Costs of Horn Fly (Diptera: Muscidae) Control for Cow-calf Producers in Tennessee and Texas, 2016.

Tennessee and Texas cow-calf producers were surveyed to assess their 2016 expenses for horn fly control methods. Cattle producers who were members of the Texas and Southwestern Cattle Raisers Association and Tennessee cattle producers who have participated in the Tennessee Agricultural Enhancement Program participated in the survey. Average horn fly management costs in Tennessee and Texas were $9.50/head and $12.40/head, respectively. An ordinary least squares regression and quantile regression were estimated to examine how horn fly costs are influenced by producer and farm demographics, seasonality of horn flies, producer horn fly perceptions, and management practices. When controlling for these variables, Tennessee and Texas cattle producers did not spend significantly different amounts on horn fly control methods. Horn fly costs were associated with producer and farm demographics, producer perceptions of horn flies, and management practices. For example, results indicate that horn fly management costs vary depending on a producer's level of education and income. Having Angus cattle and larger herd sizes were associated with lower costs per head spent on horn fly management. Producers who did not consider horn flies to be a problem until greater quantities of flies were present on the animal spent 15% less per head on managing horn flies. In terms of horn fly control methods, feedthrough insecticides increased horn fly costs the most, followed by using ear tags. This is the first known research to estimate horn fly management costs among cattle producers.

The cost of feeding bred dairy heifers on native warm-season grasses and harvested feedstuffs.

Heifer rearing is one of the largest production expenses for dairy cattle operations, which is one reason milking operations outsource heifer rearing to custom developers. The cost of harvested feedstuffs is a major expense in heifer rearing. A possible way to lower feed costs is to graze dairy heifers, but little research exists on this topic in the mid-south United States. The objectives of this research were to determine the cost of feeding bred dairy heifers grazing native warm-season grasses (NWSG), with and without legumes, and compare the cost of grazing with the cost of rearing heifers using 3 traditional rations. The 3 rations were corn silage with soybean meal, corn silage with dry distillers grain, and a wet distillers grain-based ration. Bred Holstein heifers between 15- and 20-mo-old continuously grazed switchgrass (SG), SG with red clover (SG+RC), a big bluestem and Indiangrass mixture (BBIG), and BBIG with red clover (BBIG+RC) in Tennessee during the summer months. Total grazing days were calculated for each NWSG to determine the average cost/animal per grazing day. The average daily gain (ADG) was calculated for each NWSG to develop 3 harvested feed rations that would result in the same ADG over the same number of grazing day as each NWSG treatment. The average cost/animal per grazing day was lowest for SG ($0.48/animal/grazing d) and highest for BBIG+RC ($1.10/animal/grazing d). For both BBIG and SG, legumes increased the average cost/animal per grazing day because grazing days did not increase enough to account for the additional cost of the legumes. No difference was observed in ADG for heifers grazing BBIG (0.85 kg/d) and BBIG+RC (0.94 kg/d), and no difference was observed in ADG for heifers grazing SG (0.71 kg/d) and SG+RC (0.70 kg/d). However, the ADG for heifers grazing SG and SG+RC was lower than the ADG for heifers grazing either BBIG or BBIG+RC. The average cost/animal per grazing day was lower for all NWSG treatments than the average cost/animal per day for all comparable feed rations at a low, average, and high yardage fee. Results of this study suggest that SG was the most cost-effective NWSG alternative to harvested feeds for bred dairy heifer rearing.

Improved methods for the extraction and analysis of isoflavones from soy-containing foods and nutritional supplements by reversed-phase high-performance liquid chromatography and liquid chromatography-mass spectrometry.

