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

Comments

Copyright 2024, Aaron Holliday. Used by permission

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

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