Infectious Bovine Rhinotracheitis Virus Challenge Research Articles

BEEF SPECIES-RUMINANT NUTRITION CACTUS BEEF SYMPOSIUM: Energy and roughage levels in cattle receiving diets and impacts on health, performance, and immune responses1.

Transition of newly received feedlot cattle from a forage- to grain-based diet is challenging, and the appropriate roughage level in receiving diets is debatable. Nutritionists must consider the paradox of dietary transition and roughage level to mitigate ruminal acidosis, yet concomitantly low feed intake presents difficulty in achieving nutrient requirements when metabolic demand is increased due to inherent stress and disease challenge during the receiving period. Previous research suggests that performance is improved at the expense of increased morbidity for newly received cattle consuming diets with less roughage and greater starch concentration. The clinical signs of bovine respiratory disease (BRD) and acute acidosis are analogous; therefore, it is probable that acidotic cattle are incorrectly diagnosed with BRD in both research and production settings. Additional research efforts have attempted to elucidate alterations in microbial populations and digestion, physiological response to inflammatory challenge, and immunological response to infectious bovine rhinotracheitis virus challenge in cattle consuming diets of various roughage levels. Furthermore, our understanding of the rumen microbiome is improving rapidly with culture-independent assays, products such as direct-fed microbials are available, and increased availability and use of fibrous byproduct ingredients requires further attention. Beef cattle nutritionists and producers should consider that the health benefit of receiving diets containing greater levels of roughage and lower energy may not compensate for the reduction in performance compared with feeding receiving diets with lower roughage and greater energy.

Effects of gastrointestinal parasites on parasite burden, rectal temperature, and antibody titer responses to vaccination and infectious bovine rhinotracheitis virus challenge1

Thirty-three colostrum-deprived Holstein bull calves (initial BW of 131 ± 4 kg) were used to determine the effect of timing of anthelmintic administration relative to vaccination on antibody titer response to vaccine component antigens. When calves were at least 3 mo of age, they were sorted randomly into individual pens and assigned to 1 of 3 treatment groups, treatments consisted of 1) dewormed 2 wk before vaccination (DPV), 2) dewormed at the time of vaccination (DV), or 3) control, vaccinated but not dewormed (CONT). All calves were inoculated with infective larvae of brown stomach worms (Ostertagia ostertagi) and intestinal worms (Cooperia spp.) on d 1, 7, 10, 14, and 18 for a total dose of 235,710 infective larvae per calf. Calves (DPV and DV) were dewormed on d 21 or 35 with a 10% fenbendazole suspension at 5 mg/kg of BW. On d 35, all calves were vaccinated with a modified-live virus respiratory vaccine containing IBRV (infectious bovine rhinotracheitis virus), BVDV-1 (bovine viral diarrhea virus genotype 1), BVDV-2 (BVDV genotype 2), PI-3 (parainfluenza-3), and BRSV (bovine respiratory syncytial virus). During the 103-d experiment, weekly fecal egg counts, blood, and rectal temperatures were collected and health status was recorded daily. Blood samples were obtained weekly to determine serum neutralizing (SN) antibody titers to IBRV, BVDV-1, BVDV-2, and PI-3 and cytokine levels for IL-4, IL-6, TNF-α (tumor necrosis factor-α), and IFN-γ (interferon-gamma). There was a tendency (P < 0.09) for CONT calves to have greater IL-4 concentrations. By design, control calves had greater (P < 0.01) fecal egg counts during the experiment. All calves developed antibody titers to IBRV, BVDV-1, BVDV-2, and PI-3 by d 15 postvaccination. On d 88, all calves were challenged with IBRV and blood samples were obtained on d 88, 89, 90, 93, 95, 98, 99, and 103. All calves had increased rectal temperatures during the final 7 d of the IBRV challenge. However, the CONT group had greater (P < 0.01) rectal temperatures on each sampling day except d 90 compared with the DPV and DV treatments. Therefore, deworming before or at vaccination reduced parasite burden and decreased rectal temperature increase after an IBRV challenge. Deworming strategy had no effect on antibody response to vaccination or IBRV challenge.

