Subpopulations of swine γδ T cells defined by TCRγ and WC1 gene expression

γδ T cells constitute a major portion of lymphocytes in the blood of both ruminants and swine. Subpopulations of swine γδ T cells have been distinguished by CD2 and CD8α expression. However, it was not clear if they have distinct expression profiles of their T-cell receptor (TCR) or WC1 genes. Identifying receptor expression will contribute to understanding the functional differences between these subpopulations and their contributions to immune protection. Here, we annotated three genomic assemblies of the swine TCRγ gene locus finding four gene cassettes containing C, J and V genes, although some haplotypes carried a null TRGC gene (TRGC4). Genes in the TRGC1 cassette were homologs of bovine TRGC5 cassette while the others were not homologous to bovine genes. Here we evaluated three principal populations of γδ T cells (CD2⁺/SWC5^-, CD2^-/SWC5⁺, and CD2^-/SWC5^-). Both CD2^- subpopulations transcribed WC1 co-receptor genes, albeit with different patterns of gene expression but CD2⁺ cells did not. All subpopulations transcribed TCR genes from all four cassettes, although there were differences in expression levels. Finally, the CD2⁺ and CD2^- γδ T-cell populations differed in their representation in various organs and tissues, presumably at least partially reflective of different ligand specificities for their receptors.

Effects of Deoxynivalenol and Fumonisins Fed in Combination to Beef Cattle: Immunotoxicity and Gene Expression

We evaluated the effects of a treatment diet contaminated with 1.7 mg deoxynivalenol and 3.5 mg fumonisins (B1, B2 and B3) per kg ration on immune status and peripheral blood gene expression profiles in finishing-stage Angus steers. The mycotoxin treatment diet was fed for a period of 21 days followed by a two-week washout period during which time all animals consumed the control diet. Whole-blood leukocyte differentials were performed weekly throughout the experimental and washout period. Comparative profiles of CD4+ and CD8+ T cells, along with bactericidal capacity of circulating neutrophils and monocytes were evaluated at 0, 7, 14, 21 and 35 days. Peripheral blood gene expression was measured at 0, 7, 21 and 35 days via RNA sequencing. Significant increases in the percentage of CD4-CD8+ T cells were observed in treatment-fed steers after two weeks of treatment and were associated with decreased CD4:CD8 T-cell ratios at this same timepoint (p ≤ 0.10). No significant differences were observed as an effect of treatment in terms of bactericidal capacity at any timepoint. Dietary treatments induced major changes in transcripts associated with endocrine, metabolic and infectious diseases; protein digestion and absorption; and environmental information processing (inhibition of signaling and processing), as evaluated by dynamic impact analysis. DAVID analysis also suggested treatment effects on oxygen transport, extra-cellular signaling, cell membrane structure and immune system function. These results indicate that finishing-stage beef cattle are susceptible to the immunotoxic and transcript-inhibitory effects of deoxynivalenol and fumonisins at levels which may be realistically encountered in feedlot situations.

Identification and Phenotype of MAIT Cells in Cattle and Their Response to Bacterial Infections

Mucosal-associated invariant T (MAIT) cells are a population of innate-like T cells that utilize a semi-invariant T cell receptor (TCR) α chain and are restricted by the highly conserved antigen presenting molecule MR1. MR1 presents microbial riboflavin biosynthesis derived metabolites produced by bacteria and fungi. Consistent with their ability to sense ligands derived from bacterial sources, MAIT cells have been associated with the immune response to a variety of bacterial infections, such as Mycobacterium spp., Salmonella spp. and Escherichia coli. To date, MAIT cells have been studied in humans, non-human primates and mice. However, they have only been putatively identified in cattle by PCR based methods; no phenotypic or functional analyses have been performed. Here, we identified a MAIT cell population in cattle utilizing MR1 tetramers and high-throughput TCR sequencing. Phenotypic analysis of cattle MAIT cells revealed features highly analogous to those of MAIT cells in humans and mice, including expression of an orthologous TRAV1-TRAJ33 TCR α chain, an effector memory phenotype irrespective of tissue localization, and expression of the transcription factors PLZF and EOMES. We determined the frequency of MAIT cells in peripheral blood and multiple tissues, finding that cattle MAIT cells are enriched in mucosal tissues as well as in the mesenteric lymph node. Cattle MAIT cells were responsive to stimulation by 5-OP-RU and riboflavin biosynthesis competent bacteria in vitro. Furthermore, MAIT cells in milk increased in frequency in cows with mastitis. Following challenge with virulent Mycobacterium bovis, a causative agent of bovine tuberculosis and a zoonosis, peripheral blood MAIT cells expressed higher levels of perforin. Thus, MAIT cells are implicated in the immune response to two major bacterial infections in cattle. These data suggest that MAIT cells are functionally highly conserved and that cattle are an excellent large animal model to study the role of MAIT cells in important zoonotic infections.

Astragalus root extract improved average daily gain, immunity, antioxidant status and ruminal microbiota of early weaned yak calves

BACKGROUND

Early weaning in yak calves is being attempted to improve yak reproduction rate. However, this has to be done with caution because of the high mortality rate of calves due to the lack of nutrients and the harsh environmental conditions. Twenty-four weaned male yak calves were used in a 60 day feeding trial in which astragalus root extract (ARE) was supplemented. They were assigned randomly to one of four dietary treatments (n = six per treatment) that differed in ARE level: 0 g kg^-1 (control), ARE₀ ; 20 g kg^-1 , ARE₂₀ ; 50 g kg^-1 , ARE_50; and 80 g kg^-1 dry matter intake (DMI), ARE₈₀ .

RESULTS

Final bodyweight and average daily gain (ADG) were significantly higher and the DMI/ADG ratio was significantly lower in calves with ARE supplementation than control (ARE₀ ) calves. Ruminal concentrations of acetate and propionate and serum concentration of superoxide dismutase in ARE₈₀ calves were higher than in the other groups and serum concentration of insulin was higher in ARE₈₀ calves than in ARE₂₀ calves. Serum immunoglobulin G (IgG) and interleukin-2 (IL-2) concentrations in ARE-fed calves were higher than in controls. Serum tumor necrosis factor (TNF-α) concentration was higher in ARE₅₀ and ARE₈₀ groups than ARE₀ calves and serum interleukin-6 (IL-6) concentration was higher in ARE₈₀ than in ARE₀ calves. Serum immunoglobulin A (IgA), IgG and immunoglobulin M (IgM) concentrations increased with age in ARE-fed calves. ARE supplementation increased the abundance of fiber degrading bacteria.

CONCLUSION

ARE at a dosage of 5% to 8% DMI can be supplemented to early weaned yak calves to improve growth performance, antioxidant capacity and immunity. © 2020 Society of Chemical Industry.

The Freemartin Cattle and Clinical Transplantation: From the Ancients to Modern Day

This historical retrospective explores the study of the freemartin condition and its impact on the discovery of immunologic tolerance and the field of transplant surgery-from the ancient Romans, to early modern anatomists Valsalva, Scarpa, and Hunter, to contemporary immunologists Owen, Medawar, and Billingham, and to legendary transplant surgeon Joseph Murray. The legacy of freemartin cattle in the understanding of acquired tolerance and transplant immunology represents generations of scientific inquiry guided by careful observation and occasional serendipity, and the present-day immunologists and surgeons exploring immune transplant tolerance owe much to the history of the freemartin, several millennia in the making.

Increasing serotonin bioavailability alters gene expression in peripheral leukocytes and lymphoid tissues of dairy calves

Dairy calves are born with a naïve immune system, making the pre-weaning phase a critical window for immune development. In the U.S., 40-60% of dairy farms feed milk replacer to pre-weaned calves, which are devoid of bioactive factors with immunological roles. Serotonin is a bioactive factor with immunoregulatory properties naturally produced by the calf and present in milk. Human and rodent immune cells express the serotonin machinery, but little is known about the role of serotonin in the bovine immune system. Supplementing milk replacer with 5-hydroxytryptophan (serotonin precursor) or fluoxetine (reuptake inhibitor) increases serotonin bioavailability. We hypothesized that increased serotonin bioavailability promotes serotonergic signaling and modulates the expression of immune related genes in peripheral leukocytes and immune-related tissues of dairy calves. The present experiment targeted candidate genes involved in serotonin production, metabolism, transport, signaling and immune regulation. We established that bovine peripheral leukocytes express all known serotonin receptors, and can synthesize, uptake and degrade serotonin due to the expression of serotonin metabolism-related genes. Indeed, we showed that increasing serotonin bioavailability alters gene expression of serotonin receptors and immune-related genes. Further research will determine whether manipulation of the serotonin pathway could be a feasible approach to bolster dairy calves' immune system.

Prevalence and risk factors associated with failure of transfer of passive immunity in spring born beef suckler calves in Great Britain

Calves are born agammaglobulinemic and are dependent on the intake and uptake of immunoglobulins from colostrum for protection against infectious diseases in early life. Failure to absorb sufficient immunoglobulins in the correct timeframe after birth is termed failure of transfer of passive immunity (FPT). FPT has been defined as a serum IgG concentration ([sIgG]) of under 10 g/L in dairy calves, as [sIgG] over 10 g/L has been associated with a decreased risk of mortality and morbidity. In beef calves, a [sIgG] of under 24 g/L has also been shown to be predictive of increased morbidity and mortality. Currently there is limited data relating to the prevalence and risk factors of FPT in the beef sector. This cross-sectional study quantified [sIgG] in 1131 blood samples taken from beef suckler calves born on 84 farms in Great Britain in spring 2018 (mean 13.5 calves sampled per farm, range 3-22). Age of calves at sampling ranged from 1 to 13 days. The estimated prevalence of calves with [sIgG] <10 g/L in this study population was 15 % (n = 145 calves), whilst 37 % (n = 396 calves) calves had a [sIgG] <24 g/L. 22 out of the 84 farms had no calves sampled with [sIgG] <10 g/L. Risk factors predictive of [sIgG] were calculated using generalised linear mixed models, with farm included as a random effect. Calving assistance was significant and increased the likelihood of [sIgG] concentrations <10 g/L and [sIgG] <24 g/L, Odds Ratio (OR) 1.66 (1.05-2.62 95 % CI) and 1.91 (1.33-2.74 95 % CI) respectively. All three levels of assistance with colostrum feeding used in this study were significant for calves having a [sIgG] <24 g/L (Lead to dam OR = 1.85 (1.11-3.06 95 % CI), Bottle/tube fed dam's colostrum OR = 2.35 (1.29-4.30 95 % CI), Bottle/tube fed artificial colostrum OR = 3.78 (1.86-7.70 95 % CI), whilst bottle/tube feeding either dam's or artificial colostrum were also significant for [sIgG] <10 g/L, OR 2.66 (1.32-5.36 95 % CI) and 2.34 (1.09-5.02 95 % CI) respectively. Male calves had a higher likelihood for [sIgG] <10 g/L, OR 1.68 (1.12-2.54 95 % CI) whereas being a twin or being born to a heifer were predictive of having a [sIgG] <24 g/L (OR 3.31 (1.64-6.71 95 % CI), OR 1.57 (1.05-2.35 95 % CI) respectively). This study raises important questions with respect to management practices around calving and highlights the need for reviewing protocols with respect to colostrum assistance and calving assistance on beef farms.

