Efficacy of morantel tartrate in a sustained release bolus on the control of subclinical gastrointestinal parasitism in first-year grazing dairy replacements

Thirty-four heifers (24 Holstein, 8 Ayrshire, 2 Jersey) and 12 Holstein steer calves were grouped into 23 blocks of 2 animals each according to breed, sex, and body weight. Animals in each block were randomly assigned to control or treated groups. The treated group received an anthelmintic bolus containing morantel tartrate before they were permitted access to pasture. A 2.6 ha pasture was divided in half with a double fence; the resulting two pastures had separate feed and water troughs. Steer calves were slaughtered upon termination of the trial to ascertain gastrointestinal parasite burdens. Two worm-free tracer calves were placed on each pasture every 2 mo and slaughtered after 4 wk of grazing to determine parasite infectivity of pastures. Herbage samples were obtained monthly and analyzed for infective larvae. The trial was conducted for 141 d during the grazing season. Treatment resulted in 90% reduction in infective larvae on pasture, 74% reduction in fecal worm-eggs, 91% reduction in adult worm burdens, and a trend toward reduced worm burdens in tracer calves by 52%. An overall average daily gain of .68 and .88 kg was obtained for control and treated animals. Reproductive data for the heifers remaining in the herd from the trial showed that treatment resulted in 44 less days to first breeding.     

Acidity in upland and hill soils: Cation exchange capacity,pH and lime requirement

For 30 acid upland and hill soils, with initial pH from 3.5 to 5.8, and loss on ignition from 14% to 94%, cation exchange capacity varied with pH according to the relationship CEC = m pH+C, where m and C are characteristic of each soil. The slope m depended on loss on ignition (LOI), and is given by: m=Δ CEC/Δ=0.22 LOI+1.92. Because of these relationships, CEC measured at the natural pH of the soil (in 0.025 M MgSO₄ solution) is more relevant to field conditions than a conventional measurement at pH7. An improved method for estimating lime requirement (LR) of these soils was developed, based on the relationship found between LR and the difference in CEC (ΔCEC) between that at the natural pH of the soil and that at the target pH of 5.5: LR=1.12 ΔCEC+1.48. Lime requirement can therefore also be estimated from loss on ignition using the earlier relationships, and is given by: LR=(0.25 LOI+2.15) Δ+1.48, where Δ is the difference between the natural pH (in 0.025 M MgSO₄) and the target pH. Predictions based on this agreed well with results for a further 10 soils.     

The humanist and computer-assisted library research

Conclusion Because of the success of this project as measured by the favorable comments of the participants as well as the increased search activity, the Council on the Humanities awarded an additional $1000 to continue the project in the spring of 1985. As an added feature of the new proposal, a workshop is planned for chairs of the various humanities departments as well as other interested humanists. The aim will be to encourage them and their colleagues to increase their involvement in automated literature searching, as well as to encourage their graduate students to use the service. With continued support, greater awareness of the service, and more extensive coverage of existing and future databases,³ a steady increase in computer-assisted bibliographic searching among humanists is definitely possible.     

Interconnection of Subsystem Reduced-Order Models in the Electrothermal Analysis of Large Systems

Heat conduction in an electronic device is commonly modeled as a discretized thermal system (e.g., finite element or finite difference models) that typically uses large matrices for solving complex problems. The large size of electronic-system heat transfer models can be reduced using model reduction methods and the resulting reduced-order models can yield accurate results with far less computational costs. Electronic devices are typically composed of components, like chips, printed circuit boards, and heat sinks that are coupled together. There are two ways of creating reduced-order models for devices that have many coupled components. The first way is to create a single reduced-order model of the entire device. The second way is to interconnect reduced-order models of the components that constitute the device. The second choice (which we call the "reduce then interconnect" approach) allows the heat transfer specialist to perform quick simulations of different architectures of the device by using a library of reduced-order models of the different components that make up the device. However, interconnecting reduced-order models in a straightforward manner can result in unstable behavior. The purpose of this paper is two-fold: creating reduced-order models of the components using a Krylov subspace algorithm and interconnecting the reduced-order models in a stable manner using concepts from control theory. In this paper, we explain the logic behind the "reduce then interconnect" approach, formulate a control-theoretic method for it, and finally exhibit the whole process numerically, by applying it to an example heat conduction problem     

Spray cooling effects on milk production, milk, and rectal temperatures of cows during a moderate temperate summer season

During summer 1982, responses of lactating Holstein and Guernsey cows were measured by milk temperature recorded by a Digital Dataloger with thermocouples attached to Boumatic flow meters. Maximum air temperature and temperature-humidity index averaged 30.8 degrees C and 75.6 for July. Breed did not affect milk temperature, but within-breed milk temperature increased with production. In a second study, benefits of spray cooling were evaluated with 24 Holsteins in midlactation assigned randomly to two groups of 12 and maintained under loose-housing conditions. Spray nozzles were installed in the walkways and under the manger shade for the spray treatment group. Maximum temperature and temperature-humidity index during the spray study were 27 degrees C and 73.9. Rectal temperature taken following milking averaged less for treatment than control (38.8 versus 39.1 degrees C). Milk temperature was similar (37.8 versus 38.1 degrees C). Daily milk yield was .70 kg higher than controls. Milk temperature may provide reliable indication of climate stress similar to rectal temperature, and spray cooling improves cow comfort and lessens summer decline of milk production.     

Oxygen consumption by portal-drained viscera of cattle: comparison of analytical methods and relationship to whole body oxygen consumption

Two experiments were conducted to compare methods of determining oxygen consumption by portal-drained viscera and to relate this consumption to total oxygen consumption by lactating dairy cows. Oxygen consumption was the product of portal blood flow (determined by dilution of dye infused into a mesenteric vein) and portal-arterial concentration differences of oxygen. In Experiment 1, portal-arterial concentrations of oxygen were determined in samples from three cows using equations based on blood pH, hemoglobin, partial pressure of carbon dioxide, and partial pressure of oxygen (method 1) or by direct oxygen determination with an oximeter (method 2). Overall, there were no differences in oxygen concentrations or oxygen consumption by portal-drained viscera between methods. In Experiment 2, oxygen consumption by portal-drained viscera (method 2) and total oxygen consumption were measured in two lactating cows. Oxygen consumption by portal-drained viscera accounted for 18% of total oxygen consumption.