diarrhea incidence, gastrointestinal tract (GIT) development, tight junctions (TJ), and adherens junctions in preweaning calves. Forty male calves were divided into four treatment groups: control starter (CON), control starter supplemented with free SB (USB), rapid-release SB (RSB), and slow-release SB (SSB) at a SB addition level of 3.0 g/kg (as-fed basis) in a high starch starter (380 g/kg). The calves were fed calf starter for 9 weeks and then the GIT of four calves from each group was harvested. There was no difference in the growth performance and feed efficiency under SB treatments (P > 0.05), although RSB decreased starter intake for the entire period as compared to the CON and USB (P < 0.05). Diarrhea rates and frequencies were lower with the USB and RSB treatments as compared with CON (P < 0.05). The weight and papillae surface area of the rumen in USB were higher than the CON, RSB, and SSB (P < 0.05), although RSB increased the mucosa thickness of the abomasum as compared to the other three groups (P < 0.05). The mucosa thickness of the duodenum in SSB was thicker than USB and RSB (P < 0.05). The villous height and villus height:crypt depth ratio of the ileum was higher in USB than the CON, RSB, and SSB (P < 0.05). Muscularis thickness of the cecum was higher in USB than the RSB and SSB (P < 0.05), and the parameter of the colon was higher in RSB than SSB (P < 0.05). Claudin-1 was increased in the rumen by USB (P < 0.05) and claudin-1 was increased by RSB, and occludin and zonula occludens protein-1 were increased by USB and SSB in the jejunum (P < 0.05). However, occludin was decreased by SSB, and zonula occludens protein-1 was impaired by both RSB and SSB in the colon (P < 0.05). SB treatments had no effect (P > 0.05) on the expression of e-cadherin and β-catenin in the GIT. The incidence of diarrhea was negatively correlated with the protein expression of claudin-1 (P < 0.05) within the jejunum. In conclusion, USB showed more benefits than the RSB and SSB in high starch starter on the diarrhea incidence, GIT development, and TJ in calves, and diarrhea incidence was associated with claudin-1 expression in the jejunum.

Effect of fish oil and canola oil supplementation on immunological parameters, feed intake, and growth of Holstein calves

Supplemental n-3 fatty acids (FA) may support better immune responses than n-6 and n-9 FA in dairy calves. The objective was to evaluate the effect of n-3 FA, supplemented as a fish oil product (FO) in the milk replacer (MR), in comparison to n-6 and n-9 FA, supplemented as canola oil (CO), on body weight (BW), daily gain, and immunological parameters of preweaning Holstein calves. The study was conducted from September to December 2019. Calves were randomly allocated to a control group (n = 15; BW = 36.2 ± 1.5 kg; mean ± SEM) supplemented daily with 30 mL of CO and to an experimental group (n = 15; BW = 36.3 ± 1.5 kg) supplemented with 60 g of a product containing 30 g of FO. Both treatments were added to the MR during the morning feeding. All calves were fed 4 L of MR at 12.5% solids at 0700 and 1600 h for wk 1, 6 L from wk 2 to 7, and 3 L once daily (0700 h) during wk 8 until weaning (56 d). Blood samples were collected at 7, 14, 21, 28, 35, 42, 49, and 56 d of age for serum haptoglobin, TNF-α, IL-1β, and protectin. Dry matter intake was recorded in all experimental calves daily. Seroneutralization titers to vaccination against viral diseases (infectious bovine rhinotracheitis, parainfluenza 3, bovine viral diarrhea, and bovine respiratory syncytial virus) were determined. Mixed models for repeated measures were developed to analyze variables over time. Seroneutralization titers were analyzed by the Kruskal-Wallis test. The other variables were compared by a generalized linear model. Serum FA profile at 35 d of age showed that FO supported higher concentrations of n-3 FA than CO. Final BW [65.2 vs. 62.0 kg, standard error of the mean (SEM) = 2.1 kg] and average daily gain (0.52 vs. 0.46 kg/d, SEM = 0.1 kg/d) tended to be higher for the FO than the CO group. An interaction of treatment × day for dry matter intake was observed, especially during weaning (2.17 kg vs. 1.94 kg, SEM = 0.158 kg, for FO and CO group, respectively). Blood lactate (mmol/L) was higher in the CO than in the FO group at d 7. Haptoglobin and IL-1β were higher for the CO group on d 14 than the FO group. The TNF- α concentrations for the FO group were reduced over time, whereas the concentrations in the CO group remained constant. Protectin was higher in the FO group on d 14, but was lower on d 28, 35, and 49. Seroneutralization antibody titers postvaccination for the PI3 virus were higher for the FO than the CO group. In conclusion, calves supplemented with FO had lower concentrations of blood lactate, haptoglobin, IL-1β and TNF-α than calves supplemented with CO during the study period. The FO supplementation had a higher DMI than CO supplementation. Results of this trial should be interpreted with caution due to the lack of a negative control group as well as the lower birth weight and growth rate observed under heat stress conditions.