Progesterone inhibits inflammatory response in E.coli- or LPS-Stimulated bovine endometrial epithelial cells by NF-κB and MAPK pathways

Progesterone suppresses the innate immune function of bovine endometrium, making the uterus susceptible to bacterial infection. The bovine endometrial epithelial cells (BEEC) are the first line of defense against bacteria, such as Escherichia coli (E.coli) that causes inflammation of endometrium through the recognition of lipopolysaccharide (LPS). The aim of this study was to investigate the effect of progesterone on the inflammatory response and its potential mechanism using E.coli- or LPS-induced BEEC. Concentrations of 1, 3 and 5 ng/mL progesterone were selected. The mRNA expressions of proinflammatory cytokines were determined using qPCR. The activations of NF-κB and MAPK pathways were detected by Western blot and immunofluorescence. An increase in the mRNA expression of IL-1β, IL-6, IL-8 and TNF-α was observed in BEEC treated with progesterone, LPS or E.coli alone. Progesterone inhibited the E.coli- or LPS-induced gene expression of these cytokines. Progesterone treatment alone showed little influence on NF-κB or MAPK pathway. In BEEC stimulated with E.coli or LPS, progesterone inhibited the phosphorylations of IκB, p65, ERK1/2, p38MAPK and JNK, and the translocation of p65 into the nucleus. These results suggested that progesterone has anti-inflammatory effect, which may be mediated by inhibiting NF-κB activation and MAPK phosphorylation in BEEC.

Roadmap to pregnancy in the first 7 days post-insemination in the cow: Immune crosstalk in the corpus luteum, oviduct, and uterus

The first 7 days post-insemination are critical for establishment of pregnancy. The pre-ovulatory luteinizing hormone (LH) surge induces ovulation through disruption of the follicle structure that elucidates pro-inflammatory (Th1) responses. Various types of immune cells are recruited into the corpus luteum (CL) to regulate luteal angiogenesis and progesterone (P4) secretion into the circulation to establish pregnancy. The active sperm-uterine crosstalk also induces Th1 responses, mainly via Toll-like receptor (TLR) 2/4 signaling pathway in vitro. The endometrial glands serve as sensors for sperm signals, which trigger Th1 responses. Conversely, the sperm-oviduct binding generates anti-inflammatory (Th2) responses to support sperm survival until fertilization. It is well-established that embryo-maternal crosstalk starts after the embryo hatches out from the zona pellucida (ZP). However most recently, it was shown that the 16-cell stage bovine embryo starts to secrete interferon-tau (IFNT) that induces Th2 immune responses in the oviduct. Once developing embryos descend into the uterine horn, they induce Th2 responses with interferon-stimulated genes (ISGs) expression in the uterine epithelium and local immune cells mainly via IFNT release. Likewise, multiple embryos in the uterus of superovulated donor cows on D7 post-insemination induce Th2 immune responses with ISGs expressions in circulating immune cells. These findings strongly suggest that the maternal immune system reacts to the embryo during the first 7 days post-insemination to induce fetal tolerance. It became evident that the innate immunity of the developing CL, oviduct, and uterus works together to provide optimal conditions for fertilization and early embryonic development during the first 7 days post-insemination.

RNA Viruses of Amblyomma variegatum and Rhipicephalus microplus and Cattle Susceptibility in the French Antilles

Ticks transmit a wide variety of pathogens including bacteria, parasites and viruses. Over the last decade, numerous novel viruses have been described in arthropods, including ticks, and their characterization has provided new insights into RNA virus diversity and evolution. However, little is known about their ability to infect vertebrates. As very few studies have described the diversity of viruses present in ticks from the Caribbean, we implemented an RNA-sequencing approach on Amblyomma variegatum and Rhipicephalus microplus ticks collected from cattle in Guadeloupe and Martinique. Among the viral communities infecting Caribbean ticks, we selected four viruses belonging to the Chuviridae, Phenuiviridae and Flaviviridae families for further characterization and designing antibody screening tests. While viral prevalence in individual tick samples revealed high infection rates, suggesting a high level of exposure of Caribbean cattle to these viruses, no seropositive animals were detected. These results suggest that the Chuviridae- and Phenuiviridae-related viruses identified in the present study are more likely tick endosymbionts, raising the question of the epidemiological significance of their occurrence in ticks, especially regarding their possible impact on tick biology and vector capacity. The characterization of these viruses might open the door to new ways of preventing and controlling tick-borne diseases.

Effect of Holstein genotype on innate immune and metabolic responses of heifers to lipopolysaccharide (LPS) administration

Heifers (n = 4/genotype) from unselected (stable genotype since 1964, UH) and contemporary (CH) Holsteins that differed in milk yield (6,200 and 11,100 kg milk/305 d) were used to assess the impact of selection on innate immune and acute-phase response to an endotoxin (lipopolysaccharide; LPS). Jugular catheters were implanted 24 h before LPS administration. Blood samples were collected at -1, -0.5, 0, 1, 2, 3, 4, 6, 8, and 24 h relative to iv administration of 0.5 μg LPS/kg BW. Rectal body temperature (BT) was determined at these sampling times and at 5 and 7 h. Dermal biopsies were collected after the 24 h blood sample and processed to isolate fibroblasts. Plasma was analyzed for tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), serum amyloid A (SAA), xanthine oxidase (XO), and nitrate + nitrite (NOx), cortisol, glucose, and IGF-1 content. Isolated fibroblasts were exposed to IL-1β or LPS and IL-6 and IL-8 content of culture media determined. Exposure to LPS increased BTs and plasma concentrations of TNF-α, IL-6 SAA, XO, cortisol, and glucose (P < 0.05) in both genotypes. Plasma concentrations of TNF-α, XO, NOx, and glucose did not differ (P > 0.25) between the genotypes, but IL-6 and SAA concentrations were reduced (P < 0.05) in CH relative to UH heifers while cortisol and IGF-1 concentrations tended (P < 0.08) to be reduced in CH heifers. After 36 h exposure to LPS, concentrations of IL-6 were greater (P < 0.05) in culture media from incubations of CH than UH fibroblasts but concentrations of IL-8 did not differ between genotypes. There was a trend (P = 0.08) for IL-8 concentrations to be reduced in media from CH fibroblasts exposed to IL-1β for 24 h but IL-6 concentrations did not differ between genotypes. Results indicate 50 yr of selection has reduced the robustness of the innate immune and acute-phase response to LPS in the contemporary Holstein heifer.

Characterization of the NLRP1 inflammasome response in bovine species

Inflammasomes act as sensors of infection or damage to initiate immune responses. While extensively studied in rodents, understanding of livestock inflammasomes is limited. The NLRP1 inflammasome sensor in rodents is activated by Toxoplasma gondii, Bacillus anthracis lethal toxin (LT), and potentially other zoonotic pathogens. LT activates NLRP1 by N-terminal proteolysis, inducing macrophage pyroptosis and a pro-inflammatory cytokine response. In contrast, NLRP1 in macrophages from humans and certain rodent strains is resistant to LT cleavage, and pyroptosis is not induced. Evolution of NLRP1 sequences towards those leading to pyroptosis is of interest in understanding innate immune responses in different hosts. We characterized NLRP1 in cattle (Bos taurus) and American bison (Bison bison). Bovine NLRP1 is not cleaved by LT, and cattle and bison macrophages do not undergo toxin-induced pyroptosis. Additionally, we found a predicted Nlrp1 splicing isoform in cattle macrophages lacking the N-terminal domain. Resistance to LT in bovine and human NLRP1 correlates with evolutionary sequence similarity to rodents. Consistent with LT-resistant rodents, bovine macrophages undergo a slower non-pyroptotic death in the presence of LPS and LT. Overall, our findings support the model that NLRP1 activation by LT requires N-terminal cleavage, and provide novel information on mechanisms underlying immune response diversity.

An analysis of the immune compartment within bovine adipose tissue

Adipose tissue (AT) has wide functions as an active endocrine organ acting as a site of nutrient storage and thermogenesis. Recently it has been identified as having a key role in murine and human immunity and inflammation. Type 1 or type 2 immune responses and their respective cytokines have been linked to white or brown AT, respectively. Most dramatic is the involvement of type-2 innate lymphoid cells (ILC2s) in stimulating eosinophil recruitment via interleukin (IL)-13 which in turn stimulates alternative macrophage activation via IL-4/IL-13. Recruited leukocytes are capable of influencing the cellular composition and function of adipose tissue and present a route to combat human obesity, however these processes are poorly understood in ruminants. Here we have characterised the resident leukocytes populations within bovine mesenteric AT (MAT) and subcutaneous AT (SAT), compared with the corresponding mesenteric lymph node (MLN). Concurring with related studies, we find bovine AT has its own resident leukocyte populations where eosinophils and neutrophils dominate. Importantly the proportion of eosinophils or neutrophils corresponded to the adipocyte size found in both depots. Further exploration of this area may have important implications on the food production industry or could be applied to improve the course of pathogenesis during disease.

