Search

Site characterization for subsurface contaminants is time-consuming and costly. The Tri-Service Site Characterization and Analysis Penetrometer System (SCAPS) has been developed to reduce the time and cost required for site characterization. Probes are designed to detect specific classes of contaminants such as petroleum products, explosive compounds, volatile organic compounds (VOC), and others. This article describes the Hydrosparge VOC sensor, an in situ VOC detection system that is capable of rapid subsurface site characterization of VOC contaminant distribution. The system consists of a direct push well for groundwater access, an in situ sparge module, and a direct-sampling ion-trap mass spectrometer. The results obtained with the SCAPS in situ technique indicate a strong linear relationship with EPA methods (r² = 0.84). SCAPS Hydrosparge VOC sensor has been demonstrated to reduce the time and cost required to characterize sites by directing the placement of a reduced number of conventional monitoring wells. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 89–96, 1998

Two experiments were conducted to evaluate different sources of supplemental phosphorus for growing-finishing beef steers. In the first experiment 30 Hereford weanling steer calves were placed on a phosphorus-deficient ration for 69 days, then allotted to treatment to test the availability of phosphorus from a chemical mixture of 87% mono- and 13% dicalcium phosphate, defluorinated phosphate, Mexican rock phosphate, sodium tripoly phosphate and a 1:1 mixture of defluorinated phosphate and sodium tripoly phosphate. In the second experiment 48 Hereford weanling steer calves were used to test the availability of phosphorus from a chemical mixture of 87% mono- and 13% dicalcium phosphate, Mexican rock phosphate, monosodium phosphate and two sources of defluorinated phosphate. In both experiments average daily gain, feed intake, final weight and serum inorganic phosphorus were significantly greater and serum calcium significantly lower for animals supplemented with all sources of phosphate than animals not supplemented. No significant differences were detected among phosphorus supplements for any of the parameters measuredi For most parameters measured in both experiments, the chemical mixture of 87% mono- and 13% dicalcium phosphate appeared to be the least satisfactory phosphorus supplement.

Fifty-six Holstein male calves were used in two experiments to determine the minimum toxic level of iron and the effect of high levels of dietary iron on performance and blood constituents. A ration compounded from natural feedstuffs and containing 100 ppm iron was used as the basal in both experiments. Ferric citrate was added to the basal ration to give the desired iron levels. In Experiment I the levels of iron were 100, 500, 1,000 and 2,000 ppm. Six individually fed calves received each of the four rations during a 70-day experimental period. Blood hemoglobin and serum iron were significantly increased at the high dietary levels of iron. Serum inorganic phosphorus was significantly depressed as dietary iron increased. No significant difference was found between treatments in weight gain, feed intake and feed conversion or in serum calcium, magnesium, alkaline phosphatase activity, copper and zinc. In Experiment II, the levels of iron were 100, 1,000, 2,500 and 4,000 ppm. Eight calves were individually fed each of the four rations for 98 days. No significant difference was found in serum calcium, magnesium, copper, or zinc. Significant depressions in weight gain, feed intake, and serum inorganic phosphorus were noted with increasing dietary iron. Feed necessary per pound of gain, blood hemoglobin, and serum iron were found to be increased with increasing dietary iron. The maximum level of dietary iron which the calf may consume without marked depression in feed intake and body weight gain appears to be approximately 2,000 ppm.

Two experiments utilizing 104 Hereford steers were conducted to study the influence of low levels of roughages and roughage substitutes on performance, carcass characteristics, rumen environment, rumen parakeratosis and liver abscesses of steers fed high energy rations. The treatments were: basal all-concentrate ration; basal plus 1.36 kg. hay per head daily; basal containing 5% cottonseed hulls; or 5% ground corn cobs; or 2% oyster shells, or 4% oyster shells; or 2% sand; or 5% ground polyethylene. Eighty steers were group fed in Experiment I and 24 steers were individually fed in Experiment II.The addition of low levels of roughages and roughage substitutes to the basal ration did not significantly increase body weight gains in Experiment I. In Experiment II, the addition of cottonseed hulls to the basal ration significantly increased gains (P<.05) over the basal and basal plus 2% or 4% oyster shell rations. Steers on the basal, basal plus hay and basal plus cob treatments yielded carcasses with larger ribeyes, thinner rinds and improved cutability scores, while carcass grades and marbling scores were not significantly different from the other treatments.The basal plus hay was the only treatment which gave any appreciable protection against rumen parakeratosis and liver abscesses. Total volatile fatty acids was highest and pH lowest on the basal and basal plus 2% oyster shell treatments in Experiment I.These two treatments also elicited severe rumen parakeratosis and a high incidence of liver abscesses. Rumen pH was highest on the basal plus hay treatment in both experiments. Lactic acid concentrations and molar percentages of VFA's could not be related to incidence of rumen parakeratosis and liver lesions in these experiments.

