Neonatal immune development in the calf and its impact on vaccine response

Unique adaptations in neonatal hepatic transcriptome, nutrient signaling, and one-carbon metabolism in response to feeding ethyl cellulose rumen-protected methionine during late-gestation in Holstein cows

BACKGROUND

Methionine (Met) supply during late-pregnancy enhances fetal development in utero and leads to greater rates of growth during the neonatal period. Due to its central role in coordinating nutrient and one-carbon metabolism along with immune responses of the newborn, the liver could be a key target of the programming effects induced by dietary methyl donors such as Met. To address this hypothesis, liver biopsies from 4-day old calves (n = 6/group) born to Holstein cows fed a control or the control plus ethyl-cellulose rumen-protected Met for the last 28 days prepartum were used for DNA methylation, transcriptome, metabolome, proteome, and one-carbon metabolism enzyme activities.

RESULTS

Although greater withers and hip height at birth in Met calves indicated better development in utero, there were no differences in plasma systemic physiological indicators. RNA-seq along with bioinformatics and transcription factor regulator analyses revealed broad alterations in 'Glucose metabolism', 'Lipid metabolism, 'Glutathione', and 'Immune System' metabolism due to enhanced maternal Met supply. Greater insulin sensitivity assessed via proteomics, and efficiency of transsulfuration pathway activity suggested beneficial effects on nutrient metabolism and metabolic-related stress. Maternal Met supply contributed to greater phosphatidylcholine synthesis in calf liver, with a role in very low density lipoprotein secretion as a mechanism to balance metabolic fates of fatty acids arising from the diet or adipose-depot lipolysis. Despite a lack of effect on hepatic amino acid (AA) transport, a reduction in metabolism of essential AA within the liver indicated an AA 'sparing effect' induced by maternal Met.

CONCLUSIONS

Despite greater global DNA methylation, maternal Met supply resulted in distinct alterations of hepatic transcriptome, proteome, and metabolome profiles after birth. Data underscored an effect on maintenance of calf hepatic Met homeostasis, glutathione, phosphatidylcholine and taurine synthesis along with greater efficiency of nutrient metabolism and immune responses. Transcription regulators such as FOXO1, PPARG, E2F1, and CREB1 appeared central in the coordination of effects induced by maternal Met. Overall, maternal Met supply induced better immunometabolic status of the newborn liver, conferring the calf a physiologic advantage during a period of metabolic stress and suboptimal immunocompetence.

Oocyst shedding patterns of Eimeria species and their association with management and performance at ten rose veal starter farms in the Netherlands

Coccidiosis at rose veal starter farms is often diagnosed however, this was the first study performed considering this topic on this type of rearing unit. The objective of this study was to identify Eimeria species faecal shedding patterns at ten Dutch rose veal starter farms during rearing. Further objectives were to investigate associations with (gut) health, production and management decisions. Faecal samples from twelve randomly selected calves per farm were collected weekly during 9 consecutive weeks. Thereafter samples were pooled in a predetermined composition of six. These calves were clinically evaluated every sample visit and weighed at the first and last visit. Laboratory tests included a flotation test of the samples. If this yielded Eimeria oocysts, both oocysts per gram feces (OPG) and species differentiation were established using a modified McMaster method. Management parameters and technical herd results were identified after finalizing the study period using a questionnaire. Studied patterns in oocyst shedding included the pool's cumulated OPG, maximum OPG level and the number of sample days (SD) that OPG exceeded a confirmed level. Statistical analysis included univariate and multivariate analysis. Associated (p < 0.10) OPG patterns considering rumen fill, faecal consistency and average daily weight gain (ADG) were tested using a model with herd included as random effect. RESULTS: on all ten farms E. alabamensis, E.bovis and E. zuernii besides non-pathogenic species were identified, often as mixed infections. Peak OPG occurred predominately at SD 21 and 28 (E. alabamensis and E. bovis), and at SD 42 (E. zuernii). In 16 pools, OPG levels ≥500 for E. bovis or E. zuernii, were found. Significant correlation (p < 0.0001) showed between the log₁₀ OPG of pathogenic Eimeria and of all Eimeria species. Multivariate analysis showed significant correlation between cumulative faecal consistency scores and cumulative log₁₀ OPG of pathogenic Eimeria species (β = 0.16; p = 0.008). Pools exceeding 750 OPG for E. bovis showed 93 g lower ADG and pools experiencing ≥2 SD with >1000 OPG for E. alabamensis 141 g lower ADG. From the questionnaire we identified lower cumulated OPG of all Eimeria species except for E. bovis at farms where the units were cleaned before arrival of the calves. CONCLUSION: As a rule, on Dutch rose veal starter farms, mixed Eimeria infections occur, but shedding patterns differ between farms. Clinical and growth performance is related to OPG patterns found. Cleaning units before arrival of calves lowers oocyst shedding during the rearing period.

The impact of elective caesarean section on colostrum characteristics in double-muscled Belgian Blue cows

Identification of factors associated with the quality and quantity of colostrum production has always been a major challenge in cattle industry. In purebred double-muscled Belgian Blue (BB) cows, parturition is mainly performed by elective caesarean section (CS; >90%). However, the CS itself may influence colostrum production characteristics. The present study aimed to evaluate the impact of maternal and newborn calf factors and the duration of the procedure of CS on the quality and quantity of colostrum production in BB cows. The dataset includes 551 records of cow-calf pairs that were presented for an elective CS at the Ghent University veterinary clinic between 2017 and 2019. The quality (measured via a colostrum densimeter) and the quantity (measured via a standard volume scale) of colostrum were measured within 30 min after the end of the CS. Fixed effects were fitted in mixed linear regression models to test for their potential association with colostrum quality (specific gravity; SG) and quantity (liters), and generalized mixed-effects models were constructed to test the associations of fixed effects with the optimal colostrum production index (yes vs no) based on an adequate supply of both colostrum quality and quantity. The fixed effects tested were parity, the gender of the calf, birth weight, duration of CS (min), and season of birth. Our results show that parity (primiparity), duration of CS (longer CS), and calving season (summer) had a significantly negative impact on colostrum production. Concluding, both colostrum quality and quantity can be influenced by intrinsic and extrinsic factors (including duration of CS), which should be considered while feeding newborn calves delivered via CS.

Oxidative Stress Compromises Lymphocyte Function in Neonatal Dairy Calves

Dairy calves are unable to mount an effective immune response during their first weeks of life, which contributes to increased disease susceptibility during this period. Oxidative stress (OS) diminishes the immune cell capabilities of humans and adult cows, and dairy calves also experience OS during their first month of life. However, the impact that OS may have on neonatal calf immunity remains unexplored. Thus, we aimed to evaluate the impact of OS on newborn calf lymphocyte functions. For this, we conducted two experiments. First, we assessed the association of OS status throughout the first month of age and the circulating concentrations of the cytokines interferon-gamma (IFN-γ) and interleukin (IL) 4, as well as the expression of cytokine-encoding genes IFNG, IL2, IL4, and IL10 in peripheral mononuclear blood cells (PBMCs) of 12 calves. Subsequently, we isolated PBMCs from another 6 neonatal calves to investigate in vitro the effect of OS on immune responses in terms of activation of lymphocytes, cytokine expression, and antibody production following stimulation with phorbol 12-myristate 13-acetate or bovine herpesvirus-1. The results were compared statistically through mixed models. Calves exposed to high OS status in their first month of age showed higher concentrations of IL-4 and expression of IL4 and IL10 and lower concentrations of IFN-γ and expression of IFNG and IL2 than calves exposed to lower OS. In vitro, OS reduced lymphocyte activation, production of antibodies, and protein and gene expression of key cytokines. Collectively, our results demonstrate that OS can compromise some immune responses of newborn calves. Hence, further studies are needed to explore the mechanisms of how OS affects the different lymphocyte subsets and the potential of ameliorating OS in newborn calves as a strategy to augment the functional capacity of calf immune cells, as well as enhance calves’ resistance to infections.

Innate and humoral immune parameters at delivery in colostrum and calves from heifers experimentally infected with Neospora caninum

Neospora caninum is a leading cause of abortion in cattle worldwide. The study of the immune response against N. caninum is critical to understand its epidemiology, pathogenesis, diagnosis and, ultimately, in preventing and controlling bovine neosporosis. Herein, we determined the gene expression of innate immune components endosomal RNA-sensing TLRs, BMAP28 cathelicidin, TNF-α and IL-10 and characterized the variation in both IgG ratio and avidity at delivery in N. caninum-infected heifers challenged at day 210 of gestation, colostrum and their calves. Increased BMAP28 expression was observed not only in colostrum but also in peripheral blood mononuclear cells (PBMC) and umbilical cord of calves from N. caninum-infected heifers in comparison with mock-infected control group. In addition, statistically significant decrease of TLR7 and IL-10 expression levels were observed in umbilical cord, suggesting an attempt to avoid an exacerbated immune response against the parasite. At delivery, serum and colostrum samples from infected group evidenced specific IgG anti-N. caninum. Infected heifers showed IgG₁/IgG₂ ratios <1 and high avidity specific IgG. As expected, colostrum samples of these animals exhibited a high IgG₁ concentration and elevated avidity values. Three out of four calves from N. caninum-infected heifers had specific IgG with IgG₁/IgG₂ ratios>1 and lower avidity values before colostrum intake. Interestingly, both IgG₁/IgG₂ ratios and avidity values increased in seropositive calves after colostrum intake. Overall, this study provides novel information on neonatal immunity in congenitally infected calves, which is essential to understand how the immune pathways could be manipulated or immune components could be employed in order to improve protection against neosporosis.