Transfer of passive immunity in dairy calves: the effectiveness of providing a supplementary colostrum meal in addition to nursing from the dam

Failed transfer of passive immunity (FTPI) in dairy calves - which is often due to the low amount of colostrum provided within a few hours after birth - remains a crucial issue. Enabling dairy calves to nurse colostrum from their dams could be useful in increasing intake and thus avoiding FTPI, but further potential effects on the health and welfare of both calves and dams should also be considered. In this study, 107 calf-dam pairs from two Italian dairy farms were alternately assigned to one of the following colostrum provision methods (CPMs): 'hand-fed method' (HFM) - the calf was separated from the dam immediately after birth and colostrum was provided by nipple-bottle (n = 50); 'nursing method' (NM) - the calf nursed colostrum from the dam for the first 12 h of life without farmer assistance (n = 30); and 'mixed method' (MM) - the nursing calf received a supplementary colostrum meal by nipple-bottle (n = 27). Serum of calves (1 to 5 days of age) and samples of their first colostrum meal were analysed by electrophoresis to assess immunoglobulin (Ig) concentration. Additionally, behavioural indicators of separation distress (calf and dam vocalisations; calf refusal of the first meal after separation; undesirable dam behaviour at milking) in the following 24 h were recorded as binary variables (Yes/No), and the health status of calves (disease occurrence and mortality) and dams (postpartum disorders and mastitis occurrence) were monitored for the first 3 months of life and 7 days after parturition, respectively. The lowest FTPI occurrence (calf serum Ig concentration <10.0 g/l) was found in the MM (11.1%) and the HFM (22.0%) compared with the NM (60.0%) (P<0.05), and the highest percentage of calves with optimal transfer of passive immunity (serum Ig concentration ≥16.0 g/l) was observed in the MM (55.6%). The lowest calf-dam separation distress was observed in the HFM (P<0.05). The highest calf disease occurrence was recorded in the HFM (64.0%) and the lowest in the NM (33.3%), with an intermediate value for the MM (44.4%) (P<0.05). No effect of the CPM was observed on dam health or calf mortality (P>0.05). The results of this study indicated that providing calves with a supplementary colostrum meal in addition to nursing from the dam (MM) is truly effective in maximizing passive immunity transfer. Anyway, specific strategies should be studied to minimise calf-dam separation distress.

Mucosal Immune System of Cattle: All Immune Responses Begin Here

This article discusses key concepts important for mucosal immunity. The mucosa is the largest immune organ of the body. The mucosal barrier (the tight junctions and the "kill zone") along with the mucosa epithelial cells maintaining an anti-inflammatory state are essential for the mucosal firewall. The microbiome (the microorganisms that are in the gastrointestinal, respiratory, and reproductive tract) is essential for immune development, homeostasis, immune response, and maximizing animal productivity. Mucosal vaccination provides an opportunity to protect animals from most infectious diseases because oral, gastrointestinal, respiratory, and reproductive mucosa are the main portals of entry for infectious disease.

Allele substitution and dominance effects of CD166/ALCAM gene polymorphisms for endoparasite resistance and test-day traits in a small cattle population using logistic regression analyses

The study investigated the effects of four single-nucleotide polymorphisms (SNPs) in the activated leukocyte cell adhesion molecule (ALCAM) gene on liver fluke (Fasciola hepatica) infections (FH-INF), gastrointestinal nematode infections (GIN-INF) and disease indicator traits [e.g. somatic cell score (SCS), fat-to-protein ratio (FPR)] in German dual-purpose cattle (DSN). A genome-wide association study inferred the chip SNP ALCAMc.73+32791A>G as a candidate for F. hepatica resistance in DSN. Because of the crucial function of ALCAM in immune responses, SNPs in the gene might influence further resistance and performance traits. Causal mutations were identified in exon 9 (ALCAMc.1017T>C) and intron 9 (ALCAMc.1104+10T>A, ALCAMc.1104+85T>C) in a selective subset of 94 DSN cows. We applied logistic regression analyses for the association between SNP genotypes with residuals for endoparasite traits (rINF-FH, rGIN-INF) and estimated breeding values (EBVs) for test-day traits. The probability of the heterozygous genotype was estimated in dependency of the target trait. Allele substitution effects for rFH-INF were significant for all four loci. The T allele of the SNPs ALCAMc.1017T>C and ALCAMc.1104+85T>C was the favourable allele when improving resistance against FH-INF. Significant allele substitution for rGIN-INF was only found for the chip SNP ALCAMc.73+32791A>G. We identified significant associations between the SNPs with EBVs for milk fat%, protein% and FPR. Dominance effects for the EBVs of test-day traits ranged from 0.00 to 0.47 SD and were in the direction of improved resistance for rFH-INF. We estimated favourable dominance effects from same genotypes for rFH-INF and FPR, but dominance effects were antagonistic between rFH-INF and SCS.

Vitamin E supplementation strategies during feedlot receiving: effects on beef steer performance, antibody response to vaccination, and antioxidant defense1

This study utilized 204 Angus-based beef steers (249 ± 23 kg SD) from a single ranch with initial serum α-tocopherol concentrations of 3.9 ± 1.0 mg/L to determine the effect of varying doses of vitamin E (VE) on feedlot performance, antibody response to vaccination, and antioxidant defense. Seven days after arrival, steers were blocked by body weight and weaning protocol (preweaned, unweaned heavy, and unweaned light) and randomly assigned to pens within blocks (12 pens per block). Preweaned steers had been weaned for approximately 35 d prior to arrival, and unweaned steers were weaned when leaving the origin ranch. Pens within block were randomly assigned to supplemental VE (ROVIMIX E-50 Adsorbate, DSM Nutritional Products, Heerlen, The Netherlands) treatments (n = 9 pens per treatment): no supplemental VE (CON), 25 IU/kg dry matter (DM; LOW), 500 IU per steer daily (MED), or 1,000 IU per steer daily (HIGH). Back-calculated supplemental VE intake was 0, 151 (24.8 IU/kg DM), 484, and 995 IU/d for CON, LOW, MED, and HIGH, respectively. On day 6, all steers received a booster vaccine against bovine viral diarrhea virus (BVDV; Bovi-Shield Gold, One Shot, Zoetis, Parsippany, NJ). Steers were weighed on day -1, 0, 14, 26, and 27. One steer per pen representative of the average body weight of the pen was chosen as a sampling animal for blood (day -1, 6, 14, 26, and 28) and liver (day -3 and 24). Data were analyzed as a randomized complete block design using Proc Mixed of SAS with pen as the experimental unit and the fixed effects of treatment and block. Linear, quadratic, and cubic contrast statements were constructed using Proc IML; morbidity data were analyzed using Proc Glimmix. Day 24 liver and day 26 serum α-tocopherol concentrations were linearly increased by supplemental VE (P < 0.01). Supplemental VE did not affect DM intake, average daily gain, or gain:feed from day 0 to 27 (P ≥ 0.37), or the percentage of steers treated for respiratory disease (P ≥ 0.44). Day 24 liver glutathione concentrations decreased linearly due to supplemental VE (P ≤ 0.02). Total- and Mn-superoxide dismutase activities were quadratically affected by supplemental VE (P ≤ 0.07), with MED steers exhibiting the greatest activity. Over time, BVDV type 1 and 2 antibody titers numerically decreased, whereas the decrease in BVDV type 1 titers was lesser for HIGH steers (linear P = 0.04). Increasing doses of VE improved VE status but did not affect overall receiving period performance in steers with minimal to adequate VE status upon arrival.

Ruminally protected and unprotected Saccharomyces cerevisiae fermentation products as alternatives to antibiotics in finishing beef steers1

The objectives of this study were to assess the effects of Saccharomyces cerevisiae fermentation products (SCFP; NaturSafe, SCFPns; and Original XPC, XPC; Diamond V) on growth performance, carcass traits, immune response, and antimicrobial resistance in beef steers fed high-grain diets. Ninety Angus steers (initial body weight [BW], 533 ± 9.8 kg) were assigned to a randomized complete design with 6 treatments (n = 15/treatment): 1) control, 2) low (12 g SCFPns·steer-1·d-1), 3) medium (15 g SCFPns·steer-1·d-1), 4) high SCFP (18 g SCFPns·steer-1·d-1), 5) encapsulated XPC (eXPC; 7 g XPC·steer-1·d-1 encapsulated with 9 g capsule material), and 6) antibiotics (ANT; 330 mg monensin + 110 mg tylosin·steer-1·d-1). Steers were fed ad libitum a diet containing 10% barley silage and 90% barley grain concentrate mix (dry matter basis) for 105 d. Increasing SCFPns tended (P < 0.09) to linearly increase feed efficiency. Average daily gain (ADG) tended (P < 0.10) to be greater in steers supplemented with eXPC than control. The SCFPns also tended (P < 0.10) to linearly increase marbling score. Proportion of severely abscessed livers tended (P < 0.10) to be lower in steers supplemented with medium and high SCFPns, eXPC, or ANT. A treatment × days on feed interaction were noticed (P < 0.01) for blood glucose, blood urea nitrogen (BUN), and acute phase proteins. The concentration of blood glucose responded quadratically (P < 0.05) on days 28 and 56, whereas BUN linearly (P < 0.01) increased on day 105 with increasing SCFPns dose. The SCFPns linearly increased haptoglobin (P < 0.03) and serum amyloid A (SAA;P < 0.05) concentrations on day 105, and lipopolysaccharide binding protein (LBP;P < 0.01) on days 56 and 105. The percentage of erythromycin-resistant and erythromycin + tetracycline-resistant enterococci was greater (P < 0.05) with ANT than control, SCFPns, and eXPC, whereas no difference was observed among control, SCFPns, and eXPC. No treatment effect was detected on the percentage of tetracycline-resistant enterococci. These results indicate that feeding SCFPns and eXPC was beneficial in improving ADG, feed efficiency and decreasing liver abscesses in a manner comparable to ANT. Unlike antibiotics, SCFPns or eXPC did not increase antimicrobial resistance. Both SCFPns and eXPC are potential alternatives to in-feed antibiotics.

BEEF SPECIES-RUMINANT NUTRITION CACTUS BEEF SYMPOSIUM: Maternal immune modulation prior to embryo arrival in the uterus is important for establishment of pregnancy in cattle1

In 1953, Sir Peter Medawar first recognized the allogeneic properties of a developing conceptus and rationalized that an "immune-tolerant" physiological state must exist during pregnancy. Early theories speculated that the conceptus evaded the maternal immune system completely, but 40 yr after Medawar's observations, Wegmann proposed that the maternal immune system shifts the cytokine profile away from inflammatory cytokine production when an embryo is present. The economic consequences and production losses of subfertile animals have been well documented in studies evaluating calving distribution. Despite advances in understanding infertility or subfertility, few technologies exist to identify subfertile animals or improve fertility beyond hormonal intervention associated with synchronization protocols. Work in rodents and some livestock species indicates that the uterine immune cell population shifts dramatically after copulation and these early immune-modulated events establish a receptive uterine environment. Clearly, as evident in embryo transfer, the presence of a conceptus is sufficient to establish communication for pregnancy establishment but does not rule out the importance of other physiological events to prime the maternal immune system prior to blastocyst arrival in the uterus. In support of this concept, work in our laboratory and by others has demonstrated that autologous intrauterine transfer of peripheral immune cells prior to embryo transfer can increase pregnancy rates and accelerate conceptus development in women and cattle. Understanding aberrant immune regulation in subfertile animals may provide markers for subfertility or targets for clinical intervention to enhance fertility, particularly when using reproductive technologies.