An improved method for extraction and analysis of isoflavones from soy protein, soy foods and nutritional supplements is presented. The method uses acetonitrile extraction without acidification, with apigenin as internal standard. Samples extracted in acetonitrile-water are diluted to 50% acetonitrile and directly injected for gradient HPLC separation on a C18 reversed-phase column. This method saves significant time during sample preparation and improves accuracy and precision. Conventional and rapid HPLC analysis methods compatible with the extraction scheme were developed. During development of the methods, unexpected minor forms of malonyl and acetyl isoflavones were discovered in extracts of soy proteins and in pure isoflavone standard preparations. By LC-triple MS, these peaks have identical composition to the respective 6''-O-malonyl- and 6''-O-acetyl-isoflavones from which they form. These minor forms are believed to be malonyl and acetyl isoflavones where the site of attachment is a hydroxyl other than the 6'-OH of the glucose. These compounds can represent significant minor isoflavone components of foods, which contain high concentrations of malonyl or acetyl isoflavones.

Neuromuscular and clinical effects of mivacurium chloride in healthy adult patients during nitrous oxide-enflurane anaesthesia.

We have studied the effects of mivacurium after induction of anaesthesia with alfentanil-propofol in healthy adult oral surgical patients. Anaesthesia was maintained with nitrous oxide and 0.75% (end-tidal) enflurane in oxygen after nasotracheal intubation. Recordings were made of the rectified compound adductor pollicis electromyogram in response to train-of-four (TOF) ulnar nerve stimulation. First and fourth TOF responses were defined as T1 and T4, with T1 suppression referenced to pre-mivacurium T1 height (Tc). Onset times (mean (SEM] to 90% T1 suppression were 2.5 (0.2), 2.1 (0.3) and 1.6 (0.1) min, respectively, after mivacurium 0.15 mg kg-1 (n = 18) and 0.2 mg kg-1 (n = 18) as 5-s boluses and 0.2 mg kg-1 over 30 s (n = 9). Intubating conditions 2 min after 0.15 mg kg-1 were good to excellent and not improved by a further 30-s delay or by use of a 0.2-mg kg-1 dose. Recovery to T1/Tc of 5% occurred on average in 12-13 min irrespective of dose. Thereafter, mivacurium infusions commenced at 8-10 micrograms kg-1 min-1 were adjusted at intervals of at least 3 min to achieve T1/Tc in the range 1-10%. Mean duration of infusion was 58 (3.4) min and mean infusion rate after a 15-min stabilization period was 6.6 (range 2.3-12.9) micrograms kg-1 min-1. On cessation of infusions, spontaneous recovery from T1/Tc 8% (1.0%) to T4:T1 = 0.7 took 17 (1.2) min. Neostigmine 0.04 mg kg-1 or edrophonium 0.75 mg kg-1 evoked recovery from T1/Tc 9% (SEM 1.2% and 1.0%, respectively) to T4:T1 = 0.7 in 11 (0.6) and 8 (0.9) min (both P less than 0.001 vs spontaneous recovery).

Comparison of the diagnostic utility of timed serial (slope) creatine kinase measurements with conventional serum tests in the early diagnosis of myocardial infarction.

We compared the diagnostic utility of recently proposed slope assays for serum creatine kinase and creatine kinase-2 with the optimized decision threshold assays. The former approach has been claimed to be superior to any other single diagnostic technique. We show, by ROC curve and likelihood ratio analyses, that the total creatine kinase slope assay possesses the same diagnostic power, when confidence intervals are used, as the optimized decision threshold assay. Moreover, slope assays of creatine kinase-2 were diagnostically inferior to the optimized decision threshold assays. Indeed, these latter, optimized, assays have the highest likelihood ratios for a positive test result of the available assays, and they should always be used in situations of diagnostic doubt.

The management of the second stage of labour in primiparae with epidural analgesia.

One hundred and ninety-four primiparae with lumbar epidural analgesia established during the first stage of labour were discouraged from pushing until the fetal head was visible at the perineum or until three hours had elapsed since full dilation of the cervix. The outcome in this group was compared with a similar group in whom pushing was commenced as soon as the second stage was diagnosed. The observed increase in spontaneous deliveries did not reach statistical significance. There was a reduction in non-rotational forceps (p less than 0.05), but no change occurred in the incidence of rotational forceps deliveries. The high rates of oxytocin augmentation in these primiparous labours may account for the failure of delayed pushing to increase the spontaneous delivery rate in our population.