Description of on-farm treatment compliance and risk factors for culling in sows

Abstract

Background: In commercial pig farming, sick or injured sows are often treated by producers or hired staff. To date, limited quantitative data exists on treatment compliance and the possible effect on sow longevity post-treatment. The objective of the study was to quantify on-farm compliance of treatment selection, frequency, and dosage, as well as to investigate the association between body condition scores (BCS) and other sow-level factors on post-treatment cull risk.

Results: On-farm treatment records, including culling reason or reason of death up to 6 months post-treatment, production records and sow characteristics were obtained for 134 sows over an 8-week period. Treatment compliance was based on the accuracy of recorded treatments compared to the herd veterinarian's established treatment guidelines. Univariable and multivariable logistic regression models including treatment reason, treatment compliance, BCS, parity, production stage and production metrics, were constructed to investigate associations between those variables and sow culling or death. This study found low compliance for on-farm sow treatment protocols, with only 22.4% (30/134) of the sows receiving correct and complete treatment during the duration of the study. No effect of individual treatment components (drug, dosage, or frequency) on sow culling was observed. A trend for an interaction between treatment compliance and BCS was found, and parity and number of piglets born alive were identified as predictors for sow maintenance in the herd.

Conclusions: On-farm sow treatment compliance was low, resulting in that approximately 80% of the enrolled sows were not treated according to existing guidelines. Non-compliance of treatment guidelines did not seem to affect the risk of culling in treated sows but may have prolonged any associated pain, recovery time and negatively impacted the sow welfare during that time period.

Keywords: Antimicrobial resistance; Body condition score; Drug compliance; Sow treatments.

Fig. 1

Causal diagram showing the outcome of interest (sows being culled or remaining in the herd, binary) and all predictor variables. Arrows point to possible associations. Predictors of interest: parity (continuous); condition (reason the animal was being treated, categorical); body condition score (categorical); production metrics (number of piglets born alive, number of piglets weaned, both continuous); compliance drug/ compliance dose/ compliance frequency/ overall compliance treatment (constructed by comparing reported use to veterinarian-recommended use, binary); and production stage (categorical). Treatment is listed to represent the decision to treat, which was an inclusion criteria for animals enrolled in the study

Fig. 2

Distribution of study culled sow by condition and days after treatment. Distribution of culled sows treated for either lameness (N = 35), mastitis (N = 13), reproductive disorder (N = 19) or any other illness (N = 6) (A), and the distribution of clinically diagnosed lame cull sows (N = 69) and their respective lameness score (low: score 1; intermediate: score 2 or, severe: score 3, Feet First 4-point system, Zinpro) by removal time frame in days after the first treatment day (B)

Fig. 3

Interaction plot showing the relationship between treatment compliance and culling probability. Predictive margins with 95% CIs of sows (N = 111) overall compliant (correct drug, correct drug dose and correct frequency of treatment) or non-compliant treatment (either incorrect drug, dose, or frequency) with ideal or non-ideal body condition scores (BCS), (BCS = 2; N = 83) and (BCS = 1 or BCS = 3; N = 28) respectively, plotted over the numbers of piglets born alive in sow’s past reproductive cycle