A novel long non-coding RNA regulates the immune response in MAC-T cells and contributes to bovine mastitis

The long non-coding RNAs (lncRNAs) are known to transcriptionally regulate a wide spectrum of diseases. Here, we screened for potentially functional lncRNAs in a mammary epithelial cell model of bovine mastitis by RNA-Seq technology and identified a class of previously undetected mastitis-related lncRNAs. A novel lncRNA was widely expressed in a variety of bovine tissues with diverse relative abundance and had a relatively low expression in mammary tissue. Given its predicted target gene is TUBA1C, we name it lncRNA-TUB. We found a higher expression of lncRNA-TUB in mammary epithelial cells that received a proinflammatory stimulus compared to normal cells. Knockout of lncRNA-TUB by the CRISPR/Cas9 system revealed that it plays crucial roles in the morphological shape, proliferation, migration and β-casein secretion of mammary epithelial cells. In addition, lncRNA-TUB mediates Escherichia coli-induced inflammatory factor secretion and Staphylococcus aureus adhesion to epithelial cells. Our results suggest that the lncRNAs identified here function in bovine mastitis, and that lncRNA-TUB affects the basic biological characteristics and functions of bovine mammary epithelial cells in inflammatory conditions, providing valuable insights into the mechanisms of bovine mastitis.

PHYSIOLOGY SYMPOSIUM: Effects of heat stress during late gestation on the dam and its calf12

Heat stress during late gestation in cattle negatively affects the performance of the dam and its calf. This brief exposure to an adverse environment before parturition affects the physiological responses, tissue development, metabolism, and immune function of the dam and her offspring, thereby limiting their productivity. During the dry period of a dairy cow, heat stress blunts mammary involution by attenuating mammary apoptosis and autophagic activity and reduces subsequent mammary cell proliferation, leading to impaired milk production in the next lactation. Dairy cows in early lactation that experience prepartum heat stress display reduced adipose tissue mobilization and lower degree of insulin resistance in peripheral tissues. Similar to mammary gland development, placental function is impaired by heat stress as evidenced by reduced secretion of placental hormones (e.g., estrone sulfate) in late gestation cows, which partly explains the reduced fetal growth rate and lighter birth weight of the calves. Compared with dairy calves born to dams that are exposed to evaporative cooling during summer, calves born to noncooled dry cows maintain lower BW until 1 yr of age, but display a stronger ability to absorb glucose during metabolic challenges postnatally. Immunity of the calves, both passive and cell-mediated immune function, is also impaired by prenatal heat stress, resulting in increased susceptibility of the calves to diseases in their postnatal life. In fact, dairy heifers born to heat-stressed dry cows without evaporative cooling have a greater chance leaving the herd before puberty compared with heifers born to dry cows provided with evaporative cooling (12.2% vs. 22.7%). Dairy heifers born to late-gestation heat-stressed dry cows have lower milk yield at maturity during their first and second lactations. Emerging evidence suggests that late-gestation heat stress alters the mammary gland microstructure of the heifers during the first lactation and exerts epigenetic alterations that might explain, in part, their impaired productivity.

Effect of passive transfer of immunity on growth performance of preweaned dairy calves

The primary objective of this observational study was to examine the association between passive transfer of immunity and growth performance in preweaning calves. A secondary objective was to evaluate the utility of a heart girth tape (HGT) to estimate body weight (BW) in preweaning calves. A total of 142 Holstein calves were enrolled in this study. Blood samples were collected 24 to 48 hours after birth and serum immunoglobulin G (IgG) concentration for each calf was measured by radial immunodiffusion assay. Calf BW was determined at birth, at 21 days, and at weaning using an electronic scale (ES) and HGT. A significant positive association was detected between serum IgG and both BW at 21 days and average daily gain (ADG) from 0 to 21 days of life. Additionally, ADG from 0 to 42 days of life showed a trend toward an improved rate of gain as IgG concentration increased. The Pearson correlation coefficient between BW obtained from ES and HGT was 0.81 at birth, 0.86 at 21 days, and 0.83 at weaning. The mean differences between BW obtained from ES and HGT were -3.1 kg at birth, -3.2 kg at 21 days, and -7.7 kg at weaning. In conclusion, serum IgG concentration in neonatal calves is an important contributing factor for the variation in growth performance of preweaning calves. The HGT can be used to estimate the BW of preweaning calves but has a tendency to overestimate weight, especially at weaning compared to birth and 21 days of age.

Far-off and close-up feeding levels affect immunological performance in grazing dairy cows during the transition period

During the peripartum period, dairy cows often have signs of inflammation. Various stresses, including infectious and metabolic diseases, have been discussed as causative for this inflammation. In this study, expression profiles for 17 immune markers were measured in whole blood preparations from 78 dairy cows over a time frame starting 1 wk before calving to 4 wk after calving. Additionally, the effects of far-off and close-up feeding on immune function of dairy cows during the peripartum period were investigated. Cows were assigned to 1 of 2 feeding levels in late lactation to achieve a low and high BCS at the time of dry-off (approximately 4.25 and 5.0 on a 10-point scale). Following dry-off, both herds were managed to achieve a BCS of 5.0 one month before calving; this involved controlled feeding (i.e., maintenance) and over-feeding of ME during the far-off dry period. Within each far-off feeding-level treatment, cows were offered 65, 90, or 120% of their precalving ME requirements for 3 wk precalving in a 2 × 3 factorial arrangement. Analysis of gene expression profiles from blood cells revealed effects of time indicating that the transition cow's immune system counteracts the peripartum inflammation, whereas later postcalving it becomes activated to provide protection against postpartum infections. Far-off feeding affected (P < 0.05) the expression of 2 of the investigated genes at calving. Interleukin-6 (IL-6) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression in unstimulated, peripheral leukocytes were lower (P < 0.05) in animals from the Far-Off_Over-fed group compared with the Far-Off_Control-fed group. Close-up feeding had several effects on gene expression, indicating that immune function in Feed120 animals was distinct from the Feed90 and Feed65. In conclusion, feeding management precalving becomes an important intervention to ensure immunocompetence at and after calving.

Bovine T cell receptors and γδ WC1 co-receptor transcriptome analysis during the first month of life

Here we evaluated neonatal transcription of α, β, γ and δ TCR and the γδ T cell co-receptor family WC1 in peripheral blood mononuclear cells. A previous report showed a rapid and global shift in transcription of immunoglobulin genes in neonatal calves during the first month after birth but this was not found here for the T cell genes. Transcription frequency of genes within TRAV subgroups correlated with the number of members, indicating a stochastic choice. In contrast, of the approximately 60 TRDV genes those in two of eleven TRDV1 clades and TRDVb3 were transcribed significantly more than the others while those in only one TRBV subgroup were. Transcription of genes in the TRGV5-containing cassette predominated among TRGV genes as a result of their exclusive usage by the WC1⁺ γδ T cells with a preference for transcription of two of four TRGV genes in that cassette. Finally, we report no large differences in transcription frequencies among the 13 WC1 genes.

Effect of a single dose of subcutaneous meloxicam prior to band or knife castration in 1-wk-old beef calves: II. Inflammatory response and healing

The aim of this study was to evaluate the effect of a single dose of subcutaneous (s.c.) meloxicam administered at the time of knife and band castration on inflammatory response and wound healing over 56-d post-castration. Seventy-two Angus crossbred calves (47.3 ± 6.70 kg of body weight [BW] and 7 to 8 d of age) were randomly assigned according to a 3 × 2 factorial design assessing castration method: sham (CT), band (BA), and knife (KN) castration, and pain mitigation: non-medicated (NM) and medicated calves (M) injected s.c. with meloxicam (0.5 mg/kg of BW). Calf BW, rectal temperature, swelling ("0": no swelling; "4": swelling needing intervention) and healing score ("1" to "5" with "5" being completely healed), scrotal circumference, and maximum scrotal temperature were measured on d -1, immediately before castration (d 0), and weekly thereafter over a 56-d period. Blood samples for haptoglobin (Hp), serum amyloid-A (SAA), and complete blood cell count were collected according to the same schedule. Hair samples were collected on d -1, 28, and 56 to determine cortisol concentrations. Standing and lying behaviors were measured using accelerometers that were placed on the calves on d -1 until d 35, and visual observations of behaviors related to pain were recorded once a week for 35 d. Knife-castrated calves achieved swelling scores of "3" and "2" between d 7 and 14, which was sooner (Z< 0.05) than in BA calves (from d 14 to 35). In addition, greater (P = 0.03) concentrations of SAA were observed in BA calves (76.9 ± 0.12 g/liter) compared with CT (57.6 ± 0.12 g/liter) and KN (51.6 ± 0.12 g/liter) from d 7 to 35. Healing scores of "2" and "4" tended to be achieved sooner (Z < 0.10) in KN calves than in BA calves, although healing scores of "3" tended to be achieved sooner (Z < 0.10) in BA calves than KN calves. No differences (P > 0.10) were observed among treatments for hair cortisol on d -1 and 28, but on d 56, hair cortisol concentrations in BA-NM calves were greater (P > 0.05) than for CT-NM, BA-M, KN-NM, and KN-M, and tended to be greater (P = 0.08) than for CT-M calves. Lying duration tended (P = 0.10) to be greater and suckling behavior tended (P = 0.08) to be lower in NM than M calves. A single s.c. injection of meloxicam did not reduce long-term inflammatory responses or improve wound healing; however, it may be useful in reducing pain and stress in band castrated calves as evidenced by reduced hair cortisol concentrations up to 56 d post-castration.

A novel glycosylated anti-CD20 monoclonal antibody from transgenic cattle

The monoclonal antibody (mAb) against CD20 known as Rituxan is widely used to treat autoimmune diseases and lymphomas. However, further application of Rituxan faces challenges of high production cost, which limits its availability in developing countries. Here, we report a new approach for large production of a recombinant anti-CD20 mAb in the milk of transgenic cattle (at a yield of up to ~6.8 mg/mL), with ~80% recovery rate and >99% purity. Crystallography study showed that our recombinant mAb is structurally nearly identical to Rituxan with only minor differences in N-linked glycosylation pattern. Functional study showed that, while our mAb shared similar target-cell binding capacities and complement-dependent cytotoxicity with Rituxan, our product exhibited a higher binding affinity for FcγRIIIα and a greater antibody-dependent cellular cytotoxicity. Accordingly, our recombinant mAb demonstrated a superior efficacy over Rituxan against B-cell lymphomas in severe combined immunodeficiency mice. Taken together, our data supports transgenic cattle as a novel model for cost-competitive, large-scale production of therapeutic antibodies.

