Adsorption of Atrazine and Alachlor to Aquifer Material and Soil

Atrazine [6-chloro-N-ethyl-N′-(1-methyl)-1,3,5 triazine-2,3-diamine] and alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide] are agricultural herbicides used in large quantities and, as a consequence, are common contaminants in groundwater and surface water. The retention of these herbicides in soils and their degradation in aqueous environments is highly dependent upon their adsorption to solid surfaces. The adsorption of atrazine and alachlor was investigated on three typical Kansas and underlying aquifers known to be vulnerable to contamination. More alachlor was adsorbed to the soils and sediments than atrazine. The adsorption coefficients for atrazine were 2 to 5 times higher for soils than for aquifer sediments. For alachlor, the adsorption coefficients were 4 to 20 times higher for soil than for aquifer solids. Both linear and Freundlich isotherms represented the adsorption data well in all cases. The slope of the Freundlich isotherms, 1/n, was close to one, with the exception of alachlor adsorption onto the Topeka aquifer sediment (1/n = 0.67). The K _d values found in these studies were comparable to the lower range of those reported in the literature.     

Anzahl Spermien pro Besamungsdosis und Nonreturnrate beim Rind (2. Mitteilung)

In einem Split-Sample- Versuch wurde die Beeinflussung der Nonreturnrate durch unterschiedliche Spermienzahlen untersucht. Der Samen von 25 Stieren kam in Pailletten zu 0,25 ml zum Einsatz, die rund 15 bzw. 20 × 10 ⁶ Spermien total enthielten. Insgesamt wurden 15 763 Erstbesamungen ausgeführt. Bei den Rindern war die mit der höheren Spermienzahl erzielte Nonreturnrate (75 Tage) um 2,96% besser, bei den Kuhen um 2,68%. Diese Unterschiede sind signifikant .     

Description and validation of an in situ autoperfusion method to determine nutrient absorption and metabolism in bovine small intestine

Holstein bull calves, 8 to 12 wk of age, were anesthetized with halothane gas. An approximate 20-cm section of small intestine, 60 to 90 cm proximal to the ileocecal junction was clamped to isolate blood circulation to a single set of arcuate vessels and to form an intestinal segment fitted for infusion and drainage. The vein was catheterized to allow total venous collection. Donor blood was transfused via jugular vein to replace venous drainage. This technique was evaluated in four calves by exposing the lumen to eight replications (12 or 20 min incubation, 30-min wash with 39 C saline) of 16 mM L-Met (14C-labeled). Time course appearance of Met in venous blood indicated similar rates and patterns of absorption for individual calves. There were no clinically significant alterations in jugular blood chemistry profiles across replications. Four calves were used to evaluate the effect of three isotonic perfusion media (saline, Krebs-Ringer bicarbonate and M-199 tissue culture media) on Lys and Met absorption. Venous flow rates and absorption of Lys were faster with Krebs buffer than with other media. Perfusate medium did not influence venous flow rates or absorption of Met. Effect of restricting venous flow on absorption of Lys and Met was evaluated in two calves. Flow was alternately controlled (6.5 ml/min) or allowed to flow freely (mean = 12.2 ml/min). Restricting flow decreased steady-state absorption. Light and scanning microscopy indicated maintenance of mucosal tissue integrity throughout 8 h of anesthesia. Results demonstrate validity of the in situ technique to study nutrient absorption in the young bovine.     

