Comparison of methods to predict feed intake and residual feed intake using behavioral and metabolite data in addition to classical performance variables.

Predicting dry matter intake (DMI) and feed efficiency by leveraging the use of data streams available on farm could aid efforts to improve the feed efficiency of dairy cattle. Residual feed intake (RFI) is the difference between predicted and observed feed intake after accounting for body size, body weight change, and milk production, making it a valuable metric for feed efficiency research. Our objective was to develop and evaluate DMI and RFI prediction models using multiple linear regression (MLR), partial least squares regression, artificial neural networks, and stacked ensembles using different combinations of cow descriptive, performance, sensor-derived behavioral (SMARTBOW; Zoetis), and blood metabolite data. Data were collected from mid-lactation Holstein cows (n = 124; 102 multiparous, 22 primiparous) split equally between 2 replicates of 45-d duration with ad libitum access to feed. Within each predictive approach, 4 data streams were added in sequence: dataset M (week of lactation, parity, milk yield, and milk components), dataset MB (dataset M plus body condition score and metabolic body weight), dataset MBS (dataset MB plus sensor-derived behavioral variables), and dataset MBSP (dataset MBS plus physiological blood metabolites). The combination of 4 datasets and 4 analytical approaches resulted in 16 analyses of DMI and RFI, using variables averaged within cow across the study period. Additional models using weekly averaged data within cow and study were built using all predictive approaches for datasets M, MB, and MBS. Model performance was assessed using the coefficient of determination, concordance correlation coefficient, and root mean square error of prediction. Predictive models of DMI performed similarly across all approaches, and models using dataset MBS had the greatest model performance. The best approach-dataset combination was MLR-dataset MBS, although several models performed similarly. Weekly DMI models had the greatest performance with MLR and partial least squares regression approaches. Dataset MBS models had incrementally better performance than datasets MB and M. Within each approach-dataset combination, models with DMI averaged over the study period had slightly greater model performance than DMI averaged weekly. Predictive performance of all RFI models was poor, but slight improvements when using MLR applied to dataset MBS suggest that rumination and activity behaviors may explain some of the variation in RFI. Overall, similar performance of MLR, compared with machine learning techniques, indicates MLR may be sufficient to predict DMI. The improvement in model performance with each additional data stream supports the idea of integrating data streams to improve model predictions and farm management decisions.

Using biodosimetry to enhance the public health response to a nuclear incident.

Radiation Biodosimetry is a continually developing clinical diagnostic field, which focuses on biological markers that proportionally change in relationship to the amount of ionizing radiation absorbed. Examples of host marker response include changes in white cell count, specific proteins in circulation, RNAs in white blood cells, or chromosome fidelity in affected lymphocytes. Measurements of radiation biomarkers correlate with the approximate radiation dose absorbed and indirectly provide an assessment of the likelihood of developing acute radiation syndrome. The aim of this review is to summarize four biodosimetry programs that are in advanced development, later pipeline stages with funding from the Biomedical Advanced Research and Development Authority (BARDA), an agency under the Assistant Secretary for Preparedness and Response (ASPR) in the U.S. Department of Health and Human Services (HHS). With BARDA financial support, biodosimetry diagnostic assays in development will inform patient management, improve health and psychosocial outcomes, and save lives after a nuclear disaster. These tests include an SRI International developed rapid on-site screening test requiring only a finger stick of blood to triage those who have received little or no radiation from those who have received clinically significant levels of radiation and need further immediate patient management. In addition, multiple laboratory-based, high-throughput quantitative tests, currently under development by MRIGlobal, DxTerity, and ASELL, will more accurately define dose levels and possibly predict cellular and organ-damage and other longer-term effects of radiation. In the future, when clinical and analytical validation of these assays is complete, the data is reviewed by the FDA, and agency use status is obtained, rapid triage and laboratory-based biodosimetry test results will enable emergency medical teams to do the most good for the largest number of people after a nuclear blast.

Anemochory of diapausing stages of microinvertebrates in North American drylands.