Protective effects of zymosan on heat stress-induced immunosuppression and apoptosis in dairy cows and peripheral blood mononuclear cells

Dairy cows exposed to heat stress (HS) show decreased performance and immunity, but increased heat shock protein expressions and apoptosis. Zymosan, an extract from yeast cell walls, has been shown to modulate immune responses and defense against oxidative stress. However, few literatures are available about the effects of zymosan on immune responses and other parameters of the dairy cows under HS. Here, both primary peripheral blood mononuclear cell (PBMC) and dairy cow models were established to assess the effects of zymosan on performance, immunity, heat shock protein, and apoptosis-related gene expressions of dairy cows under HS. In vitro study showed that proliferation, IL-2 production, and Bcl-2/Bax-α ratio of cow primary PBMC were reduced, whereas hsp70 mRNA and protein expressions, as well as Annexin V-bing, were increased when PBMCs were exposed to heat. In contrast, zymosan significantly reversed these above changes induced by the HS. In the in vivo study, 40 Holstein dairy cows were randomly selected and assigned into zymosan group (supplemental zymosan; n = 20) and control group (no supplemental zymosan; n = 20). The results showed that zymosan improved significantly the dry matter intake and milk yield, increased IgA, IL-2, and tumor necrosis factor-α (TNF-α) contents in sera, as well as hepatic Bcl-2/Bax-α ratio, but decreased respiration rate and hepatic hsp70 expressions in the dairy cows under HS. Taken together, zymosan could alleviate HS-induced immunosuppression and apoptosis and improve significantly the productive performance and immunity of dairy cows under HS.

Genomic signatures of adaptive introgression and environmental adaptation in the Sheko cattle of southwest Ethiopia

Although classified as an African taurine breed, the genomes of Sheko cattle are an admixture of Asian zebu and African taurine ancestries. They populate the humid Bench Maji zone in Sheko and Bench districts in the south-western part of Ethiopia and are considered as a trypanotolerant breed with high potential for dairy production. Here, we investigate the genome of Sheko cattle for candidate signatures of adaptive introgression and positive selection using medium density genome-wide SNP data. Following locus-ancestry deviation analysis, 15 and 72 genome regions show substantial excess and deficiency in Asian zebu ancestry, respectively. Nine and 23 regions show candidate signatures of positive selection following extended haplotype homozygosity (EHH)-based analyses (iHS and Rsb), respectively. The results support natural selection before admixture for one iHS, one Rsb and three zebu ancestry-deficient regions. Genes and/or QTL associated with bovine immunity, fertility, heat tolerance, trypanotolerance and lactation are present within candidate selected regions. The identification of candidate regions under selection in Sheko cattle warrants further investigation of a larger sample size using full genome sequence data to better characterise the underlying haplotypes. The results can then support informative genomic breeding programmes to sustainably enhance livestock productivity in East African trypanosomosis infested areas.

Flavonoids, a Potential New Insight of Leucaena leucocephala Foliage in Ruminant Health

We investigated the constituents of Leucaena leucocephala foliage collected from Guangdong province in China and isolated 17 diverse flavonoids (1-17), including flavones (5-9, 11, and 12), flavonols (1, 10, and 16), flavanone 4, flavanonol 15, and flavonol glycosides (2, 3, 13, 14, and 17). Flavonoids quercetin (1), quercetin-3- O-α-rhamnopyranoside (2), and myricetin-3- O-α-rhamnopyranoside (17) were the major flavonoids components in L. leucocephala leaves, at a total concentration of about 2.5% of dry matter. pHRE-Luc inductive activity to mimic the activation of erythropoietin (EPO) gene, anti-inflammatory, antidiabetic, and antioxidant activities of isolated flavonoids (1-17) were evaluated. Flavonoids 7, 10, and 13 could strongly induce the transcriptional activity of pHRE-Luc, which indicated their potential to induce the expression of EPO. Flavonoids 7, 10, 13, and 17 displayed strong anti-inflammatory activity, relatively equal to the positive control dexamethasone. Flavonoids 1, 2, 3, 11, 12, 16, and 17 showed stronger antioxidant activities of DPPH radical scavenging capacity than ascorbic acid. Flavonoids 1, 2, and 10 showed weak cellular antioxidant activities against tert-butyl hydroperoxide (tBHP) induced ROS formation. Flavonoid rhamnoside 2 and arabinoside 3 undergone deglycosylation to the aglycone quercetin under anaerobic incubation with cattle rumen microorganisms. Furthermore, the potential health benefits for ruminant of flavonoids, which was rich in L. leucocephala foliage, was also discussed.

Sheep and cattle exposed to Mycobacterium avium subspecies paratuberculosis exhibit altered total serum cholesterol profiles during the early stages of infection

Pathogenic mycobacteria such as Mycobacterium tuberculosis are capable of utilising cholesterol as a primary carbon-based energy source in vitro but there has been little research examining the significance of cholesterol in vivo. Johne's disease is a chronic enteric disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). This study sought to evaluate the levels of total serum cholesterol in the host following exposure to MAP. Blood samples were collected from both sheep and cattle prior to experimental challenge with MAP and at monthly intervals post-challenge. Total serum cholesterol levels in sheep challenged with MAP were significantly elevated at 9 weeks post-inoculation (wpi) in comparison to controls. When stratified based on disease outcome, there was no significant difference in serum cholesterol at the timepoints examined between MAP exposed sheep that were susceptible and those that were resistant to Johne's disease. There was a similar elevation in serum cholesterol at 9 wpi in cattle with histopathological gut lesions associated with disease or those with an early high IFN-γ response. Total serum cholesterol in exposed cattle was significantly lower when compared to controls at 13 wpi. Taken together, these results demonstrate changes in serum cholesterol following MAP exposure and disease progression which could reflect novel aspects of the pathogenesis and immune response associated with MAP infection in both sheep and cattle.

Impact of exercise on productivity, behavior, and immune functioning of weaned Bos indicus-cross calves housed in drylots

The effects of 2 exercise regimes on cattle productivity, immune function, and behavior were evaluated against a control ( = 4 pens/treatment) using weaned -cross calves ( = 203) housed in drylots (16-18 calves/single sex pens). Three treatments were applied 3 times per week for 4 wk: 1) programmatic exercise (PRO), in which cattle and a stockperson walked in the alleyway behind their home pen for 20 min; 2) free exercise (FREE), in which cattle were moved into the drovers alley for 60 min, not exercised by a stockperson, and were allowed free access to their home pen and alleyway; and 3) control (CON), in which calves were removed from their home pen only for routine husbandry. Behavior observations were conducted on d -2 and -1 relative to treatment implementation (d 0) and on d 5, 6, 12, 13, 19, 20, 26, and 27. Instantaneous scan sampling was used to create behavioral profiles for cattle (posture: stand, lie, and walk; and behavior: feed, drink, and ruminate). Focal observations recorded the incidence of social behaviors (allogrooming, social play, and agonistic interactions) and animal-environment interactions (AEI; fencepost licking, rock eating, tongue rolling, and cross-suckling). Body weights, exit velocities, and antibody titers to a bovine viral diarrhea virus type 1b vaccine were measured on d -10, 10, and 28. A linear mixed model (PROC MIXED) was used to evaluate the impact of exercise treatment, sex, time, and their interactions on cattle behavior, health, and productivity. Statistical differences were not observed ( = 0.11) for overall ADG among cattle receiving FREE (1.00 kg ± 0.04) PRO (0.85 kg ± 0.04), or CON (0.86 kg ± 0.05) exercise treatments. Allogrooming ( = 0.05), lying ( < 0. 01), AEI ( < 0.01), rumination ( < 0.01), and agonistic interactions ( < 0.01) increased over time. Comfort-related behaviors (e.g., lying, rumination) increased over the evaluation period, suggesting that calves became acclimated to the environment. Exercise did not alter behaviors or vaccine response and did not reduce the performance of production-critical (e.g., feeding, resting, ruminating) behaviors.

Genetic variation in humoral response to an Escherichia coli O157:H7 vaccine in beef cattle

Individuals often respond differently to the same vaccine; some of this variation may be caused by genetic differences among animals. Our objective was to estimate heritability and identify genomic regions associated with humoral response to an Escherichia coli O157:H7 vaccine in beef cattle. Crossbred beef cattle (n = 651) were vaccinated with a commercially available E. coli O157:H7 vaccine. Serum was collected at time of initial vaccination (d 0), booster (d 21), and d 56 after initial vaccination. Total antibodies specific to siderophore receptor and porin proteins in the vaccine were quantified by enzyme-linked immunosorbent assay. Genomic DNA was isolated from whole blood and genotyped with the bovine GeneSeek Genomic Profiler-High Density 78K or 26K Single Nucleotide Polymorphism BeadChip and imputed to 777,000 SNP genotypes. Heritability was estimated by restricted maximum likelihood (REML) using both 1) pedigree and 2) genomic relationships among individuals. Fixed effects were contemporary group, calf age, sex, principal components from SNP genotype data, and pedigree-derived heterozygosity effects. Additive and dominance effects of SNPs were estimated individually while accounting for contemporary group, sex, and the top 20 principal components calculated from the genomic relationship matrix. Heritability of initial response to vaccination (d 21 –d 0) was 0.10 ± 0.175 using pedigree relationships and 0.14 ± 0.149 using genomic relationships, but neither estimate was statistically different from zero. Heritability of booster (d 56 –d 21) and overall (d 56 –d 0) responses were low and not statistically significant from zero. There were no clusters of linked SNP associated with vaccine response, but eight regionally isolated SNPs were significantly associated with initial or overall response to vaccination. Regional genetic variation for initial response to an E. coli O157:H7 vaccine was observed, although overall heritability of this response was not statistically significant from zero.

Bovine respiratory syncytial virus-specific IgG-1 in nasal secretions of colostrum-fed neonatal calves

In order to determine whether nasal secretions of young calves contain passively derived antibodies to bovine respiratory syncytial virus (BRSV) and if there are differences in presence and/or subclass of these antibodies between calves fed different colostrum replacement products, 17 Holstein calves were fed 150 g of IgG in either a sprayed-dried colostrum-based (CR; n = 8) or a plasma-based colostrum replacement product (PR; n = 9) within 6 h of birth. Venous blood and nasal secretions obtained before feeding and at 24 h of age were assayed for total IgG (serum) by radial immunodiffusion and for BRSV-specific total IgG, IgG-1, and IgG-2 by indirect enzyme-linked immunosorbent assay (ELISA). Calves that were fed a CR had higher concentrations of BRSV-specific IgG and IgG-1 in their serum and nasal secretions compared to calves fed product PR; calves fed the PR had higher levels of serum BRSV-specific IgG-2. The only subclass of antibodies detected in nasal secretions was IgG-1. Re-secretion of passive IgG with neutralizing activity, onto the nasal mucosa could contribute to BRSV-associated disease-sparing observed in the laboratory and in the field. Use of PR will result in lower nasal antibodies since IgG-2 is not re-secreted.

