Sixty market hogs originating from one producer and finished in a concrete and steel facility were divided into two groups of 30 and housed for approximately 60 h on either straw (control group) or pentachlorophenol (PCP) treated wood shavings (test group). Feed, straw, and shavings were analyzed for PCP residues. Both feed and straw yielded nondetectable levels of PCP residues, while shavings ranged from 0.03 to 12.0 ppm.
The hogs were shipped to slaughter without bedding, and liver, fat and muscle (muscle from the test group only) samples were collected postmortem. The mean level of PCP residue in control (straw) hog livers was 0.037 ppm, while that of livers of hogs bedded with contaminated shavings was 0.342 ppm, a highly significant difference. The t-value using Welch's approximation equalled 9.77 using 28.5 degrees of freedom, indicating the mean PCP residue level was higher for the treated than the control group at a 0.01% level of significance.