Off-target glyphosate deposits from aerial silvicultural applications under various meteorological conditions

Aerial spray applications of the herbicide glyphosate were made over a forest canopy under various meteorological conditions. A ‘Thru Valve Boom’ dispersal system carried by a Cessna 188 fixed-wing aircraft flying at 49 m s^?1 was used to generate an aqueous spray cloud with a volume median diameter of 150 μm. Glyphosate deposits from multiple overlaid crosswind line sources released at 10 m above ground level were measured on ground sheets and artificial foliage at downwind distances between 50 and 400 m. Trials were conducted in stable, neutral and unstable atmospheric boundary layers with average wind speeds between 2·2 and 5·7 m s^?1 and vertical intensities of turbulence between 0·07 and 0·16. Linear regression lines fitted to logarithmically transformed measurements and downwind distances (x) gave statistically significant correlation coefficients (P = 0·01), and were compared by ANOVA. Glyphosate deposits on ground sheets and artificial foliage were attenuated at rates inversely proportional to x to the power 1·7-4·3. Regression line comparison showed that, in general, deposits on ground sheets decreased with increasing wind speed and intensity of turbulence, and some statistically significant differences were found in slopes and elevations of regression lines from different trials. However, deposits at the 50-m station increased with wind speed due to the large-drop cloud component. Regression line comparison for deposits on artificial foliage showed that, in general, they were highest in the intermediate wind speed-neutral stability case and similar in the high wind speed-unstable and low wind speed-stable boundary layers, although deposits at the 50-m station also increased with wind speed.     

鄂北地区栗瘿蜂综合防治技术研究

栗瘿蜂在鄂北地区一年发生一代，以初龄幼虫在被害芽内越冬。翌年4月上旬栗芽萌动时开始为害，使被害芽形成虫瘿抑制新梢生长，导致减产甚至绝收。当地该瘿蜂优势种天敌是中华长尾小蜂，益害比1∶5时能抑制栗瘿蜂的大发生。以冬季清园铲除杂草，剪除病虫枝等农业防治为基础，收集虫瘿于3月下旬挂于栗园保护天敌为主导，辅之以化学防治的综合防治措施能有效地控制栗瘿蜂的为害。     

Effects of dietary electrolyte balance on the chemistry of blood and urine in lactating sows and sow litter performance

One hundred fifty-three sows (average parity of 2.2) were used to determine the effects of dietary electrolyte balance (calculated as mEq/kg of diet for Na + K - Cl) on sows and their litters during lactation. The sows were fed corn-soybean meal-based diets (1.0% lysine, 1.0% valine, 0.95% Ca, and 0.80% P; as-fed basis) starting on d 109 of gestation and throughout the 21-d lactation experiment. Dietary electrolyte balance (dEB) was 0, 100, 200, 350, and 500 mEq/kg (as-fed basis), well above and below the dEB of 185 mEq/kg found in a simple corn-soybean meal-based lactation diet. To achieve the desired dEB, diets had the following: 1) 1.8% HCl (6 N) and 1.06% CaCl2, 2) 1.0% CaCl2, 3) 0.04% NaHCO3, 4) 1.29% NaHCO3, and 5) 2.54% NaHCO3 (as-fed basis). Increasing dEB increased blood pH (linear and quadratic effects, P < 0.001), partial pressure of carbon dioxide (linear effect, P < 0.001), HCO3- concentration (linear and quadratic effects, P < 0.001), and blood base excess (linear and quadratic effects, P < 0.001). However, increased dEB resulted in lower blood concentrations of K (linear and quadratic effects, P < 0.04), Cl (linear and quadratic effects, P < 0.001), and ionized Ca (linear and quadratic effects, P < 0.001). Changing dEB did not affect ADFI; water usage, litter weight gain; sow weight change; sow backfat change; percentages of CP, lactose, and fat in the milk; percentage of sows returning to estrus; days to estrus; and number of pigs born alive in the subsequent litter (P = 0.06). However, piglet survivability to d 10 and overall was greatest with the lower dEB treatments (linear effect, P < 0.05). The pH (linear and quadratic effects, P < 0.001) and colony forming units of total bacteria (linear effect, P < 0.03) in the urine increased as dEB of the diet was increased. In conclusion, dEB had pronounced effects on the physiological status of sows and decreasing dEB below that in a simple corn-soybean meal-based diet decreased bacterial counts in the urine and increased piglet survivability. However, milk composition, sow and litter weights at weaning, and subsequent rebreeding performance of the sows were not affected by dEB.     