Supplementation of overripe pulp extract and green peel extract or powder of banana fruit peel (musa. cavendish) to diets of neonatal dairy calves: Effects on haematological, immunological and performance characteristics

The present study investigated the effects of overripe pulp and green peel extract and powder of banana fruit (Musa. cavendish) on haematological, biochemical, immunological, health, and performance of Holstein dairy calves. In all, 40 newborn calves were randomly divided into four groups of 10 animals. In the control group, animals received no banana meal. In group 1, calves were supplemented with 2 g (dry matter)/kg body weight/day of overripe banana pulp extract. The calves in group 2 were supplemented with 1 g (dry matter) of overripe banana pulp extract/kg body weight/day and 1 g (dry matter) of green banana peel extract/kg body weight/day. The animals in group 3 were supplemented with 2 g/kg body weight/day of green banana peel powder. The feeding period of calves on the tested supplements was 5 days. Blood samples and other evaluations were taken on day 0 (at birth, before supplementation) and on days 7, 15 and 30. Just a trend towards better average daily weight gain was seen in groups 2 and 3 than others (p = 0.073). Significant group and sampling time interactions were seen for the quantities of RBC (group 1 was lower than other groups at day 30), MCV (group 3 was lower than other groups at day 30) and MCH (group 1 was higher than other groups at day 30) (p < 0.05). A trend towards significance in values of IgG (group 1 was lower than other groups at days 15 and 30) and bilirubin (higher values at day 7 in groups 1 and 2 than control, higher amounts at days 15 and 30 in groups 3 and 2 than control, respectively) was also observed. In conclusion, banana supplementation in neonatal calves had beneficial effects on the values of RBC, MCV, MCH, bilirubin, IgG and average daily weight gain in dairy calves.

Milk supplemented with dried seaweed affects the systemic innate immune response in preweaning dairy calves

Intact seaweed or seaweed extracts are used as feed supplements to improve the gut microbiome in young animals. Seaweeds provide functional polysaccharides, and they are a good source of vitamins, minerals, and phenolic compounds, all of which are relevant for immune system development. However, literature on the effects of dried seaweed supplementation on immune system development is limited, especially in calves. This experiment aimed to study the effect of feeding milk supplemented with Ulva lactuca, Ascophyllum nodosum, or Saccharina latissima on the systemic immune status of preweaning dairy calves. Forty male Holstein calves with birth body weight 41 ± 4 kg and plasma Brix percentage ≥8.7% at d 2 after birth were used in this study. Calves were fed 4 L of cow milk twice a day (total 8 L/d). From d 2 to d 28, calves in the control group (n = 10) received milk without seaweed supplementation. Over the same period, experimental calves received milk supplemented with Ulva lactuca (SW1; n = 10), Ascophyllum nodosum (SW2; n = 10), or Saccharina latissima (SW3, n = 10). Dried and ground seaweeds were offered at a daily allowance of 50 g/8 L of milk (i.e., approximately 5% inclusion rate on a dry matter basis). Blood samples were collected from a jugular vein on d 2, 4, 7, 14, 21, and 28 after birth. Plasma concentrations of total protein, albumin, immunoglobulins, and acute-phase proteins (i.e., serum amyloid A, fibrinogen, and haptoglobin) were measured. We detected no differences in average daily gain, plasma immunoglobulins, albumin, or total protein. However, the contrast analysis revealed that plasma concentrations of fibrinogen (SW1 and SW2) and serum amyloid A (SW2 and SW3) were significantly higher in the seaweed groups compared with the control group. We also found a tendency for high plasma haptoglobin in the seaweed groups (SW1 and SW2) compared with the control group. Differences in acute-phase protein concentrations could be partially explained by the large differences in micromineral intake between control and seaweed-supplemented calves. Feeding milk supplemented with dried seaweed increased plasma concentrations of variables related to the innate immune response in preweaning dairy calves.

Effects of Vitamin C Supplementation on The Blood Oxidative Stress and Antibody Titre Against Histophilus Somni Vaccination in Calves

Introduction

The purpose of this study was to determine the effects of vitamin C supplementation on blood oxidative stress biomarkers and antibody response to vaccination in calves.

Material and methods

Thirty-four clinically healthy 2 week old Japanese Black calves were randomly assigned to two groups. Seventeen calves formed the VC group which received 1,000 mg of vitamin C daily from 2 to 8 weeks of age, and the other 17 calves of the control group did not receive supplementation. All calves received an inactivated Histophilus somni vaccine at 4 and 8 weeks of age. Blood samples were taken at 2, 4, 8 and 12 weeks of age.

Results

The concentration of the serum reactive oxygen metabolites (d-ROMs), and the oxidative stress index (OSI), which is calculated from the d-ROMs and biological antioxidant potential, were significantly lower at 8 weeks of age in the VC group than in the control group (P < 0.05). The antibody titres to H. somni in the VC group were significantly higher than those in the control group at 12 weeks of age after the second vaccination (P < 0.05).

Conclusion

Vitamin C supplementation to calves may reduce oxidative stress and enhance the antibody production after vaccination with H. somni.

MicroRNAs as Biomarkers for Animal Health and Welfare in Livestock

MicroRNAs (miRNAs) are small and highly conserved non-coding RNA molecules that orchestrate a wide range of biological processes through the post-transcriptional regulation of gene expression. An intriguing aspect in identifying these molecules as biomarkers is derived from their role in cell-to-cell communication, their active secretion from cells into the extracellular environment, their high stability in body fluids, and their ease of collection. All these features confer on miRNAs the potential to become a non-invasive tool to score animal welfare. There is growing interest in the importance of miRNAs as biomarkers for assessing the welfare of livestock during metabolic, environmental, and management stress, particularly in ruminants, pigs, and poultry. This review provides an overview of the current knowledge regarding the potential use of tissue and/or circulating miRNAs as biomarkers for the assessment of the health and welfare status in these livestock species.

Applications of Nanovaccines for Disease Prevention in Cattle

Vaccines are one of the most important tools available to prevent and reduce the incidence of infectious diseases in cattle. Despite their availability and widespread use to combat many important pathogens impacting cattle, several of these products demonstrate variable efficacy and safety in the field, require multiple doses, or are unstable under field conditions. Recently, nanoparticle-based vaccine platforms (nanovaccines) have emerged as promising alternatives to more traditional vaccine platforms. In particular, polymer-based nanovaccines provide sustained release of antigen payloads, stabilize such payloads, and induce enhanced antibod- and cell-mediated immune responses, both systemically and locally. To improve vaccine administrative strategies and efficacy, they can be formulated to contain multiple antigenic payloads and have the ability to protect fragile proteins from degradation. Nanovaccines are also stable at room temperature, minimizing the need for cold chain storage. Nanoparticle platforms can be synthesized for targeted delivery through intranasal, aerosol, or oral administration to induce desired mucosal immunity. In recent years, several nanovaccine platforms have emerged, based on biodegradable and biocompatible polymers, liposomes, and virus-like particles. While most nanovaccine candidates have not yet advanced beyond testing in rodent models, a growing number have shown promise for use against cattle infectious diseases. This review will highlight recent advancements in polymeric nanovaccine development and the mechanisms by which nanovaccines may interact with the bovine immune system. We will also discuss the positive implications of nanovaccines use for combating several important viral and bacterial disease syndromes and consider important future directions for nanovaccine development in beef and dairy cattle.

Ginseng Stem-Leaf Saponins in Combination with Selenium Promote the Immune Response in Neonatal Mice with Maternal Antibody

Neonates acquire from their mothers maternal antibody (MatAb) which results in poor immune response to vaccination. We previously demonstrated that ginseng stem-leaf saponins in combination with selenium (GSe) had adjuvant effect on the immune response to an attenuated pseudorabies virus (aPrV) vaccine. The present study was to evaluate GSe for its effect on the immune response to aPrV vaccine in neonatal mice with MatAb. Results showed that GSe had adjuvant effect on the immune response to aPrV vaccine in neonates. When GSe was co-administered with aPrV vaccine (aP-GSe), specific gB antibody, Th1 cytokines (IL-2, IL-12 and IFN-γ) and Th2 cytokines (IL-4, IL-6 and IL-10) responses were significantly increased in association with enhanced protection of vaccinated neonates against the lethal PrV challenge even though MatAb existed when compared to the neonates immunized with aPrV vaccine alone. GSe-enhanced immune response depended on its use in the primary immunization. The mechanisms underlying the adjuvant effect of GSe may be due to more innate immune related pathways activated by GSe. Transcriptome analysis of splenocytes from neonates immunized with aP-GSe, aPrV or saline solution showed that there were 3976 differentially expressed genes (DEGs) in aP-GSe group while 5959 DEGs in aPrV group when compared to the control. Gene ontology (GO) terms and Kyoto encyclopedia of genes and genomes (KEGG) pathways analysis showed that innate immune responses and cytokine productions related terms or pathways were predominantly enriched in aP-GSe group, such as “NOD-like receptor signaling pathway”, “Natural killer cell mediated cytotoxicity”, “NF-κB signaling pathway”, “cytokine-cytokine receptor interaction”, and “Th1 and Th2 cell differentiation”. Considering the potent adjuvant effect of GSe on aPrV vaccine in neonatal mice with MatAb, it deserves further investigation in piglets.

Maternal body condition influences neonatal calf whole-blood innate immune molecular responses to ex vivo lipopolysaccharide challenge

Managing body condition in dairy cows during the close-up period could alter the availability of nutrients to the fetus during the final growth stages in utero. We investigated how maternal body condition score (BCS) in late pregnancy affected calf whole-blood mRNA abundance and IL-1β concentrations after ex vivo lipopolysaccharide (LPS) challenge. Thirty-eight multiparous Holstein cows and their calves from a larger cohort were retrospectively grouped by prepartal BCS as normal BCS (≤3.25; n = 22; NormBCS) and high BCS (≥3.75; n = 16; HighBCS). Calf blood samples collected at birth (before receiving colostrum, d 0) and at ages 21 and 42 d (at weaning) were used for ex vivo whole-blood challenge with 3 µg/mL of LPS before mRNA isolation. Target genes evaluated by real-time quantitative PCR were associated with immune response, antioxidant function, and 1-carbon metabolism. Plasma IL-1β concentrations were also measured. Responses in plasma IL-1β and mRNA abundance were compared between LPS-challenged and nonchallenged samples. Statistical analyses were performed at all time points using a MIXED model in SAS 9.4. Neither birth body weight (NormBCS = 43.8 ± 1.01 kg; HighBCS = 43.9 ± 1.2 kg) nor colostrum IgG concentration (NormBCS = 70 ± 5.4 mg/mL; HighBCS = 62 ± 6.5 mg/mL) differed between groups. At birth, whole blood from calves born to HighBCS cows had greater mRNA abundance of IL1B, NFKB1, and GSR and lower GPX1 and CBS abundance after LPS challenge. The longitudinal analysis of d 0, 21, and 42 data revealed a BCS × age effect for SOD2 and NOS2 due to lower mRNA abundance at 42 d in the HighBCS calves. Regardless of maternal BCS, mRNA abundance decreased over time for genes encoding cytokines (IL1B, IL6, IL10, TNF), cytokine receptors (IRAK1, CXCR1), toll-like receptor pathway (TLR4, NFKB1), adhesion and migration (CADM1, ICAM1, ITGAM), and antimicrobial function (MPO). Concentration of IL-1β after LPS challenge was also markedly lower at 21 d regardless of maternal BCS. Overall, results suggested that maternal BCS in late prepartum influences the calf immune system response to an inflammation challenge after birth. Although few genes among those studied were altered due to maternal BCS, the fact that genes related to oxidative stress and 1-carbon metabolism responded to LPS challenge in HighBCS calves underscores the potential role of methyl donors (e.g., methionine, choline, and folic acid) in the early-life innate immune response.

