Animal Science, Department of
First Advisor
Ty B. Schmidt
Date of this Version
5-2-2024
Document Type
Article
Citation
A thesis presented to the faculty the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Animal Science
Under the Supervision of Professor Ty B. Schmidt
Lincoln, Nebraska, May 2024
Abstract
This study aimed to evaluate the changes in activity of group-housed, newly weaned pigs challenged with lipopolysaccharide (LPS). At weaning, pigs (n = 192, 5.73 ± 1.8 kg) were stratified by sex, litter, and body weight (BW) and randomly assigned to one of three treatments (16 pigs/pen, 4 pens/treatment): 1) Saline-injected (SAL), 2) 50% challenged [50%-LPS) – only half of the pigs in a pen (8 pigs) were challenged with LPS and 3) 100% challenged (100%-LPS) – all pigs in a pen were challenged with LPS. Pigs in the SAL and 32 in the 50%-LPS treatment received a 3.0 mL subcutaneous saline injection. The remaining pigs in the 50%-LPS treatment and all in the 100%-LPS treatment received a 3.0 mL subcutaneous LPS (Escherchia coli O111:B4) injection to challenge each pig with 300 µg/kg of BW. Pigs were monitored for the 42 days of the nursery period via the NUtrack system. Active behaviors included meters walked/day (m/d), percentage of time spent at the feeder, and standing (% of day) and were analyzed using the PROC GLIMMIX procedure of SAS. When main effects or interactions were significant (P ≤ 0.05), specific comparisons were made using the PDIFF option. Activity changes were observed (P ≤ 0.03) in both LPS treatments 3-4 days after the challenge. During this period, 50%-LPS and 100%-LPS pigs walked less (P ≤ 0.001) and spent less (P ≤ 0.002) time standing and less (P ≤ 0.03) time at the feeder compared to SAL pigs. Activities were similar (P ≥ 0.07) on d5 between the three treatments and remained similar (P ≥ 0.38) until 9 d after the challenge. On d11-15, there was an increase (P ≤ 0.03) in meters walked/day and time spent standing for 100%-LPS pigs compared to the SAL pigs. Furthermore, on d10-15, 50%-LPS and 100%-LPS pigs spent more (P ≤ 0.05) time at the feeder when compared to the SAL pigs. However, increased time at the feeder from d 9-15 for 100%-LPS pig s did not offset the impact of the challenge on BW. On d42, 100%-LPS pigs had reduced (P ≤ 0.04) BW and ADG compared to SAL pigs. Results suggest that changes in activities following an LPS challenge are not limited to the days immediately following the challenge.
Advisor: Ty B. Schmidt
Comments
Copyright 2024, Aaron Holliday. Used by permission