LAUSR

Vitamin B12, sodium salicylate, and electrolyte treatments are commonly used to modulate pathogen induced fevers and aid in appetite stimulation. Therefore, the objective of this study was to determine the extent to which a B12 and sodium salicylate or an isotonic electrolyte treatment could improve growth performance and feed intake, and reduce the febrile response in porcine reproductive and respiratory syndrome (PRRS) virus inoculated pigs. A total of 32 PRRS-naïve gilts (7.7 ±1.5 kg BW; PIC Camborough x PIC 337) were selected and randomly assigned to individual pens across four treatments (n = 8/trt): 1) Control, PRRS-naïve, 2) PRRS virus infected, 3) As #2 plus B12 and sodium salicylate supplementation, and 4) As #2 plus isotonic electrolyte supplementation. On days post inoculation (dpi) 0, pigs were inoculated with PRRS virus. B12 was administered weekly, sodium salicylate and the electrolyte solution were given orally daily in the water or fed daily from dpi 4-18. Body temperatures and feed intakes were measured daily, and body weights, G:F, and PRRS serology assessed weekly for 21 dpi. Over the 21 day test period, irrespective of treatment, PRRS virus infection resulted in a significant increase in PRRS viremia and antibody titers compared to the control (P < 0.05). Compared to treatment #2, B12 + sodium salicylate and electrolyte treatments did not have differing body temperatures, ADG, ADFI or G:F. However, PRRS infection resulted in a significant increase in average body temperature compared to the control (39.8 vs. 39.3 oC, respectively, P = 0.021). Compared to the control, PRRS infection reduced overall ADG by 83% (0.54 verses 0.09 g/d, P < 0.001), end BW by 9 kg (P < 0.001) and ADFI by 11% (P < 0.001) compared to the control. Although treatment did not improve pig performance in the face of PRRS, mortality rates were significantly (P < 0.050) reduced compared to the PRRS only treatment.