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Abstract

Objective—To evaluate whether pedal bacteremia develops following regional IV perfusion (RIVP) of a 2% lidocaine hydrochloride solution in cattle with deep digital sepsis (DDS) and to determine which bacterial pathogens are most commonly isolated from the pedal circulation.

Design—Prospective observational cohort study.

Animals—9 adult cattle with DDS in 10 limbs and 10 healthy adult cattle with no evidence of lameness or digital infection.

Procedures—Blood samples were obtained aseptically from the dorsal common digital vein immediately following tourniquet application and 30 to 60 minutes after aseptic RIVP with a 2% lidocaine solution. Aerobic and anaerobic bacterial cultures were performed on all samples collected. For cattle with DDS, clinical examination with or without debridement of digital lesions was performed after RIVP.

Results—Bacteria were isolated from pedal blood prior to RIVP in 1 cow with DDS and after RIVP and examination with or without debridement in that cow and 4 additional cattle with DDS. Bacteria were not isolated from any blood sample obtained from the healthy cattle. Of the 8 bacterial isolates identified, 5 were gram-positive facultative anaerobes. Cattle with DDS were significantly more likely to develop bacteremia in the pedal circulation than were healthy cattle following RIVP.

Conclusions and Clinical Relevance—Results indicated that bacteremia may be present in the pedal circulation before and following RIVP and examination with or without debridement in cattle with DDS. Thus, systemic or local antimicrobial treatment might be warranted prior to or concurrently with RIVP in cattle with DDS.

Full access
in Journal of the American Veterinary Medical Association

Abstract

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.

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in American Journal of Veterinary Research

Abstract

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.

Full access
in American Journal of Veterinary Research