1. Dry, ephemeral, desert wetlands are major sources of windblown sediment, as well as repositories for diapausing stages (propagules) of aquatic invertebrates. Zooplankton propagules are of the same size range as sand and dust grains. They can be deflated and transported in windstorm events. This study provides the evidence that dust storms aid in dispersal of microinvertebrate propagules via anemochory (aeolian transport). 2. We monitored 91 windstorms at six sites in the southwestern U.S. over a 17-year period. The primary study site was located in El Paso, Texas in the northern Chihuahuan Desert. Additional samples were collected from the Southern High Plains region. Dust carried by these events was collected and rehydrated to hatch viable propagules transported with it. 3. Using samples collected over a six-year period, 21 m above the ground which included 59 storm events, we tested the hypothesis that transport of propagules is correlated with storm intensity by monitoring meteorological conditions such as storm duration, wind direction, wind speed, and PM10 (fine dust concentration). An air quality monitoring site located adjacent to the dust samplers provided quantitative hourly measurements. 4. Rehydration results from all events showed that ciliates were found in 92% of the samples, rotifers in 81%, branchiopods in 29%, ostracods in 4%, nematodes in 13%, gastrotrichs in 16%, and tardigrades in 3%. Overall, four bdelloid and 11 monogonont rotifer species were identified from rehydrated windblown dust samples. 5. PCA results indicated gastrotrichs, branchiopods, nematodes, tardigrades, and monogonont rotifer occurrence positively correlated with PM10 and dust event duration. Bdelloid rotifers were correlated with amount of sediment deposited. NMDS showed a significant relationship between PM10 and occurrence of some taxa. Zero-inflated, general linear models with mixed-effects indicated significant relationships with bdelloid and nematode transport and PM10. 6. Thus, windstorms with high particulate matter concentration and long duration are more likely to transport microinvertebrate diapausing stages in drylands.

Effect of UV-C light or hydrogen peroxide wipes on the inactivation of methicillin-resistant Staphylococcus aureus, Clostridium difficile spores and norovirus surrogate.

AIMS: The current study aimed to assess the potential of a new high dose ultraviolet (UV) disinfection device to inactivate methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile and a norovirus surrogate on handheld mobile devices, and to compare the efficacy of the UV-C device to hydrogen peroxide disinfection wipes. METHODS AND RESULTS: Suspensions of MRSA, C. difficile spores and a surrogate for norovirus (MS2) were inoculated onto glass or plastic coupons, with or without organic contamination and were exposed to continuous UV-C light for 15-60 s (165-646 mJ cm-2 ) in a self-contained UV-C chamber or treated with hydrogen peroxide wipes. Increasing the UV-C dose from 310 to 650 mJ cm-2 did not result in greater levels of inactivation. UV-C light inactivated all three micro-organisms, in the absence of organic contamination, by >2·9 log. Treatment of MRSA, C. difficile spores or MS2, in the presence of organic contamination, with UV-C light (310-646 mJ cm-2 ) resulted in 2·3-3·7 log reductions. Treatment of MRSA with UV-C light provided levels of inactivation comparable to treatment with hydrogen peroxide wipes used following the manufacturer's instructions. CONCLUSIONS: UV-C light and hydrogen peroxide wipes had strong antimicrobial activity against MRSA, C. difficile spores and a norovirus surrogate, in the presence or absence of organic contamination. SIGNIFICANCE AND IMPACT OF THE STUDY: Chemical disinfection wipes are widely used in healthcare facilities, but they are not recommended for use on handheld mobile devices which may harbour pathogenic micro-organisms. The powerful bactericidal, sporicidal and virucidal activity of this high dose UV-C light device, shows that this technology is a promising alternative to chemical disinfectants, particularly for control of MRSA.

Evidence for regional aeolian transport of freshwater micrometazoans in arid regions.

While separated by large expanses of dry terrain unsuitable for aquatic biota, aridland waters possess high biodiversity. How aquatic micrometazoans disperse to, and colonize, these isolated ephemeral habitats are not well understood. We used a multi-faceted approach including wind tunnel and rehydration experiments, and next-generation sequencing to assess potential movement of diapausing propagules of aquatic invertebrates by anemochory across regional scales (102-105 km). Wind tunnel experiments using dry playa sediments with added micrometazoan propagules demonstrated that after entrainment by saltation and downwind transport were subsequently recoverable as viable animals when rehydrated. Further, rehydration of fallen natural dust yielded micrometazoans, including rotifers, gastrotrichs, microcrustaceans, and nematodes. Using conserved DNA primers, we identified >3,300 eukaryotic Operational Taxonomic Units (excluding fungi) in the dust including some taxa found in rehydration experiments. Thus, we provide strong evidence that anemochory can disperse micrometazoans among isolated, ephemeral ecosystems in North American deserts and likely elsewhere.

Non-steroidal anti-inflammatory drug-induced cardiovascular adverse events: a meta-analysis.

