Investigating perinatal calf mortality in beef herds

This article summarizes the information presented in this issue to identify the reasons for a perinatal calf mortality (PCM) problem through a risk-factor-evaluation approach. The benefits of necropsies in PCM investigations are discussed, and the gross lesions of the major causes of PCM are described. The use of 2 x 2 tables to calculate odds ratios and the Chi-square method to test the validity of the odds ratios are presented as methods to determine suspected risk factors. The article concludes with a discussion of the management plan used to solve a PCM problem.

Residential radon exposure and lung cancer: evidence of an urban factor in Iowa

An ecological study of lung cancer, cigarette smoking, and radon exposure was conducted in 20 Iowa counties. County-based lung cancer incidence data for white female residents of Iowa were stratified according to radon level and smoking status. Cancer incidence data for the period 1973-1990 were obtained from the State Health Registry of Iowa. Smoking level was determined from a randomly mailed survey. Radon level was determined according to an EPA supported charcoal canister survey. Within low smoking counties, rates for all lung cancer and small cell carcinoma were significantly lower (p < 0.05) in the high radon counties relative to the medium and low radon counties. However, within high smoking counties, rates for all lung cancer, adenocarcinoma, and small cell carcinoma were significantly higher (p < 0.05) in the high radon counties relative to the low radon counties. Variations in socioeconomic data for these counties, available through the 1980 and 1990 census, did not explain these results. Lung cancer rates also were significantly increased in urban counties even after holding smoking status constant. Multivariate analyses revealed significant interactions between smoking, urbanization, radon levels, and lung cancer. The results of this hypothesis generating study will be tested in a case/control study now ongoing in Iowa. Analysis will need to include separate evaluations by smoking status, radon level, and residence in urban or rural areas for the major morphologic types of lung cancer.

Pure Sequence Vibrational Spectra of Small Polyatomic Molecules

Highly excited (0&lt;E&lt;4 eV) vibrational levels in the electronic ground state of small, gas phase, polyatomic molecules can be examined by a variety of Franck-Condon controlled laser spectroscopic schemes: one-laser (Dispersed Fluorescence: DF), two-laser (Stimulated Emission Pumping: SEP) and three-laser (IR-SEP). The DF spectra contain patterns of vibrational level spacings and transition intensities that can provide a basis for assigning nonrigorous quantum numbers to individual eigenstates or feature states (which consist of clusters of unresolved eigenstates) or refining a superpolyad fit model. The SEP spectra contain a quantity (∼103) of features sufficient to invite application of a variety of statistical measures. Rigorously pure sequences (same total symmetry, same J) can be constructed. The &gt; 103: 1 dynamic range of these spectra combined with the ability to vary systematically the electronically excited rovibronic level from which these spectra emanate, can produce nearly complete pure sequences. Low resolution spectra correspond to early time, localized dynamics. Such spectra often contain fully resolved Franck-Condon bright feature states, each of which can be unambiguously assigned to a set of normal mode vibrational quantum numbers. Sometimes, such assignments can only be secured by high resolution detective work. Viewed at higher resolution, feature states often split up, revealing several layers of underlying structure. The hierarchy of splittings in the frequency domain corresponds to sequential spreading of the initially localized excitation in the time domain. Elaborate but traditional multi-resonance superpolyad effective Hamiltonian (ℌeff) matrix fit models can describe the coarse structure in the spectrum and the early time intramolecular dynamics. Since the superpolyad model is based on matrix elements of a relatively small number of anharmonic coupling terms (e.g., k122Q1Q22) evaluated in a normal mode, harmonic oscillator, product basis set, the superpolyad model is readily scaled to higher energy. The superpolyad model provides an accurate and refinable model for early time sequential Intramolecular Vibrational Redistribution (IVR) processes. Upon scaling to higher energy, the model provides testable predictions as the early time dynamics becomes more rapid and more complex. The most informative, reliable, and robust statistical measures applicable to polyatomic molecule vibrational spectra are those based on the well characterized initial localization and its early time dynamics, as described by a superpolyad ℌeff model. Superpolyad models describe how the remnants of regular dynamics are encoded in the spectrum at both high and low resolution. The models predict characteristic patterns of frequency separations and relative intensities which will be approximately replicated many times in the spectrum. The Extended Autocorrelation (XAC) pattern recognition method allows these patterns to be detected and located in the spectrum. Another scheme is based on the appearance in the spectrum of fine permutation splittings superimposed on a much coarser manifold of vibrational levels. These identical atom permutation splittings become resolvable when a molecule begins to tunnel between different chemically bonded networks on a time scale comparable to the inverse of the spectral resolution (1/δν). A third technique, tree-based hierarchical analysis (e.g., parsimonious trees) can reveal, without an a priori specified model, a hierarchy of coupling matrix elements (or delocalization rates). Spectroscopic detective work can identify the approximately conserved quantities that are destroyed by each of the hierarchical couplings. Because of the wide variety of approximately conserved quantities and coupling mechanisms responsible for the sequential destruction of these quantities, it is likely that the usual statistical measures developed by “quantum chaologists” for locating a system on the Poisson (regular, localized) ↔GOE (chaotic, delocalized) continuum, are too inflexible and reductionistic to yield useful insights into polyatomic molecule rotation-vibration dynamics. We believe that the important question is not whether molecules ever achieve the “bag of atoms limit”, but how they approach this limit. How fast does the initially localized excitation decay? Where does the energy go? What are the mechanisms that cause the energy to flow?

