Mean ± SD of serum concentrations of Hp-MMP 9, total Hp, SA A and serum AGP in peripheral blood of Jersey calves after an intravenous bolus dose of E. coli LPS (O111:B4; 2.5 ug/Kg solubilized in autologous serum). Concentrations of serum Hp-MMP 9 (B) is several orders of magnitude lower than total haptoglobin (Hp) (A) and far lower than SAA (C) or AGP (D). Serum concentrations of Hp-MMP 9 are in ng/mL. Serum concentrations of Hp, SAA and AGP were converted to ng/mL for comparison to Hp-MMP 9 and as shown, the serum concentrations are reported as logarithm (base 10). Significant increases in serum Hp were detected at 12 hours post-LPS challenge in comparison to pre-LPS time points (-24 hour time points; p < 0.0006) and remained significant through the 96 hour sampling time (p < 0.0087 compared to -24 hour time point). Serum Hp-MMP 9 complex concentrations appeared by 0.5 hrs and were significantly greater than baseline at 16 hour post-LPS challenge (p < 0.008 compared to -24 sample) and returned to baseline values after the 48 hour sampling time (72 hour; p = 0.1254 compared to -24 hour time point). Serum AGP increased to significantly greater than the -24 hour sampling point at 16 hours post-LPS challenge (p < 0.05) and remained significantly greater than baseline through the 96 hour post-LPS time point (p < 0.007). Serum amyloid A concentrations were significantly greater than baseline (-24 hour time point) by 8 hours post-LPS (p < 0.05) and remained greater than baseline through the 96 hour time point (p < 0.05, compared to -24 hour time point).