WHAT IS KNOWN AND OBJECTIVE: Although non-steroidal anti-inflammatory drugs (NSAIDs) have been studied in randomized, controlled trials and meta-analyses in an effort to determine their cardiovascular (CV) risks, no consensus has been reached. These studies continue to raise questions, including whether cyclooxygenase-2 (COX-2) selectivity plays a role in conferring CV risk. We performed a meta-analysis of current literature to determine whether COX-2 selectivity leads to an increased CV risk. METHODS: We utilized randomized, controlled trials and prospective cohort studies. We selected eight NSAIDs based on popularity and COX selectivity and conducted a search of the MEDLINE, EMBASE, and Cochrane databases. Primary endpoints included any myocardial infarction (MI), any stroke, CV death, and a combination of all three (composite CV outcomes). Twenty-six studies were found that met inclusion and exclusion criteria. Comparisons were made between all included drugs, against placebo, and against non-selective NSAIDs (nsNSAIDs). Drugs were also compared against COX-2 selective inhibitors (COXIBs) with and without inclusion of rofecoxib. RESULTS AND DISCUSSION: Incidence of MI was increased by rofecoxib in all comparison categories [all NSAIDs (OR: 1·811, 95% CI: 1·379-2·378), placebo (OR: 1·655: 95% CI: 1·029-2·661), nsNSAIDs (OR: 2·155, 95% CI: 1·146-4·053), and COXIBs (OR: 1·800, 95% CI: 1·217-2·662)], but was decreased by celecoxib and naproxen in the COXIB comparison [(OR: 0·583, 95% CI: 0·396-0·857) and (OR: 0·609, 95% CI: 0·375-0·989, respectively]. Incidence of stroke was increased by rofecoxib in comparisons with all NSAIDs and other COXIBs [(OR: 1·488, 95% CI: 1·027-2·155) and (OR: 1·933, 95% CI: 1·052-3·549), respectively]. Incidence of stroke was decreased by celecoxib when compared with all NSAIDs, nsNSAIDs, and COXIBs [(OR: 0·603, 95% CI: 0·410-0·887), (OR: 0·517, 95% CI: 0·287-0·929), and (OR: 0·509, 95% CI: 0·280-0·925), respectively]. No NSAID reached statistical significance in regard to CV death. Incidence of the composite endpoint was increased by rofecoxib when compared against all NSAIDs, placebo, and other COXIBs [(OR: 1·612, 95% CI: 1·313-1·981), (OR: 1·572, 95% CI: 1·123-2·201) and (OR: 1·838, 95% CI: 1·323-2·554), respectively]. Incidence of composite endpoint was decreased by celecoxib in the all NSAIDs and COXIBs comparisons [(OR: 0·805, 95% CI: 0·658-0·986) and (OR: 0·557, 95% CI: 0.404-0.767), respectively]. When rofecoxib was removed from the COXIBs group, no difference was found with any comparison, suggesting rofecoxib skewed the data. WHAT IS NEW AND CONCLUSION: This instead of the meta-analysis suggests that COX-2 selectivity may not play a role in the CV risk of NSAIDs. Rofecoxib was the only drug to demonstrate harm and skewed the data of the COX-2 selective group.

Inverse four-wave-mixing and self-parametric amplification effect in optical fibre.

An important group of nonlinear processes in optical fibre involves the mixing of four waves due to the intensity dependence of the refractive index. It is customary to distinguish between nonlinear effects that require external/pumping waves (cross-phase modulation and parametric processes such as four-wave mixing) and self-action of the propagating optical field (self-phase modulation and modulation instability). Here, we present a new nonlinear self-action effect, self-parametric amplification (SPA), which manifests itself as optical spectrum narrowing in normal dispersion fibre, leading to very stable propagation with a distinctive spectral distribution. The narrowing results from an inverse four-wave mixing, resembling an effective parametric amplification of the central part of the spectrum by energy transfer from the spectral tails. SPA and the observed stable nonlinear spectral propagation with random temporal waveform can find applications in optical communications and high power fibre lasers with nonlinear intra-cavity dynamics.

A study of methods for evaluating the success of the transition period in early-lactation dairy cows.

