Effects of pigs per feeder hole and group size on feed intake onset, growth performance, and ear and tail lesions in nursery pigs with consistent space allowance

Objective: To determine the effects of varying the number of pigs per feeder hole and group size on feed intake onset, growth performance, and lesions in nursery pigs. Materials and methods: A total of 630 pigs were randomly assigned at weaning (mean [SD] age of 20.5 [0.9] d and weight of 5.59 [0.9] kg) to one of four treatments: 3.75, 5.00, 6.25, or 7.50 pigs per feeder hole, which was achieved by altering group size with 15, 20, 25, or 30 pigs per pen, respectively. Pigs were fed a meal diet containing 1% iron oxide dye for three days post-weaning. Rectal swabs were evaluated to assess the onset of feed intake. Pigs were weighed weekly and presence of ear and tail lesions were recorded. Results: Decreasing the number of pigs per feeder hole resulted in a decrease in onset of feed intake (P < .001). Average daily gain tended to increase linearly as the number of pigs per feeder hole decreased (P = .06). No statistically significant responses were observed for average daily feed intake and feed efficiency (P > .12). The lowest occurrence of tail lesions (P < .05) was observed in the treatment with 3.75 pigs per feeder hole. The highest incidence (P < .05) of ear lesions occurred in the treatment containing 7.50 pigs per feeder hole. Implications: Decreasing the number of pigs per feeder hole in the nursery period may result in faster onset of feed intake, improved growth performance, and reduced ear and tail lesions.