Gut health, stress, and immunity in neonatal dairy calves: the host side of host-pathogen interactions

The cumulative evidence that perinatal events have long-lasting ripple effects through the life of livestock animals should impact future nutritional and management recommendations at the farm level. The implications of fetal programming due to malnutrition, including neonatal survival and lower birth weights, have been characterized, particularly during early and mid-gestation, when placental and early fetal stages are being developed. The accelerated fetal growth during late pregnancy has been known for some time, while the impact of maternal stressors during this time on fetal development and by extent its postnatal repercussions on health and performance are still being defined. Maternal stressors during late pregnancy cannot only influence colostrogenesis but also compromise adequate intestinal development in the fetus, thus, that further limits the newborn's ability to absorb nutrients, bioactive compounds, and immunity (i.e., immunoglobulins, cytokines, and immune cells) from colostrum. These negative effects set the newborn calf to a challenging start in life by compromising passive immunity and intestinal maturation needed to establish a mature postnatal mucosal immune system while needing to digest and absorb nutrients in milk or milk replacer. Besides the dense-nutrient content and immunity in colostrum, it contains bioactive compounds such as growth factors, hormones, and cholesterol as well as molecular signals or instructions [e.g., microRNAs (miRNAs) and long non-coding RNAs (lncRNAs)] transferred from mother to offspring with the aim to influence postnatal gut maturation. The recent change in paradigm regarding prenatal materno-fetal microbiota inoculation and likely the presence of microbiota in the developing fetus intestine needs to be addressed in future research in ruminants. There still much to know on what prenatal or postnatal factors may predispose neonates to become susceptible to enteropathogens (e.g., enterotoxigenic Escherichia coli), causing diarrhea. From the host-side of this host-pathogen interaction, molecular data such as fecal RNA could, over time, help fill those gaps in knowledge. In addition, merging this novel fecal RNA approach with more established microbiome techniques can provide a more holistic picture of an enteropathogenesis and potentially uncover control points that can be addressed through management or nutrition at the farm level to minimize preweaning morbidity and mortality.

Efficacy of a live intranasal vaccine against parainfluenza type 3 and bovine respiratory syncytial virus in young calves with maternally derived antibodies

Trial design

Two randomised controlled vaccination trials with artificial challenges were carried out in addition to a serological survey of levels of maternally derived antibodies (MDA) to parainfluenza type 3 virus (PI3V) and bovine respiratory syncytial virus (BRSV) in European calves.

Participants

Ten-day-old calves with and without MDA were included in the two vaccine trials.

Interventions

Intranasal administration of a bivalent modified live (PI3V/BRSV) vaccine followed by artificial challenge approximately three months post vaccination.

Objective

The study aimed to assess the efficacy of a modified live respiratory vaccine, Bovalto Respi Intranasal (Boehringer Ingelheim). In order to assess the interference of MDA, both seropositive and seronegative calves were used.

Randomisation

PI3V and BRSV serological status was determined seven days before vaccination; calves without maternal antibodies became the MDA− vaccinates. Calves with MDA were ranked according to individual titres and allocated alternately to MDA+ vaccinate and MDA+ control groups.

Blinding

Treatment was carried out by the unblinded study director. Animal care and veterinary examinations were conducted by personnel unaware of the treatments received. The serological survey used blood samples obtained from calves on commercial farms in five European countries, Germany, Spain, Italy, Ireland and the UK, to determine the levels of MDA to PI3V and BRSV in calves approximately two weeks of age.

Results

A total of 36 calves were included in the two challenge studies and 32 of these completed the challenge studies. Twenty-one calves were included in the PI3V challenge study, with six of six MDA− and six of seven MDA+ vaccinated calves and five of five MDA+ unvaccinated control calves being challenged with PI3V. Fifteen calves were included in the BRSV challenge study, with five of five MDA− and five of five MDA+ vaccinated calves and five of five MDA+ unvaccinated control calves being challenged with BRSV.

Outcome

For both challenges, clinical scores and nasal shedding were significantly higher in control animals compared with vaccinates (PI3V challenge: clinical scores P=0.001, nasal shedding P=0.001; BRSV challenge: clinical scores P=0.016, nasal shedding P=0.002) and not significantly different between MDA+ and MDA− vaccinated animals for both challenges (P>0.05). A total of 254 samples from six countries were tested in the serological survey of MDA.

Conclusion

The results of the challenge studies demonstrated the efficacy of the vaccine in the presence of BRSV and PI3V MDA under laboratory conditions. The field assessment confirmed that the MDA titres in the MDA+ calves corresponded to those typically found on farms.

Influence of feeding fresh colostrum from the dam or frozen colostrum from a pool on indicator gut microbes and the inflammatory response in neonatal calves

The aim of this study was to evaluate the capacity of cells from colostrum to modulate the intestinal microbial colonization, the activity of the inflammatory response, and for their influence on the development of diarrheal disease in calves. Twenty calves were distributed into two groups: COL+ (n = 10) receiving fresh whole colostrum; COL- (n = 10) receiving pooled frozen colostrum, containing no viable cells. All assessments were made before colostrum intake (D0), the next day (D2), and weekly on the 7th (D7), 14th (D14), 21st (D21) and 28th (D28) day of age. Diarrhea was assessed using a fecal score, and the systemic inflammatory status was assessed using a combination of temperature, anemia, total serum iron level, total haptoglobin concentration and the need for systemic antimicrobial treatment. The number of indicator bacteria present in the fecal population was estimated using qPCR. However, COL- calves presented more frequent signs of systemic inflammatory response including, fever at D7 (P = 0.011); indicator haptoglobin levels on D7 and D14, and lower levels of iron on D7, D14. Anemia was detected more often in the COL- calves on D21 (P = 0.043) and D28 (P = 0.016). COL- calves had a 1.66 greater chance of having elevated haptoglobin and a 1.8 greater chance of needing treatment with antimicrobials than COL+. A lower number of DNA copies of Clostridium perfringens were detected in COL+ calves on D2 (P = 0.088) and D7 (P = 0.040). Similarly, a low number of DNA copies was observed for Escherichia coli and Lactobacillus spp. (P = 0.012) in the fecal samples of COL+ calves on D7.

Effects of the Administration of a Non-specific Immune Stimulant Around Transportation on Health and Performance of Jersey and Jersey-Cross Heifer Calves During the Rearing Period: Randomized Clinical Trial

Our objective was to evaluate the effects of a non-specific immune stimulant (IS) administered around transportation on health scores (HS), average daily gain (ADG), disease treatment and mortality of Jersey and Jersey-cross calves during the rearing period. Newborn calves (4 d ± 1) were randomly allocated to receive either 1 mL of saline (CON; n = 438), 1 mL of IS before transport (BTIS; n = 431), or 1 mL of IS immediately after transport (ATIS; n = 436). Calves were health scored weekly for 3 weeks after transport. The data were analyzed using multivariable linear mixed models and multivariable logistic regression models. Kaplan-Meier survival analysis was performed for time to event analysis. Treatment, birth weight, breed, site of birth, serum total solids, dam parity, season of enrollment, and metaphylaxis were offered to models. Differences in respiratory and fecal HS, and ADG between treatment groups were not statistically significant. A total of 196 (15.0%) calves were treated at least once for any disease and 52 calves were treated multiple times. The proportion of calves treated for respiratory disease and/or diarrhea were 14.4, 14.4, and 16.2% for BTIS, ATIS and CON groups, respectively. Although the differences in the likelihood of treatment for both respiratory disease and/or diarrhea during the first 9 weeks of life was not statistically different between groups, we observed that more calves in the control group received disease treatments around 15 days of age compared with calves that received IS. The likelihood of treatment for respiratory diseases alone during the first 30 days of life was smaller in the calves that received IS before transportation when compared to the control group. Only 18 (1.4%) calves died within the study period. The calf mortality likelihood was not statistically different between study groups; however, fewer calves in the IS groups died when compared to CON. In conclusion, the use of IS around transportation did not influence weekly HS, ADG, and the number of disease treatments during the rearing period, but administering IS before transportation resulted in fewer treatments of respiratory diseases during the first 30 days post-transport and marginally lower mortality rates during the rearing period.

