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Body condition scoring (BCS) and body weight (BW) are observations associated with labile tissue reserves, health, and reproduction efficiency of dairy cows. The effect of parity (1 through to ≥5) and feeding system (pasture-based and TMR) on BCS and BW were evaluated utilizing raw data sets from 16 retrospective studies that totaled 24,807 Holstein cows across 3 nations (Australia, Canada, and the United States). Linear regression models were used to investigate the 5 outcome variables of precalving BCS, peak milk BCS, change in BCS from precalving to peak milk, and peak milk BW and their respective associations with parity and feeding system. To help control for the influence of calendar time, study treatment protocols when applicable, and genetic change, all outcome variables were center-transformed around each study group mean. Including feeding system as a covariate improved model fit for most outcome variables; however, the relative effect size of parity was generally much greater than feeding system effect size. Parity 2 cows had the lowest precalving BCS of -0.087 [95% confidence interval (CI): -0.107, -0.065] less than the mean, whereas parity 1 cows had the greatest, 0.068 (95% CI: 0.043, 0.092) above mean, regardless of feeding system. Peak milk BCS overall decreased with increasing parity (parity 1 to parity ≥5: -0.13, 95% CI: -0.19, -0.08) and BCS change during the transition period monotonically decreased with increasing parity (parity 1 to parity ≥5: -0.22, 95% CI: -0.26, -0.17). Peak milk BW monotonically increased with increased parity (parity 1 to parity ≥5: 114 kg, 95% CI: 104, 125). A waffle plot was used to present the proportions of cows, by parity, that were partitioned into "low BCS and low BW," "low BCS and high BW," "high BCS and low BW," or "high BCS and high BW" groups. Cows were assigned either a high or low status by being above or below their specific centered study group means, respectively. Considering a null hypothesis of 25% per BCS-BW category, there was a striking change in category from parity 1 cows that were predominantly in the "high BCS and low BW" category (61.2%) to parity ≥5 cows that were predominantly in the "low BCS and high BW" category (55.5%). The study supports studies showing increased weight and change in BCS with increased parity. We highlight the associations among production system, BCS, BW, and parity.

We conducted a retrospective meta-analysis based on individual cow data to assess the associations of parity, level of production, and pasture-based or intensively fed systems with fertility. Our goal was to provide understandings of the role of parity in risks for removal and reproductive failure. Multilevel models were used to evaluate the fixed effects of parity, milk, milk solids, milk fat and protein percentage and yield, and production system [intensively fed (n = 28,675) or predominantly pasture fed (n = 4,108)] on reproductive outcomes. The outcomes were the hazard of not being bred (HNBRED), hazard of pregnancy (HPREG), pregnancy to first breeding (PREG1), and odds of becoming pregnant in a lactation (OPAL). The 32,783 cows were in 13 studies conducted in Australia (14.6% of cows), Canada (2.4% of cows), and the United States (83.0% of cows). There were 38.5% of cows in the sample in parity 1, 27.3% in parity 2, 16.7% in parity 3, 9.0% in parity 4, and 8.6% in parity ≥5. Compared with cows of parity 1, parity ≥5 cows had a greater HNBRED [hazard ratio (HR) = 2.45], lesser HPREG (HR = 0.73), and reduced OPAL (odds ratio = 0.36). However, the parity ≥5 cows had similar PREG1 to other parities except for parity 1. This suggests the possibility of a higher proportion of subfertile parity ≥5 cows than for other parities. Associations between parity and reproductive measures were influenced by the different milk production measures, indicating that milk yield and milk component percentages and yields modified the odds or hazards of successful reproduction. All milk production measures had quadratic associations with OPAL, indicating that either low or high production or concentration of solids within a cohort reduced OPAL. This reduced OPAL reflected a greater HNBRED for lower milk yield and milk protein and fat yielding cows. Both milk yield and milk protein percentage had quadratic associations with HPREG. When centered milk yield was categorized into quartiles, small differences in HPREG existed. A more marked association of milk protein percentage occurred with HPREG, with optimal HPREG at approximately 0.5% above group mean milk protein percentage. Milk fat percentage (HR = 0.901), fat yield (kg/d; HR = 0.78), protein yield (kg/d; HR = 0.71), and milk solids yield (kg/d; HR = 0.84) were all linearly associated with reduced HPREG. Difference in production systems did not have substantive effects on PREG1 but did for HNBRED, HPREG, and OPAL. Estimates of associations of parity with reproductive outcomes HNBRED, HPREG, and OPAL were influenced by milk and milk solids yield; older cows had markedly lower reproductive outcomes. Interestingly, for PREG1, there were few differences among parities and differences were less influenced by milk yield and constituent measures. The marked associations of parity with removal for all reasons, deaths and culling, and reductions in HNBRED, HPREG, and OPAL indicate a need to focus on the physiological changes with parity to produce better strategies to support optimal longevity of cows.