There remains little doubt that beef cattle may be finished successfully on all-concentrate rations. Bodyweight gains comparable to those on conventional rations can be obtained. It logically follows that dressing percentage will be somewhat improved due to lack of “wastiness” in cattle receiving rations which are not bulky. Finished weights are reduced about 20 kg. by this system of feeding. Compared to cattle on more conventional feeding systems, the quantity of feed necessary per unit of gain is decreased by the use of high energy feeds and the attendant feed mixing and handling is reduced accordingly. The system also lends itself to mechanical handling of feed as well as taking advantage of the highly mechanized production of grains and the present low cost of nutrients from grains compared to roughages when these items must be purchased and transported.On the other hand, it must be recognized that we do not really know why the animal fed an all-concentrate ration will limit its feed intake to an energy level comparable to that on a conventional ration or what can be done to increase consumption to take advantage of the “extra space” in the rumen resulting from the removal of roughage.It seems logical and important to keep feed before the animals at all times with facilities that are conducive to frequent eating to minimize problems of bloat and founder. Best methods of getting animals on full feed and keeping them eating at optimum levels have not been fully investigated; however, a gradual change from a high roughage ration appears preferable to an abrupt change.The last word has not been said regarding the use of buffers. Trace mineral and vitamin fortification as influenced by removal of roughage needs further investigation. Although liver abscesses may be prevented by low-level continuous feeding of a broad spectrum antibiotic, no product other than roughage has yet been discovered which will prevent rumen parakeratosis. Depending on the nature of the roughage it appears that about 10 to 15% is necessary to maintain a healthy rumen epithelium. More attention to feeding and management details is necessary with allconcentrate feeding programs and should be attempted only by those producers who are able and willing to give this attention.In conclusion, it appears that all-concentrate feeding has many features which are attractive to cattle feeders but there are still many attendant problemsto be solved. Given time and research effort these problems will no doubt be solved and all-concentrate feeding of beef cattle will take its place along with other cattle feeding systems with economic factors determining the extent of its use.

Two experiments involving four trials were conducted over a 2-year period to determine the influence of added roughages in various physical forms and chlortetracycline on performance, rumen characteristics and liver abscesses of steers fed a ration based largely on ground shelled corn. A 2×4 factorial arrangement of treatments was used to compare the basal all-concentrate ration with rations containing limited roughage (ground rice hulls, whole rice hulls, and long hay) fed with and without chlortetracycline. Feedlot performance and carcass data were not significantly influenced by roughage or antibiotic treatment.Steers fed long hay had a significantly higher percent of rumen acetic acid with a correspondingly lower percent of propionic acid than steers fed other feeding treatments. Adding fiber in the form of ground rice hulls and hay resulted in significantly (P<.05) higher percentages of butyric acid (Experiment I) when compared to the basal ration. Altering the physical form of the rice hulls or antibiotic treatment had no consistent effect on rumen VFAs. Rumen fluid of steers fed hay had considerable higher pH values than steers fed no hay. Ruminal pH of steers fed either the basal or rice hull rations was similar.Severe rumen parakeratosis was observed in steers fed no roughage or ground roughage. Coarse roughage in limited amounts (either 5% whole rice hulls or 1.36 kg. long hay) significantly improved health of the rumen epithelium. Steers fed the basal or basal plus ground rice hulls exhibited severe clumping and sloughing of papillae with considerable hair accumulation in the rumen mucosa. Chlortetracycline appeared to be ineffective in improving health of the rumen epithelium.Twenty-three of 128 steers involved in this study had abscessed livers. Sixteen of the 23 were found in steers fed the basal or ground rice hull rations. Five of the abscessed livers were found in steers fed whole rice hulls and two in steers fed hay. A marked reduction in abscessed livers was achieved by the inclusion of 75 to 85 mg. of chlortetracycline per head daily (33 vs.3%).

Sixty-four Holstein male calves were used in two experiments to study the effect of nitrite and hydroxylamine on the performance and vitamin A and carotene metabolism of ruminants.The results of the combined analysis of Experiments I and II indicated that the levels of hydroxylamine (2.2 gm. and 4.4 gm./100 kg. body weight) fed in the experiments lowered feed intake and weight gain. The feeding of potassium nitrite had no effect on performance. The 4.4 gm. level of hydroxylamine also resulted in lower hemoglobin and higher methemoglobin levels. Neither level of hydroxylamine or potassium nitrite had any effect on the vitamin A status of the calves as measured by serum vitamin A, serum carotene and liver vitamin A levels. There was no indication of an interaction between nitrate reduction products and vitamin A.Experiments III and IV were conducted to determine if nitrate or nitrate reduction products accelerate the destruction of vitamin A or carotene when incubated with rumen fluid in vitro. Vitamin A and carotene destruction was no more rapid in the incubation flasks containing rumen fluid from nitrate and nitrite-fed steers (17.6 gm. and 4.4 gm. per kg. bodyweight, respectively) than in those containing fluid from control steers. The addition of hydroxylamine to incubation flasks did not significantly accelerate vitamin A or carotene destruction.The results of these investigations indicate that the nitrate reduction products, NH2OH and KNO2do not interfere with vitamin A and carotene metabolism of ruminants.