Radon testing behavior in a sample of individuals with high home radon screening measurements

Although radon exposure has been identified as the second leading cause of lung cancer, fewer than 6% of U.S. homeowners test their homes for radon. This report examines participants' follow-up radon testing behavior subsequent to receiving an initial screening radon level greater than 20 pCi/L. Sixty-two participants in the Iowa State-Wide Rural Radon Screening Survey who had radon screening measurements over 20 pCi/L were questioned by phone survey 3 months after receipt of their radon screening result to assess: whether participants were aware of radon's health risk; if participants recalled the radon screening results; how participants perceived the relative health risk of radon and whether participants planned follow-up radon testing. Only 19% of the respondents specifically identified lung cancer as the possible adverse health outcome of high radon exposure, and the majority of participants underestimated the health risks high radon levels pose when compared to cigarettes and x-rays. In addition, less than one third (29%) of the participants actually remembered their radon screening level within 10 pCi/L 3 months after receiving their screening results. Only 53% of the individuals correctly interpreted their screening radon level as being in the high range, and only 39% of the participants planned follow-up radon measurements. Receipt of radon screening test results indicating high radon levels was not an adequate motivational factor in itself to stimulate further radon assessment or mitigation. Our findings suggest that free radon screening will not result in a dramatic increase in subsequent homeowner initiated remediation or further recommended radon testing.

Factors associated with elevated 222Rn levels in Iowa

The University of Iowa, in conjunction with the Environmental Protection Agency's State Radon Survey Assistance Program, performed a 222Rn screening survey of 582 rural households in the winter of 1989. The distribution of maximum indoor 222Rn concentrations throughout Iowa as well as the relationship between 222Rn screening measurements, detector placement, and housing characteristics are summarized. This report is unique in that site-specific home construction characteristics were collected in the field from participants prior to 222Rn monitoring. The findings of the survey indicate that the significance of a particular housing characteristic on a 222Rn screening measurement is dependent on the placement of the radon detector.

137Cs levels in deer following the Three Mile Island accident

White-tailed deer (Odocoileus virgianus) tongues were assayed to assess whether or not significant widespread 137Cs contamination occurred in the vicinity of Three Mile Island Nuclear Station as a result of the 1979 accident. White-tailed deer tongues harvested from 10 Pennsylvania counties more than 88 km away from Three Mile Island had significantly higher 137Cs levels than deer tongues harvested from counties surrounding the nuclear plant. The mean deer tongue 137Cs levels found in Pennsylvania white-tailed deer were lower than 137Cs levels found in deer from other parts of the U.S. sampled shortly after culmination of major atmospheric nuclear testing. These findings support the conclusions of previous studies suggesting that only minimal quantities of 137Cs escaped from the damaged Three Mile Island plant after the accident.