The occurrence and distribution of livestock-associated methicillin-resistant Staphylococcus aureus ST398 on German dairy farms

The objective of this study was to investigate the occurrence and distribution of methicillin-resistant Staphylococcus aureus (MRSA) on 20 German dairy farms. Farms were selected based on previous MRSA reports from phenotypic susceptibility testing of mastitis pathogens. Samples were collected from predefined groups of cows, young stock, farm personnel, and the environment. A high MRSA-positive test rate was detected in swab samples from milk-fed calves (22.7%; 46/203). In postweaning calves, the MRSA-positive test rate was 9.1% (17/187). From prefresh heifers, both nasal swabs and udder cleft swabs were collected if possible. Including both sample types, the MRSA-positive test rate in prefresh heifers was 13.0% (26/200). The positive test rate was 8.9% (17/191) in nasal swabs and 6.5% (11/170) in udder cleft swabs. In quarter milk samples (QMS), the MRSA-positive test rate was 2.9% (67/2347), and on cow level, 7.9% (47/597) of the dairy cows were affected. Among all cows included in this study, the geometric mean of somatic cell counts was higher in QMS that carried MRSA (345,000 cells/mL) in comparison to all QMS (114,000 cells/mL). No differences in parity or the affected mammary quarter position on the udder were observed among the 47 infected cows. Methicillin-resistant S. aureus was also detected in boot swab samples (dust), teat liners, and in suckers from automatic calf feeders. All isolates belonged to livestock-associated sequence type 398 and most common staphylococcal protein A (spa)-types were t011 and t034. Most isolates harbored the staphylococcal cassette chromosome mec (SCCmec)-type V, with the exception of some isolates with SCCmec-type IVa on 1 farm. Similar MRSA genotypes in samples from humans and dairy cows underline the possible zoonotic and reverse-zoonotic transmission of livestock-associated MRSA strains from dairy farms. Similar MRSA genotypes in pig and cattle barns were detected on only 1 of 5 farms that kept both cattle and pigs. Similar MRSA spa-types were detected in samples from different sources (dairy cows, young stock, environment, and humans), suggesting a possible contagious transmission on some of the farms. Sporadically, up to 3 different MRSA spa-types were detected in QMS from the respective farms. On MRSA-affected farms, improper milking hygiene procedures and elevated bulk-tank milk somatic cell counts (>250,000 cells/mL) were observed. The occurrence of livestock-associated MRSA ST398 in different samples from dairy farms, and especially in young calves, should be considered for future MRSA-monitoring programs and biosecurity guidelines.

Ruminant pestiviruses in North Africa

Ruminant pestiviruses are widely distributed worldwide, causing congenital disease and massive economic losses. Although ruminant production is an important economic sector in North Africa, the knowledge about pestiviruses is scarce. The present study aimed at assessing the presence of Pestivirus in cattle in Algeria, and to review the data available on ruminant pestiviruses in North Africa. A cross-sectional study was conducted on dairy farms from North-Western Algeria. Blood samples from 234 dairy cattle from 31 herds were collected. All sera were analysed for the presence of antibodies using a commercial iELISA. The presence of Pestivirus RNA was also assessed by using a Reverse Transcription-PCR, and PCR-positive samples were sequenced. Risk factors related to Pestivirus infection were also analysed. The review of the presence of ruminant pestiviruses in North Africa was performed using a systematic search and compilation methodology of the peer-reviewed literature available in order to identify gaps of knowledge for future research. The seroprevalence at population and farm levels obtained in the present study (59.9% and 93.5%, respectively) concur with data reported in neighbouring countries. Risk factors associated with Pestivirus infection in cattle were the presence of sheep in the herd and the animal category (cow vs heifer). Furthermore, we confirmed the presence of BVDV-1a in Algeria. The scarce data suggest an endemic epidemiological scenario of pestivirus in livestock. The lack of studies about the epidemiology and molecular variability of ruminant pestiviruses in livestock and wildlife in North Africa is of concern for animal health and wildlife conservation, and needs to be addressed.

Effectiveness of two intranasal vaccines for the control of bovine respiratory disease in newborn beef calves: A randomized non-inferiority multicentre field trial

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Multicentre field trials with natural pathogen exposure complement challenge trials.

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Beef calves housed with their dams were assessed for bovine respiratory disease (BRD).

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Two commercial intranasal live vaccines for BRSV-bPI3V were evaluated.

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New Vaccine A demonstrated non-inferiority compared to benchmarked Vaccine B.

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Difference in BRD prevalence between Vaccines A and B was −0.4% (95% CI −1.6 to 0.8%).

Bovine respiratory syncytial virus (BRSV) and bovine parainfluenza-3 virus (bPI3V) are major causes of bovine respiratory disease (BRD) in newborn calves worldwide. Vaccination is widely used to prevent BRD, and intranasal vaccines for BRSV and bPI3V were developed to overcome interference from BRSV and bPI3V-specific maternally derived antibodies. Many experimental challenge trials have demonstrated that intranasal vaccines for BRSV and bPI3V are efficacious, but effectiveness under field conditions has been demonstrated less often, especially for newborn beef calves. The objective of this field trial was to compare the effectiveness of a newly available commercial BRSV-bPI3V intranasal vaccine with that of a benchmarked one in newborn beef calves reared in a cow-calf system. A total of 935 calves from 39 farms were randomized into two vaccine groups (Bovalto Respi Intranasal [Vaccine A], n = 468; Rispoval RS + PI3 Intranasal [Vaccine B], n = 467), and monitored during the in-house risk period up to three months after vaccination. Non-inferiority analysis was performed by calculating the difference in BRD prevalence between the two vaccine groups.

No significant differences were observed between vaccines regarding clinical outcomes of morbidity, mortality, duration between vaccination and BRD occurrence, or treatments required. Because the upper limit of the 2-sided 95% confidence interval of the difference in BRD prevalence between the two treatment groups (0.8%) was less than the margin of non-inferiority (δ = 5%), a non-inferiority of Vaccine A was concluded. In conclusion, Vaccine A is at least as effective as Vaccine B for the prevention of BRD in newborn beef cattle in a cow-calf system under field conditions.

A survey of management practices that influence calf welfare and an estimation of the annual calf mortality risk in pastured dairy herds in Uruguay

Despite the importance of dairy farming in Uruguay, little information on dairy systems in this country is available in the scientific literature, and management practices that influence calf welfare at the herd level have not been explored. The aims of this study were to (1) describe the prepartum and calf-rearing systems, as well as the management practices that may influence calf welfare in pastured dairy herds in Uruguay, (2) estimate the annual calf mortality risk from birth to weaning, and (3) identify the primary clinical disease syndromes shown by the calves before death. A survey comprising a farm visit and a questionnaire was conducted on 225 randomly selected dairies with >30 milking cows, in 3 strata (31-99, 100-299, and ≥300 milking cows) of 6 Uruguayan departments where dairies are concentrated. Retrospective information from July 2013 to June 2014 was collected. A descriptive analysis was performed and results were inferred into the national dairy cattle population. Several management practices that could contribute to poor calf welfare were identified in a large proportion of farms. The annual calf mortality risk (calves that died between birth and weaning/calves born death or alive × 100, n = 149 farms) was 15.2%. Age at weaning averaged 75 d. Farmers reported that the most common clinical syndromes were diarrhea and respiratory disease in 85.2% and 47.5% of the farms, respectively. There was no continuous veterinary advice in 61.3% of the farms, 20.0% lacked data records, 38.5% had poor drainage in the prepartum area with waterlogging after rainfall, 52.1% monitored the prepartum area ≤2 times per day during the calving season, 65.1% did not perform navel antisepsis on newborns, 62.3% separated the calves from their dams at >24 h postpartum, 95.2% did not have a colostrum management program, 72.4% did not rotate the calf-rearing areas, 59.0% did not disinfect the calf feeders, 85.7% did not have staff dedicated exclusively to calf rearing, and 39.8% did not separate sick from healthy calves. The average volume of milk or milk replacer offered per calf was 4.5 L/day. Several of the identified management practices that affect calf welfare in the prepartum and calf-rearing periods could explain the high mortality risk. An effort should be made to conduct extension work focusing on the dissemination of good management practices to improve calf welfare and reduce calf mortality in Uruguayan dairy farms.

Association of antimicrobial usage with faecal abundance of aph(3')-III, ermB, sul2 and tetW resistance genes in veal calves in three European countries

BACKGROUND

High antimicrobial use (AMU) and antimicrobial resistance (AMR) in veal calves remain a source of concern. As part of the EFFORT project, the association between AMU and the abundance of faecal antimicrobial resistance genes (ARGs) in veal calves in three European countries was determined.

METHODS

In 2015, faecal samples of veal calves close to slaughter were collected from farms located in France, Germany and the Netherlands (20 farms in France, 20 farms in the Netherlands and 21 farms in Germany; 25 calves per farm). Standardized questionnaires were used to record AMU and farm characteristics. In total, 405 faecal samples were selected for DNA extraction and quantitative polymerase chain reaction to quantify the abundance (16S normalized concentration) of four ARGs [aph(3')-III, ermB, sul2 and tetW] encoding for resistance to frequently used antimicrobials in veal calves. Multiple linear mixed models with random effects for country and farm were used to relate ARGs to AMU and farm characteristics.

RESULTS

A significant positive association was found between the use of trimethoprim/sulfonamides and the concentration of sul2 in faeces from veal calves. A higher weight of calves on arrival at the farm was negatively associated with aph(3')-III and ermB. Lower concentrations of aph(3')-III were found at farms with non-commercial animals present. Furthermore, farms using only water for the cleaning of stables had a significantly lower abundance of faecal ermB and tetW compared with other farms.

CONCLUSION

A positive association was found between the use of trimethoprim/sulfonamides and the abundance of sul2 in faeces in veal calves. Additionally, other relevant risk factors associated with ARGs in veal calves were identified, such as weight on arrival at the farm and cleaning practices.

The occurrence of diseases and their relationship with passive immune transfer in Holstein dairy calves submitted to individual management in southern Brazil

ABSTRACT Calves are extremely dependent on colostrum intake for the acquisition of passive immunity. This study aimed to determine the occurrence of diarrhea and respiratory diseases and the impact of Failure of Passive Immune Transfer (FPIT) on the health and zootechnical performance of Holstein dairy calves in individual management. This study has been carried out in five commercial farms in Rio Grande do Sul State, Brazil, from March 2017 to January 2018. In this study, 131 calves were followed from birth to 60 days of age. Total Plasmatic Protein (TPP) has been performed to determine passive immune transfer quality in 53 calves (53/131). A daily clinical follow-up has been accomplished aiming at diagnosing diseases and their incidences, and zootechnical measures such as withers height, width of the croup and weight have been evaluated. FPIT rate was 32.07%, diarrhea occurrence and respiratory diseases were 77.9% and 49.6%, respectively. FPIT increased the chances of calves presenting diarrhea and developing respiratory diseases, but no differences on zootechnical performance were found. The frequency of FPIT is still high and is a factor that corroborated the increased risk for diarrhea and respiratory disease but did not influence the performance of calves in the preweaning phase.