Comparison of three models to estimate breeding values for percentage of loin intramuscular fat in Duroc swine

Three selection models were evaluated to compare selection candidate rankings based on EBV and to evaluate subsequent effects of model-derived EBV on the selection differential and expected genetic response in the population. Data were collected from carcass- and ultrasound-derived estimates of loin i.m. fat percent (IMF) in a population of Duroc swine under selection to increase IMF. The models compared were Model 1, a two-trait animal model used in the selection experiment that included ultrasound IMF from all pigs scanned and carcass IMF from pigs slaughtered to estimate breeding values for both carcass (C1) and ultrasound IMF (U1); Model 2, a single-trait animal model that included ultrasound IMF values on all pigs scanned to estimate breeding values for ultrasound IMF (U2); and Model 3, a multiple-trait animal model including carcass IMF from slaughtered pigs and the first three principal components from a total of 10 image parameters averaged across four longitudinal ultrasound images to estimate breeding values for carcass IMF (C3). Rank correlations between breeding value estimates for U1 and C1, U1 and U2, and C1 and C3 were 0.95, 0.97, and 0.92, respectively. Other rank correlations were 0.86 or less. In the selection experiment, approximately the top 10% of boars and 50% of gilts were selected. Selection differentials for pigs in Generation 3 were greatest when ranking pigs based on C1, followed by U1, U2, and C3. In addition, selection differential and estimated response were evaluated when simulating selection of the top 1, 5, and 10% of sires and 50% of dams. Results of this analysis indicated the greatest selection differential was for selection based on C1. The greatest loss in selection differential was found for selection based on C3 when selecting the top 10 and 1% of boars and 50% of gilts. The loss in estimated response when selecting varying percentages of boars and the top 50% of gilts was greatest when selection was based on C3 (16.0 to 25.8%) and least for selection based on U1 (1.3 to 10.9%). Estimated genetic change from selection based on carcass IMF was greater than selection based on ultrasound IMF. Results show that selection based on a combination of ultrasonically predicted IMF and sib carcass IMF produced the greatest selection differentials and should lead to the greatest genetic change.     

Preliminary results on detection of maize treated with electrons for seed dressing and according decontamination and infestation

Saatgut und Getreide kann mit niederenergetischen Elektronen (<300 kev) oder=" hochenergetischen=" elektronen=" (1–10 mev)=" wirksam=" behandelt=" werden,=" um=" mikroorganismen=" und=" insekten=" abzutöten.=" in=" dieser=" vorläufigen=" studie=" wurde=" mais=" mit=" niederenergetischen=" (125 kev)=" und=" hochenergetischen=" elektronen=" (10 mev)=" behandelt.=" um=" diese=" elektronenbehandlung=" nachzuweisen,=" wurden=" verschiedene=" verfahren=" eingesetzt:=" photostimulierte=" lumineszenz=" (psl),=" thermolumineszenz=" (tl)=" und=" dna-kometentest.=" für=" diese=" drei=" nachweismethoden=" existieren=" bereits=" europäische=" normen=" und=" sie=" sind=" als=">Allgemeine Codex Methoden zum Nachweis bestrahlter Lebensmittel etabliert. Die Ergebnisse zeigen, dass PSL und TL geeignete Verfahren sind, um sowohl eine Behandlung von Mais mit niederenergetischen als auch mit hochenergetischen Elektronen zu erkennen. Der DNA-Kometentest erwies sich als weniger geeignet: die Behandlung mit niederenergetischen Elektronen konnte—wie erwartet—nicht nachgewiesen werden. Die Behandlung mit hochenergetischen Elektronen konnte bei einer Maissorte erkannt werden, jedoch nicht bei einer anderen Sorte.     

Development of a computerized systems model for health management decision support in growing hogs

A study was designed to provide decision support for health management in growing hogs. A dynamic, stochastic systems model for a confinement, continuous production hog growing enterprise (including nursery, grower and finisher phases) was developed to simulate the economic effects of disease, available floor space and feed additives using farm- specific data. Modeling techniques included: discrete and distributed (continuous) delays; triangular probability density functions; autocorrelation; table look-up functions; an alpha-beta tracker; non-linear, constrained optimization. The model was designed to be initialized with the system's current status, using an accompanying production/financial database to achieve individual-farm specificity. Initialization of rate variables required ‘reverse optimization’ of historical system performance. Model predictions are based on an adjustment approach, where changes in current performance are dictated by changes in disease rates, available floor space and feed additive use. These effects vary randomly, but are autocorrelated between production phases, between similar diseases and over time.     