Animal models to study the impact of nutrition on the immune system of the transition cow

The immune system is particularly challenged in transition cows as marked physiological changes occur in this period which are driven by late gestation, partus and onset of lactation. As a consequence, the metabolic and nutritional state of the cow also changes significantly with possible implications for the plasticity and flexibility of the immune system. In order to understand how the balance between metabolism, nutritional status and the immune system is maintained under challenging conditions, such as an infection, various animal models can be used which specifically manipulate the nutritional status through various feeding and management strategies. Such models aim at exploring the immunological response to a challenge under largely varying nutritional and metabolic states. As energy balance (EB) is strongly associated both with the metabolic state and with the immunoreactivity of the cows the manipulation of the EB by either influencing energy intake or energy excretion with milk, or by both, offers model opportunities for studying EB effects on the immune system. For example, assigning cows with a higher body condition score (BCS) at least 6 weeks prior to calving to an energy-dense diet exceeding the energy requirement in combination with a decelerated increase in the concentrate feed proportion post partum was shown to be effective in inducing a ketotic metabolic state under ad libitum feeding conditions. Compared to an adequately managed control group this model allows studying immune responses in the transit period and in dependence on dietary interventions.

Evaluation of essential oils and prebiotics for newborn dairy calves

A blend of essential oils (EO; carvacrol, caryophyllene, -cymene, cineole, terpinene, and thymol) and prebiotics (arabinogalactans; Stay Strong; Ralco, Inc., Marshall, MN) was designed to promote immunity and stimulate appetite to diminish health challenges and stresses experienced by newborn calves. It was hypothesized that calves supplemented with the medium dose (2.5 g/feeding) of the commercial EO would demonstrate the optimal response. The study objective was to determine the optimal feeding rate of EO when added to a milk replacer (MR) compared with feeding a control or a yeast cell wall additive (YCW). One hundred Holstein calves from a commercial dairy farm were blocked by birth date and randomly assigned to 1 of 5 treatments. Treatments were a control (CON), a 24:20% CP:fat (as-fed basis) MR (24:20 MR) without EO; EO mixed into the 24:20 MR at a rate of 1.25 g/feeding (EO-0.5), EO mixed into the 24:20 MR at a rate of 2.5 g/feeding (EO-1.0), or EO mixed into the 24:20 MR at a rate of 3.75 g/feeding (EO-1.5); or 24:20 MR with YCW mixed in at a rate of 2 g/calf at each feeding. The 24:20 MR was fed in a bucket 2 times/d at a rate of 0.28 kg/calf daily for 14 d, which was increased to 0.43 kg/calf at 2 times/d until d 35 and then reduced to 1 time/d at d 36 to facilitate weaning at d 42. Decoquinate was added to the MR at 41.6 mg/kg for coccidiosis control. Calves were housed in individual hutches bedded with straw with ad libitum access to a 20% CP pelleted calf starter and water. All data were analyzed using PROC MIXED as a completely random design. Calves fed EO-0.5 demonstrated greater ( < 0.05) ADG (0.65, 0.71, 0.64, 0.64, and 0.63 kg/d for the CON, EO-0.5, EO-1.0, EO-1.5, and YCW, respectively) through d 56 compared with calves fed EO-1.0 and YCW and tended ( < 0.10) to have greater ADG than calves fed the CON and EO-1.5. Total BW gains were greater ( < 0.05) for calves fed EO-0.5 compared with calves fed EO-1.0 and YCW, with calves fed the CON and EO-1.5 being intermediate and similar. Body length and wither height gains (final - initial) were greater ( < 0.05) for calves fed EO-0.5 compared with calves fed the other treatments. Hip width gains were similar ( < 0.10) among treatments. Hip height gains were increased ( < 0.05) for calves fed EO-0.5 compared with calves fed the CON, EO-1.0, EO-1.5, and YCW. These results demonstrate that supplementing EO-0.5 (1.25 g/calf daily) in a 24:20 MR may be the optimal feeding rate to enhance growth rates compared with feeding a 24:20 MR and a 24:20 MR containing YCW or other inclusion rates of EO.

Effects of feeding pregnant beef cows selenium-enriched alfalfa hay on selenium status and antibody titers in their newborn calves

In newborn dairy calves, it has been demonstrated that supranutritional maternal and colostral Se supplementation using Se yeast or sodium selenite, respectively, improves passive transfer of IgG. In beef cattle, agronomic biofortification with Se is a more practical alternative for Se supplementation, whereby the Se concentration of hay is increased through the use of Se-containing fertilizer amendments. It has been previously demonstrated that agronomic Se biofortification is an effective strategy to improve immunity and performance in Se-replete weaned beef calves. The objective of this experiment was to determine the effects of feeding beef cows Se-enriched alfalfa (Medicago sativa) hay during the last 8 to 12 wk of gestation on passive transfer of antibodies to calves. At 10 wk ± 16 d before calving, 45 cows were assigned to 1 of 3 treatment groups with 3 pens (5 cows/pen) per treatment: Control cows were fed non-Se-fortified alfalfa hay plus a mineral supplement containing 120 mg/kg Se from sodium selenite, Med-Se cows were fed alfalfa hay fertilized with 45.0 g Se/ha as sodium selenate, and High-Se cows were fed alfalfa hay fertilized with 89.9 g Se/ha as sodium selenate; both the Med-Se and the High-Se groups received mineral supplement without added Se. Colostrum and whole blood (WB) were collected from cows at calving, and WB was collected from calves within 2 h of calving and at 12, 24, 36, and 48 h of age. Concentrations of IgG1 and J-5 Escherichia coli antibody in cow colostrum and calf serum were quantified using ELISA procedures. Selenium concentrations linearly increased in WB (P < 0.001) and colostrum (P < 0.001) of cows and in WB of newborn calves (P < 0.001) with increasing Se concentration in alfalfa hay. Colostrum concentrations of IgG1 (P = 0.03) were increased in cows fed Se-biofortified alfalfa hay, but J-5 E. coli antibody (P = 0.43) concentrations were not. Calf serum IgG1 (P = 0.43) and J-5 E. coli antibody (P = 0.44) concentrations during the first 48 h of age were not affected by prior Se treatment of cows. These data suggest that feeding Se-biofortified alfalfa hay promotes the accumulation of Se and antibodies in colostrum but does not affect short-term serum antibody concentrations in calves.

Different durations of whole raw soybean supplementation during the prepartum period: Measures of cellular immune function in transition cows

The objective of this study was to evaluate different durations of whole raw soybean (WS) supplementation (diet rich in n-6 fatty acid) during the prepartum period on cellular immune function of dairy cows in the transition period and early lactation. Thirty-one Holstein cows were used in a completely randomized design and assigned to 4 experimental groups (G) [G90, G60, G30, and G0 (control)] supplemented with a diet containing 12% of WS from 90, 60, 30 and 0 d relative to the calving date, respectively. Cows were dried off 60 d before the expected calving date. After parturition, all cows were fed a diet containing 12% of WS until 84 DIM. Blood samples were collected before the morning feeding (d -56 ± 2, -28 ± 2, -14 ± 2, -7 ± 2, at the day of partum, 7 ± 2, 14 ± 2, 28 ± 2, and 56 ± 2 relative to parturition). Cell phenotyping and phagocytosis assays were carried out using monoclonal antibodies and flow cytometry technique. Duration of WS supplementation linearly increased the percentage of blood CD3+ cells, as well as increased the percentage of blood CD8+ cells in the postpartum period, notably in G30, whereas the lowest values were observed in G0. Further, the duration of WS supplementation linearly increased the reactive oxygen species median fluorescence intensity of CH138+ cells after phagocytizing Staphylococcus aureus in the postpartum period. Longer periods of WS supplementation linearly increased phagocytosis median fluorescence intensity of CH138+ cells in the prepartum period of cows. Duration of WS supplementation linearly increased the percentage of blood CD14+ cells producing reactive oxygen species when stimulated either by Staph. aureus or Escherichia coli in the postpartum period. In conclusion, longer periods of WS supplementation during late lactation and the dry period (beginning on d 90 of the expected calving date) alter the leukocyte population and improve neutrophil immune response in the postpartum period with no detrimental effects on cow performance.

Effect of experimentally increased protein supply to postpartum dairy cows on plasma protein synthesis, rumen tissue proliferation, and immune homeostasis

The effect of experimentally increasing the postpartum protein supply on plasma protein synthesis, rumen tissue proliferation, and immune homeostasis was studied using 8 periparturient Holstein cows in a complete randomized design. At calving, cows were assigned to abomasal infusion of water (CTRL) or casein (CAS) in addition to a lactation diet. Casein infusion was gradually decreased from 696 ± 1 g/d at +2 d relative to calving (DRTC) to 212 ± 10 g/d at +29 DRTC to avoid excessive supply. Synthesis rate of plasma proteins was measured at -14, +4, +15, and +29 DRTC by measuring [C]Phe isotopic enrichment in arterial plasma free Phe, total plasma proteins, and albumin after 3, 5, and 7 h of jugular ring[C]Phe infusion. Plasma volume was determined at +4 and +29 DRTC by dilution of a [I]BSA dose. Synthesis rate of tissue protein in biopsied rumen papillae was determined by measuring [C]Phe isotopic enrichment, and mRNA expression of selected genes was measured by real-time qPCR. Total and differential leukocyte counts were performed and immune responsiveness of monocytes was evaluated by tumor necrosis factor ɑ (TNFɑ) concentration on ex vivo whole blood stimulation with Escherichia coli lipopolysaccharide (LPS) and responsiveness of T-lymphocytes by interferon γ (IFNγ) concentration on stimulation with Staphylococcus aureus enterotoxin β (SEB). Further, ELISA plasma concentrations of IgM, IgA, and IgG were determined. The DRTC affected the majority of investigated parameters as expected. The CAS treatment increased milk protein yield (P = 0.04), and tended to lower TNFɑ (P = 0.06), and lowered IFNγ (P = 0.03) responsiveness per monocyte and lymphocyte, respectively, compared with CTRL. Further, fractional synthesis rate of albumin was greater at +4 DRTC for CAS compared with CTRL but did not differ by +29 DRTC (interaction: P = 0.01). In rumen papillae, synthesis rate of tissue protein was greater for CAS compared with CTRL (P < 0.01) and mRNA expression of genes for cell proliferation tended to be or were greater for CAS compared with CTRL (P ≤ 0.07). In conclusion, increased postpartum protein supply seem to enhance vital body functions as interpreted from increased liver synthesis of albumin, increased rumen papillae proliferation, and stabilized the ex vivo inflammatory responsiveness of leukocytes. Further studies are needed to enlighten the importance of increased postpartum protein supply in periparturient cows.

