A feeding experiment was conducted to study the metabolism and excretion of Gardona [2-chloro-1-(2,4,5-trichlorophenyl)vinyl dimethyl phosphate] insecticide in the dairy cow. At an insecticide level of 5 ppm in the daily ration, no residues of Gardona were found in milk or urine. A metabolite was found in hydrolyzed urine with a retention time identical to 1-(2,4,5-trichlorophenyl)ethanol. It corresponded to about 75.7x of the total Gardona fed.In the presence of beef liver 10,000 X g supernate, Gardona completely disappeared with production of a metabolite again with the retention time of 1-(2,4,5-trichlorophenyl)ethanol. About 0.6% of the total dose was found as the intact compound in feces. 2,4,5-Trichloroacetophenone, a possible metabolite of Gardona, was not detected in milk, urine, or feces. Gardona was stable when incubated with rumen fluid.ardona [2-chloro-l-(2,4,5-trichlorophenyl)vinyl dimethyl phosphate] is an insecticide of the Shell G Chemical Co. which effectively controls corn earworm, fall armyworm, codling moth, gypsy moth, houseflies, and arthopod parasites of poultry. The metabolism of Gardona has been studied in the dog and rat (Akintonwa and Hutson, 1967). Residues of the insecticide have been studied in tissues and eggs of chickens when the compound was used in chicken houses (Ivey et al., 1969). Residues of Gardona were determined in tissues of sprayed cattle (Ivey et al., 1968). Degradation of the compound in plants and soils has also been investigated (Beynon and Wright, 1969). This paper reports the results of a feeding study with the insecticide in a lactating dairy cow. EXPERIMENTAL A Holstein cow weighing 705 kg and with an average daily milk production of about 19.8 kg (3.7% butterfat) was catheterized and fed Gardona at the 5-ppm level (based on a daily ration of 22.7 kg) for 4 days. The pure compound in acetone was thoroughly mixed with the evening grain. Morning and evening subsamples of the total mixed milk were taken 1 day prior to feeding (control sample), daily throughout the feeding period, and for 6 days thereafter. The total daily urine and manure samples were similarly collected, weighed, mixed, and subsampled during the same test period. The manure samples were collected in specially constructed trays. All samples were immediately frozen prior to analysis.
IN VITRO STUDIESRumen Fluid. The stability of Gardona in the presence of fresh rumen fluid was studied. One milliliter of a solution of Gardona in acetone (500 pg per ml) was thoroughly mixed with 100 ml of fresh filtered rumen fluid and held at 38" C. At measured intervals 5 ml of fluid were removed and 5 ml of acetone were added. The mixture was filtered and the filter was rinsed with acetone to a total volume of 25 ml. One milliliter of the acetone filtrate was partitioned with 5 ml of hexane and 44 ml of 2 z sodium sulfate solution. A portion of the upper hexane layer (10 pl) was analyzed for Gardona by electron affinity gas chromatography.Liver. Possible metabolism of Gardona was studied in the presence of the 10,0...