Identification of transgenes from wood of genetically transformed poplar trees

We have extracted total DNA from different fractions of fresh wood as well as from cold-stored and air-dried wood harvested from transgenic aspen grown in the field. The highest amounts of DNA were obtained from bark/cambium tissue; the DNA quality, however, was poor. Best results in PCR and Southern blot analyses were obtained from DNA extracted from early wood. Using appropriate primer pairs, amplification products were obtained from both the foreign gene (transgene) and aspen genomic sequences. In Southern blot analyses transgene-specific hybridisation signals were obtained. This is the first report on the detection of foreign genes in wood sampled from genetically modified trees.     

Spatial risk assessment of herd sero-status of Aujeszky's disease in a county in Hungary

A Geographic Information System (VetEpiGIS) was used to analyze the ADV (Aujeszky's disease virus) sero-status in large-scale pig units regarding certain geographical features in a county of southern Hungary. The ADV sero-statuses were collected from all swine units in Csongrád county in 1998-2000. The units' coordinates were combined with a vector graphical digital map of the county, with a resolution of 1:100,000. Logistic regression tested the associations between sero-status of large-scale units and presence of topographical features, other units and villages in the neighborhood. "Neighborhood" was defined by circular zones with radius 1-10km around the unit (in 1km increments; one logistic regression for each radius). The following topographical features showed significant positive association with the ADV seropositivity: lake (3km OR: 5.7; 5km OR: 7.5; 6km OR: 6.1; 10km OR: 5.4) and highway (5km OR: 4.2; 6km OR: 5.3). Other features had negative association with ADV seropositivity: forest (3km OR: 0.13; 4km OR: 0.15; 5km OR: 0.15; 6km OR: 0.10; 7km OR: 0.10; 8km OR: 0.23) and uninfected large-scale unit (4km OR: 0.07; 5km OR: 0.27; 6km OR: 0.32; 7km OR: 0.31).     

Ionophore taste preferences of dairy heifers

Two taste preference studies were conducted using six Holstein heifers in each experiment to determine preferences for no ionophore, lasalocid, or monensin in the diet. In Exp. 1, individually penned (approx. 5 mo old; 220 +/- 14 kg BW) heifers were fed a basal total mixed ration containing 46% corn silage, 46% grass haylage, and 8% soybean meal (DM basis). There were five treatments (mg/kg BW(-1)*d(-1)): 0 ionophore (control), 1 lasalocid (1L), 2 lasalocid (2L), 1 monensin (1M), or 2 monensin (2M). Ionophores were provided as part of the mineral mix that had been added to the control diet and through an ionophore-grain by-product mix to make the 2L and 2M treatments. All five diets were offered for 7 d, with the first 2 d for adaptation and the last 5 d for measurement of feed intake. The most preferred diet was then removed and the study continued with the four remaining diets. The most preferred diets were again eliminated sequentially, so that only two diets remained on d 13 and 14. Each feeding segment ranking of treatment preferences was determined based on the weight of feed refused at the end of each feeding segment. In Exp. 2, six 6-wk-old heifers (75 +/- 5 kg of BW) were individually fed either 0, 1L, or 1M in a study similar to Exp. 1, except that the most preferred diet was removed after 4 d, with the first day for adaptation and the last 3 d for measurement of feed intake. In Exp. 1, orthogonal contrasts indicated that heifers preferred the 1L and 2L diets over the 1M and 2M diets. Preferences between diet concentrations of ionophores (1 and 2 mg/kg of BW; Exp. 1) and the control and ionophore treatments did not differ, nor was there an interaction between ionophores and their concentration. Dairy heifers previously fed lasalocid prefer lasalocid over monensin when given a choice; however, heifers without previous exposure to an ionophore did not indicate a preference (Exp. 2).