The application of omics in ruminant production: a review in the tropical and sub-tropical animal production context

The demand for animal products (e.g. dairy and beef) in tropical regions is expected to increase in parallel with the public demand for sustainable practices, due to factors such as population growth and climate change. The necessity to increase animal production output must be achieved with better management and production technologies. For this to happen, novel research methodologies, animal selection and postgenomic tools play a pivotal role. Indeed, improving breeder selection programs, the quality of meat and dairy products as well as animal health will contribute to higher sustainability and productivity. This would surely benefit regions where resource quality and quantity are increasingly unstable, and research is still very incipient, which is the case of many regions in the tropics. The purpose of this review is to demonstrate how omics-based approaches play a major role in animal science, particularly concerning ruminant production systems and research associated to the tropics and developing countries. SIGNIFICANCE: Environmental conditions in the tropics make livestock production harder, compared to temperate regions. Due to global warming, the sustainability of livestock production will become increasingly problematic. The use of novel omics technologies could generate useful information to understand adaptation mechanisms of resilient breeds and/or species. The application of omics to tropical animal production is still residual in the currently available literature. With this review, we aim to summarize the most notable results in the field whilst encouraging further research to deal with the future challenges that animal production in the tropics will need to face.

Early supplementation of Saccharomyces cerevisiae boulardii CNCM I-1079 in newborn dairy calves increases IgA production in the intestine at 1 week of age

The early development of immunity and microbiota in the gut of newborn calves can have life-long consequences. Gut microbiota and the intestinal barrier interplay after birth, establishing a homeostatic state whereby mucosal cells cohabit with microorganisms to develop a healthy gut. We hypothesized that postnatal codevelopment of gut immunity and microbiota could be influenced by early-life supplementation with live yeast. Starting from birth, calves either received a daily supplementation of Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB, 10 × 10⁹ cfu/d, n = 10) in the morning meal for 7 d or no supplementation (n = 10). Each animal received 2 adequate colostrum replacer meals at 2 and 12 h of life (expected total IgG fed = 300 g) before being fed milk replacer twice a day. Passive transfer of immunity (total protein, IgG, and IgA) through colostrum was evaluated and endogenous production of IgA was investigated by measuring IgA-producing plasma cells, IgA relative gene expression (PIGR and CD79A), and secretory IgA concentration in the gut. The concentration of targeted microbial groups was evaluated with quantitative PCR in the gut digesta collected at d 7 of life. Early SCB supplementation did not impair immunoglobulin absorption and all calves had successful passive transfer of immunity (serum IgG concentration >15 mg/mL at d 1 and d 7 of age). Although the expression of IgA relative gene expression (PIGR and CD79A) was not different, SCB calves had higher secretory IgA concentrations in the ileum (1.98 ± 0.12 mg/g of dry matter; DM) and colon (1.45 ± 0.12 mg/g of DM) digesta compared with control animals (1.18 and 0.59 ± 0.12 mg/g of DM, respectively). In addition, the number of IgA-producing plasma cells were greater in both ileum (2.55 ± 0.40 cells/mm²) and colon (3.03 ± 0.40 cells/mm²) tissues for SCB calves compared with control (respectively 1.00 ± 0.40 and 0.60 ± 0.42 cells/mm²). Endogenous IgA production in the gut of SCB calves was enhanced, which could make them less prone to pathogen intrusion. In addition, SCB calves had higher Lactobacillus and tended to have higher Faecalibacterium prausnitzii in the jejunum compared with control calves, which suggests that SCB supplementation during early-life gut colonization may have a positive effect in newborn calves. Direct SCB supplementation or the cross-talk between SCB and bacteria may be responsible for stimulating IgA production and may play a key role in shaping early colonization in the gut of newborn calves.

Passive Immunity Transfer in Water Buffaloes (Bubalus bubalis)

This study aimed to evaluate passive immunity transfer in healthy buffalo calves. Colostrum samples from heifers (without previous calving) and primiparous and pluriparous dams and blood samples from their offspring were obtained at calving, before colostrum intake, and at 24, 48, and 72 h after calving for determination of serum activities of gammaglutamyltransferase and alkaline phosphatase and serum concentrations of total protein (TP), immunoglobulin A (IgA) and IgG, and lactoferrin. The results were analyzed as repeated measures, and differences were considered statistically significant at P ≤ 0.05. Considering that the buffalo calves were born hypogammaglobulinemic (4.23 ± 0.33 mg/ml) and, at 24 h, the mean serum concentration of IgG was 34.5 ± 1.48 mg/ml, passive immunity transfer was successful. Moreover, colostrum IgG concentrations at 0 h were correlated with serum IgG concentrations at 24 h in buffalo calves. Additionally, TP concentrations were highly correlated with IgG in both colostrum at calving and blood in calves at 24 h. TP is recommended as a reliable indirect parameter to evaluate both colostrum quality and passive immunity transfer in buffalo calves.

Correlations between single nucleotide polymorphisms in bovine CD209, SLC11A1, SP110 and TLR2 genes and estimated breeding values for several traits in Spanish Holstein cattle

Little is known about the correlations between the genetic susceptibility/resistance to Mycobacterium avium subsp. paratuberculosis (Map) infection and the estimated breeding values for type, production and functional traits. Previously, we identified 70 combinations of five single nucleotide polymorphisms (SNPs) in four bovine innate immune genes (SLC11A1, SP110, TLR2, CD209) that are associated with the genetic risk of paratuberculosis (PTB) or Johne's disease progression, which can be graded as low (LOWIN), latent (LATIN), or patent (PATIN) risk. Other possible combinations of these 5 SNPs were grouped in the average group (AVERIN). In the current study, differences in estimated breeding values (EBVs) for several traits were analyzed using linear models in a large cohort of Holstein cows (N = 15656) genotyped across Spain in 2016 or 2017. After the assignment of each genotyped cow to a risk group, cows within the PATIN risk group (N = 1448) had a superior combined genetic index (2797.57), type genetic index (524.62), milk yield (653.92 kg), protein yield (21.77 kg), fat yield (24.82 kg) and economic merit index (125 Euros) compared with the other three risk groups. Statistically significant differences in the longevity scores between the cows that were included in the PATIN risk group (108.85) and the LOWIN (107.82) and AVERIN (107.92) groups were also observed. The associations between the genetic risk groups and PTB diagnostic results were validated in a population of 99 cows from a Spanish farm with a high prevalence of PTB. Significant differences in ELISA readings between the PATIN (65.49 %) and the AVERIN (15.97 %), LATIN (2.11 %), and LOWIN (3.27 %) groups were observed. In addition, significant differences in Map DNA copies/gram of feces were observed between the PATIN and the other three risk groups. These results together with the substantial economic impact of PTB in dairy cattle support the selection of the animals with less susceptibility to PTB in the Spanish breeding program.

Innate Immunomodulation in Food Animals: Evidence for Trained Immunity?

Antimicrobial resistance (AMR) is a significant problem in health care, animal health, and food safety. To limit AMR, there is a need for alternatives to antibiotics to enhance disease resistance and support judicious antibiotic usage in animals and humans. Immunomodulation is a promising strategy to enhance disease resistance without antibiotics in food animals. One rapidly evolving field of immunomodulation is innate memory in which innate immune cells undergo epigenetic changes of chromatin remodeling and metabolic reprogramming upon a priming event that results in either enhanced or suppressed responsiveness to secondary stimuli (training or tolerance, respectively). Exposure to live agents such as bacille Calmette-Guerin (BCG) or microbe-derived products such as LPS or yeast cell wall ß-glucans can reprogram or "train" the innate immune system. Over the last decade, significant advancements increased our understanding of innate training in humans and rodent models, and strategies are being developed to specifically target or regulate innate memory. In veterinary species, the concept of enhancing the innate immune system is not new; however, there are few available studies which have purposefully investigated innate training as it has been defined in human literature. The development of targeted approaches to engage innate training in food animals, with the practical goal of enhancing the capacity to limit disease without the use of antibiotics, is an area which deserves attention. In this review, we provide an overview of innate immunomodulation and memory, and the mechanisms which regulate this long-term functional reprogramming in other animals (e.g., humans, rodents). We focus on studies describing innate training, or similar phenomenon (often referred to as heterologous or non-specific protection), in cattle, sheep, goats, swine, poultry, and fish species; and discuss the potential benefits and shortcomings of engaging innate training for enhancing disease resistance.

The effect of early burn injury on sensitivity to future painful stimuli in dairy heifers

Animals that experience painful procedures as neonates are more sensitive to pain later in life. We evaluated whether disbudding with a heated iron at 3 (n = 12), 35 (n = 9), or 56 (n = 20) d of age affected heifers’ pain responses to vaccine injections at 11 mo of age. Heifers responded to the injection procedure with struggling and changes in eye temperature and heart rate variability compared to a sham procedure the day before, and still had a heightened response 6 d later, regardless of disbudding age. However, some heart rate variability indices suggested increased sympathetic dominance in heifers disbudded at 35 d, compared to the other 2 age groups, independent of the injection procedure. We also found that heifers disbudded at 3 or 35 d had a higher mean heart rate after the injection procedure compared to those disbudded at 56 d. We conclude that: (1) heifers find injections aversive; and (2) there is some evidence that disbudding age influences autonomic nervous system activity later in life.

Short communication: Plasma concentration and tissue mRNA expression of haptoglobin in neonatal calves

Haptoglobin (Hp), one of the major positive acute phase proteins in cattle, is released in response to proinflammatory cytokines. Colostrum intake might influence the response of the innate immune system, including Hp gene expression. Thus, we hypothesized that plasma concentrations and tissue mRNA expression of Hp in neonatal calves might be influenced by early nutrition in the neonatal calf and would thus be greater if receiving colostrum compared with milk-based formula. Two trials were performed. In trial 1, German Holstein calves were fed either colostrum (COL; n = 7) or milk-based formula (FOR; n = 7) up to 4 d of life. Blood was sampled from d 1 to 4 before morning feeding and before and 2 h after feeding on d 4. Tissue samples from liver, kidney fat, duodenum, and ileum were collected after slaughter on d 4 at 2 h after feeding. In trial 2, calves born preterm (n = 7) or at term (n = 7) received colostrum only at 24 h post natum. Blood was sampled at birth, and before and 2 h after feeding. Tissue samples from liver and kidney fat were collected after slaughter at 26 h after birth. Blood plasma, colostrum, and formula Hp concentrations were determined using a competitive ELISA. Tissue expression of Hp mRNA was quantified by real-time quantitative PCR. The formula contained much less Hp (≤0.5 µg/mL) than colostrum (69.3, 93.9, and 20.4 µg/mL from d 1 to d 3, respectively). In trial 1, before colostrum or formula feeding, plasma concentrations of Hp were comparable in both groups. Plasma Hp increased in FOR after feeding, resulting in greater or a trend for greater plasma Hp concentrations in FOR than in COL calves. The mRNA abundance of Hp in liver and kidney fat was 3- and 2.2-fold greater in FOR than in COL calves, respectively, whereas duodenal and ileal abundance of Hp mRNA did not differ between groups. In trial 2, plasma Hp concentrations decreased slightly over time in term calves, but they did not differ in both groups before and 2 h after feeding on d 2. The abundance of Hp mRNA in liver was 5.3-fold greater in term than in preterm calves, whereas its abundance in kidney fat did not differ between groups. Contrasting our hypothesis, formula, but not colostrum feeding was associated with greater Hp mRNA abundance in liver and adipose tissue, indicating that the response of innate immune system seems to be modulated by formula feeding because of the lack of immunoglobulin intake. The lower hepatic abundance of Hp mRNA in preterm calves than in term calves may indicate lower synthetic capacity of the liver for Hp in preterm calves shortly after birth.

