ANCILLARY EQUIPMENT TO INCREASE QUALITY AND REDUCE RADIATION EXPOSURE IN THE EQUINE NUCLEAR MEDICINE LABORATORY

The construction of ancillary equipment used to improve image quality and reduce personnel radiation exposure in the equine nuclear medicine laboratory is illustrated. The devices include a self supporting lead sheet for shielding the distal limb or limb pair, a hanging lead sheet for shielding the proximal limb, a lead square for shielding the urinary bladder or jugular catheter, a restraining board for acquiring a palmar view of the foot, a head support to stabilize the head for imaging and a head support for stabilizing the neck for imaging. The restraining board and head supports decrease patient motion, improve image quality, and decrease the number of repeat acquisitions so that the time to perform the complete study is shortened. The self supporting shielding device allows the handlers to increase their distance from the horse which enhances radiation safety.     

Impact of biological and economic variables on optimal parity for replacement in swine breed-to-wean herds

Voluntary and involuntary culling practices determine the average parity when sows are replaced in a herd. Underlying these practices is the economic effect of replacing a sow at different parities. A dynamic programming model was used to find the optimal parity and net present value in breed-to-wean swine herds. The model included income and costs per parity weighted by the discount rate and sow removal rate. Three scenarios that reflect a wide range of cases were considered: low removal rates per parity with no salvage value (LRNS), high removal rates per parity with no salvage value (HRNS), and high removal rates per parity with a percentage of the sows having a salvage value (HRYS). The optimal parity of replacement for the base biological and economic conditions was 4 and 5 parities in the high and low removal scenarios, respectively. Sensitivity analyses identified the variables influencing the optimal replacement parity. Optimal parity of replacement ranged from 3 to 7 parities in the low replacement scenario, compared with 1 to 5 parities in the high replacement scenarios. Sow replacement cost and salvage value had the greatest impact on optimal parity of replacement followed by revenues per piglet weaned. The discount rate and number of parities per year generally had little influence on optimal parity. For situations with high sow costs, low salvage values, and low revenues per piglet, the optimal parity at removal was as high as 6 to 10 parities, and for situations with low sow cost, high salvage values, and high revenues per piglet, the optimal parity at removal was as low as 1 to 2 parities depending on removal rates. The modified internal rate of return suggested that, for most LRNS and HRYS scenarios considered, investment in a swine breed-to-wean enterprise was favored over other investments involving a similar risk profile. Our results indicate that in US breeding herds, sows are culled on average near the optimal parity of 4. However, the optimization process should be a dynamic one that adapts to changes in replacement rates, salvage value, replacement cost, and revenues per piglet.     

Movement patterns and habitat use of smalltooth sawfish,Pristis pectinata,determined using pop‐up satellite archival tags

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