Effects of dietary source and intake of energy on immune competence and the response to an infectious bovine rhinotracheitis virus (IBRV) challenge in cattle

Objectives were to evaluate how dietary energy intake and source affect immune competence and response to an infectious bovine rhinotracheitis virus (IBRV) challenge in cattle. Forty-eight crossbred beef steers were stratified by body weight within two periods and randomized to 1 of 3 dietary treatments (8 steers/treatment within period). Treatments were: a 70% concentrate diet fed ad libitum (70AD); a 30% concentrate diet fed ad libitum (30AD); and 70% concentrate diet restricted to the net energy for gain intake of 30AL (70RES). Ex vivo immune responses were evaluated after treatments were applied for 28d, after which cattle were moved into individual pens (d 28 to 40) and intranasally challenged with IBRV on d 30. On d 34, all cattle were offered a 50% concentrate diet ad libitum until d 50. Both energy source (P<0.02) and intake level(P<0.04) affected peripheral blood mononuclear cell synthesis of tumor necrosis factor-α, with cell culture supernatant concentrations averaging 2264, 1887, and 1241pg/mL for 70AD, 70RES, and 30AD, respectively. Neither whole blood killing of Mannheimia haemolytica nor neutrophil oxidative burst in response to M. haemolytica was affected by treatments. Serum neutralizing IBRV antibody titers were not different among treatments either before or after the IBRV challenge. Rectal temperature following IBRV peaked 3d after the IBRV challenge and returned to baseline by d 6, but it was not affected by treatment. No differences were observed in dry matter intake among treatments while the cattle were individually penned and fed a 50% concentrate diet from d 34 to 40. When cattle were group-penned from d 40 to 50 of the study (d 10 to 20 after the IBRV challenge), the 70RES cattle had greater DMI (P<0.04) than cattle in the other two groups. Following the IBRV challenge, serum glucose concentrations did not differ among treatments; however, the 70AD cattle had greater blood urea N concentrations (P<0.01). There was a treatment×time interaction (P<0.01) for non-esterified fatty acids, such that cattle fed the 70AD had increased non-esterified fatty acids on d 3 and 5 after the IBRV challenge. Results indicate that cattle fed diets with a greater energy concentration and to an extent a greater percentage of concentrates had a more pronounced pro-inflammatory response, but other aspects of innate immune responses were not influenced by intake or source of energy.

Supplemental Selenium Source in Holstein Steers Challenged with Intranasal Bovine Infectious Rhinotracheitis Virus: Blood Metabolites, Hormones, and Cytokines

As an integral constituent of glutathione peroxidase (GSH-Px), Se is a vital antioxidant during stress. Calves are exposed to multiple factors that can lead to oxidative stress, including viral infection. Our objective was to evaluate the effects of supplementation of Se and Se source on immune function of Holstein steer calves challenged with infectious bovine rhinotracheitis virus (IBRV). Twentyfour Holstein steers (initial BW = 170 ± 0.6 kg) were assigned randomly to 3 treatments: 1) no supplemental Se (control); 2) 1 mg/steer daily of Se from Se yeast (Sel-Plex, Alltech Inc., Nicholasville, KY); or 3) 5 mg/steer daily of Se from sodium selenite. Treatments were fed for 35 d before intranasal inoculation with IBRV (d 0) and were continued through 21 d after the challenge. Whole blood Se was greater (P 0.80) was not affected by treatment. Serum interleukin-1β concentrations tended to be greater (P = 0.09) in steers fed selenite compared with control steers, and tumor necrosis factor-α concentrations 12 h after the challenge tended (P = 0.09) to be greater in steers fed Sel-Plex compared with control steers. Steers in the selenite group had decreased (P ≤ 0.02) serum urea N at 4 and 72 h after the challenge compared with control steers, and steers receiving Sel-Plex had increased serum urea N at 72 h (P = 0.008) after the IBRV challenge compared with control steers. Serum glucose concentrations tended (P = 0.06) to be

Effect of dietary lipoic acid on metabolic hormones and acute-phase proteins during challenge with infectious bovine rhinotracheitis virus in cattle

