Monensin toxicity in cattle   总被引：3，自引：0，他引：3  

E L Potter  R L VanDuyn  C O Cooley 《Journal of animal science》1984,58(6):1499-1511

Monensin has been tested to determine its toxicity and safety in cattle. Single dose acute toxicity and signs associated with toxicity were determined by oral gavage, 7-d oral gavage and feeding experiments with high concentrations of monensin in feed. Oral feeding studies indicated a near complete anorexia resulting from intake of sublethal amounts of monensin. In these cases, cattle recovered from the insulting dose and resumed growth and feed intake. In long-term chronic feedlot, pasture supplement, and reproduction safety studies conducted with monensin administered in the feed, the high concentrations caused cattle to show signs of mild monensin intoxication. Mortality resulted from feeding groups of cattle large quantities of monensin in small quantities of feed. Furthermore, these studies have demonstrated no detrimental effects upon reproduction. Collectively, these studies indicate that the greatest risk of intoxication occurs when cattle first receive a feed containing monensin. Mixing errors and misuse situations under actual use conditions have resulted in cases of cattle mortality. In most cases the mortality was predictable based upon the exposure in controlled studies.  相似文献   

Manual of Anaesthesia for Small Animal Practice,     

KA Brock 《Australian veterinary journal》1992,69(12):300-300

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Phylogenetic characterisation of bluetongue viruses from naturally-infected insects, cattle and sheep in Australia   总被引：1，自引：0，他引：1  

KA McCOLL  AR GOULD  LI PRITCHARD  L MEL VILLE†  G. BELLIS† 《Australian veterinary journal》1994,71(4):102-105

SUMMARY The polymerase chain reaction was used to detect the presence of blue-tongue virus (BTV) in a number of clinical and insect samples collected in the Northern Territory of Australia. Sequence analyses of the amplified BTV genes differentiated endemic Australian and exotic viruses. Two potential exotic BTV were detected as a result of PCR analyses of blood from sentinel animals and of the insect vector, Culicoides wadai. The detection of BTV in C wadai was the first direct demonstration of the presence of BTV in this potential vector. This new technology can significantly reduce the time taken for a diagnosis from a clinical sample and increase the amount of useful information obtained on a BTV isolate by using rapid sequencing techniques. Sequence data were used to differentiate between BTV20 isolated in 1975 and two isolates of the same serotype, isolated in 1992, and indicated that the latter were probably a recent incursion into Australia from Indonesia due to their greater VP3 sequence homology to the BTV9 (Java) than to Australian BTV isolates.  相似文献   

Plasma aldosterone and electrolyte concentrations in exercising thoroughbred horses fed two diets in summer and winter     

M.A. Hower  G.D. Potter  L.W. Greene  J.R. Coast  T.H. Welsh Jr. 《Journal of Equine Veterinary Science》1995,15(10)

In a replicated 4 × 4 Latin square experiment conducted in summer, eight mature Thoroughbred horses received two diets, control and fat-supplemented, and were exercised at two fitness levels designed to increase daily digestible energy (DE) requirements to approximately 150% (fitness level I) and 200% (fitness level II) of maintenance. In a second experiment during the winter, horses received the two diets in a switchback design and exercised at fitness level II. After 3 wk adaptation to treatments, feed and fecal samples were collected and horses galloped a standardized exercise test (SET) designed to increase the heart rate above 185 bpm for 1200 m. Vital signs were monitored and blood samples were obtained. Feed intake increased as fitness level increased (P < .05). Horses on the fat-supplemented diet required less feed (P < .05) to meet the energy requirements at a given fitness level. Daily DE intake was higher (P < .05) for the horses exercised at fitness level II to meet the increased metabolic demands. Heart rate, respiration rate and rectal temperature all increased (P < .05) with exercise. No treatment effects were found for heart rate (P >. 10) or rectal temperature (P > .30). Horses exercised in the winter had lower (P < .05) respiration rates, indicative of less problems dissipating excess body heat. Plasma aldosterone concentrations increased (P < .05) with exercise, corresponding to an increase in plasma K concentrations. Horses exercised in the summer exhibited higher (P < .05) plasma aldosterone concentrations than horses worked in the winter. Plasma CI and Na concentrations did not change (P > .30) with any treatment or exercise, indicating that the horses were not sufficiently stressed to induce any significant dehydration.  相似文献   

Growth and feed utilization by yearling horses fed added dietary fat     

B.D. Scott BS MS  G.D. Potter PhD  J.W. Evans PhD  J.C. Reagor PhD  G.W. Webb PhD  S.P. Webb MS 《Journal of Equine Veterinary Science》1989,9(4)

Twenty-four yearlings were used to evaluate the efficacy of feeding feed-grade fat to growing horses. All horses were started on trial at 13-months-of-age and were fed for 112 days. The experimental diets, containing similar nutrient-to-calorie ratios, were: 1) control (no added fat; 2) 5% added fat and; 3) 10% added fat. There was a trend for yearlings fed the 10% added fat diet to grow faster and eat less feed than those on the control diet. Data from this study indicate that feed-grade fat can be safely fed to growing horses. Feeding fat to yearlings stimulated growth and efficiency of feed utilization initially, but these effects were not maintained as the yearlings grew toward maturity.  相似文献   

Evaluation of bovine viral diarrhea virus uptake by preimplantation embryos     

M L Potter  R E Corstvet  C R Looney  R W Fulton  L F Archbald  R A Godke 《American journal of veterinary research》1984,45(9):1778-1780

