Abstract Movement and mixing of nursery pigs are common management practices used to manage body weight variation and provide targeted care to compromised pigs. However, regrouping may influence pathogen exposure, and overall performance. The objective of this study was to evaluate the impact of nursery pig movement and mixing strategies on growth performance, health indicators, and mortality within two distinct commercial nursery barn environments. A total of 4,736 pigs (DNA L600 x L241) weaned at approximately 21 days of age were enrolled across two nursery barns differing in structural design. Trial 1 was conducted in an older-style barn consisting of 16 rooms (n = 2,208), and Trial 2 was conducted in a newer-style barn consisting of 8 rooms (n = 2,528). Within each barn, rooms were randomly assigned to one of three movement-management treatments. Treatment 1 distributed pigs across all pens (one pen designated for smalls) without any relocation throughout the study period. Treatment 2 applied a pull protocol in which pigs identified as compromised were moved to a recovery pen through Day 28 and remained there for the remainder of the trial. Treatment 3 used the same pull protocol through Day 28, after which a subset of pigs in the recovery pen were reassigned to general population pens beginning on Day 29. Pigs were individually identified and weighed at placement, Day 28, and Day 42. Pen level oral fluids for Rotavirus A, B and C we collected at the same timepoints. Mortality and pig movement events were recorded throughout. In Trial 1, body weight did not differ at Day 28, but by Day 42 pigs in treatment 1 were heavier (23.50 ± 0.012 kg) than pigs in treatment 2 (22.86 ± 0.011 kg) and treatment 3 (22.86 ± 0.012 kg; P 0.001). From Day 28 to Day 42, Treatment 1 also had greater ADG than Treatment 2 and 3 (P 0.0001). Mortality did not differ among treatments (P = 0.28), however there was a trend for treatment 3 to have lower Ct values (stronger) at 42 days than treatment 1 for Rotavirus C (P 0.1) and lower for Rotavirus B than treatment 2 (P 0.1). In Trial 2, at Day 42, treatment 1 (20.91 ± 0.010 kg) and treatment 2 (21.09 ± 0.012 kg) were heavier than pigs in treatment 3 (19.91 ± 0.010 kg; P 0.001). From Day 28 to Day 42, ADG was greater in Treatments 1 and 2 compared with Treatment 3 (P 0.001). Mortality did not differ among treatments (P = 0.16). These results indicate that while pulling compromised pigs for recovery did not negatively affect outcomes, returning recovery pigs to general population pens was associated with reduced performance in both trials.
McNeil et al. (Wed,) studied this question.