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Lameness is a common animal health condition with significant production and welfare implications. The transdermal formulation of flunixin meglumine is the only approved drug for pain control in cattle in the United States. Thirty adult dairy cows were enrolled in a study to determine the effect of transdermal flunixin on cattle with induced lameness. Cows were allocated to 1 of 3 treatment groups, with 10 cows per group: lameness and flunixin (L+F), lameness and placebo (L+P), or sham induction and placebo (S+P). An arthritis-synovitis was induced in the distal interphalangeal joint of the left hind lateral digit, using 20 mg of amphotericin B, 6 h before the application of treatment. Cows enrolled into the sham induction group had 4 mL of isotonic saline injected into the joint. Cows were dosed with transdermal flunixin at 3.33 mg/kg (1 mL/15 kg), or a placebo at 1 mL/15 kg, every 24 h for 3 d. The first treatment of flunixin or placebo was considered the start of the study, identified as time 0 h. Data were collected from all cows for 120 h following the initial treatment application. Outcome measures included plasma cortisol; substance P; visual lameness assessment; mechanical nociception threshold (MNT), presented as difference between left and right feet; infrared thermography (IRT), presented as difference between left and right feet; and gait analysis using a pressure mat. Cortisol concentrations were lower for the L+F group starting at 1.5 h after drug administration. Substance P levels showed no evidence for treatment differences among groups. Differences between the left hind MNT and right hind MNT were detected, with S+P having the lowest difference at −0.04 kilograms-force (kgf; 95% CI: −1.86 to 1.78 kgf), and L+P having the highest at −2.96 kgf (95% CI: 1.55 to 4.36 kgf). The L+F group was intermediate at −2.08 kgf (95% CI: 0.89 to 3.27 kgf). Similarly, when the difference between the maximum temperatures of the coronary band were examined via IRT, the L+P group had the highest difference at 1.64°C (95% CI: 1.02 to 2.26°C), with the L+F and S+P groups measuring 0.57°C (95% CI: 0.06 to 1.08°C) and 0.53°C (95% CI: −0.2 to 1.25°C) respectively. We found no evidence for differences among treatment groups when analyzing force, contact pressure, step impulse, or stride length. Based on differences in MNT, IRT, and cortisol, transdermal flunixin is an effective analgesic agent for induced lameness. Multiple doses of transdermal flunixin may be required to be clinically effective, based on MNT and IRT data. Further investigation of transdermal flunixin and its analgesic effects is warranted in naturally occurring lameness. [ABSTRACT FROM AUTHOR]

Bovine lameness has relatively large negative economic and welfare implications on the U.S. dairy industry. Due to the ramifications, early lameness detection will aid in assisting dairy producers to mitigate downstream effects through early treatment. The objective of this study was to determine the minimum standing time required among 2-, 3-, 4-, 5-, and 10 min time intervals to obtain an accurate weight distribution estimate for each leg when attempting to detect lameness. An embedded microcomputer-based force plate system was developed to measure vertical forces from individual cow limb weight distribution to detect bovine lameness when utilizing an induced synovitis lameness model. The force plate has four quadrants, with each load cell quadrant measuring the force placed on it from a single limb. The force plate recorded weight (kg) every second from each load cell quadrant, after which, a 60 s moving average for weight distribution was calculated. A sequential study design was employed to evaluate non-lame and induced lameness to ensure time requirements were consistent. Prior to induction, the force plate system was used to measure weight distribution every second for 15 min. After lameness induction, additional 15 min increments were recorded every 24 h for seven days. Lameness was induced by injecting the left hind distal interphalangeal joint in three cows with amphotericin B, 12 h prior to the start of the study. Data were analyzed using a linear mixed effect that included the fixed effects of day relative to lameness induction, time period, foot and injected foot. Cow within replicate was included as a random effect. Cumulative minutes were assessed up to 15 min by comparing the least square rolling 60 s cumulative means expressed as a percentage of each animal's BW percentage placed on each leg for 2-, 3-, 4-, 5-, and 10 min intervals. Results indicate that the minimum time needed for accurate lameness detection in cows was 2 min. [ABSTRACT FROM AUTHOR]