The Sow Body Condition Caliper

Abstract. Sows throughout the world are commonly fed to a subjective body condition target. Therefore, the objective of the study was to develop a fast and accurate, objective tool to measure sow body condition. A prototype caliper was developed to quantify the angularity from the spinous process to the transverse process of a sow’s back. The sow caliper technology is based on the premise that as a sow loses weight, fat and muscle her back becomes more angular. The arms of the caliper were 3.8 cm tall and could be adjusted to 16.5, 21.6, 26.7, or 31.8 cm wide. Landrace × Large White gilts and multiparous sows (n = 315) were utilized to associate the caliper with weight, backfat, muscling, and visual body condition at commercial sow farms in eastern North Carolina. The caliper was evaluated at locations on the sow’s back: behind the shoulder, middle of the back, and at the last rib. Sow weight was estimated and parity recorded. Backfat (BF) and loin depth (LD) were measured using an Aloka 500V SSD ultrasound machine. Visual body condition (BCS) was scored using a scale of 1 (thin) to 5 (over conditioned). Weight, BF, LD, and BCS explained 51% to 71% of the variation in caliper measures. Results suggest the optimal sow caliper width was 26.7 cm and measurements should be taken at the last rib. The sow body condition caliper is an objective tool that can be used by farmers to standardize sow body condition.