Three transition monitors were developed in this study that serve on 2 levels: the individual cow level and the herd level. On the first level they screen all cows for potential onset of postparturient health disorders and could be used to trigger implementation of more specific diagnostic initiatives. On the second level they can be used within herd to monitor the implementation of transition protocols and evaluate the transition management on the farm, signaling potential problems before clinical disease onset. The performance of 3 transition monitors based on daily milk yield (MY) within the first 7d in milk was evaluated in 3 herds with differing transition management intensity. The 3 monitors considered were increase in MY (LINE), average MY (MY7), and the difference between MY7 and expected MY (transition success measure, TSM). Transition monitors were evaluated not only as within-herd predictors of individual cow transition problems but also as indicators of herd transition management failures by relating their value with probability of early-lactation health disorders, culling, and treatment cost. Analysis of logistic models, correlations, and sensitivity and specificity estimates identified TSM as the most reliable measure of transition failure on both the individual cow level as well as the farm level across all study herds, with best performance achieved in herds with the most intensive postpartum cow management. As evaluated by logistic regression models, TSM was able to successfully predict the probability of a cow remaining healthy for the first 21d of lactation (c-statistic between 0.68 and 0.78), and probability of culling by 100d in milk (c-statistic between 0.73 and 0.86). Total cost of treatment by 21d in milk also showed the strongest correlation with TSM, with correlation coefficients ranging between 0.2 and 0.4. Statistical-process control cumulative sum charts for TSM designed to monitor postpartum management process in the herd identified transition failure events with at least 90% sensitivity at specificity above 92% within a 14-d window of 7d before and 7d after the event.

Visceral adipose tissue mass in nonlactating dairy cows fed diets differing in energy density(1).

Our objective was to determine dietary energy effects on feed intake, internal fat deposition, body condition score (BCS), visceral organ mass, and blood analytes in Holstein cows. Eighteen nonpregnant, nonlactating cows (BCS = 3.04 ± 0.25) were blocked based on initial BCS and were randomly assigned within each block to 2 treatments. Treatments were either high energy [HE; net energy for lactation (NEL)=1.62 Mcal/kg] or low energy (LE; NEL = 1.35 Mcal/kg) diets fed as total mixed rations for 8 wk. The LE diet consisted of 81.7% forage, including 40.5% wheat straw and 28.3% corn silage, whereas the HE diet contained 73.8% forage with no straw and 49.9% corn silage (dry matter basis). Cows were fed for ad libitum intake once daily at 0800 h. Feed intake was recorded daily, blood was sampled at wk 1, 4, and 7, and BCS was assigned at wk 1, 4, and 7. Cows were killed following the 8-wk period, and visceral organs, mammary gland, and internal adipose tissues were weighed and sampled. The HE group had greater dry matter intake (15.9 vs. 11.2 ± 0.5 kg/d) and energy intakes than cows fed LE, but neutral detergent fiber intake did not differ (5.8 vs. 5.6 ± 0.25 kg/d for HE and LE). Final body weight was greater for cows fed HE (807 vs. 750 kg), but BCS did not differ between groups (3.52 vs. 3.47 for HE and LE). Omental (26.8 vs. 15.2 ± 1.6 kg/d), mesenteric (21.5 vs. 11.2 ± 1.9 kg), and perirenal (8.9 vs. 5.4 ± 0.9 kg) adipose tissue masses were larger in HE cows than in LE cows. Although subcutaneous adipose mass was not measured, carcass weight (including hide and subcutaneous fat) did not differ between HE (511 kg) and LE (496 kg). Liver weight tended to be greater for cows fed HE, but weights of gastrointestinal tract, heart, and kidney did not differ. Serum insulin tended to be greater and the glucose to insulin ratio was lower for cows fed HE. Serum concentrations of ß-hydroxybutyrate and cholesterol were greater for HE cows than for LE cows but concentrations of glucose, nonesterified fatty acids, total protein, and albumin did not differ. Final BCS was correlated with masses of omental (r = 0.57), mesenteric (r = 0.59), and perirenal (r = 0.72) adipose tissue, but mesenteric adipose mass increased more as BCS increased for cows fed HE. The similar final BCS between HE and LE cows demonstrates that BCS may lack sensitivity to detect differences in visceral fat deposition that might increase risk for peripartal diseases and disorders.

Effects of source of trace minerals and plane of nutrition on growth and health of transported neonatal dairy calves.

