OBJECTIVE To evaluate the effects of meloxicam on movement, feeding, and drinking behaviors of transported and nontransported cattle.
ANIMALS 100 crossbred beef steers.
PROCEDURES During experiment 1 of a 2-experiment study, calves from a livestock auction received meloxicam (1 mg/kg, PO; n = 50) or a lactose placebo (1 capsule/calf; 50; control), then calves were transported approximately 1,000 km overnight to a feedlot, where they were instrumented with a real-time location-monitoring ear tag, placed in randomly assigned pens (n = 5 pens/treatment), and monitored for 21 days. During experiment 2, calves in pens were administered the treatment opposite that of experiment 1, returned to their pens without undergoing transportation, and monitored for another 21 days. For each experiment, mean daily distance traveled and percentage time spent near feed (PNF) and water (PNW) were calculated on a pen basis and compared between treatments.
RESULTS During experiment 1, mean daily distance traveled, PNF, and PNW did not differ significantly between meloxicam-treated and control calves; however, all 3 behaviors varied significantly by day. During experiment 2, although mean distance traveled was significantly associated with the interaction between day and treatment, it did not differ significantly between meloxicam-treated and control calves within any specific day. Mean PNF and PNW were significantly associated with day only, although no pattern in that effect was evident.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a single dose of meloxicam prior to transportation did not significantly affect the behaviors of transported and nontransported calves.
OBJECTIVE To investigate the effects of meloxicam administration before long-distance transport on inflammatory mediators and leukocyte function of cattle at feedlot arrival.
ANIMALS 60 healthy yearling beef steers.
PROCEDURES Single-source steers were assigned to a transported (n = 40) or nontransported (20) group. Then, half of the steers within each group were assigned to receive meloxicam (1 mg/kg, PO) or a lactose placebo (1 bolus/steer, PO). All steers were transported approximately 1,300 km overnight to a feedlot; however, the nontransported group was moved before treatment (meloxicam or placebo) administration and allowed a 17-day acclimation period, whereas the transported group was moved immediately after treatment administration on day −1. Blood samples for measurement of inflammatory mediators and leukocyte function were collected from all steers on days −1, 0, and 3.
RESULTS For steers that received meloxicam, mean plasma meloxicam concentration for the transported group was significantly greater than that for the nontransported group on day 0. For steers that received the placebo, mean haptoglobin-matrix metalloproteinase-9 complex for the transported group was significantly greater than that for the nontransported group on day 0. Mean haptoglobin concentration, neutrophil L-selectin intensity, and polymorphonuclear leukocyte count for the transported group were significantly greater than those for the nontransported group. Mean substance P concentration for nontransported steers that received meloxicam was significantly lower than that for the other 3 treatment groups.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated meloxicam administration to healthy steers immediately before long-distance transport did not significantly mitigate the effects of transport-induced stress on leukocyte function or inflammatory markers.
OBJECTIVE To compare predictive values, extent of agreement, and gamithromycin susceptibility between bacterial culture results of nasopharyngeal swab (NPS) and bronchoalveolar lavage fluid (BALF) samples obtained from calves with bovine respiratory disease (BRD).
ANIMALS 28 beef calves with clinical BRD.
PROCEDURES Pooled bilateral NPS samples and BALF samples were obtained for bacterial culture from calves immediately before and at various times during the 5 days after gamithromycin (6 mg/kg, SC, once) administration. For each culture-positive sample, up to 12 Mannheimia haemolytica, 6 Pasteurella multocida, and 6 Histophilus somni colonies underwent gamithromycin susceptibility testing. Whole-genome sequencing was performed on all M haemolytica isolates. For paired NPS and BALF samples collected 5 days after gamithromycin administration, the positive and negative predictive values for culture results of NPS samples relative to those of BALF samples and the extent of agreement between the sampling methods were determined.
RESULTS Positive and negative predictive values of NPS samples were 67% and 100% for M haemolytica, 75% and 100% for P multocida, and 100% and 96% for H somni. Extent of agreement between results for NPS and BALF samples was substantial for M haemolytica (κ, 0.71) and H somni (κ, 0.78) and almost perfect for P multocida (κ, 0.81). Gamithromycin susceptibility varied within the same sample and between paired NPS and BALF samples.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated culture results of NPS and BALF samples from calves with BRD should be interpreted cautiously considering disease prevalence within the population, sample collection relative to antimicrobial administration, and limitations of diagnostic testing methods.