A comparison of three anti-inflammatory drugs in weaner pigs using Improvac^® as an inflammation model

Analgesic/anti-inflammatory drugs must be effective to ensure appropriate treatment of sick/injured animals. Wilson et al. (2014) reported that meloxicam is the anti-inflammatory drug most frequently used on pig farms in Australia. However, it appears that ketoprofen may have a greater analgesic effect in young pigs than meloxicam (Fosse et al. 2011a, 2011b). It was hypothesised that ketoprofen would have a greater analgesic/anti-inflammatory effect than meloxicam and dexamethasone in weaner pigs.

This experiment used 32, 10-week-old male Landrace x Large White weaner pigs [n = 8/treatment; body weight 34.5 ± 0.51 kg (mean ± SE)]. Pigs were housed in pens of four (one per treatment group). Inflammation was induced using a single subcutaneous injection of Improvac^® (2 mL; Zoetis, Sandton, South Africa) behind the right ear on d 1. Pigs were injected intramuscularly daily for 3 d with physiological saline (2 mL, 0.9% NaCl), ketoprofen (3 mg/kg Ketofen^®; Merial, North Ryde, Australia), meloxicam (0.04 mg/kg Metacam^®; Boehringer Ingelheim Vetmedica, North Ryde, Australia) or dexamethasone (1 mg/10 kg Dexason^®; Illium, Glendenning, Australia). Inflammation was assessed by measuring haptoglobin and C-reactive protein concentrations (CRP) in blood samples collected on d 0, 2 and 4 after Improvac^® treatment using Tridelta^® Phase™ Range assays. Rectal temperatures (RT; MC-246, Omron Healthcare, Australia) were measured daily. Haptoglobin, CRP and RT data were analysed using linear mixed models (Genstat, 17th Edition; UK).

The administration of ketoprofen and meloxicam caused a decreased RT (P < 0.05) compared to control animals. Haptoglobin concentrations were lower in ketoprofen-treated pigs compared to all other treatment groups (P < 0.001, Table 1). No treatment effects were evident for CRP, however a day effect was evident where CRP concentrations increased from 2028 (± 330.8) to 6612 (± 330.8) and lowering to 4436 (± 330.8) ng/mL (P < 0.001).

Table 1.  Haptoglobin and C reactive protein (CRP) concentrations, and the rectal temperature (RT), after treatment for inflammation with either saline, ketoprofen, meloxicam or dexamethasone. Values are mean ± SE

The haptoglobin responses suggest that ketoprofen may be a more effective analgesic agent than meloxicam or dexamethasone in weaner pigs. Further research needs to be completed using a larger range of responses to inflammation, for example, behaviour and feed intake of individual pigs, before it can be conclusively determine that ketoprofen is a more effective analgesic/anti-inflammatory agent.