Factors associated with the recovery of non-claw-associated lameness in gestating sows: A special focus on acute phase proteins and clinical signs

The prevalence of lameness in group-housed gestating sows is high and lameness associated with reduced sow welfare and longevity is one of the main reasons for involuntary culling. C-reactive protein (CRP) and pig major acute phase protein (Pig-MAP) are elevated in lameness in sows, and acute phase proteins are associated with prognosis in cows and humans. This study aimed to investigate whether CRP and Pig-MAP, combined with clinical signs, could be used prognostically to predict recovery of lameness in gestating sows. This was investigated using a longitudinal study design with sows from three conventional herds. The sows were included if moderately to critically lame and followed for up to 28 days. The treatment consisted of relief in a sick pen, antibiotics, and NSAIDs. A blood sample was taken at inclusion and at exit from the study to determine CRP and Pig-MAP levels. Of the 116 sows, included 54.3% recovered, and 3.4% had to be euthanised. The mean CRP levels at inclusion were 240.5 µg/mL in the recovery group and 327.4 µg/mL in the non-recovery group. The Pig-MAP levels were 2.03 mg/mL and 2.29 mg/mL in the recovery and non-recovery groups, respectively. The logistic regression revealed that the odds of recovery were not significantly affected by clinical signs or acute phase protein levels. In conclusion, neither clinical signs nor CRP and Pig-MAP levels could be used to predict recovery in lame gestating sows.