Bovine embryos were exposed to bovine viral diarrhea (BVD) virus in vitro. An uptake of BVD virus by the embryos could not be detected by several assay systems. A significant decrease in the titer of BVD virus was found to occur when the virus was incubated in saline solution + 5% goat serum or minimal essential medium + 5% goat serum for 24 hours at 37 C. Since there was significant inactivation of the BVD virus during the incubation period, lack of viral infectivity of the embryos may have been due to adverse effects of the experimental environmental conditions on the virus or the embryos or upon viral-embryo interaction.  相似文献   

Meal size and feeding frequency influence serum leptin concentration in yearling horses     

Steelman SM  Michael-Eller EM  Gibbs PG  Potter GD 《Journal of animal science》2006,84(9):2391-2398

Energy is an essential nutrient for all horses, and it is especially important in performance horses, pregnant and lactating mares, and young growing horses. A negative energy balance in horses such as these may result in unsatisfactory performance, decreased fertility, or slow growth. Therefore, ensuring adequate energy intake is an important aspect of the nutritional management of the equine. This study was undertaken to investigate the effects of feeding large, carbohydrate-rich, concentrate meals on the satiety-inducing hormone, leptin. Three groups of yearling horses were rotated through 3 feeding schedules in a replicated 3x3 Latin square design. Horses were fed 2, 3, or 4 times per day (2x, 3x, and 4xfeeding schedules, respectively), each for a period of 11 d, with the total amount of daily feed held constant. Horses were weighed and BCS was determined on the first day of each period. Blood samples were collected before the morning meal on d 1, 4, and 7 of each period. Additionally, blood was sampled for the last 24 h of the 2xand 4xdietary periods. Neither weight nor BCS changed during the study (P = 0.99 and P = 0.28, respectively). Both mean and peak plasma glucose were greatest in 2xhorses (P < 0.05), as were mean areas under the curve. Serum leptin concentration increased in 2xhorses (P < 0.05), but not in horses fed 3 or 4 times daily. Leptin was elevated in horses with greater BCS (P < 0.05) and increased steadily throughout the study (P < 0.05). Data from the 24-h collection indicated that 2xhorses had fluctuations in leptin production throughout the day (P < 0.05), whereas horses fed 4 times daily did not. Overall, this study indicates that feeding horses 2 large concentrate meals daily can increase mean serum leptin concentrations and may cause fluctuations in leptin production over a 24-h period. This departure from baseline leptin concentration has the potential to affect appetite, along with numerous other physiological processes.  相似文献   

Drenching adult ewes: implications of anthelmintic treatments pre- and post-lambing on the development of anthelmintic resistance     

Leathwick DM  Miller CM  Atkinson DS  Haack NA  Alexander RA  Oliver AM  Waghorn TS  Potter JF  Sutherland IA 《New Zealand veterinary journal》2006,54(6):297-304

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Immune responses to a Staphylococcus aureus GapC/B chimera and its potential use as a component of a vaccine for S. aureus mastitis     

Perez-Casal J  Prysliak T  Kerro-Dego O  Potter AA 《Veterinary immunology and immunopathology》2006,109(1-2):85-97

Bovine mastitis caused by strains of S. aureus is the most economically important disease affecting the dairy industry worldwide. Commercially available vaccines show various degrees of success and work in research laboratories with experimental vaccines suggests that in part, the failure of these vaccines lies in the limited antigenic repertoire contained in the vaccine formulations. Since it seems impractical to produce a vaccine containing antigens from all major S. aureus mastitis isolates, we took the approach of using two surface antigens GapB and GapC that appear to be conserved and constructed a GapC/B chimera as the basis for a vaccine. The humoral and cellular immune responses to GapC/B were compared to the responses to the individual proteins, alone or in combination. The GapC/B protein elicited strong humoral and cellular responses in mice as judged by the levels of total IgG, IgG1, IgG2a, and number of IL-4- and IFN-gamma-secreting cells. These results suggest that this chimeric protein could be an attractive target for further vaccine efficacy studies.  相似文献   

Determining suitable locations for seed transfer under climate change: a global quantitative method   总被引：1，自引：1，他引：0  

Kevin M. Potter  William W. Hargrove 《New Forests》2012,43(5-6):581-599

Changing climate conditions will complicate efforts to match seed sources with the environments to which they are best adapted. Tree species distributions may have to shift to match new environmental conditions, potentially requiring the establishment of some species entirely outside of their current distributions to thrive. Even within the portions of tree species ranges that remain generally suitable for the species, local populations may not be well-adapted to altered local conditions. To assist efforts to restore forests and to maximize forest productivity in the face of climate change, we developed a set of 30,000 quantitatively defined seed transfer “ecoregions” across the globe. Reflecting current and future conditions, these were created by combining global maps of potentially important environmental characteristics using a large-scale statistical clustering technique. This approach assigns every 4?km² terrestrial raster cell into an ecoregion using non-hierarchical clustering of the cells in multivariate space based on 16 environmental variables. Two cells anywhere on the map with similar combinations of environmental characteristics are located near each other in this data space; cells are then classified into relatively homogeneous ecoregion clusters. Using two global circulation models and two emissions scenarios, we next mapped the predicted environmentally equivalent future locations of each ecoregion in 2050 and 2100. We further depicted areas of decreasing environmental similarity to given ecoregions, both in current time and under climate change. This approach could help minimize the risk that trees used for production, restoration, reforestation, and afforestation are maladapted to their planting sites.  相似文献