Heat Stress Impacts Immune Status in Cows Across the Life Cycle

Heat stress has a myriad of effects on dairy cattle across the life cycle. Whereas, the most commonly recognized impacts are associated with production responses, emerging evidence indicates that heat stress profoundly alters the immune response of calves and cows, from the prenatal stage through lactation. For example, in utero heat stress reduces passive immune transfer regardless of colostrum source, relative to normothermic conditions in late gestation. Dry cows exposed to heat stress have lower immunoglobulin responses to ovalbumin vaccination, but this effect dissipates with cooling following parturition. Conversely, cows under heat stress when dry exhibit carryover effects on the innate arm of the immune system in early lactation. In this paper we review the effects of heat stress throughout the life cycle of the dairy cow, with particular emphasis on the impact of heat stress during late gestation on the cow and the developing fetus, both before and after parturition. In addition, the impact of altered immune status under heat stress on other physiological systems, especially those supporting milk production, are considered. Finally, management interventions to prevent and reverse the effect of heat stress are presented.

Effect of an injectable trace mineral supplement on the immune response of dairy calves

On a spring calving, pastoral dairy farm, the first 40 heifer calves born after calving mid-point (50% of the herd calved) were blood sampled within 24 h. Thirty were selected, using stratified randomisation to form two equal groups (treatment and control) with the same distribution of serum total protein, copper, selenium, zinc, and manganese concentrations, age and breed. From the remaining 10 calves, five were randomly selected into a sentinel group to assess field exposure to Salmonella spp. All calves received two injections of a killed vaccine containing Salmonella spp. antigens at 2 and 6 weeks of age. Concurrently, the treatment group were injected with 1 mL/50 kg trace mineral supplement (TMS) containing 40 mg zinc, 10 mg manganese, 5 mg selenium, 15 mg copper per mL. Sentinel animals received no injections. All animals were bled from 2 to 9 weeks for assay of immune function. At three and four weeks, white blood cells from TMS calves had an increased percentage of cells phagocytosing (effect size = 9.36 and 4.35) and increased number of bacteria ingested per cell (effect size = 0.93 and 1.52). No differences were detected in gamma interferon response (effect size <0.15) or Salmonella sp. antibody titres (effect size <0.20).

Symposium review: Late-gestation maternal factors affecting the health and development of dairy calves

Efficient production of heifers is fundamental to the productivity and sustainability of dairy farms. However, high preweaning morbidity and mortality rates are frequently reported worldwide, imposing substantial welfare and economic implications. A major contributing factor to disease susceptibility in the neonatal stage is the inability of calves to mount an effective immune response. Appreciation is now greater that exposure in utero to several stresses (nutritional, social, metabolic, and so on) during the last stages of pregnancy have downstream carryover effects in calves' health, growth, and development. Suboptimal intrauterine conditions during critical periods of development lead to changes in tissue structure and function that may have long-term consequences on the offspring's physiology and disease susceptibility. Indeed, preweaning metabolic function and growth are associated with future milk production. Thus, late-gestation carryover effects span into the lactating stage of the heifers. Nevertheless, researchers have been studying how to minimize these effects. This review will discuss the effects of maternal stress during late gestation on the offspring's growth, productivity, metabolism, and health. In addition, strategies focusing on maternal interventions that improve neonatal health will be discussed. A better understanding of the intrauterine conditions affecting calf health and growth may facilitate the design of management practices that could improve neonatal development and future cow productivity.

Influence of early use of antimicrobial on the health and performance of Holstein calves in the first month of life

ABSTRACT: The early use of antimicrobial therapy has been introduced in many farms to prevent diarrhea and respiratory disease in young calves; however, there is controversy about whether this practice has a beneficial effect on the health of these animals. This study evaluated the influence of the early use of antimicrobials on the health and performance of neonatal Holstein calves. Twenty-six Holstein calves were screened and divided into two groups, according to the administration (ATB+), or not (ATB-) of tulathromycin (2.5mg/kg, subcutaneously) within the first 12 hours of life. Calves were evaluated by general clinical examination, fecal score, respiratory score, and external palpation of the umbilical region, besides fecal output of dry matter. Anemia was determined by using an automatic system and, also, using a commercial kit for iron dosage. Diarrhea was diagnosed by a centrifuge-flotation technique using a sugar solution (Cryptosporidium) and multiplex semi-nested RT-PCR (rotavirus/coronavirus). The performance of the calves was estimated by Daily Weight Gain (DWG). The young dairy calves were evaluated within 12 hours of birth (≤12h) and at 3-5th (D3-5), 7-9th (D7-9), 13-15th (D13-15), 20-23rd (D20-23), and 27-30th (D27-30) days of life. No difference was noted between the ATB+ and ATB- groups concerning heart rate, respiratory frequency, and rectal temperature. Erythrogram showed a higher frequency of anemia in ATB- group (P=0.016) at the D3-5 check-up; lower values of serum iron were also observed simultaneously (P=0.051). Thirteen cases of respiratory disease were detected during this study; however, no significant difference was observed between the groups in this regard. The frequency of diarrhea (fecal score 2-3) was high in both groups, peaking at D13-D15. No differences were noted between the groups regarding the frequency of diarrhea when considering the dry fecal matter. The predominant etiological agent for diarrhea was Cryptosporidium spp.. The DWG was similar between groups, with maximum weight reduction on D13-15. The administration of tulathromycin in prophylactic dose (2.5mg/kg) at birth decreased the frequency of anemia but did not influence weight gain or the prevalence of diarrhea.

Effects of Pair Versus Individual Housing on Performance, Health, and Behavior of Dairy Calves

Simple Summary

In modern dairy farming systems, calves are often housed in individual pens or hutches, which results in less social interaction with their peers during the milk-feeding period. The aim of this study was to evaluate the effects of pair versus individual housing on performance, health, and behavior of dairy calves from the milk-feeding period to the first week after mixing. Results showed that pair versus individual housing had no effects on body weight, starter intake or average daily gain during the milk-feeding period, while pair housing increased the growth performance of calves during weaning and postweaning periods, and the beneficial effects of pair housing on growth faded after calves were mixed and moved to group housing. Paired calves showed higher diarrhea frequency only in week three. The behavior of calves was altered at different periods, including increased time spent in feeding, chewing and ruminating, and decreased self-grooming time, and a drop of non-nutritive manipulation for all calves after they were mixed and moved to group housing. We also found less social contact may lead to more non-nutritive manipulation.

Abstract

The aim of this study was to evaluate the effects of pair versus individual housing on performance, health, and behavior of dairy calves. Thirty female Holstein dairy calves were assigned to individual (n = 10) or pair housing (n = 10 pairs). The results showed that both treatments had a similar starter intake and average daily gain (ADG) during the preweaning period. During weaning and postweaning periods, paired calves had a higher starter intake, and the ADG of paired calves continued to increase but calves housed individually experienced a growth check. Paired calves showed higher diarrhea frequency only in week three. The results on behavior showed that feeding, chewing and ruminating time increased, and self-grooming time decreased with age during weaning and postweaning periods, and paired calves spent less time feeding, standing and self-grooming but more time lying during this time. After mixing, feeding, and chewing and ruminating time continued to rise, and self-grooming time continued to decline for both treatments. All calves spent less time standing and non-nutritive manipulation after mixing, and previously individually housed calves tended to increase non-nutritive manipulation. These results showed that pair housing improved growth during weaning and postweaning periods and that calves altered their behavior at different phases. Less social contact may lead to more non-nutritive manipulation.

Genomic analysis of bovine respiratory disease and lung consolidation in preweaned Holstein calves using clinical scoring and lung ultrasound

Bovine respiratory disease (BRD) is a leading cause of morbidity and mortality in dairy calves, with detrimental long-term effects that include stunted growth, increased age at first calving, and decreased milk production in first lactation. The objectives of this study were to establish a protocol for objective and efficient assessment of BRD phenotypes in preweaned dairy calves, develop a genomic reference population with well-defined clinical and subclinical phenotypes, identify chromosomal regions associated with BRD in a genome-wide association study, estimate genetic parameters of BRD, and predict genomic breeding values of dairy calves. A total of 1,107 Holstein calves from 6 dairy farms in southern Wisconsin were examined using clinical respiratory scoring and lung ultrasound at 3 and 6 wk of age. The clinical respiratory score was based on visual appraisal of eyes, nose, ears, cough, and temperature. Lung ultrasound scores were assigned based on the amount of consolidation present. Calves were genotyped with a commercially available SNP array and after quality control and imputation to higher density, 690,291 SNP markers and 1,014 individuals remained. Single-step genome-wide association study and single-step genomic best linear unbiased prediction were applied to binary 3- and 6-wk phenotypes considered as overall respiratory healthy versus affected (RESP3, RESP6) or as presence or absence of lung consolidation (CON3, CON6). Lung ultrasound combined with a clinical scoring system allowed for efficient and objective assessment for the prevalence of BRD. Proportions of variance attributed to 1-Mb non-overlapping windows suggested genomic regions that may contain putative candidate genes, most notably regions on Bos taurus autosomes 1, 6, 7, 10, 11, 12, 15, 17, 18, 27, and 28 that explained 0.70 to 1.45% of the genetic variance. Heritability estimates were higher at 3 wk (0.214 and 0.241 for CON3 and RESP3, respectively) than 6 wk (0.084 and 0.111 for CON6 and RESP6, respectively), and mean reliabilities of genomic estimated breeding vales for calves with genotypes and phenotypes ranged from 0.12 for CON6 to 0.30 for RESP3.

