419 Comparative analyses of caliper models for body condition assessment in reproductive females across physiological stages.

Abstract The objective of this study was to compare the performance of five caliper versions in assessing body condition scores across distinct reproductive stages of gilts and sows. A total of 572 PIC Camborough sows were utilized, including 98 gilts due to farrow, 151 sows due to farrow, 173 sows at pregnancy checking, and 150 weaned sows. Five caliper versions were evaluated on each individual sows: Caliper 1: Knauer (V30), metal, no handlebar (weight: 275 g); Caliper 2: Knauer (V31), metal, no handlebar (weight: 360 g); Caliper 3: Alternative (Alt-M), metal, no handlebar (weight: 255 g); Caliper 4: Knauer (V20), metal, with handlebar (weight: 433 g), and Caliper 5: Alternative (Alt-P), plastic, no handlebar (weight: 46 g). All calipers were marked with caliper units, classifying sows with a score of 10 to 13 as under-conditioned and those with a score of 13 to 16 as ideal-conditioned according to PIC Nutrition and Feeding Guidelines. Measurements were conducted blindly by two operators using a cross-over design: each operator independently scored the same group of sows per caliper version without prior knowledge of the other’s results. Data were analyzed using linear mixed models with caliper version, operator, and reproductive stage as fixed effects, and interactions included if statistically significant. Caliper scores differed (P < 0.05) across reproductive stages: sows due to farrow (15.3) and gilts due to farrow (15.0) exhibited higher scores than sows at pregnancy checking (14.7), all of which had a greater score than weaned sows (12.6). Sow due to farrow had a greater score than gilts due to farrow (P < 0.05). No operator effect was observed (14.4 vs. 14.4; P > 0.10). No interaction between operator and reproductive stage was observed. Caliper scores did not differ among Calipers 1, 2, and 3 (14.6, 14.5, 14.7; P > 0.10), but all three had a greater caliper score than Caliper 4 (13.8; P < 0.05). Caliper 5 yielded the lowest scores (13.4; P < 0.05 vs. others) on average. In summary, caliper design (presence of a handlebar) and material composition (metal vs. plastic) significantly influenced body condition scoring outcomes using calipers