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 develop and use a sensitive molecular
assay for detecting the phospholipase D (PLD) exotoxin
gene of Corynebacterium pseudotuberculosis in
an attempt to identify insect vectors that may be
important in transmission of clinical disease in horses.
Sample Population—2,621 flies of various species.
Procedure—A real-time polymerase chain reaction
(PCR)-based fluorogenic 5' nuclease (TaqMan) system
(ie, TaqMan PCR assay) was developed for the
detection of the PLD gene in insects. Flies were collected
monthly (May to November 2002) from 5 farms
in northern California where C pseudotuberculosis
infection in horses is endemic. Three of the 5 farms
(which housed a total of 358 horses) had diseased
horses during the study period. A total of 2,621 flies
of various species were tested for the PLD gene of C
Results—Evidence of bacterial DNA for the PLD
gene was detected in skin biopsy specimens from
clinically affected horses and from 3 fly species collected
from farms where affected horses were
housed. Farms with a high incidence of diseased
horses had a high proportion of insects carrying the
organism. High percentages of flies with positive
results for the PLD gene were observed in October,
when most clinically affected horses were observed.
Conclusions and Clinical Relevance—Our results
are consistent with the hypothesis that C pseudotuberculosis
may be vectored to horses by flies. Three
potential vectors were identified, including
Haematobia irritans, Stomoxys calcitrans, and Musca
domestica. The organism can be identified in up to
20% of house flies (Musca domestica) in the vicinity
of diseased horses. (Am J Vet Res 2004;65:829–834)