To determine the effect of dietary supplemental lipoic acid (LA) on serum concentrations of metabolic hormones and acute-phase proteins of steers challenged with infectious bovine rhinotracheitis virus (IBRV). 32 steers. Steers were randomly assigned to 4 treatments: negative control (NC; no LA, no IBRV challenge), control (CON; no LA, IBRV challenge), 16 mg of LA/kg of body weight (BW)/d plus IBRV challenge (LA16), and 32 mg of LA/kg of BW/d plus IBRV challenge (LA32). Following a 21-day adaptation period, CON, LA16, and LA32 steers received IBRV (2 mL/nostril [day 0]); NC steers received saline (0.9% NaCl) solution. Blood samples, nasal swab specimens, BW, and rectal temperatures were obtained 0, 1, 3, 5, 7, 14, and 21 days after challenge. Serum was analyzed for concentrations of haptoglobin, amyloid-A, leptin, and anti-IBRV antibodies. Steers fed LA32 began gaining BW by day 7, whereas BW of CON and LA16 steers declined. Serum haptoglobin concentration of LA32 steers was lower than that of CON and LA16 steers on day 7. Serum neutralization titers for 30 of 32 steers were negative for anti-IBRV antibodies before challenge; however, all steers (including NCs) had antibodies on day 21. Results suggested that LA supplementation augmented certain aspects of the immune response; LA32 steers had a more rapid recovery from IBRV viral challenge than did others.

Dietary zinc and manganese sources administered from the fetal stage onwards affect immune response of transit stressed and virus infected offspring steer calves

Nutritional stress encountered during the marketing and transportation of calves often results in excessive loss of micronutrients including zinc and manganese. The role of dietary zinc (Zn) and manganese (Mn) sources in enhancing the total body immune response of steer calves stressed by transportation and challenged with infectious bovine rhinotracheitis virus (IBRV) was investigated in this study. Forty steer calves (average body weight (BW) = 232 kg) were used in an experiment to determine the effects of the type of Zn and Mn supplementation to dams (100 days pre-partum) and calves (pre- and post-transit), on calf performance, dry matter intake (DMI), rectal temperature (RT) and BW changes after transit and after IBRV challenge. Data were also analyzed for the period after transit and following IBRV challenge. From pregnancy to weaning, the dams and calves received the following mineral supplements: (1) zinc methionine+manganese methionine (ZnMnMet; Zn=50 mg/kg, Mn=40 mg/kg), or (2) ZnO+MnO (ZnMnO; Zn=50 mg/kg, Mn=40 mg/kg). Calves were weaned and shipped approximately 2500 km from Raleigh, NC, to Bushland, TX. At the feedlot, the calves received the same supplements in a complete diet for 28 days (stress phase), and subsequently were challenged with IBRV (IBRV phase). During the 28-day period after transit, steers fed the ZnMnMet had higher ( P<0.05) DMI and gained (weight) faster ( P<0.05) than those fed ZnMnO. During the IBRV challenge phase, steers fed ZnMnMet averaged 20.4% higher ( P<0.05) DMI than the steers fed ZnMnO. These steers also exhibited lower ( P<0.05) RT and retained higher ( P<0.05) BW than those fed ZnMnO. These data indicate that a dietary organic Zn and Mn combination mitigated transit stress and IBRV infection of steer calves better than its inorganic counterpart.

Effect of shipping and chromium supplementation on performance, immune response, and disease resistance of steers.

Forty-eight Angus crossbred steers (263 +/- 2 kg initial BW) were blocked by weight and randomly assigned within weight group to treatment. Treatments consisted of control or .4 mg of supplemental Cr as Cr-nicotinic acid complex/kg of DM. Steers were fed diets containing 90% corn silage (DM basis) and 10% of a soybean meal-mineral-vitamin supplement. After 56 d on the dietary treatment, half of the steers in each treatment were transported 343 km and unloaded in an unfamiliar location. The next day, d 58, shipped steers were returned to the feedlot (50 km). On d 58 after shipped steers were returned to the feedlot, all steers were inoculated with infectious bovine rhinotracheitis virus (IBRV) intranasally. Average daily gain from d 0 to 80 was increased (P < .10) by supplemental Cr. There was a shipping x time interaction for serum cortisol concentrations. Shipping increased (P < .02) serum cortisol on d 58, but 7 d after transport there were no effects of shipping on serum cortisol. Transportation increased (P < .05) the ratio of neutrophils to lymphocytes. Supplemental Cr did not affect rectal temperature after the IBRV challenge or the antibody response to IBRV or porcine red blood cells. Immunoglobulin G antibody response to porcine red blood cells was decreased (P < .09) by shipping. Supplemental Cr as Cr-nicotinic acid improved ADG of growing steers, regardless of whether they had been stressed by shipping. Supplemental Cr did not affect any of the immune responses that were measured.