Data were obtained from studies in Australia, Canada, and the United States using individual cow data from 28,230 Holstein cows to evaluate associations between parity and disease. Our goal was to develop understanding of disease risks for cows of differing parity. We hypothesized that there would be increased risks of disease and changes in metabolite concentrations with increased parity. Parity ≥5 represented 2,533 cows or 9.0%, parity 4 was 9.8% (2,778), parity 3 as 19.0% (5,355), parity 2 as 28.1% (7,925), and parity 1 was 34.1% (9,639) of the sample. Of these cows, 15.5% were in Australia, 14.7% in Canada, and 69.8% in the United States. Lactational incidence (LI) risk of clinical hypocalcemia increased with parity from 0.1% for parity 1 to 13% for parity ≥5 cows. The marked increase suggests profound differences in metabolism with increased parity. The LI of clinical mastitis was 17.4%. The odds of mastitis increased with parity to 2.5 times greater in parity ≥5 than in parity 1. The LI of lameness increased with parity; specifically, the odds of lameness was 5.6 times greater for parity ≥5 than parity 1. Dystocia incidence was 8.7% and greatest for parity 1 cows. The LI of retained placenta was 7.4% and increased with parity, with the odds for parity ≥5 2.3 times greater than for parity 1. The LI of metritis was 10% and of endometritis 14%, with the greatest odds in parity 1. The LI of clinical ketosis was 3.3% with a marked increase in odds with parity. The prevalence of subclinical ketosis was 26.8% with only cows in parity 1 having lower odds than other parities. Parity ≥5 cows had greater odds (odds ratio = 1.7) of respiratory disease than parity 1 cows, which were lesser than other parities. Metabolite concentrations were evaluated in 5,154 Holstein cows in the precalving, calving, and immediate postcalving data sets. Metabolic measures near peak lactation provided 1,906 observations. Concentrations of β-hydroxybutyrate (BHB) and nonesterified fatty acids increased with parity on d 1 to 3 of lactation and at peak lactation. On d 1 to 3 after calving differences in glucose, nonesterified fatty acids, and BHB indicated a greater reliance on mobilized lipid to export energy to peripheral tissues as BHB for greater parity cows. Differences in concentrations among parity groups were marked at times, for example0.20 mM in Ca for parity 1 and 2 to parity ≥5 and0.33 mM for all older parities compared with parity 1 for P on the day of calving. The marked increase suggests profound differences in metabolism with increased parity are probably influenced, in part, by increased production. We found marked differences in concentrations of metabolites with parity that are consistent with reduced reproduction, health, and body condition for higher parity cows. These unfavorable differences in metabolism in Ca, P, glucose, and cholesterol concentrations for higher parity cows also complement the often-substantial differences in disease risk with parity and suggest a need to carefully consider the parity structure in study design. Managers and advisors will need to consider methods to reduce risk of health disorders tailored to cows of different ages.

Impetigo herpetiformis (IH), or generalized pustular psoriasis of pregnancy, is an exceedingly rare, generalized pustular skin eruption occurring during pregnancy associated with hypovolemia, sepsis, hypocalcemia, and airway edema. Fetal outcomes are generally poor, and parturients with IH may present with emergent indications for cesarean delivery due to placental insufficiency. We present a case of IH in a 19-year-old G1P0 who underwent successful general anesthesia for cesarean delivery. Her case highlights the anesthetic implications for patients afflicted with this rare disease, including perioperative pain management, airway concerns, considerations for neuraxial anesthesia, and monitoring challenges.