Effects of dexamethasone treatment and respiratory vaccination on rectal temperature, complete blood count, and functional capacities of neutrophils in beef steers

The objective of this research was to examine the effects of dexamethasone (DEX) treatment on various aspects of immunity following administration of a multivalent respiratory vaccine, using a model intended to mimic acute versus chronic stress. Angus × Hereford steers ( = 32; 209 ± 8 kg) were stratified by BW and randomly assigned to 1 of 3 treatments: 1) acute stress (ACU), in which 0.5 mg/kg BW DEX was intravenously administered at 1000 h only on d 0; 2) chronic stress (CHR), in which 0.5 mg/kg BW DEX was intravenously administered at 1000 h on d -3 to 0; or 3) control (CON), in which no DEX was administered. Steers were fitted with indwelling jugular catheters and rectal temperature (RT) recording devices on d -4 relative to vaccination and placed in individual stanchions in an environmentally controlled facility. Blood samples were collected and serum was isolated at -74, -50, and -26 h; at 0.5-h intervals from -4 to 6 h; and at 12, 24, 36, 48, and 72 h relative to multivalent respiratory vaccination at 1200 h on d 0. Additional blood samples were used to analyze complete blood cell count (CBC) and functional capacities of neutrophils. There was a treatment × time interaction ( < 0.01) for RT such that DEX treatment in CHR and ACU steers decreased RT on d -3 and 0, respectively. A treatment × time interaction ( < 0.01) was observed for total white blood cells (WBC), neutrophils, lymphocytes, and monocytes. Specifically, DEX increased WBC and neutrophils in CHR and ACU steers ( < 0.001) yet decreased lymphocytes in CHR steers ( = 0.02) compared with CON steers. Neutrophil concentration increased rapidly, within 2 h of the DEX infusion, in ACU steers. Monocytes transiently increased ( < 0.001) in response to DEX treatment in CHR and ACU steers. In contrast, eosinophils were greater ( < 0.01) in CON steers than in ACU and CHR steers. A treatment × time interaction ( = 0.004) was observed for interferon-γ, with CON cattle exhibiting greater concentrations than the ACU and CHR cattle at 5 h after vaccination, through d 3. Treatment also influenced ( ≤ 0.001) the expression of L-selectin on the surface of neutrophils. The percentage of neutrophils engaging in phagocytosis and the oxidative burst were suppressed ( ≤ 0.001) among only the CHR steers, whereas the intensity of the oxidative burst was suppressed ( ≤ 0.001) for both ACU and CHR steers. These data suggest that our model induced acute and chronic immunosuppression and defined the acute response to a multivalent vaccine in CON steers.

Frequency of wet brewers grains supplementation during late gestation of beef cows and its effects on offspring postnatal growth and immunity

Our objectives were to evaluate postnatal growth and measurements of innate and humoral immunity of beef calves born to dams fed wet brewers grains (WBG) daily or 3 times weekly during late gestation. On d 0 (approximately 60 d before calving), 28 multiparous, spring-calving Angus cows (BW = 578 ± 19 kg; age = 4.7 ± 0.65 yr; BCS = 7.0 ± 0.18) were stratified by sire, age, BW, and BCS and then randomly allocated into 1 of 14 drylot pens (2 cows/pen; 18 by 3 m; 27 m/cow). Cows were offered ground tall fescue hay ad libitum and received similar weekly WBG supplementation (DMI = 0.5% of BW multiplied by 7 d). Treatments were randomly assigned to pens (7 pens/treatment) and consisted of cows receiving WBG supplementation daily (S7; weekly DMI of WBG divided by 7 d) or 3 times weekly (S3; weekly DMI of WBG divided by 3 d; Mondays, Wednesdays, and Fridays) from d 0 until calving. Cow-calf pairs were managed as a single group on tall fescue pastures from calving to weaning (d 226). Calves were immediately submitted to a preconditioning period from d 226 to 266 and vaccinated against infectious bovine rhinotracheitis, bovine viral diarrhea virus, , and on d 231 and 245. Decreasing the frequency of WBG supplementation did not impact ( ≥ 0.21) precalving intake of total DM, CP, and TDN; BW and BCS change; overall plasma cortisol concentrations; and postcalving growth and pregnancy rate of cows. Overall plasma concentrations of glucose and insulin did not differ ( ≥ 0.28) between S3 and S7 cows, whereas S3 cows had greater ( = 0.002) plasma glucose concentrations and tended ( = 0.06) to have greater plasma insulin concentrations on days they were not fed WBG vs. days of WBG supplementation. Calf plasma concentrations of haptoglobin and cortisol at birth but not serum IgG ( = 0.63) tended ( = 0.10) to be greater for S3 vs. S7 calves. However, additional calf growth and immunity variables obtained during pre- and postweaning phases did not differ between S3 and S7 calves ( ≥ 0.21). Hence, decreasing the frequency of WBG supplementation during late gestation caused oscillations on precalving plasma glucose and insulin concentrations but did not affect plasma cortisol concentrations, growth, and pregnancy rate of cows. Also, reduced frequency of WBG supplementation during late gestation did not have carryover effects on postnatal calf growth and immunity.

Identification and characterization of a protective antigen, PlpB of bovine Pasteurella multocida strain LZ-PM

The Pasteurella multocida lipoprotein B (PlpB) was cloned from Pasteurella multocida (P. multocida) strain LZ-PM (serotype A) and expressed in Escherichia coli (E. coli). Sequence analysis showed that PlpB from different strains of P. multocida exhibited 80.8-99.4% sequence identity to each other, suggesting that PlpB might serve as a cross-protective antigen. The purified PCR product of PlpB gene consisting of 831 base pairs was inserted into the pET-32a (+) plasmid, and then transferred into E. coli. The protective immunity conferred by recombinant PlpB (rPlpB) on mice was evaluated. The results showed that mice immunized with 200 μg of purified rPlpB were protected (60% survival rate) against challenge infection with 1 MLD of P. multocida strain LZ-PM. In conclusion, our data indicated that the PlpB protein may be a potential target as a candidate subunit vaccine for P. multocida infection.

Effect of timing of challenge following short-term natural exposure to bovine viral diarrhea virus type 1b on animal performance and immune response in beef steers

Bovine respiratory disease (BRD) is the most common and economically detrimental disease of beef cattle during the postweaning period, causing the majority of morbidity and mortality in feedlots. The pathogenesis of this disease often includes an initial viral infection, which can predispose cattle to a secondary bacterial infection. The objective of this experiment was to determine the effects of timing of an intratracheal (MH) challenge relative to 72 h of natural exposure to bovine viral diarrhea virus (BVDV) type 1b persistently infected (PI) calves on performance, serum antibody production, total and differential white blood cell (WBC) count, rectal temperature, clinical severity score (CS), and haptoglobin (Hp). Steers ( = 24; 276 ± 31 kg initial BW) were randomly allocated to 1 of 3 treatments (8 steers/treatment) in a randomized complete block design. Treatments were steers not exposed to calves PI with BVDV 1b and not challenged with MH (CON), steers intratracheally challenged with MH 84 h after being exposed to calves PI with BVDV 1b for 72 h (LateCh), and steers intratracheally challenged with MH 12 h after being exposed to calves PI with BVDV 1b for 72 h (EarlyCh). Performance (ADG, DMI, and G:F) was decreased ( < 0.001) for both EarlyCh and LateCh from d 0 to 4. From d 5 to 17, LateCh appeared to compensate for this lost performance and demonstrated increased ADG ( = 0.01) and G:F ( = 0.01) compared with EarlyCh. Both EarlyCh and LateCh had decreased platelet counts ( < 0.001) compared with CON. Antibody concentrations of BVDV and MH were higher ( < 0.05) for both EarlyCh and LateCh compared with CON. Rectal temperature, CS, and Hp increased ( < 0.001) across time from h 4 to 48, h 4 to 36, and h 8 to 168, respectively. Within 24 h of MH challenge, WBC and neutrophil concentrations within the blood increased whereas lymphocyte concentrations decreased. The timing of BVDV exposure relative to a MH challenge appears to influence the CS and acute phase response associated with BRD. As typical beef cattle marketing channels allow for variation in the timing of respiratory pathogen exposure, understanding the physiological changes in morbid cattle will lead to improved management of BRD.

Peste des petits ruminants infection in domestic ruminants in Sudan

The existence of peste des petits ruminants (PPR) in domestic ruminants and camels in Sudan during 2008-2012 was investigated. Lung tissues and serum samples were randomly collected from sheep, goats, cattle, and camels at different areas of Sudan. A total of 12,384 serum samples were collected from clinically healthy 7413 sheep, 1988 camels, 1501 cattle, 1459 goats, and 23 gazelles at different areas in the Sudan. They were examined for PPR antibodies using competitive ELISA (cELISA). The overall detected seroprevalence of PPR in tested sera was 49.4%; seroprevalence values within species were 67.1, 48.2, 25.8, 2.1, and 21.7% in sheep, goat, cattle, camels, and gazelles, respectively. The highest seroprevalence (68.1%) was observed in sera collected from Darfur states, then the central states (54.3%). A total of 1276 lung tissue samples (623 sheep, 324 cattle, 220 camels, and 109 goats) were collected. The majority of lung samples were collected from clinically healthy animals that showed lesions on PM in slaughterhouses (95%) and during PPR outbreaks; samples were tested for PPR antigen using immunocapture ELISA (IcELISA). PPR antigen was detected in 233 out of the 1276 tested samples (18.3%). Positive results were observed in samples collected from clinically healthy and diseased animals. The observed prevalence values in each species were 33.6, 21.1, 15.4, and 12.3% in camel, goat, sheep, and cattle, respectively. PPR antigen was detected in samples from different areas; however, the highest prevalence (63.9%) was found in samples collected from the eastern states, then Khartoum state (28%). Trials for virus isolation were done in different cell cultures. Out of 30 IcELISA-positive samples inoculated in primary bovine and ovine kidney cells, Vero cells, the PPR virus was successfully isolated from 15 (eight sheep, five camels, and two goats) samples in the three cell culture types. Using RT-PCR, PPRV nucleic acid was detected in all 25 IcELISA-positive tested samples.