Influence of triiodothyronine injections on calf immune response to an infectious bovine rhinotracheitis virus challenge and nitrogen balance of lambs.

Three experiments were conducted to determine the influence of triiodothyronine (T3) or propylthiouracil (PTU) on the humoral immune response of calves challenged with infectious bovine rhinotracheitis virus (IBRV) and on nitrogen depletion and repletion of lambs deprived of feed and water for 3 d. In Exp. 1, 18 steer calves (BW 284 +/- 6 kg) challenged with IBRV were limit-fed (1.5% BW) a 60% concentrate diet and injected (s.c.) daily with alkaline saline, .4 mg of T3, or .8 mg of T3. Injections of T3 did not affect serum antibody titers to IBRV, blood leukocyte counts, or plasma free fatty acid, ceruloplasmin, and cholesterol concentrations but increased (P < .05) plasma glucose concentrations and decreased (P < .05) plasma urea N concentrations. In Exp. 2, 36 IBRV-challenged steers (BW 266 +/- 8 kg) were given ad libitum access to a 60% concentrate diet and injected (s.c.) daily with alkaline saline, .2 mg of T3, or .4 mg of T3. In contrast to Exp. 1, injections of T3 did not affect plasma glucose or urea N concentrations and reduced (P < .05) serum antibody titers to IBRV. In Exp. 3, eight wether lambs were limit-fed (600 g/d) a 36% concentrate pelleted diet and assigned to one of four treatments in a replicated 4 x 4 Latin square designed nutrient balance experiment involving periods of nutrient depletion and repletion. Treatments were as follows: 1) alkaline saline injection (s.c.), 2) 4 mg of PTU/kg BW in water, 3) .15 mg of T3 s.c. daily for 15 d, and 4) .15 mg of T3 s.c. daily for 7 d after the 3-d feed and water deprivation period. Thyroid status affected (P < .05) predeprivation N balance but did not affect N losses during the feed and water deprivation period. Retention of N during realimentation was affected (P < .05) by T3 treatment. Results of these experiments indicate that there is a complex interrelationship among stress, nutrient status, and thyroidal status and that the effects of T3 injections on immune and metabolic responses may be dependent on the nutritional status of the animal.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of copper deficiency on tissue, blood characteristics, and immune function of calves challenged with infectious bovine rhinotracheitis virus and Pasteurella hemolytica.

Fourteen Holstein steers, averaging 30 d of age, were fed a semipurified diet (1.5 mg of Cu/kg) supplemented with 0 (-Cu) or 10 mg of Cu/kg of diet (+Cu) for 5 mo. Calves were then challenged by consecutive exposure to aerosol preparations of infectious bovine rhinotracheitis virus (IBRV) and Pasteurella hemolytica on d 0 and 7, respectively, of the 30-d study. Serum ceruloplasmin and plasma copper were higher in +Cu calves throughout the challenge period and increased in +Cu calves after microbial challenge. Heart weights were higher in -Cu calves, although weights of liver, spleen, and thymus were not different between treatments. Copper concentrations in all tissues as well as thymus zinc were higher in +Cu calves. Serum immunoglobulin M tended to be higher in +Cu calves and increased in both treatments after IBRV challenge. Serum IBRV antibody titers were higher in -Cu calves with detectable seroconversion by d 10 postinfection. In contrast, antigen-specific antibodies to P. hemolytica tended to be higher in +Cu calves on d 21. Copper status did not affect blastogenic response, but phytohemagglutinin (PHA)-stimulated blastogenesis was higher in both treatments after IBRV challenge. Repletion of lymphocyte cultures with copper chloride increased proliferative responses to PHA in both +Cu and -Cu calves, and greater responses at all levels of copper (1 to 16 micrograms/mL) were noted in -Cu calves. These results indicate that copper deficiency affects various physiological characteristics that may be important in immunological defense to pathogenic challenge.

