Effects of substituting barley grain with corn on ruminal fermentation characteristics, milk yield, and milk composition of Holstein cows

The influence of corn or barley, or the equal mixture of both, on digestion characteristics and dairy cow performance was evaluated in metabolic and production experiments. Three rumen-cannulated early-lactation cows were used in a 3 x 3 Latin square design experiment to study the effect on ruminal fermentation characteristics and whole-tract digestion of substituting barley grain with corn. Production responses were determined by the use of 27 early-lactation Holstein cows. Cows in the production study were fed the test diets for 12 wk after a 2-wk covariate period. Results from the metabolic study indicated the effects of grain source on ruminal and total-tract digestion to be minimal. Total ruminal volatile fatty acids and acetate concentrations decreased linearly, butyrate increased linearly, and pH and lactic acid concentration were not affected by increasing levels of corn. Apparent digestibility of DM and organic matter showed a quadratic response with increasing the corn level in the diet, with no dietary effect on neutral detergent fiber, acid detergent fiber, and cellulose digestion. Ruminal fermentation characteristics suggest that substitution of barley grain with corn may alter the site of digestion and the end products of digestion that are absorbed by the animal. Multiparous cows failed to respond to treatment, whereas primiparous animals showed the greater response in milk yield and milk-component yield to diets that contained an equal mixture of corn and barley. These results probably reflect a more optimal synchronization of dietary protein and energy for dairy cows fed the 50:50 barley/corn diet.     

Current-Mode Active RC Filters Using Current Followers

In this letter, a realization of current-mode active filter using current followers as active element is described. We show the constructions of second-order lowpass, highpass and bandpass filters. The high-order filters can be realized by a cascade connection of these second filters. As examples, the second-order lowpass and highpass filters are designed for frequency of 5 MHz. The effectiveness of the proposed method is demonstrated through SPICE simulation.     

A Comparative Analysis of Two Artificial Neural Networks Using Pavement Performance Prediction

The management of pavements requires the ongoing allocation of substantial manpower and capital resources by the responsible agencies. These agencies ultimately report to the executive and legislative branches of government, which require justification and proof of the efficacy of these expenditures. This and the need for improved engineering technical feedback have encouraged the development of pavement management systems (PMS). One goal of a PMS is to provide decision makers at all levels with optimal resource-allocation strategies. This requires evaluation of alternatives over an analysis period based on predicted values of pavement performance. This necessitates more reliable pavement performance prediction models. Traditional modeling uses multiple regression techniques to predict pavement performance from traffic, time, and pavement distress or various combinations of these factors. Within the last 10 years, new modeling techniques, including artificial neural networks (ANNs), have been applied to transportation problems. The ANNs examined usually have been of a single type called a dot product ANN. This paper examines a different type called the quadratic function ANN and compares the results to the dot product ANN. The quadratic function ANN is a generalized adaptive, feedforward neural network that combines supervised and self-organizing learning. Models were developed to predict roughness using both types of ANN on the same data samples and the results compared. The data samples were drawn from the Kansas Department of Transportation's PMS database. The results indicate a significant improvement in the use of the self-organizing quadratic function ANNs and lead to recommendations for specific areas of additional research.     

Realization of a multiport gyrator using current mirror circuits

A current‐mode signal processing circuit is quite attractive for low supply voltage operation and high‐frequency application. A current‐mode continuous‐time filter consists of simple bipolar current mirrors and capacitors, and are quite suitable for monolithic integration. In this paper, we propose a design for a multiport gyrator using current mirror circuits. Using the multiport gyrator and capacitors, we can simulate passive LC filters. The tuning of the filter frequency can be achieved by adjusting the current of a single dc current course. As examples, third‐ and fifth‐order low‐pass filters are designed for frequencies of 20 to 80 MHz, and SPICE simulation results are shown to demonstrate the effectiveness of the proposed method. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(4): 41–47, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.1167     

Intestinal nutrient-gene interaction: the effect of feed deprivation and refeeding on cholecystokinin and proglucagon gene expression

We tested the hypothesis that dietary components reaching the bovine small intestine influence the expression of genes that encode the gastrointestinal neuropeptides cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1). The amount of digesta reaching the intestine was manipulated during the experiment by withholding feed from five heifers fitted with ruminal, duodenal, and ileal cannulas for 48 h and then subsequent refeeding. Duodenal and ileal biopsies were collected using a fiber-optic endoscope. A Northern hybridization procedure was used to evaluate changes in gene expression. Blood concentrations of CCK and GLP-1 were determined with RIA. The data indicate that CCK blood concentration and mRNA abundance decreased during the period of feed deprivation, but they returned to predeprivation values within 16 to 24 h of refeeding. The GLP-1 blood concentration also decreased during feed deprivation and returned to predeprivation values within 4 to 8 h of refeeding, despite the fact that proglucagon mRNA abundance did not change significantly during feed deprivation and refeeding. These findings provide evidence that CCK and GLP-1 are released in response to nutrients that reach the small intestine and may be involved in the physiological process of digestion and possibly play a role in regulating feed intake in ruminants.     