We report far infrared (FIR) studies of plasmons in spatially modulated two‐dimensional electron gases (2DEGs) in AlGaAs/GaAs heterostructures using biased overlaid metal gratings, including interdigitated gratings, both as optical couplers and as spatially modulating gates. Comparison of the experimental results with the predictions of scattering matrix calculations of the FIR response of a modulated 2DEG in the presence of a perfectly conducting lamellar grating allow us to deduce the spatial variation of the number density distribution in the 2DEG as a function of grating bias. For the interdigitated grating gates, the 2DEG can be modulated at a period of twice that of the grating fingers by differentially biasing alternate fingers; 2D plasmon resonances have been observed at half‐integral values of the grating wave vector G, corresponding to the electrically induced periodicity of the 2DEG modulation itself acting as an optical coupler in addition to the metal grating. The observed G/2 plasmon frequencies decrease with increasing amplitude of the 2DEG number density modulation, in quantitative agreement with those obtained from scattering matrix calculations of the optical response of a modulated 2DEG under a perfectly conducting lamellar grating; calculations of the oscillating charge density profiles show that this occurs because, as the modulation amplitude increases, the oscillation becomes localized in regions of low 2DEG number density which are also under one of the sets of grating fingers, and is therefore better screened.

The frequencies and the absorption cross sections of infrared active phonons show anomalies related to the transition between the normal and superconducting phase in YBa2Cu3O7. The excess intensity of the absorption line and the frequency shift of the mode near 585 cm-1 are proportional to each other. Correlating these parameters with the thermodynamic order parameter using hard model spectroscopy leads to an order parameter of the superconducting phase which follows formally mean field theory of the BCS or Landau-Ginzburg type.

Urinary 3 methyl-histidine excretion was measured in high yielding dairy cows between 10 and 3 d precalving and between 3 and 9 d postcalving. Cows received a sodium monensin controlled-release capsule or a placebo 3 wk before calving. Monensin did not affect urinary 3 methyl-histidine. Average urinary 3 methyl-histidine excretion was significantly higher postcalving (4.11mmol d –1 ) than precalving (2.48 mmol d –1 ). This increase is assumed to be predominantly due to the negative nitrogen balance in the postcalving period caused by insufficient nutrient intake to meet nutrient requirements, which necessitates catabolism of mainly myofibrillar protein.

The effect of tilmicosin on the incidence of clinical mastitis and subsequent lamb performance was studied in 9 sheep flocks in Ontario. Ewes were treated randomly with either tilmicosin or placebo approximately one month prior to lambing. Outcome was assessed by comparing rates of clinical mastitis, palpable udder abnormalities, and preweaning (50-day) lamb weights between the 2 treatment groups, while controlling for other important variables. Lambs raised by multiparous ewes treated with tilmicosin were significantly heavier than lambs from placebo-treated multiparous ewes at 50 days. Lambs from tilmicosin-treated ewes were on average 0.52 kg heavier than lambs in the placebo group. There was no difference between treatment groups in the weight of lambs from first parity ewes. Tilmicosin treatment resulted in a 43% decrease in palpable udder abnormalities. Incidence of clinical mastitis did not differ between experimental groups. The administration of tilmicosin prelambing, at the time of routine clostridial disease vaccination, may be a beneficial and convenient way to reduce mastitis infection and improve the preweaning gain of lambs.

Infrared absorption spectroscopy has been used to investigate the complete phonon frequency range (20 cm-1-700 cm-1) at temperatures between 10 K and 300 K. A direct coupling of bulk phonon modes in YBa2Cu3O7- delta with the superconductor order parameter is deduced from the critical temperature dependence in the superconducting low temperature phase (Tc approximately 92 K). The excess intensity and the frequency shift of the mode near 580 cm-1 are shown to be proportional to the square of a BCS-like order parameter in agreement with the predictions of Hard Mode Spectroscopy.

First Dairy Herd Improvement Corporation (DHI) test milk that was sampled prior to displaced abomasum (DA) diagnosis was used to examine the association between milk yield (kg), fat (%), protein (%), or fat/protein ratio and DA in dairy cows. 27 DA cases were matched to 3 controls per case by herd and calving date. Logistic regression was used to examine the effect of each milk parameter on the odds of DA, adjusting for lactation number and days in milk (DIM) at test. Higher odds of DA diagnosis was found with lower milk yield, higher milk fat percentage, lower milk protein percentage and higher fat/protein ratio. We conclude that milk yield, fat percentage, protein percentage and fat/protein ratio may be used to detect cows at risk for DA. Our findings also indicate that cows diagnosed with DA were energy deficient prior to DA diagnosis.