Feed intake, rectal temperature, and serum mineral concentrations of feedlot cattle fed zinc oxide or zinc methionine and challenged with infectious bovine rhinotracheitis virus4

Three experiments were conducted using feedlot steers in a randomized block design to determine the effect of zinc methionine (ZnMet) and zinc oxide (Exp. 3) on feed intake (DMI), rectal temperature, and serum mineral concentrations of feedlot cattle challenged with infectious bovine rhinotracheitis virus (IBRV). All the steers used were seronegative to IBRV. Steers were adapted for 7 d to their respective diets and challenged with 3.7 x 10(5) plaque forming units of IRBV on d 0 of each experiment. Live BW, rectal temperature, and individual daily DMI were recorded for 14 d. Blood samples were taken on d 0, 7, and 14. In Exp. 1, daily DMI of the control steers (Zn = 31 ppm) decreased 50% compared with 15% in the ZnMet (Zn = 90 ppm) steers 3 d after IBRV challenge. By d 6, the ZnMet steers had regained their pretrial mean daily DMI, but the control steers took 11 d. The ZnMet steers had lower (P less than .05) mean rectal temperature than the control steers on d 7 and 12. In Exp. 2, the control (Zn = 35 ppm) steers had lower (P less than .05) daily DMI on d 8 to 12 than the ZnMet (Zn = 89 ppm) steers. In Exp. 3, the mean decrease in daily DMI tended to be more rapid in the ZnO steers than in the control and ZnMet steers. All steers had the lowest daily DMI on d 5 and 6, coinciding with the highest rectal temperature. Serum Zn, P, and Mg concentrations decreased and serum Cu increased in all steers after infection. These data suggest that dietary Zn enhanced the recovery rate of IBRV-stressed cattle.

Effect of Dietary Selenium on the Primary and Secondary Immune Response in Calves Challenged with Infectious Bovine Rhinotracheitis Virus

The present study was conducted to determine if a selenium deficiency affects the primary and secondary humoral immune response of calves challenged with infectious bovine rhinotracheitis virus (IBRV) and to evaluate changes in glutathione peroxidase (GSH-Px) and creatine phosphokinase activities associated with selenium deficiency and viral stress. Treatments included 1) +Se (0.2 mg/kg diet) and 2) -Se (0.03 mg/kg diet). Calves were adapted to their assigned diets during an 84-d depletion period. By d 42 of the depletion period, whole-blood GSH-Px was lower for -Se calves than for +Se calves. Differences between treatments in plasma GSH-Px were observed by d 14. On d 84, Se-dependent GSH-Px activity in liver was higher in +Se calves. After depletion of -Se calves, animals in both treatments were intranasally inoculated with IBRV on d 0 and 35 of the 70-d challenge phase. Whole-blood and plasma GSH-Px increased after IBRV inoculation in +Se calves but not in Se-deficient calves. Serum IgM was higher for +Se calves throughout the challenge phase. Serum IgM increased in both treatments after primary IBRV inoculation but was unaffected by secondary challenge. Serum IgG was not affected by selenium status but increased in both treatments after secondary IBRV challenge. Serum IBRV antibody titers increased after inoculation on d 0 and 35. By d 49, IBRV antibody titers were higher for +Se calves than in Se-deficient calves. These results indicate that selenium deficiency may depress the immune response of calves challenged with a foreign pathogen.

Nitrogen kinetics of infectious bovine rhinotracheitis-stressed calves.

Eight crossbred feeder steers were used in two consecutive N balance studies to investigate the effects of infectious bovine rhinotracheitis virus (IBRV) on N kinetics. Balance Study 1, which followed a 10-d acclimation phase, consisted of 7 d of sample collection referred to as the healthy phase (d -7 to d -1). Study 2, the IBRV-infected phase, began 2 d after a nasal IBRV challenge and continued for 6 d (d 2 to d 8). A stable isotope, [15N]-glycine, was used to determine N kinetics in both studies. Steers weighed 203 kg at the beginning of the study, 208 kg at IBRV infection and 194 kg at the end of study. Infection with IBRV increased (P less than .05) urinary N excretion from 17.9 to 31.5 g/d. Daily N balance was reduced (P less than .05) during infection from 21.2 to -3.3 g/d. Total serum proteins increased (P less than .05) during infection from 6.6 to 7.1 g/100 ml, the increase being predominantly in the alpha and gamma globulin fractions. Blood urea-N increased (P less than .05) during infection from 6.5 to 12.9 mg/100 ml. The urine excretion curve of the stable isotope and the N balance data indicated that IBRV infection increased N turnover and altered tissue utilization of N.