Evaluation of foot and mouth vaccination for yak (Bos grunniens) in Pakistan

In northern Pakistan, many farming communities rely on domestic yak (Bos grunniens) as a principle source of income. A 2006 participatory disease surveillance report from this region indicated that foot-and-mouth disease (FMD) is the most prevalent annual disease of yak. Our objectives of this study were to determine exposure levels of yak to FMD virus; implement a vaccination program based on current, regional FMD virus serotypes and subtypes; and quantify immune responses following vaccination. Blood samples were used to determine pre-vaccination exposure of animals to FMD virus by antibody presence to non-structural proteins of FMD virus using a 3-ABC trapping indirect ELISA. Vaccine used consisted of FMD serotypes 'O' (PanAsia-2), 'A' (Iran-05), and 'Asia-1' (Shamir), but changed later during the study to match newly circulating viruses in the country ('O'-PanAsia-2; 'A'-Turk-06 and Asia-1-Sindh-08). Three hundred sixty-three blood samples were tested from selected villages to determine pre-vaccination FMD virus exposure in yak with an average of 37.7%. Immune responses from initial vaccination and booster dose 30 days later showed clear protective levels (as mean percent inhibition) of antibodies against structural proteins of serotypes 'O,' 'A,' and 'Asia-1.' These responses remained above threshold positive level even at day 210 following initial vaccination. Results of sero-surveillance and anecdotal information of repeated FMD outbreaks demonstrate the persistence of FMD virus of yak in northern Pakistan. Laboratory results and field observations clearly indicated that yak can be protected against FMD with a good quality vaccine with FMD serotype(s) matching current, regionally circulating FMD virus.

Characterization and signaling pathway analysis of interferon-kappa in bovine

A bovine interferon-kappa (BoIFN-κ) gene was amplified, which encodes a protein of 215 amino acids sharing 63% identity with human IFN-κ. BoIFN-κ was demonstrated to have antiviral and antiproliferative activities. Moreover, BoIFN-κ was shown to be highly sensitive to trypsin, however, it remained stable despite changes in pH and temperature. Result showed that BoIFN-κ can bind with bovine type I IFN receptors, and the antiviral activity can be blocked by antibodies against type I IFN receptors or BoIFN-κ. Additionally, BoIFN-κ can induce the transcription of Mx1, ISG15 and ISG56 gene, as well as the expression of Mx1 protein. The NF-κB, ISRE, and BoIFN-β promoter can all be activated by BoIFN-κ. This study revealed that BoIFN-κ exhibits the typical characteristics of type I IFNs and exerts antiviral activity via activation of the JAK-STAT signaling pathway. Overall, these findings will enrich the current knowledge about IFN-κ and facilitate further research on the role of type I IFN in antiviral defense responses in bovine.

Preferential expression of IGHV and IGHD encoding antibodies with exceptionally long CDR3H and a rapid global shift in transcriptome characterizes development of bovine neonatal immunity

With an objective to understand natural development of bovine neonatal immunity, we analyzed 18 RNA-seq libraries from peripheral blood lymphocytes of three neonatal calves pre- (day 0) and post-colostrum (7, 14 and 28) uptake as compared to their dams. A significant global shift in neonatal transcriptome occurs within first week post-birth, in contrast to dams, with an upregulation of 717 genes. Global pathway analysis of the transcriptome revealed 110 differentially expressed immune-related genes, such as, complement, MHCII, chemokine receptors, defensins and cytokines, at birth. The signaling molecules (LAX1, BLK) and transcription factors (GATA3, FOXP3) are expressed at high levels. High expression of GATA3 transcription factor at birth seems to skew the neonatal immune response towards TH2 type. The high levels of T-cell signaling molecules, CD3G and CD3D, at birth are important in neonatal T cell development. Unlike adults, IGKC expression is high in the neonates where IGKV12 is preferentially expressed at birth. But IGLC is predominant in both neonates and adult where IGLV3.4 is preferentially expressed in B cells at birth. Both IGHM and IGHD are expressed at birth and IGHM achieves adult levels by day 7. This is followed by IGHA and IGHG expression 14-28 days post-birth. Importantly, preferential expression of IGHV1S1(BF4E9) and longest IGHD2(D_H2) genes that encode immunoglobulin with exceptionally long CDR3H at birth indicates their critical role, as B cell antigen receptor, in the B cell development via idiotype-anti-idiotype interactions. The transcriptome signatures described here permit assessment bovine neonatal immunocompetence. Bovine neonates acquire innate and IgM-mediated humoral immunocompetence within first week post-birth.

Characterization of a Broadly Reactive Anti-CD40 Agonistic Monoclonal Antibody for Potential Use as an Adjuvant

Lack of safe and effective adjuvants is a major hindrance to the development of efficacious vaccines. Signaling via CD40 pathway leads to enhanced antigen processing and presentation, nitric oxide expression, pro-inflammatory cytokine expression by antigen presenting cells, and stimulation of B-cells to undergo somatic hypermutation, immunoglobulin class switching, and proliferation. Agonistic anti-CD40 antibodies have shown promising adjuvant qualities in human and mouse vaccine studies. An anti-CD40 monoclonal antibody (mAb), designated 2E4E4, was identified and shown to have strong agonistic effects on primary cells from multiple livestock species. The mAb recognize swine, bovine, caprine, and ovine CD40, and evoked 25-fold or greater proliferation of peripheral blood mononuclear cells (PBMCs) from these species relative to cells incubated with an isotype control (p<0.001). In addition, the mAb induced significant nitric oxide (p<0.0001) release by bovine macrophages. Furthermore, the mAb upregulated the expression of MHC-II by PBMCs, and stimulated significant (p<0.0001) IL-1α, IL6, IL-8, and TNF-α expression by PBMCs. These results suggest that the mAb 2E4E4 can target and stimulate cells from multiple livestock species and thus, it is a potential candidate for adjuvant development. This is the first study to report an anti-swine CD40 agonistic mAb that is also broadly reactive against multiple species.

Immune Response in Calves Vaccinated with Type Three Secretion System Antigens and Shiga Toxin 2B Subunit of Escherichia coli O157:H7

Ruminants are the primary reservoir of Shiga-toxin producing Escherichia coli (STEC) O157:H7 and the main source of infection for humans. The aim of this study was to assess the immunogenic properties of a candidate vaccine consisting on the recombinant proteins of E. coli O157:H7 IntiminC280, the carboxy-terminal fraction of Intimin γ, EspB and the fusion protein between the B subunit of Stx2 and Brucella Lumazine Synthase (BLS)(BLS-Stx2B), in Holstein Fresian calves.To accomplish this goal we vaccinated calves with two doses of different vaccine formulations: 2 antigens (IntiminC280, EspB), 3 antigens (IntiminC280, EspB, BLS-Stx2B), BLS-Stx2B alone and a control non-vaccinated group. All antigens were expressed as recombinant proteins in E. coli. Specific IgG titres increased in vaccinated calves and the inclusion of BLS-Stx2B in the formulation seems to have a stimulatory effect on the humoral response to IntiminC280 and EspB after the booster. The neutralizing activity of antibodies against these two antigens was assessed in Red Blood Cell lysis assays and adherence to Hep-2 cells as a correlate of T3SS activity. Both sera from animals vaccinated with 2 or 3 antigens inhibited both virulence properties. Serological response to Stx2 was observed in animals vaccinated only with BLS-Stx2B and with 3 antigens and neutralization of Stx2 cytotoxicity was also observed in both groups. In conclusion, immunization of calves with BLS-Stx2B, IntiminC280 and EspB elicited a potent humoral response able to neutralize Shiga toxin 2 cytotoxity and the T3SS virulence properties in vitro. These results suggest that this formulation is a good candidate vaccine to reduce STEC shedding in cattle and needs to be further assessed in vivo.

BILL E. KUNKLE INTERDISCIPLINARY BEEF SYMPOSIUM: Impact of mineral and vitamin status on beef cattle immune function and health

The importance of optimal mineral and vitamin nutrition on improving immune function and health has been recognized in the preceding decades. In the southeast, beef cattle are raised predominantly on forages that may be limiting in nutrients for optimal health, especially trace minerals such as Cu, Zn, and Se. Clinical deficiencies of these nutrients produce classic symptoms that are common to several nutrient deficiencies (e.g., slow growth and unthrifty appearance); however, subclinical deficiencies are more widespread and more difficult to detect, yet may result in broader economic losses. Dietary mineral concentrations often considered adequate for maximum growth, reproductive performance, or optimal immune function have been found to be insufficient at times of physiological stress (weaning, transport, comingling, etc.), when feed intake is reduced. The impacts of these deficiencies on beef cattle health are not apparent until calves have been subjected to these stressors. Health problems that are exacerbated by mineral or vitamin deficiencies include bovine respiratory disease, footrot, retained placenta, metritis, and mastitis. Many micronutrients have antioxidant properties through being components of enzymes and proteins that benefit animal health. In dairy cattle, high levels of supplemental Zn are generally associated with reduced somatic cell counts and improved foot health, possibly reflecting the importance of Zn in maintaining effective epithelial barriers. Neutrophils isolated from ruminants deficient in Cu or Se have reduced ability to kill ingested bacteria in vitro. Supplemental vitamin E, in its role as an intracellular antioxidant has been shown to decrease morbidity in stressed calves. There is more understanding of the important biological role that these nutrients play in the functioning of the complex and multifaceted immune system. However, there is still much to be learned about determining the micronutrient status of herds (and hence when supplementation will be beneficial), requirements for different genetic and environmental conditions, understanding the bioavailability of these nutrients from feedstuffs and forages, quantifying the bioavailability of different supplemental sources of these nutrients, and identifying the impact of dietary antagonists on these nutrients.

Modulatory effects of interferon-γ and interleukin-4 on cellular immune responses against Hypoderma lineatum antigens

This study investigates the in vitro modulatory effects of interferon-γ (IFN-γ) and interleukin-4 (IL-4) on both proliferative bovine T cell responses and IL-10 production induced by different antigens [crude larval extract and the purified fractions hypodermin A, B and C (HyA, HyB, HyC)] obtained from first instars of Hypoderma lineatum (Diptera: Oestridae), alone or in the presence of the mitogen concanavalin A. Incubation with the different parasitic antigens resulted in significant inhibition of T cell proliferation and IL-10 production, which, in general, did not revert after the addition of IFN-γ and IL-4. In the absence of antigens, IL-4 induced significant inhibition of mitogen-induced T cell responses. Exogenous IFN-γ exhibited an inhibitory effect on cell proliferation in the presence of the purified fractions HyB and HyC. These in vitro data suggest that far from neutralizing the effects of larval antigens, the addition of IFN-γ potentiates their anti-proliferative activity; by contrast, IL-4 had no consistent effects on proliferative responses to Hypoderma. IL-4 provoked an increment of IL-10 levels in supernatants of HyB-stimulated cells. In conclusion, exogenous IFN-γ and IL-4 were unable to counteract the suppressor effects of H. lineatum antigens.