Prediction of strain recovery during solid-phase forming of thermoplastics

An approach to predict the strain recovery behavior of polycarbonate (PC) and high impact polystyrene (HIPS) under isothermal and non-isothermal conditions in a solid-phase forming environment is presented in this paper. The constants A and n of a power law relationship of the form ?(t) or δ(t) = Atⁿ, fitted to isothermal creep and stress relaxation data, were determined over a wide range of temperatures for both materials. An expression for isothermal recovery was derived and compared to experimental data. Master curves and the resultant shift factors, obtained by superposing the stress relaxation and creep data (both in tension and compression) were used with the time-temperature super position principle to numerically evaluate uniaxial strain recovery under a specific temperature history. The average temperature history obtained by numerically solving for the temperature distribution in a disc, at an initially high temperature and in contact with a cold metal surface, was used for the non-isothermal case. The theoretical results were compared with recovery data obtained from non-isothermal backward extrusion tests with a temperature history similar to the one described above. Reasonably good agreement was obtained.     

Estimates of genetic parameters for fatty acids in brisket adipose tissue of Canadian commercial crossbred beef steers

Heritability and genetic and phenotypic correlations between 15 individuals and 10 groups of fatty acids with a concentration greater than 0.5% in the brisket adipose tissue of 223 Angus and Charolais based crossbred commercial steers were estimated using univariate and bivariate animal models. Individual saturated fatty acids were low to moderately heritable, with heritability estimates ranging from 0.05 (C16:0) to 0.31 (C15:0). Individual monounsaturated fatty acids were low to moderately highly heritable ranging from 0.04 (9c C17:1 and 11c C18:1) to 0.51 (9c C14:1). Polyunsaturated fatty acid C18:2n − 6 was moderately heritable (0.17). Among groups of fatty acids, heritability estimates ranged from 0.03 for branched chain fatty acid (BCFA) and n − 6/n − 3 to 0.16 for n − 6 and Health Index. A range of low (0.00) to high (1.00) phenotypic and genetic correlations was observed among the 25 fatty acids considered in this study. In general, fatty acids such as conjugated linoleic acid (CLA) and 11t C18:1, with potential health benefits, showed significant antagonistic correlations with unhealthy fatty acids such as C14:0 and C16:0. The results from this study provide insight into the direct genetic control of host genes on fatty acid composition of beef tissues and will facilitate designs of genetic selection and/or genetic based diet management to improve fatty acid composition in beef cattle.     

Sensitivity analysis of a scrap tire embankment using Bayesian influence diagrams

Scrap tires have several properties that make them preferable to other materials as fills for embankment construction, including light weight (the dry unit weight is 1/3 that of soils), high hydraulic conductivity (up to 23.5 cm/s), and low thermal conductivity. These properties of scrap tire fills result in low lateral pressures on the abutment wall and in reduced design and construction costs. The low thermal conductivity helps to prevent permafrost action of soil layers beneath it and failure of the subgrade due to frost penetration.However, scrap tires possess high compressibility, a property that leads to settlement of the fill and consequent failure of the embankment. Other undesirable attributes of scrap tire embankments are susceptibility to internal heating and leaching of substances into surrounding water.An efficient means of controlling such undesirable attributes in the field is by comparing them with those simulated from a model embankment developed using Bayesian influence diagrams. In this work, the essential responses simulated using the Analytica^® software program are the temperature, lateral pressure, settlements, and leachate characteristics. The most critical embankment characteristics, based on the maximum probability densities, are the settlement and horizontal pressures, which are relatively low at 0.428 and 0.0034, respectively, because the likelihood that these values will be exceeded in the field is high. Temperature response was not considered critical because the maximum probability density simulated was 0.9301. Limits for leachate concentrations were also obtained for the model embankment based on ASTM D 6270 (1998) standards.     

Effects of forage source and amount of concentrate on rumen and intestinal digestion of nutrients in late-lactation cows

The objectives of this study were to determine the effects of dietary forage source with two concentrate concentrations on dry matter (DM) intake, rumen fill, ruminal and intestinal digestibility of nutrients, and duodenal N fractions in lactating cows. Four rumen and duodenal cannulated Holstein cows in late lactation were used in 4 x 4 Latin square design experiment with 21-d periods. Diets were 1) 65% first-cut alfalfa silage and 35% concentrate, 2) 50% alfalfa and 50% concentrate, 3) 65% bromegrass silage and 35% concentrate, and 4) 50% bromegrass and 50% concentrate. Dry matter intake was not affected by forage source but tended to be (P = 0.08) higher for cows fed diets with 50% concentrate. Rumen fill was greater (P < 0.01) for cows fed bromegrass compared with those fed alfalfa silage. Ruminal and intestinal digestion of DM was not affected by dietary forage source or concentrate level. Total N intake was greater for cows fed alfalfa-based diets, reflecting the higher crude protein content of alfalfa. However, total N flow at the duodenum was not affected by either forage source or concentrate in the diet. Although forage source influenced the site of digestion of some nutrients no significant effects on total tract digestibilities were observed.