The aims of the experiment were to evaluate the effects of source of trace minerals (TM) and plane of nutrition (PN) early in life on growth and health of transported calves. Ninety male Holstein calves <1 wk old were assigned to treatments in a 2×2 factorial arrangement of PN and TM source in a randomized complete block design. Calves assigned to low PN (LPN) received milk replacer [22% crude protein (CP), 20% fat, 568 g of powder/d for wk 1 to 4, and 284 g of powder/d for wk 5] plus ad libitum access to starter [18% CP, dry matter (DM) basis, for wk 1 to 12] and a limited amount of hay (0.5 kg/d as fed, for wk 10 to 12); LPN calves were weaned at 6 wk. During wk 13 to 20, LPN calves were fed 3.2 kg/d of grower mix (16% CP, DM basis) plus chopped hay for ad libitum intake. Calves assigned to high PN (HPN) received variable amounts of milk replacer (28% CP; 20% fat; and 810, 1,136, and 568 g of powder/d for wk 1, 2 to 6, and 7, respectively) plus ad libitum access to starter (22% CP, DM basis, wk 1 to 12) and limited hay (0.5 kg/d as fed, for wk 10 to 12); HPN calves were weaned at wk 7. Calves assigned to HPN were offered grower mix for ad libitum intake plus a limited amount of chopped hay (0.5 kg/d, as-fed basis) from wk 13 to 20. Milk replacers were formulated to contain balanced amounts of either inorganic (I) or organic (O) TM (50, 50, 10, and 100mg/kg of Zn, Mn, Cu, and Fe, respectively), whereas respective ITM or OTM starters and growers contained Zn, Mn, Cu, and Co at 70, 55, 12, and 1mg/kg. The HPN treatments increased final body weight and stature measurements, average daily gain, and gain-to-feed ratio through wk 20. Starter intake was lower for calves fed HPN. The OTM increased growth when supplemented to HPN but not when supplemented to LPN. During the liquid-feeding period, fecal scores were more fluid for calves fed HPN but measures of health status did not differ among diets. Results indicated that an enhanced nutritional program during early life allowed calves to have greater overall growth and maintain a normal health status throughout the preweaning period. High PN and OTM were synergistic in increasing early growth of calves.

Blood immunometabolic indices and polymorphonuclear neutrophil function in peripartum dairy cows are altered by level of dietary energy prepartum.

Cows experience some degree of negative energy balance and immunosuppression around parturition, making them vulnerable to metabolic and infectious diseases. The effect of prepartum feeding of diets to meet (control, 1.34 Mcal/kg of dry matter) or exceed (overfed, 1.62 Mcal/kg of dry matter) dietary energy requirements was evaluated during the entire dry period (∼45 d) on blood polymorphonuclear neutrophil function, blood metabolic and inflammatory indices, and milk production in Holstein cows. By design, dry matter intake in the overfed group (n=9) exceeded energy requirements during the prepartum period (-4 to -1 wk relative to parturition), resulting in greater energy balance when compared with the control group (n=10). Overfed cows were in more negative energy balance during wk 1 after calving than controls. No differences were observed in dry matter intake, milk yield, and milk composition between diets. Although nonesterified fatty acid concentration pre- (0.138 mEq/L) and postpartum (0.421 mEq/L) was not different between diets, blood insulin concentration was greater in overfed cows prepartum (16.7 µIU/mL) compared with controls pre- and postpartum (∼3.25 µIU/mL). Among metabolic indicators, concentrations of urea (4.63 vs. 6.38 mmol/L), creatinine (100 vs. 118 µmol/L), and triacylglycerol (4.0 vs. 8.57 mg/dL) in overfed cows were lower prepartum than controls. Glucose was greater pre- (4.24 vs. 4.00 mmol/L) and postpartum (3.49 vs. 3.30 mmol/L) compared with control cows. Among liver function indicators, the concentration of bilirubin increased by 2 to 6 fold postpartum in control and overfed cows. Phagocytosis capacity of polymorphonuclear neutrophils was lower prepartum in overfed cows (32.7% vs. 46.5%); phagocytosis in the control group remained constant postpartum (50%) but it increased at d 7 in the overfed group to levels similar to controls (48.4%). Regardless of prepartum diet, parturition was characterized by an increase in nonesterified fatty acid and liver triacylglycerol, as well as blood indices of inflammation (ceruloplasmin and haptoglobin), oxidative stress (reactive oxygen metabolites), and liver injury (glutamic oxaloacetic transaminase). Concentrations of the antioxidant and anti-inflammatory compounds vitamin A, vitamin E, and ß-carotene decreased after calving. For vitamin A, the decrease was observed in overfed cows (47.3 vs. 27.5 µg/100 mL). Overall, overfeeding energy and higher energy status prepartum led to the surge of insulin and had a transient effect on metabolism postpartum.

Inclusion of psyllium in milk replacer for neonatal calves. 2. Effects on volatile fatty acid concentrations, microbial populations, and gastrointestinal tract size.

