ESTIMATING INDIVIDUAL BODY WEIGHTS OF GROUP-HOUSED GROWING-FINISHING PIGS USING A FORELEGS WEIGHING SYSTEM

In two experiments, a method to estimate the individual body weight of group-housed growing-finishing pigs using a forelegs weighing system was developed. In Exp. 1, the forelegs weight of 12 crossbred pigs (si x gilts and six barrows, from 52.8 +/- 1.3 to 106.5 +/- 1.0 kg) was me asured up to 5000 times (20 measurements per second) during every meal at a feeding station using a balance. From these measurements, one fo relegs weight per meal was calculated using a mathematical method. In Exp. 2, 24 crossbred pigs were used to develop (trial 1, six gilts and six barrows, from 34.0 +/- 0.9 to 110.1 +/- 1.6 kg) and validate (tri al 2, six gilts and six barrows, from 31.8 +/- 0.4 to 106.1 +/- 0.6 kg ) a regression equation for prediction of the individual body weight u sing the calculated forelegs weight of the pig. Results in Exp. 1 show ed that the duration of a meal had to be at least 2 min to obtain a ca lculated forelegs weight of one pig within a day with a standard devia tion (SD) less than 1 kg. In Exp. 2, the equation used to estimate ind ividual body weight (BW) from the forelegs weight (FW) was: BW = 1.761 x FW. Using the equation the deviation of the estimated body weight w as less than 5% of the measured body weight on 95 +/- 2.2% of the weig hing days for 11 of the 12 pigs. It was concluded that a forelegs weig hing system is a suitable method to estimate the individual body weigh t of growing-finishing pigs housed in groups.