SPATIAL ANALYSIS OF FEEDER CATTLE HEDGING RISK

Optimal hedge ratios are estimated for various weights of feeder cattle in four cash markets based on CME data from 1992 to 1999. Three-month uniform hedges are simulated for every weight, contract, and cash market combination. Hedging effectiveness is compared empirically across locations to identify spatial differences in hedging risk.feeder cattle, hedging risk, hedge ratios, Livestock Production/Industries, Risk and Uncertainty,

GLUMIP 2.0: SAS/IML Software for Planning Internal Pilots

Internal pilot designs involve conducting interim power analysis (without interim data analysis) to modify the final sample size. Recently developed techniques have been described to avoid the type~I error rate inflation inherent to unadjusted hypothesis tests, while still providing the advantages of an internal pilot design. We present GLUMIP 2.0, the latest version of our free SAS/IML software for planning internal pilot studies in the general linear univariate model (GLUM) framework. The new analytic forms incorporated into the updated software solve many problems inherent to current internal pilot techniques for linear models with Gaussian errors. Hence, the GLUMIP 2.0 software makes it easy to perform exact power analysis for internal pilots under the GLUM framework with independent Gaussian errors and fixed predictors.

OPTIMAL HEDGING RATIOS AND HEDGING RISK FOR GRAIN BY-PRODUCTS

Optimal cross hedge ratios are estimated for a number of grain by-products used as livestock feed. Risk associated with these cross hedge ratios is measured to determine if cross hedging reduces grain by-product price risk. Results provide useful risk management guidelines for livestock and dairy producers.Marketing,

Calculation of multiple-trait sire reliability for traits included in a dairy cattle fertility index

The advent of genetic evaluations for fertility traits in the UK offers valuable information to farmers that can be used to control fertility problems and safeguard against involuntary culling. In addition to estimated genetic merit, proof reliabilities are required to make correct use of this genetic information. Exact reliabilities, based on the inverse of the coefficient matrix, cannot be estimated for large data sets because of computational restrictions. A method to calculate approximate reliabilities was implemented based on a six-trait sire model. Traits considered were interval between first and second calving, interval between first calving and first service, non-return rate 56 days post first service, number of inseminations per conception, daily milk yield at test nearest day 110 and body condition score. Sire reliabilities were calculated in four steps. Firstly, the number of effective daughters was calculated for each bull, separately for each trait, based on total number of daughters and daughter distribution across herd-year-seasons. Secondly, multiple-trait reliabilities were calculated, based on bull daughter contribution, applying selection index theory on independent daughter groups. Thirdly, (great-) grand-daughter contribution was added to the reliability of each bull, using daughter-based reliability of sons and maternal grandsons. An adjustment was made to account for the probability of bull and son or grandson having daughters in the same herd-year-season. Without the adjustment, reliabilities were inflated by proportionately 0·15 to 0·25. Finally, parent (sire and maternal grandsire) contribution was added to the reliability of each bull. The procedure was first tested on a data subset of 28 061 cow records from 285 bulls. Approximate reliabilities were compared with exact estimates based on the inverse of the coefficient matrix. Mean absolute differences ranged from 0·014 to 0·020 for the six traits and correlation between exact and approximate estimates neared unity. In a full-scale application, sire reliability for the fertility traits increased by proportionately 0·47 to 0·79 over single-trait estimates and the number of bulls with a reliability of 0·60 or more increased by 42 to 115%

For fibromyalgia, which treatments are the most effective?

There is no single most effective modality for the treatment of fibromyalgia syndrome, and no objective comparison of the results from the different studies is available. Low-dose tricyclic antidepressants (TCAs) improve sleep quality and global well-being and have a moderate beneficial effect on tenderness and stiffness (strength of recommendation [SOR]: A, based on a systematic review of randomized controlled trials [RCTs]). Selective serotonin reuptake inhibitors (SSRIs) may moderately improve fibromyalgia-related symptoms (SOR: B, based on a few RCTs). The serotonin and norepinephrine reuptake inhibitors (SNRIs) duloxetine (Cymbalta) and milnacipran (Ixel, not currently available in the US) improve pain and other symptoms (SOR: B, based on single RCTs). Tramadol (Ultram) improves pain and other outcomes (SOR: A, based on a few RCTs). Cyclobenzaprine (Flexeril) improves both pain and sleep quality (SOR: A, based on a systematic review of RCTs). Aerobic exercise improves overall functional capacity and sense of well-being for patients with fibromyalgia (SOR: A, based on a systematic review of RCT). Cognitive behavioral therapy improves patients' self-reported symptoms (SOR: A, based on RCTs)

Are overweight children more likely to be overweight adults?

Overweight at any age in childhood increases the risk for overweight in adulthood. The relative risk (RR) ranges from 1.9 to 10.1 and increases as children get older. Not all overweight children become overweight adults, however (strength of recommendation: A, systematic review of consistent prospective and retrospective cohort studies)

What is the best management for patients who have a TIA while on aspirin therapy?

Alternative antiplatelet therapy for stroke prevention is indicated for patients who experience transient ischemic attacks (TIAs) while on aspirin therapy (strength of recommendation [SOR]: A, based on 1 meta- analysis and 1 randomized controlled trial). The combination of aspirin and extended- release dipyridamole reduces the risk of stroke following a TIA (SOR: A). Thienopyridines (eg, clopidogrel and ticlopidine) are an alternative for patients at high risk for a cardioembolic event. Ticlopidine reduces the risk of stroke following TIA, specifically showing benefit for patients previously on aspirin (SOR: A). Clopidogrel has not shown significant reduction in reoccurrence of stroke and has not been studied for patients with a previous TIA. Aspirin and a thienopyridine do not provide significant additional reduction in secondary strokes (SOR: A)