Fermentable fibers such as psyllium increase volatile fatty acid (VFA) concentrations in the lower digestive tract and increase the gastrointestinal tract (GIT) mass of many mammals. We reasoned that psyllium inclusion in milk replacer might produce similar effects in neonatal dairy calves, which could lead to improved growth and health. Male Holstein calves were fed a milk replacer (22% crude protein, 20% fat) either without or with psyllium (1.1% of dry matter, DM) from 2 d through 28 d of age. Milk replacer was reconstituted to 12.5% DM and fed at 12% of calf body weight, adjusted weekly. Water was offered ad libitum but no starter was fed. Three calves per treatment were harvested weekly to sample digesta from the reticulo-rumen, abomasum, jejunum, proximal colon, and distal colon, and to determine length and mass of GIT components. Psyllium in milk replacer increased the proportion of butyrate in reticulo-rumen contents from 2.4 to 3.2% of total but did not affect total VFA concentrations. Total VFA concentrations were very low in the jejunum but psyllium tended to increase total VFA, acetate, and valerate concentrations; valerate accounted for 15.9 and 16.7% of total VFA (molar basis) for control and psyllium calves, respectively. Psyllium increased total VFA concentrations in the proximal and distal colon by 104.4 and 45.6%, respectively, but had little effect on the profile of VFA. Psyllium in milk replacer increased populations of bifidobacteria (from 9.7 to 10.3 log(10) cfu/g of DM) and lactobacilli (from 8.2 to 9.4 log(10) cfu/g of DM) in the reticulo-rumen, but did not affect populations in jejunum or colon. Calves fed psyllium had 12.0% greater total GIT mass and 9.4% greater GIT as a percentage of body weight. Psyllium tended to increase mass of the reticulo-rumen and significantly increased mass of duodenum (34.2%), jejunum (14.5%), and colon (14.6%). Density of intestinal tissues from calves fed psyllium-supplemented milk replacer was 25.9% greater in the jejunum and 25.3% greater in the ileum, and tended to be greater in duodenum and colon than tissue from control calves. Supplementation of psyllium to milk replacer increased fermentation in the colon, mass of the total GIT, and populations of bifidobacteria and lactobacilli in the reticulo-rumen.

Effects of the peroxisome proliferator-activated receptor-alpha agonists clofibrate and fish oil on hepatic fatty acid metabolism in weaned dairy calves.

Peroxisome proliferator-activated receptor-alpha (PPARalpha) agonists increase fatty acid oxidation in liver of nonruminants. If similar effects occur in dairy cattle, enhanced hepatic oxidative capacity could decrease circulating nonesterified fatty acids and hepatic triacylglycerol accumulation in periparturient cows. The objectives of this study were 1) to determine whether partitioning of fatty acid metabolism by liver slices from weaned Holstein calves treated with PPARalpha agonists in vivo is altered compared with partitioning by liver slices from control (untreated) calves, and 2) to measure in vitro metabolism of palmitate and oleate by bovine liver slices and relate these to mRNA abundance for key enzymes. Weaned male Holstein calves (7 wk old; n=15) were assigned to 1 of 3 groups for a 5-d treatment period: control (untreated), clofibrate (62.5 mg/kg of BW), or fish oil (250 mg/kg of BW). Calves treated with clofibrate consumed less dry matter. Body weight, liver weight, liver weight:body weight ratio, blood nonesterified fatty acids, beta-hydroxybutyrate, and liver composition were not significantly different among treatments. Liver slices were incubated for 2, 4, and 8 h to determine in vitro conversion of [1-(14)C] palmitate and [1-(14)C] oleate to CO(2), acid-soluble products, esterified products, and total metabolism. In liver slices incubated for 8 h, conversion of palmitate to CO(2) was greater for calves treated with clofibrate compared with control calves or calves treated with fish oil. Conversion of palmitate to esterified products, total palmitate metabolism, and metabolism of oleate were not different among treatments. Conversion of palmitate to CO(2) was greater than that from oleate for all treatments, but rates of total metabolism did not differ. Clofibrate increased or tended to increase liver expression of several PPARalpha target genes involved in fatty acid oxidation (e.g., ACADVL, ACOX1, CPT1A), whereas fish oil did not significantly affect genes associated with fatty acid oxidation but tended to increase DGAT1. Overall, our data indicated that bovine liver responded to clofibrate treatment but not fish oil, although increases in hepatic lipid metabolism were much less than those reported in rodents treated with clofibrate or fish oil. Applications of PPARalpha agonists may be of interest to increase the rate of hepatic fatty acid oxidation and decrease triacylglycerol accumulation in periparturient dairy cows.

Short-day photoperiod increases milk yield in cows with a reduced dry period length.

