| A cohort study using RFID system with automatic sorting scales to monitor weights of swine finishers was conducted. Weight data from 2,057 barn-raised pigs were monitored to assess tag retention, frequency of scale visits, data capture, and outlier detection. Results showed tag loss rate highest around 12th and 13th week of finishing; crowded pens more likely to lose tags; and pen-averaged daily scale visits ranged from 2.45-2.74 visits. Using a system that removes outliers and inaccurate weights, weight data from 100 randomly selected swine finishers in four time-points were evaluated. Sample pigs were bled monthly for three months, tested for PRRS virus infection using ELISA and RT-PCR, and grouped based on test results. Repeated measures analysis revealed significant interaction between group and time (P=0.014). The group (2 head) with the largest mean final weight (224.38 +/- 14.79) was negative in both tests while the group (28 head) with the lowest mean final weight 207.56 +/- 4.29 was positive in either test for three time-points. |
