To quantify acute immunologic and metabolic responses of beef heifers following topical administration of transdermal flunixin meglumine (TDFM) at various times relative to bovine herpesvirus 1 (BHV1) and Mannheimia haemolytica challenges.
32 beef heifers (mean body weight, 170 kg).
Heifers were assigned to 1 of 4 groups. Heifers in the control group did not receive TDFM, whereas 1 dose of TDFM (3.3 mg/kg) was topically applied to heifers of groups A, V, and B at −144, −72, and 0 hours. All heifers were inoculated with 1 × 108 plaque-forming units of BHV1 in each nostril at −72 hours and with 1.18 × 106 CFUs of M haemolytica intratracheally at 0 hours. Vaginal temperature was recorded and blood samples were collected for quantification of select immunologic and metabolic biomarkers at predetermined times from −144 to 360 hours.
Mean vaginal temperature was similar between group A and the control group. Mean vaginal temperatures for groups V and B were generally lower than that for the control group following BHV1 and M haemolytica challenges, respectively. Mean neutrophil oxidative burst capacity and L-selectin expression at 0 hours were significantly decreased for group V relative to the other groups. Other biomarkers did not differ among the groups at any time.
CONCLUSIONS AND CLINICAL RELEVANCE
Results suggested that topical administration of TDFM to beef cattle effectively alleviated pyrexia without adverse effects on acute immunologic or metabolic responses when TDFM was administered at the same time as, but not before, respiratory pathogen challenge.
Objective—To evaluate serum haptoglobin concentration at feedlot arrival and subsequent performance and morbidity and mortality rates of calves that developed bovine respiratory disease.
Animals—360 heifer calves and 416 steer and bull calves.
Procedures—Serum samples were obtained from cattle at the time of arrival to a feedlot (day −1) and analyzed for haptoglobin concentration. In experiment 1, calves were classified into groups with a low (< 1.0 μg/mL), medium (1.0 to 3.0 μg/mL), or high (> 3.0 μg/mL) serum haptoglobin concentration and allotted into pens on the basis of group. In experiment 2, calves were classified as having or not having detectable serum haptoglobin concentrations.
Results—In experiment 1, average daily gain from days 1 to 7 decreased as haptoglobin concentration increased. Dry-matter intake (DMI) from days 1 to 21 decreased with increasing haptoglobin concentration, and DMI typically decreased from days 1 to 63. Total bovine respiratory disease morbidity rate typically increased with increasing haptoglobin concentration. At harvest, no differences in carcass characteristics were observed on the basis of haptoglobin concentration. In experiment 2, cattle with measureable serum haptoglobin concentrations at arrival weighed less throughout the experiment, gained less from days 1 to 7, and had lower DMI from days 1 to 42. Overall morbidity rate was not different between groups, but cattle with detectable serum haptoglobin concentrations had higher odds of being treated 3 times.
Conclusions and Clinical Relevance—Serum haptoglobin concentration in cattle at the time of feedlot arrival was not associated with overall performance but may have limited merit for making decisions regarding targeted prophylactic treatment.
Objective—To compare effects of administration of a modified-live respiratory virus vaccine once with administration of the same vaccine twice on the health and performance of cattle.
Design—Randomized, controlled trial.
Animals—612 mixed-breed male cattle with unknown health histories.
Procedures—Cattle were randomly assigned to 1 of 2 treatment groups (single vaccination treatment group [SVAC group] vs revaccination treatment group [REVAC group]) during the preconditioning phase of production. All cattle were given a modified-live respiratory virus vaccine. Eleven days later, REVAC group cattle received a second injection of the same vaccine. During the finishing phase of production, cattle from each treatment group were either vaccinated a third time with the modified-live respiratory virus vaccine or given no vaccine. Health observations were performed daily. Blood and performance variables were measured throughout the experiment.
Results—During preconditioning, no significant differences were observed in performance or antibody production between groups. Morbidity rate from bovine respiratory disease was lower for SVAC group cattle; however, days to first treatment for bovine respiratory disease were not different between groups. No significant differences in body weights, daily gains, or dry-matter intake between groups were observed during the finishing phase. Revaccination treatment group cattle had improved feed efficiency regardless of vaccination protocol in the finishing phase.
Conclusions and Clinical Relevance—Vaccination once with a modified-live respiratory virus vaccine was as efficacious as vaccination twice in the prevention of bovine respiratory disease of high-risk cattle, although feed efficiency was improved in REVAC group cattle during the finishing period.
Objective—To determine efficacy of a modified-live virus (MLV) vaccine containing bovine viral diarrhea virus (BVDV) 1a and 2a against fetal infection in heifers exposed to cattle persistently infected (PI) with BVDV subtype 1 b.
Animals—50 heifers and their fetuses.
Procedures—Susceptible heifers received a placebo vaccine administered IM or a vaccine containing MLV strains of BVDV1a and BVDV2a administered IM or SC. On day 124 (64 to 89 days of gestation), 50 pregnant heifers (20 vaccinated SC, 20 vaccinated IM, and 10 control heifers) were challenge exposed to 8 PI cattle. On days 207 to 209, fetuses were recovered from heifers and used for testing.
Results—2 control heifers aborted following challenge exposure; both fetuses were unavailable for testing. Eleven fetuses (8 control heifers and 1 IM and 2 SC vaccinates) were positive for BVDV via virus isolation (VI) and for BVDV antigen via immunohistochemical analysis in multiple tissues. Two additional fetuses from IM vaccinates were considered exposed to BVDV (one was seropositive for BVDV and the second was positive via VI in fetal tissues). A third fetus in the SC vaccinates was positive for BVDV via VI from serum alone. Vaccination against BVDV provided fetal protection in IM vaccinated (17/20) and SC vaccinated (17/20) heifers, but all control heifers (10/10) were considered infected.
Conclusions and Clinical Relevance—1 dose of a BVDV1a and 2a MLV vaccine administered SC or IM prior to breeding helped protect against fetal infection in pregnant heifers exposed to cattle PI with BVDV1b.
Objective—To evaluate exhaled N2O (eN2O), exhaled CO (eCO), and serum haptoglobin concentrations as diagnostic criteria for bovine respiratory disease (BRD) and determine whether a combination of biomarkers would be useful for predicting health outcomes of heifer calves.
Animals—337 heifer calves newly arrived at a feedlot.
Procedures—Body weights, serum haptoglobin concentrations, and rumen temperatures were determined. Calves (n = 183) were randomly selected for breath sampling. Variables were compared among calves that remained healthy and those requiring treatment.
Results—Body weight at the time of first and second antimicrobial treatments did not differ from that at arrival, whereas body weight at the time of third antimicrobial treatment was lower. Temperature was lower at arrival, compared with that during antimicrobial treatment. Ratio of eN2O:eCO2 was lowest at arrival, intermediate at the first and second antimicrobial treatments, and greatest at the third antimicrobial treatment. Ratio of eCO:eCO2 was greater at times of antimicrobial treatment, compared with arrival. Concentration of serum haptoglobin was greatest at the time of the first antimicrobial treatment, lowest at the times of second and third treatments, and intermediate at arrival. Arrival ratios of eN2O: eCO2 and eCO:eCO2 and concentration of haptoglobin did not differ among heifers subsequently treated 1, 2, or 3 times.
Conclusions and Clinical Relevance—Although breath analysis was successfully implemented in a research feedlot, arrival rumen temperature, eN2O, eCO, and haptoglobin concentration were not accurate in predicting occurrence of BRD during a preconditioning program. However, these biomarkers might support the diagnosis of BRD.