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Labor requirements and repeatability of sow body condition measures
The objective of the study was to estimate the labor requirements and repeatability of common sow body condition measures. Two technicians each evaluated crossbred sows (n=25) twice for body condition score (BCS), sow caliper score and backfat (BF). Sows were housed in individual gestation stalls. Visual BCS was scored from the rear of the sow by palpating the spinous process. A scale of 2 (thin) to 4 (over conditioned) was used. The sow caliper was used to measure the angularity from the spinous process to the transverse process at the last rib. An angle of <125° was classified as score of 2 (thin), 125 to 132.5° was a 3 (ideal) and >132.5° was categorized as a 4 (over conditioned). Backfat was measured 6 cm from the spinous process at the last rib using a Renco Lean-Meater® A-mode ultrasound machine. Time required to measure all 25 sows was captured for each body condition trait and replicate. Data were analyzed in SAS. The PROC GLM procedure was used to estimate labor requirements on a per sow basis. Fixed effects included body condition measure, technician and replicate. The PROC CORR procedure was used to calculate the repeatability within and between technicians. Measuring sow body condition using the caliper and BCS required less (P<0.01) labor than BF (5.5 and 4.9 vs. 14.2 s per sow, respectively). Yet labor required to measure sows did not differ (P>0.05) between technicians or replicates. Repeatability for BCS, the sow caliper and BF was 0.82, 1.00 and 0.89, respectively, for Technician A and 0.90, 0.89 and 0.93, respectively for Technician B. Between technicians, repeatability for BCS, the sow caliper and BF was 0.85, 0.97, and 0.96, respectively. In comparison with Technician A, Technician B had similar (P>0.05) mean values for BCS (3.60 vs. 3.74, respectively), the sow caliper (3.76 vs. 3.78, respectively) and BF (18.48 vs. 18.40 mm, respectively). Results suggest measuring BCS or sow caliper score requires less labor than evaluating BF and all three methods are highly repeatable.
Keywords: caliper, labor, repeatability