Exposure of cows to a short-day photoperiod (SDPP; 8 h light:16 h dark) during a 60-d dry period increases milk yield in the subsequent lactation compared with cows exposed to a long-day photoperiod (LDPP; 16 h light:8 h dark). Whereas the traditional recommendation for dry period length is 60 d, recent studies indicate that the dry period length can be reduced without depressing the yield in the next lactation. However, the optimal duration of the dry period appears to be between 40 and 60 d, because fewer than 30 d could result in a significant loss of milk production. Our main objective was to determine whether treatment with SDPP combined with a reduced dry period length of 42 d would increase milk yield in the next lactation relative to treatment with LDPP, even though SDPP exposure was limited to 42 d. Multiparous Holstein cows (n = 40) were randomly assigned to 1 of 2 treatments during the dry period: LDPP or SDPP. Each treatment group (n = 20) was balanced according to the previous 305-d mature equivalent milk yield. To quantify plasma prolactin (PRL) concentration, blood samples were collected weekly during the dry period. Dry matter intake (DMI) was recorded during the dry period. Health was monitored weekly during the dry period and at calving. During lactation, milk yield and DMI were recorded for 120 and 42 d, respectively. Cows exposed to SDPP calved 4.8 d earlier than cows exposed to LDPP and days dry averaged 37 and 42 d for cows exposed to SDPP and LDPP, respectively. Cows on SDPP consumed more dry matter (17.0 +/- 1.1 kg/d) during the dry period than did cows on LDPP (15.9 +/- 1.1 kg/d), but DMI after parturition did not differ. In the first 42 d of lactation, cows exposed to SDPP and LDPP consumed 18.0 and 17.7 +/- 1.4 kg/d, respectively. The periparturient PRL surge was greater in cows exposed to LDPP (22.6 +/- 3.2 ng/mL) than in those exposed to SDPP (17.1 +/- 4.1 ng/mL). Milk yield was inversely related to the magnitude of the periparturient PRL surge, but was directly related to the expression of PRL-receptor mRNA in lymphocytes during the dry period. Through 120 d of lactation, cows exposed to SDPP when dry produced more milk (40.4 +/- 1.1 kg/d) than cows exposed to LDPP (36.8 +/- 1.1 kg/d). These results support the concept that SDPP, combined with a targeted 42-d dry period, increases milk yield in the subsequent lactation, relative to a 42-d dry period combined with LDPP, and that exposure to 42 d of SDPP in the dry period is sufficient to increase milk yield in the next lactation.

Hot topic: effects of frequent milking in early lactation on milk yield and udder health.

A field study was conducted to evaluate the influence of milking frequency (3 or 6 times/d [3x or 6x, respectively]) during the initial 21 d of lactation on milk and milk component yield and mammary gland health as indicated by somatic cell count. During 2 seasons, spring and fall, multiparous cows were milked 6 times/d until d 21 of lactation and then returned to the 3 times/d frequency for the remainder of lactation (6x; n = 9). Multiparous cows milked 3 times/d from the beginning of lactation served as a control group (3x; n = 17). With the exception of milking frequency, all other aspects of management, including housing, milk harvesting, and feeding, were identical between the groups and were consistent with industry norms. Retrospective analysis of Dairy Herd Improvement Association records was used to evaluate milk yield, milk component yield, and somatic cell scores. As expected, 6x cows produced more milk on the first test day than 3x cows. Compared with 3x cows, higher milk yields persisted for 6x cows from test day 2 through 6, indicating a persistent effect of early lactation milking frequency on milk yield potential for that lactation. Milk component yield followed a similar pattern: 6x cows produced significantly more protein, fat, and total solids than did control cows throughout the study. With regard to udder health, 6x cows had lower somatic cell counts at the first test day relative to 3x cows and had reduced somatic cell scores for the first 3 mo of lactation, which suggests that early lactation milking frequency influences the mammary gland capacity to resist infection in addition to improving milk production efficiency.

Web-based Loansome Doc, librarians, and end users: results from a survey of the Southeast Region.

OBJECTIVES: The study examines how Loansome Doc services are implemented and used by libraries in the Southeast Region and describe end users' experiences with and attitudes toward Loansome Doc. METHODS: 251 active DOCLINE libraries and 867 Loansome Doc users were surveyed. RESULTS: Roughly one half of the libraries offered Loansome Doc services. Of those that did not, most indicated no plans to offer it in the future. The majority had a small number of end users and experienced minimal increases in interlibrary loan activity. Problems were relatively rare. Satisfaction with Loansome Doc was high among all types of libraries. End users were usually physicians or other health care professionals who requested articles for research and patient care. Most learned about Loansome Doc through PubMed or Internet Grateful Med. End users appeared to be largely self-taught or received informal instruction in Loansome Doc. Loansome Doc filled document requests in a timely manner, and end users reported being satisfied with the service. CONCLUSIONS: Greater promotion of what Loansome Doc is and how it can benefit libraries can increase the number of participating libraries. While satisfaction of Loansome Doc end users is high, satisfaction could be increased with more help on the PubMed screen, more library training, and faster delivery methods.

