The prevalence of lameness in group-housed gestating sows can be high. Lameness is often associated with reduced sow welfare and longevity and 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. Research has shown that acute phase proteins are associated with the prognosis of recovery from lameness in cows and humans. These Danish researchers wanted to identify clinical information that could have the potential to inform the prognosis for recovery in lame sows. Understanding the most likely outcome could help in deciding which sows should undergo treatment and which sows should be shipped (if eligible for transport) or humanely euthanized. The researchers investigated whether a certain measure of CRP and Pig-MAP, combined with clinical signs, could be used prognostically to predict recovery of lameness in gestating sows. This study utilized a longitudinal study design with sows from three conventional herds. Sows were not enrolled in the study if they were in the immediate post mixing period given that traumatic lameness from fighting was more evident. Lame sows with claw lesions were not included in the study as the researchers felt that claw lesions were predominantly preventable and the cause of lameness was more easily diagnosed with certainty (you can see the problem). The sows were included if moderately to critically lame, were all treated for lameness and followed for levels of lameness up to 28 days after enrollment. The treatment consisted of movement to a hospital pen, antibiotics, and Nonsteroidal Anti-inflammatory Drugs (NSAIDs). Causes of lameness could be infectious or structural or both. All sows were treated in the same way as it was decided that understanding the exact cause of lameness was difficult. Interestingly the researchers commented that , based on previous studies, it was very difficult to identify the exact cause of lameness in individual sows based on clinical signs alone and based on follow up post mortem many sows actually have more than one cause of lameness at the same time.
They also found that even trained health professionals agreed only 50 % of the time on the causes of lameness.
The researchers found the following:
- There were 54.3% of sows that recovered from lameness
- There were 3.4% of sows that had to be euthanized
- The mean CRP levels at inclusion were 240.5 µg/mL in the group that were able to recover and 327.4 µg/mL in the non-recovery group.
- The mean Pig-MAP levels at inclusion were 2.03 mg/mL in the group that were able to recover and 2.29 mg/mL in the non-recovery group
- Interestingly moderately and severely affected sows at enrollment had similar recovery rates.
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