Field comparison of several commercially available radon detectors

To determine the accuracy and precision of commercially available radon detectors in a field setting, 15 detectors from six companies were exposed to radon and compared to a reference radon level. The detectors from companies that had already passed National Radon Measurement Proficiency Program testing had better precision and accuracy than those detectors awaiting proficiency testing. Charcoal adsorption detectors and diffusion barrier charcoal adsorption detectors performed very well, and the latter detectors displayed excellent time averaging ability. Alternatively, charcoal liquid scintillation detectors exhibited acceptable accuracy but poor precision, and bare alpha registration detectors showed both poor accuracy and precision. The mean radon level reported by the bare alpha registration detectors was 68 percent lower than the radon reference level.

Effect of induction of parturition on immunoglobulin content of colostrum and calf serum

Thirty-four pregnant crossbred beef cows were injected with prostaglandin F(2) alpha (PGF group, n = 11), dexamethasone (DEX group, n = 11), or saline (control group, n = 12) on Day 270 of gestation. Immediately after calving, all colostrum was milked from each cow. A sample was taken, and the remainder was fed to that cow's calf within one hour of birth. Serum was collected from each calf at 0 and 24 h of age. Immunoglobulin G (IgG) content of colostrum and serum was determined with commercial radial immunodiffusion plates. The data from four PGF cows that did not calve until after 140 h post injection were excluded from the results. Mean (+/- SD) volumes (ml) of colostrum were 2086 (+/-1148.4) for the PGF group, 1336 (+/-583.7) for the DEX group, and 2404 (+/-1140.7) for the control group. Mean (+/- SD) concentrations (mg/dl) of IgG in colostrum were 6017 (+/-3351.2) for PGF, 10285 (+/-5370.7) for DEX and 10766 (+/-5098.3) for the control group. Mean (+/- SD) total quantities of IgG (g) in colostrum were 133.9 (+/-120.03) for PGF, 134.1 (+/-96.67) for DEX and 235.6 (+/-147.22) for the control. IgG concentrations were very low or were not detectable in serum of all calves prior to administration of colostrum. Mean (+/- SD) concentrations (mg/dl) of IgG in serum of calves at 24 h of age were 1469 (+/-905.8) for calves from PGF cows, 1819 (+/-1289.8) for calves from DEX cows, and 3317 (+/-1888.2) for calves from control cows. Calves from control cows had significantly more IgG at 24 h than calves from PGF cows or DEX cows (p<0.05). Calves born to cows induced to calve early may be at an increased risk of failure of passive transfer and so should be monitored for IgG concentrations.

Use of the sustained-release morantel bolus in stocker calves in southern United States

Two groups of 21 mixed-breed heifers were wintered on separate permanent pastures. Each heifer from one group was administered a sustained-release morantel bolus on October 7 (day 0), and the other group remained as untreated controls. Body weights were determined and fecal samples were taken at 28-day intervals. At the onset of the trail and at every 56 days, 6 heifers were removed from each group for slaughter to determine the developmental stages and the number of gastrointestinal nematodes. In addition, 3 tracer calves that were free of gastrointestinal nematodes were released on each pasture for 28 days at the beginning of the trail and after the last experimental-group calves had been removed. The 6 calves slaughtered on day 0 of the trail had a mean of 5,544 gastrointestinal nematodes. Tracer calves released on day 0 and removed on day 28 of the trial acquired 31,143 and 30,530 gastrointestinal nematodes from the pastures containing the treated and control heifers, respectively. Throughout the trial, the number of nematodes in the control calves increased at each sampling date (mean, 126,168 worms), whereas the mean number of worms in the treated heifers was 45,458. Tracer calves placed in the pastures after the 168-day trail acquired significantly more worms (9,632 vs 2,899; P less than 0.05) from grazing the pastures with control heifers than from grazing the pastures with treated heifers. Counts of eggs per gram of feces were significantly different (P less than 0.01) between the 2 groups from day 28 through day 112.(ABSTRACT TRUNCATED AT 250 WORDS)