Strong nonlinear response is an essential feature of narrow band transport. These potentially strong nonlinearities derive from the fact that a perturbation applied to a narrow band will exhaust the spectrum of states and the response will be saturated. The most exciting example is the long sought for but never achieved Bloch oscillation [1]. Here, we describe two different experiments that explore the saturated response of a narrow conduction band. First we discuss the effect of magnetic fields that drive the cyclotron resonance above the top of the mini-band and then, secondly, we document quenching of the narrow band conductivity at temperatures that exceed the mini-band width.

We have studied the effect of superlattice structure on the 1s to 2p + transition energy of shallow donors. In a strong magnetic field along the growth direction the transition is inhomogeneously broadened with absorption features that can be correlated with the position of the donor with respect to the barriers and wells. The results compare well with recent theory of donors in superlattices and are potentially important for the determination of donor distributions in superlattices.

We have observed breakdown of cyclotron resonance in large magnetic fields oriented perpendicular to the growth direction in semiconductor superlattices. At small magnetic fields conventional cyclotron resonance is observed with the mass related to the miniband mass. At large magnetic fields, when the cyclotron diameter approaches the superlattice period, the resonance frequency appears to saturate and is determined by orbits impaled on the barrier. A model calculation gives good account of the magnetic field dependence of the resonance position and line width.

Measurements of the magnetocaloric effect in two different spin glasses, CuMn and LaGdAl2 are presented and compared with the predictions of equilibrium thermodynamics. It is shown that LaGdAl2 is an extremely reversible system that exhibits a relatively large amount of adiabatic cooling below TG and very little irreversibility. CuMn, on the other hand, is much more irreversible and a definite observation of adiabatic cooling has not been made. It is proposed on the basis of these results that the spin-glass phenomenon is fundamentally an equilibrium one that is often obscured by secondary irreversible properties.

Calorimetric measurements on the hysteresis loop of the spin glass CuMn show that the energy changes take place on those legs of the loop which correspond to reversals of the remanent magnetisation and that it is always heating which occurs, irrespective of the direction of the applied magnetic field. Cycling through successive hysteresis loops causes large initial changes in sample heating and loop area, with both of these quantities tending to a temperature-independent limit. Although the limit cycle is displaced from the origin, the thermal energy changes on both irreversible legs are approximately equal, indicating a change of internal magnetic energy on reversal of the remanence. It is argued that the energy released in the initial magnetisation reversals is attributable to irreversible rearrangements of the relative spin directions and that it is only in the limit cycle that energy changes represent exclusively the intrinsic irreversible processes of magnetisation reversal.

Using the requirements of a quantized multiple access voice communications system as a base, an investigation of several methods of modulation was conducted. Two frequency modulation (FM) techniques and one amplitude modulation (AM) technique were investigated in detail. The AM technique is the quantized pulse position modulation-AM (QPPM-AM) method used in the U. S. Army random access-discrete address (RADA) communications system. The quantized FM techniques were investigated as possible alternates to the RADA technique. Comparisons between the techniques are made in the areas of required transmitter power, RF bandwidth, circuit complexity, and several other areas relevant to communications systems of this type. The results indicate superior performance of one FM technique in several areas.

We report the observation of photovoltaic infrared photodetection in an n‐type GaAs/AlGaAs superlattice within the optical range 3.6–6.2 μm. A built‐in graded AlGaAs barrier (∼0.2 eV) provides charge polarization in the sample by allowing the optically excited electrons in the second miniband of the superlattice to diffuse over this barrier. The optical polarization of the infrared signal is consistent with the selection rules applicable to the superlattice. The infrared photoresponse results from first‐to‐second miniband as well as shallow donor‐to‐second miniband photoexcitations within the superlattice. Donor‐to‐second miniband photoexcitation is dominant at low temperatures (

One of the more remarkable achievements in the field of materials science has been the growth of semiconductor single crystals atomic layer by atomic layer. By varying the composition along the growth direction a very great degree of control can be exercised over semiconductor doping and bandgaps. Although the scientific understanding and technological development of these materials has been unusually rapid, the early vision[1] that focused on the engineering of bulk, 3-dimensional, bandstructures has been largely forsaken in favor of properties that emerge due to confinement of the electron states to the two dimensions of a single layer.

The question of closed-loop pole placement for linear multivariable systems decoupled by output feedback is considered. The class of decoupling feedback matrices is extended to include those which are proper functions of s . This result insures that all uncancelled poles of the resulting closed-loop system can be reassigned to any desired location by suitable choice of the feedback matrix.