Evaluation of an acriflavine disk assay for differentiating Staphylococcus aureus from other staphylococci isolated from bovine milk.

OBJECTIVE: To develop an acriflavine disk assay for identification of Staphylococcus aureus and to test whether the acriflavine disk assay could be used to differentiate S aureus from other staphylococci isolated from bovine milk samples. DESIGN: Prospective study. SAMPLE POPULATION: 882 staphylococcal isolates from bovine milk samples and 3 S intermedius isolates from dogs. PROCEDURE: Paper disks saturated with various amounts of acriflavine were used in a growth inhibition assay to determine the amount of acriflavine that would most reliably differentiate S aureus from other staphylococci. For all isolates, hemolytic pattern, results of tube coagulase tests after 4 and 24 hours of incubation, growth on acriflavine-supplemented media, results of an acriflavine disk assay, and results of an automated identification system were determined. RESULTS: 10 micrograms of acriflavine/disk was determined to be the most appropriate concentration for use in the assay. All 112 isolates identified as S aureus by the automated identification system were resistant to this concentration of acriflavine, and only 1 of 236 isolates identified as non-S aureus staphylococci was resistant. There was substantial agreement between results of using the acriflavine disk assay as a diagnostic criterion for differntiating S aureus isolates from non-S aureus staphylococci and results of the automated identification system. Agreement between results of determining hemolytic pattern and results of other diagnostic tests was only moderate. CLINICAL IMPLICATIONS: The acriflavine disk assay, using 10 micrograms of acriflavine/disk, was a practical, accurate method for differentiating S aureus isolates from non-S aureus staphylococci.

External cephalic version with tocolysis. Observations and continuing experience at the Los Angeles County/University of Southern California Medical Center.

We considered 113 consecutive patients for attempted external cephalic version with tocolysis (ECV-T) after 37 weeks' gestation. We randomized the first patients to the control group (no ECV-T attempted, 23 patients) or the study group (ECV-T attempted, 25 patients). Nine patients were excluded, and ECV-T was then considered for 88 patients, with a success rate of 77% for the 104 total attempts. Six patients were lost to follow-up. In the successful ECV-T group, 71 of 75 patients (95%) presented the vertex in labor, while 4 patients (5%) reverted to breech. Uterine exploration at delivery revealed uterine anomalies in three of the patients who reverted. The cesarean rate was 25% in the successful-ECV-T group and 87% in the failed-ECV-T group. In the initial group, four patients (18%) spontaneously converted to cephalic presentations after 37 weeks. None of the failed-ECV-T patients spontaneously converted to cephalic presentations. The cesarean rate for the control and failed-ECV-T patients presenting the breech intrapartum was 88%. Complications included transient fetal bradycardia in 37 patients (36%), evidence of fetomaternal bleeding (positive Kleihauer-Betke test) in 2 patients (2%) and one fetal demise three weeks following successful ECV-T and diagnosed at the onset of labor. We lowered the cesarean section rate for breech presentation in labor with the selective application of ECV-T late in gestation. We consider this technique to be a powerful addition to our armamentarium for managing the term breech presentation.

The delivery route for very-low-birth-weight infants. A preliminary report of a randomized, prospective study.

A major problem facing the perinatal team remains the care of the very-low-birth-weight infant (less than 1,500 gm), which includes not only the neonatal aspects but also the specific management aspects of labor and delivery. Numerous retrospective studies have suggested the potential benefits of cesarean delivery in the very-low-birth-weight group. In order to specifically address the question of the delivery route and its impact on neonatal outcome, a randomized, prospective study was designed. The study design specifically attempted to exclude the usual clinical estimation of fetal weight and sought to rely on other factors, which included the clinical availability of ultrasound as utilized by the physician staff. As the study proceeded, it became apparent on numerous occasions that the birth weights of infants who had been entered into this study were, in fact, in excess of the targeted weight range of 750-1,500 gm. In one instance an infant weighed in excess of 3,000 gm, and these observations led to a temporary discontinuation of the study. Data evaluation was undertaken from the first 40 patients entered into the study. This limited comparison failed to demonstrate significant differences regarding measures chosen to evaluate neonatal condition. It did define the limitations of correctly choosing infants for inclusion in this study. It is clear that more precise selection criteria must be available before the study of the effects of delivery route on outcome can be resumed appropriately.