Influence of Colostrum and Vitamins A, D3, and E on Early Intestinal Colonization of Neonatal Holstein Calves Infected with Mycobacterium avium subsp. paratuberculosis

Exposure of neonates to Mycobacterium avium subsp. paratuberculosis (MAP) via infected dams is the primary mode of transmission of Johne’s disease. Little is known about the impacts of feeding colostrum and supplemental vitamins on the gut microbiome in calves exposed to MAP. In the present study, calves were assigned at birth to one of six treatment groups: (1) Colostrum deprived (CD), no vitamins; (2) colostrum replacer (CR), no vitamins; (3) CR, vitamin A; (4) CR, vitamin D₃; (5) CR, vitamin E; (6) CR, vitamins A, D₃, E, with five calves per treatment in a 14-day study. All calves were orally inoculated with MAP on days 1 and 3 of the study. Differences due to vitamin supplementation were not significant but treatment groups CR-A, CR-E, and CR-ADE had higher numbers of MAP-positive tissues overall. Shannon diversity indices demonstrated regional differences in microbial communities, primarily Proteobacteria, Bacteroidetes, and Firmicutes, between the ileum, cecum, and spiral colon of all calves. CD calves exhibited increased richness compared with CR calves in the cecum and spiral colon and harbored increased Proteobacteria and decreased Bacteroidetes in the mucosa compared with the lumen for all three tissues. Overall, supplementation with vitamins did not appear to influence gut microbiome or impact MAP infection. Feeding of colostrum influenced gut microbiome and resulted in fewer incidences of dysbiosis.

Short communication: Effect of granulocyte-macrophage colony-stimulating factor on neonatal calf peripheral blood neutrophil function in vitro

Neutrophils are innate immunity cells that represent the first line of cellular defense against invading pathogens. Dairy calves, however, experience neutrophil dysfunction during the first weeks of age, contributing to increased disease susceptibility during this period. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that improves neutrophil function in neonates of other species and mature cows. However, its capability to improve neonatal calf neutrophil function is unknown. Therefore, our objective was to evaluate the effect of GM-CSF on the functional capabilities of neutrophils of neonatal calves in vitro. We hypothesized that supplementation of neonatal neutrophils with GM-CSF would increase microbicidal functions to levels comparable with those of mature immunocompetent cattle. For this, we isolated blood neutrophils from 12 healthy 2- to 3-d-old Holstein calves, and neutrophils from 6 mid-lactation Holstein cows were used as a reference of robust neutrophil function. Subsequently, neutrophils from both calves and cattle were incubated for 9 h with 4 concentrations (0, 0.005, 0.05, or 0.5 µg/mL) of GM-CSF, and microbicidal function of neutrophils was assessed in terms of phagocytosis, respiratory burst, myeloperoxidase (MPO) activity, and extracellular trap formation. Mixed models with Tukey pairwise comparisons were used to identify differences among treatment and age groups. Supplementation of GM-CSF in vitro increased phagocytosis and MPO activity of calf and cow neutrophils, although not in a concentration-dependent manner. Respiratory burst and extracellular trap formation were not affected by GM-CSF supplementation. All the microbicidal capacity functions assessed were lower in neutrophils from calves, but supplementation with GM-CSF increased phagocytosis and MPO activity of calf neutrophils to levels comparable with unsupplemented cow neutrophils. Collectively, our results demonstrated that in vitro supplementation of calf neutrophils with GM-CSF enhanced some functional microbicidal capabilities to levels comparable with immunocompetent cattle. Hence, it may be possible to augment the functional capacity of calf neutrophils in vivo through the therapeutic application of GM-CSF and consequently enhance calves' resistance to infections. This should be tested in future in vivo studies.

Invited review: MicroRNAs in bovine colostrum-Focus on their origin and potential health benefits for the calf

Colostrum is the first milk produced by a cow after she gives birth. Compared with mature milk, it has a high concentration of immunoglobulin G. Calves are born without circulating antibodies, thus ingestion of colostrum is necessary to protect the calf against pathogens in the first challenging weeks of life. In addition to the life-saving supply of antibodies, colostrum contains minerals, vitamins, growth factors, and immune cells. Recently, microRNAs (miRNAs) were added to that list. MicroRNAs are short, non-coding RNA molecules that can regulate gene expression at the post-transcriptional level. They are thought to act as key regulators of diverse biological and developmental processes. Colostrum contains higher amounts of miRNAs than mature milk; immune- and development-related miRNAs are prominent. Their expression pattern in milk is likely to be influenced by maternal nutrition and environment. The fat content of the maternal diet appears to have a major effect on expression of miRNAs in milk and in the neonate. The immunological state of the mammary gland seems to affect miRNA expression as well. In cows diagnosed with subclinical mastitis, alterations in the expression of miRNAs in milk have been observed. It is believed that miRNAs in colostrum and milk are signaling molecules passed from mother to newborn. They are packaged in extracellular vesicles, which makes them resistant to the harsh conditions in the gastrointestinal tract. Therefore, they can reach the small intestine, where they are absorbed and transferred into the bloodstream. MicroRNAs are important for the development of the intestines. For example, miRNAs stimulate cell viability, proliferation, and stem cell activity of the intestinal epithelium. Furthermore, miRNAs seem to act as key players in the development of the complete immune system. They can, among other things, regulate B- and T-cell differentiation and affect interleukin production of macrophages. The abundance of miRNAs in colostrum and milk and the possibility for their absorption in the intestines of the neonate supports the hypothesis that these tiny molecules are important for the development of the newborn. The probable relation of diet to the expression of miRNAs by the mother creates a possible avenue to optimize expression of miRNAs and improve neonatal maturation.

Gamma Delta T Cell Function in Ruminants

Gamma delta (γδ) T cells constitute a major lymphocyte population in peripheral blood and epithelial surfaces. They play nonredundant roles in host defense against diverse pathogens. Although γδ T cells share functional features with other cells of the immune system, their distinct methods of antigen recognition, rapid response, and tissue tropism make them a unique effector population. This review considers the current state of our knowledge on γδ T cell biology in ruminants and the important roles played by this nonconventional T cell population in protection against several infectious diseases of veterinary and zoonotic importance.

Vaccinating Calves in the Face of Maternal Antibodies: Challenges and Opportunities

A growing body of evidence has shown that calves can mount an immune response when vaccinated in the face of maternal antibodies (IFOMA), albeit inconsistently and often in ways that differ from seronegative calves or older cattle. Several previous reviews have endeavored to explain bovine neonatal immunology and have documented the issue of vaccinating young calves. However, as preweaning vaccination becomes more common in both beef and dairy production systems, so too has research on the impacts of such vaccination programs. This article aims to briefly review the challenges and opportunities for vaccinating calves IFOMA.

Short communication: Supply of methionine during late pregnancy enhances whole-blood innate immune response of Holstein calves partly through changes in mRNA abundance in polymorphonuclear leukocytes

The supply of methionine (Met) in late pregnancy can alter mRNA abundance of genes associated with metabolism and immune response in liver and polymorphonuclear leukocytes (PMN) of the neonatal calf. Whether prenatal supply of Met elicits postnatal effects on systemic inflammation and innate immune response of the calf is not well known. We investigated whether enhancing the maternal supply of Met via feeding ethyl-cellulose rumen-protected Met (RPM) was associated with differences in calf innate immune response mRNA abundance in PMN and systemic indicators of inflammation during the first 50 d of life. Calves (n = 14 per maternal diet) born to cows fed RPM at 0.09% of diet dry matter per day (MET) for the last 28 ± 2 d before calving or fed a control diet with no added Met (CON) were used. Blood for biomarker analysis and isolation of PMN for innate immune function assays and mRNA abundance was harvested at birth (before colostrum feeding) and at 7, 21 and 50 d of age. Whole blood was challenged with enteropathogenic bacteria (Escherichia coli 0118:H8) and phagocytosis and oxidative burst of neutrophils and monocytes were quantified via flow cytometry. Although concentration of haptoglobin and activity of myeloperoxidase among calves from both maternal groups increased markedly between 0 and 7 d of age followed by a decrease to baseline at d 21 the responses were lower in MET compared with CON calves. Nitric oxide concentration decreased markedly between 0 and 7 d regardless of maternal group but MET calves tended to have lower overall concentrations during the study. In vitro phagocytosis in stimulated neutrophils increased markedly over time in both CON and MET calves but responses were overall greater in MET calves. Oxidative burst in both neutrophils and monocytes increased over time regardless of maternal treatment. The mRNA abundance of lactate dehydrogenase (LDHA) signal transducer and activator of transcription 3 (STAT3) and S100 calcium binding protein A8 (S100A8) in PMN was overall greater in MET calves. Overall data suggest that increasing the maternal supply of Met during late pregnancy could affect the neonatal calf inflammatory status and innate immune response. Although changes in mRNA abundance could play a role in coordinating the immune response the exact mechanisms merit further study.

