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The gas phase infrared spectra of monoisotopic H3Si35Cl and H3Si37Cl have been studied in the v6 region with a resolution of 0·05 and 0·04 cm-1, respectively. For both species about 1200 lines have been assigned to v6 and fitted by a least squares procedure, σ(J, K)=4 × 10-3 cm-1, sets of 9 molecular parameters being refined for each molecule. The hot bands (v3 + v6) - v3 and 2v6±2 - v+-1 as well as v6 of H329Si35Cl and H329Si37Cl have been detected, and information concerning the υ3=υ6=1 state of H328Si35Cl and H328Si37Cl and the υ6=1 state of the 29Si isotopic species has been obtained. Within the limits of the precision of the measurement the υ6=1 state, v0=664·1317(3)/663·7370(3) cm-1 (H328Si35/37Cl), is essentially unperturbed.

The effects of rose bengal, erythrosin B and fluorescein on ruminant digestion were evaluated by an in vitro rumen technique. Rose bengal reduced in vitro dry matter disappearance (IVDMD) values starting at .5 mM in the nutrient media and erythrosin B reduced IVDMD values starting at .05 mM in the nutrient media. Maximum reduction in IVDMD values was observed at 3.0 mM of rose bengal and erythrosin B. Fluorescein depressed digestion but not as severely as rose bengal or erythrosin B. Dry matter digestibility (DMD) values for steers given erythrosin B at a daily dosage of 6.5 mg/kg body weight were higher (P<.05) than DMD values for control steers. DMD values were higher for steers given 16.3 or 26.1 mg erythrosin B/kg body weight daily than for the control steers, but the differences were not significant. There were no significant differneces among animals given the different dosages in digestible energy. Recovery of erythrosin B from feces of treated steers varied with time, indicating that steers fed erythrosin B at a dosage of 6.5 mg/kg body weight might excrete feces during some periods of the day which would not control facefly development; however, administration of erythrosin B at a dosage of 16.3 mg/kg body weight would provide enough erythrosin B in feces to control face fly development throughout a 24-h period.

This study involved monitoring the depletion of DDT, DDD and DDE in the fat of eight steers (U.S.D.A. Good and Choice) that had been fed gin trash, for 216 days, contaminated with DDT and DDE. Perianal adipose tissue was obtained from each steer when they were changed to finishing diets that were not contaminated with DDT. Subsequent adipose tissue was obtained every 14 days for 56 days while steers were fed the finishing diets. The mean initial total DDT (DDT + DDD + DDE) level for the eight steers was 10.14 ppm (range 7.92 to 13.32 ppm) on a rendered fat basis. After 14, 28, 42 and 56 days the mean total DDT levels were 8.16, 6.41, 5.53 and 5.54 ppm, respectively. The additional reduction after 28 days was not significant (P>.05), whereas the 14- and 28-day values were (P<.01) different from each other and from the initial level. The addition of .5% choline chloride or .9 kg activated charcoal per head daily to the feed, singly or in combination, during the 56-day finishing phase did not (P>.05) influence DDT depletion.

Thirty-six bull calves representing the Angus, Barzona, Brahman, Hereford, Santa Gertrudis and Shorthorn breeds were used to investigate breed differences in utilization of three different rations varying in energy and roughage content. Digestible dry matter (DDM), digestible energy (DE) and energy digestion coefficient (EDC) values for Hereford bulls fed a high energy ration were higher (P<.05) than values for Brahman bulls. There were no significant differences for DDM, DE and EDC values among breeds fed the medium energy ration. DDM, DE and EDC values for Brahman bulls fed the low energy ration were higher (P<.05) than values for Hereford bulls. Hereford bulls exhibited higher (P<.05) nitrogen retention values than did Brahman bulls fed the high energy ration. There were no significant differences in nitrogen retention values among breeds fed medium and low energy rations. Brahman bulls fed the low energy ration excreted feces with a higher (P<.05) dry matter content than those of bulls of the other breeds. Comparisons of in vitrodry matter disappearance values using inoculum from the Hereford and Brahman breeds indicated that IVDMD values for inoculum from the Brahman were higher (P<.001) than values for inoculum from the Hereford, which supported the DDM values obtained in the digestion study.

The total edible portion of carcasses of two steers that had been fed cotton gin trash contaminated with DDT was broiled and the broiled ground beef, less fat drippings, was fed to rats for 120 days. There were no differences (P>.05) in carcass DDT residues of rats fed ground beef from steers that initially contained either 7.55 ppm of DDT (above FDA tolerance) or 4.25 ppm (within FDA tolerance) of DDT on a rendered fat basis. The addition of .5% choline chloride to ground beef diets did not alter (P>.05) total DDT residue in rat carcasses. There was a sex by treatment interaction (P<05) for rats fed the High diet (1.24 ppm DDT as fed) plus .5% choline chloride (High + CC), the Low diet (.45 ppm DDT as fed) plus p,p-DDT (Low + DDT) and the High diet plus p,p-DDT (High + DDT). In all three treatments, females retained more DDT residues than did males. Females fed the High + DDT diet and the High + CC diet retained more (P<05) total DDT than did rats in all other treatments.Two parameters were utilized to determine primary effect of DDT ingestion. They were mixed function oxidase (MFO) activity and the development of smooth endoplasmic reticulum (SER) in rat livers. MFO activity appeared to increase with ingestion of DDT in the all meat diets but was lower than MFO activity for rats fed the control diet. Electron microscopy examination of liver samples revealed no SER proliferation in livers of rats fed DDT when compared to livers from rats fed no DDT.