DDT residues in beef cows fed apple pomace.

D RIED apple pomace and apple pomace silage have been fed successfully to ruminants (Hills, 1902; Lindsey et al., 1921; Walton and Bidwell, 1923; Holdaway, 1925; Atkeson and Anderson, 1927; Knott et al., 1932; Perkins and Monroe, 1935). I t has replaced all of the roughage normally used for wintering beef cows (Burris and Priode, 1957). However, in the past, apple pomace has contained up to 40 parts per million (ppm) residues of DDT [1, 1, 1-trichloro-2, 2-bis (p-chlorophenyl) ethane] which accumulated (75.7 ppm) in omental fat of beef steers (Bovard et al., 1961). Currently the U. S. Food and Drug Administration tolerance of DDT residues is 7.0 ppm in animal fat and, therefore, apple pomace is not being used as a feed source. Recently, many apple producers have been using little or no DDT in their pest control programs. Pomace, from the same processors who supplied Bovard et al. (1961) in 1959, contained 1.2 ppm in 1965 and 0.6 ppm in 1966 as analyzed for this present study. If this trend continues, increased use of apple pomace as a practical cattle feed could result. This study was conducted to determine if the current level of DDT residues in apple pomace is low enough to alleviate the residue problem in cattle and, if not, at what levels apple pomace may be fed to wintering pregnant beef cows without causing a build-up of tissue residues above the legal tolerance level in either the cows or their calves.