Figure 1.

Regression tree analysis used to estimate cut-off values for birth and weaning BW to identify slow growing pigs within a batch. Model included the days to target slaughter weight (DTSW; i.e., 110 kg of BW) as the outcome variable, and birth body weight and weaning body weight as predictor variables. Pigs with body weight lower than 3.7 kg of BW at weaning (i.e., 28 days of age) would be considered slow growing pigs. Regression tree analysis was performed using the rpart package [26] of R v3.5.2 [27].