Use of a three-drill-tract technique for arthrodesis of the distal tarsal joints in horses with distal tarsal osteoarthritis: 54 cases (1990-1999)

OBJECTIVE: To assess the long-term clinical outcome of horses with distal tarsal osteoarthritis (OA) in which a 3-drill-tract technique was used to induce arthrodesis of the affected joints, identify any preoperative or operative factors associated with outcome, and describe any complications associated with the technique. DESIGN: Retrospective study. ANIMALS: 54 horses. PROCEDURE: Medical records were reviewed for information on signalment, use, history, physical and lameness examination findings, surgical technique, and postoperative care. Radiographs were examined, and severity of OA was graded. Follow-up information was obtained through telephone interviews with owners at least 13 months after the procedure. RESULTS: 32 (59%) horses had a successful outcome, 6 (11%) improved but were not sound after surgery, and 16 (30%) did not improve following surgery. Outcome was negatively associated with the previous use of intra-articular injections. Few postoperative complications were evident. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that distal tarsal OA in horses can be successfully treated by means of distal tarsal arthrodesis with a 3-drill-tract technique. Horses with advanced distal tarsal OA are likely to have poorer outcomes, and the procedure will likely be of minimal benefit in horses with concomitant causes of hind limb lameness prior to surgery and in horses with preexisting proximal intertarsal joint disease.     

Effect of immunosuppressive doses of cyclosporine on pancreatic beta cell function in pigs

OBJECTIVE: To evaluate whether immunosuppressive doses of cyclosporine (CsA) have an adverse effect on the liver, kidney, and pancreatic beta cells of pigs. ANIMALS: 8 juvenile 8-week-old Landrace X Large White crossbred pigs. PROCEDURE: CsA (100 to 140 mg/kg) was administered orally to euglycemic pigs to reach whole blood trough concentrations of approximately 1500 ng/mL. To determine pancreatic beta cell function, plasma C-peptide and insulin concentrations were measured in response to i.v. administration of glucose, glucagon, arginine, and oral administration of glucose. Effects on liver and kidney were determined by monitoring serum measurements of liver function and serum creatinine concentrations, respectively. RESULTS: Plasma concentrations of C-peptide were significantly lower in euglycemic CsA-treated pigs, compared with control pigs, following i.v. administration of glucose, glucagon, arginine, and oral administration of glucose. Furthermore, the glucose clearance rate was decreased in euglycemic CsA-treated pigs, compared with control pigs. Serum creatinine concentrations and 4 of 7 serum measurements of liver function were not adversely affected by CsA administration. Serum concentrations of bilirubin and albumin were significantly increased, and serum alanine aminotransferase activity was significantly decreased in CsA-treated pigs, compared with control pigs. Histologic evaluation of liver and kidney sections revealed no pathologic findings in CsA-treated or control pigs. CONCLUSIONS AND CLINICAL RELEVANCE: In our study, immunosuppressive doses of CsA caused an impairment of porcine pancreatic beta cell function, but did not have toxic effects on the kidney. However, on the basis of changes in serum bilirubin and albumin concentrations and alanine aminotransferase activity, subclinical toxic effects on the liver did occur when immunosuppressive doses of CsA were administered.     

Arthroscopic removal of dorsoproximal chip fractures of the proximal phalanx in standing horses

OBJECTIVE: To report a technique for, and outcome after, arthroscopic removal of dorsoproximal chip fractures of a proximal phalanx in standing horses. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: A total of 104 horses, 1 to 13 years of age, with a dorsoproximal chip fracture of a proximal phalanx. METHODS: Horses were restrained in standing stocks and sedated with intravenous xylazine, detomidine, or a combination of both drugs. Local analgesia was achieved with 2% mepivacaine administered intra-articularly and by subcutaneous infiltration in a crescent-shaped block dorsal to the fetlock. Sterile drapes were placed on the surgical field, and impervious drapes were used on the hoof and floor. Arthroscopic portals were created in the dorsal pouch of the metacarpophalangeal or metatarsophalangeal joints to remove chip fractures. Statistical analysis was performed on race records for all Thoroughbred racehorses and compared with previously published studies. Operative and hospitalization times were compared with those of the general hospital population, and risks associated with general anesthesia were examined. RESULTS: No major operative or postoperative complications occurred. Ninety-one percent of racehorses raced after surgery with 78% returning to race at the same or higher level. CONCLUSION: Standing arthroscopic surgery can be performed successfully to remove dorsoproximal chip fractures of the proximal phalanx. CLINICAL RELEVANCE: Standing arthroscopic surgery is a valid alternative treatment for experienced surgeons to avoid the expense and potential risks associated with general anesthesia.