Effect of FMD vaccination schedule of dams on the level and duration of maternally derived antibodies

Vaccination against Foot and Mouth Disease (FMD) in pregnant cows is crucial to produce greater immunity in new born calves, especially in late gestation, as this directly affects neonatal immunity. Therefore, we aimed to investigate how late gestation FMD vaccination of pregnant cows affects the maternally derived antibodies in their offspring. Pregnant cows were vaccinated with and without booster vaccination during the 3rd months (early gestation vaccination, EGV) or the 6.5th months (late gestation vaccination, LGV). Their offspring were investigated for passive immunity transfer, maternal antibody duration, and the first vaccination age of calves (when the maternal antibody has waned sufficiently to allow the first vaccination). Antibody titers were analyzed by a virus neutralization test (VNT). A digital Brix refractometer (% Brix) was used to estimate passive antibody transfer efficiency measuring total protein (TP) content of calf blood sera and also colostrum IgG content. Two linear mixed effects models were fitted: one for the antibody titer values of the dams, and the other for the antibody titer values of calves before the vaccination. A marginal fixed effects model was also fitted to explore the effects of the dam titers on the antibody titers of the calves after their vaccinations. As a result, the average neutralizing antibody titers did not differ between the EGV and LGV groups nor were any differences detected between dams that received a booster and those that were not boosted. However, the LGV calves' mean maternally derived antibody titers were significantly higher (p-values = 0.0001 for both groups) and the duration was longer than that of the EGV calves (120 days in LGV, 60 days in EGV, p < 0.05). Since no statistical difference was found between the titers of either group of dams at the beginning of the experiment and parturition, it does not appear that the higher VN titers in LGV calves compared to titers in EGV are directly related to the circulating antibody levels in the dams. Furthermore, the TP value (% Brix) of calf blood sera was higher than>8.4% in both calf groups (9.3 ± 0.33 in LGV and 8.6 ± 0.40 in EGV, p > 0.05) indicating that passive immunity transfer had occurred for both groups. In addition, we found that the % Brix mean colostrum IgG content of the LGV (25.8 ± 1.30) was higher than the EGV (21.8 ± 0.58) dams (p < 0.01) and a significant positive correlation found between the colostrum density of LGV dams and TP (% Brix) value of their offspring (r = 0.73, p < 0.01). Our results show that vaccination during the late gestation period increased the colostrum IgG content of dams of LGV in addition to the maternally derived antibody duration and potentially provided greater protection of the offspring.

Beef producer survey of the cost to prevent and treat bovine respiratory disease in preweaned calves

OBJECTIVE To estimate costs associated with prevention and treatment of bovine respiratory disease (BRD) in preweaned calves on US beef cow-calf operations. DESIGN Cross-sectional survey. SAMPLE 43 beef cow-calf producers whose operations had a history of BRD in preweaned calves. PROCEDURES Mail and electronic surveys were developed and administered to producers in Nebraska, North Dakota, and South Dakota to obtain information regarding costs of BRD prevention and treatment. Descriptive statistics were generated. Mixed linear regression models were used to assess factors associated with the costs of vaccines, medicine, and labor and percentage time spent on prevention and treatment of BRD in cows, replacement heifers, and preweaned calves. RESULTS 7 mail and 36 electronic surveys were completed. Median annual costs for BRD vaccines were $2.25, $4.00, and $6.25/animal, and median annual labor costs for vaccination were $4.58, $3.00, and $5.00/animal for cows, heifers, and preweaned calves, respectively. Median annual costs for medicine and labor to treat preweaned calves for BRD were $11.00 and $15.00/ affected calf, respectively. Adjusted mean annual BRD vaccine cost for preweaned calves ($7.67/animal) was significantly greater than that for cows ($3.18/animal) and heifers ($4.48/animal). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that labor costs associated with BRD vaccination and treatment were similar to or exceeded the cost of vaccines and medicine, and most of those labor costs were associated with gathering and sorting cattle. Therefore, costs associated with labor as well as medicine and vaccines should be considered during the development of BRD prevention and treatment plans.

Randomized field trial on the effects of body weight and short transport on stress and immune variables in 2- to 4-week-old dairy calves

Background

Whether underweight calves respond differently to transport stress, enhancing their disease risk, is currently unknown.

Objective

To determine the effects of low body weight and transport stress on immune variables.

Animals

Twenty‐one 2‐ to 4‐week‐old male Holstein calves, housed on a commercial farm.

Methods

Randomized clinical trial. Full factorial design with 4 treatment groups: low body weight (≤46 kg)/no transport (LOWCON); low body weight/transport (LOWTRANS); normal body weight (>46 kg)/no transport (NORMCON), and normal body weight/transport (NORMTRANS). Transport duration was 2 hours.

Results

Transport significantly increased serum cortisol concentration (77.8 μg/mL; 95% confidence interval [CI], 37.8‐131.6; P < .001), interleukin (IL)‐17A (344.9 pg/mL; 95% CI, 32.2‐556.5; P = .04), and tumor necrosis factor‐α (TNF‐α) (218.2 pg/mL; 95% CI, 32.5‐368.3; P = .03) production after lipopolysaccharide (LPS) stimulation. Body weight did not affect any of the studied variables. However, the interaction of transport and body weight was significant. LOWTRANS calves showed increased monocyte count (2.0 × 10⁹/L; 95% CI, 0.6‐4.2; P < .05) and interleukin IL‐17A production (106.0 pg/mL; 95% CI, 4.2‐306.9; P = .03) compared to normal weight calves and increased TNF‐α production (275.6 pg/mL; 95% CI, 2.6‐463.0; P = .02) compared to LOWCON calves in unstimulated peripheral blood mononuclear cells (PBMCs) after transport.

Conclusion and Clinical Importance

These findings contribute to our understanding of increased disease susceptibility of underweight calves when transported. Gamma globulin concentration was identified as important interfering factor in studies on immune variables in neonatal calves.

The Bos taurus maternal microbiome: Role in determining the progeny early-life upper respiratory tract microbiome and health

Natural transference of maternal microbes to the neonate, especially at birth via the vaginal canal, has recently been recognized in humans and cows; however, its microbial influence on calf health has not yet been documented. We compared the bacterial communities in vaginal and fecal samples from 81 pregnant dairy cows versus those in nasopharyngeal and fecal samples collected at 3, 14 and 35 days of life from their respective progeny. The microbiota of the calf upper respiratory tract (URT), regardless of calf age, was found to be highly similar to the maternal vaginal microbiota. Calf fecal microbiota clustered closely to the maternal fecal microbiota, progressing toward an adult-like state over the first 35 days when relative abundances of taxa were considered. Sixty-four, 65 and 87% of the detected OTUs were shared between cow and calf fecal microbiota at days 3, 14 and 35 respectively, whereas 73, 76 and 87% were shared between maternal vaginal microbiome and calf URT microbiota at days 3, 14 and 35, respectively. Bacteroidetes, Ruminococcus, Clostridium, and Blautia were the top four genera identified in maternal and calf fecal samples. Mannheimia, Moraxella, Bacteroides, Streptococcus and Pseudomonas were the top five genera identified in maternal vaginal and calf URT samples. Mannheimia was relatively more abundant in the vaginal microbiota of cows whose progeny were diagnosed with respiratory and middle ear disease. Our results indicate that maternal vaginal microbiota potentially influences the initial bacterial colonization of the calf URT, and that might have an important impact on the health of the calf respiratory tract and middle ear.

Influence of prenatal transportation stress on innate immune response to an endotoxin challenge in weaned Brahman bull calves†,‡

The objective of this study was to assess the influence of prenatal stress (PNS) on innate immune responses to an endotoxin challenge in weaned bull calves. Altered innate immune response to lipopolysaccharide (LPS), as characterized by changes in a range of variables was hypothesized in PNS bull calves. Brahman cows (n = 96; 48 stressed by transportation at five stages of gestation and 48 Controls) produced 85 calves, from which 16 uncastrated male (bull) calves from each PNS and Control treatment were selected for an LPS challenge period. Rectal temperature (RT), sickness behavior score (SBS), serum concentrations of cortisol, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and complete blood count (CBC) variables were assessed in response to intravenous LPS (0.25 μg/kg body weight) administration. Each reported variable increased or decreased following LPS administration. Prior to LPS, PNS bull calves exhibited increased TNF-α, IL-6, and monocyte counts, but decreased IFN-γ, eosinophils, and basophils (p < .05). Compared with Control, in response to LPS, PNS bull calves exhibited greater circulating concentrations of cortisol. PNS bull calves exhibited lower (p < .05) eosinophil and basophil counts at time 0 (time of LPS administration) but similar counts to Control bull calves 2 h after LPS. PNS bull calves exhibited a greater change from baseline for IFN-γ and monocytes in response to LPS administration. No other variables were influenced by prenatal treatment (p > .05). These findings suggest that PNS did not adversely affect basal or induced components of the innate immune response to an immunological challenge. Lay summary Our laboratory studied the influence of prenatal stress (i.e., transportation of pregnant cows) on immune function of bull calves at 8 months of age. This was accomplished by studying aspects of their innate immune response to an immunological challenge. Prenatal stress did not adversely affect basal or induced components of the innate immune response to an immunological challenge.

Longitudinal surveillance of rotavirus A genotypes circulating in a high milk yield dairy cattle herd after the introduction of a rotavirus vaccine

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RVA vaccination program reduces the frequency and intensity of diarrhea in dairy calves.

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The vaccination immune pressure can select specific genotypes in RVA field strains.

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RVA genotype G10P[11] in fecal samples of calves from G6P[5] vaccinated dairy cattle herds.

Worldwide, neonatal diarrhea is one of the most important health issues affecting dairy calves, and rotavirus A (RVA) is one of its primary causes. Among the measures to mitigate the risk of diarrhea outbreaks, cow vaccination stands out as one of the most important. However, the immune pressure resulting from routine vaccination may be able to select specific G and P genotypes in RVA field strains. This study aimed to determine the frequency and intensity of neonatal diarrhea and the incidence of RVA and attempted to monitor the G and P genotypes present in the RVA strains circulating in a high milk yield cattle herd vaccinated with RVA G6P[5] strain. Fecal samples (n = 1220) from 122 Holstein heifer calves between 0–30 days old that were born from RVA-vaccinated cows were collected at 10 different time points, regardless of the presence or absence of diarrhea. The presence of RVA in fecal samples was determined by the polyacrylamide gel electrophoresis (PAGE) technique and confirmed by reverse transcription polymerase chain reaction (RT-PCR). G and P amplicons from 10 RVA-positive fecal samples from calves of different ages and collections were subjected to nucleotide sequencing. The proportion of the calves and fecal samples that were positive for RVA were 62.3% (76/122) and 8.1% (99/1220), respectively. Using sequence analysis, all 10 RVA field strains presented genotype G10P[11]. The protection of G6P[5] vaccination is clear, as this genotype was not detected in this study, and it is known that vaccination against RVA reduces the incidence of diarrhea independent of genotype involved. This result demonstrates the importance of epidemiological monitoring of RVA genotypes circulating in vaccinated dairy cattle herds to the early detection of new potential pathogenic RVA strains.