Nonlinear wave transmission and pressure on the fixed truncated breakwater using NURBS numerical wave tank

Fully nonlinear wave interaction with a fixed breakwater is investigated in a numerical wave tank (NWT). The potential theory and high-order boundary element method are used to solve the boundary value problem. Time domain simulation by a mixed Eulerian-Lagrangian (MEL) formulation and high-order boundary integral method based on non uniform rational B-spline (NURBS) formulation is employed to solve the equations. At each time step, Laplace equation is solved in Eulerian frame and fully non-linear free-surface conditions are updated in Lagrangian manner through material node approach and fourth order Runge-Kutta time integration scheme. Incident wave is fed by specifying the normal flux of appropriate wave potential on the fixed inflow boundary. To ensure the open water condition and to reduce the reflected wave energy into the computational domain, two damping zones are provided on both ends of the numerical wave tank. The convergence and stability of the presented numerical procedure are examined and compared with the analytical solutions. Wave reflection and transmission of nonlinear waves with different steepness are investigated. Also, the calculation of wave load on the breakwater is evaluated by first and second order time derivatives of the potential

Stability of commercially available lactobacillus products

A study was conducted to determine the viability of three commercially available lactobacillus products in nonmedicated and medicated (lincomycin at 100 grams per ton) swine feed in several different environments over a 3-month period. Each product was stored in five environments: refrigeration (40°F), room temperature (70°F) in sealed container, room temperature in unsealed container, swine nursery (90°F) in a sealed container, and swine nursery in an unsealed container. Feed samples were counted for lactobacillus at weeks 0, 1, 3, 5, 7, and 12 with four replications. The three commercial products differed in stability while maintained in the various environmental conditions. Refrigerated storage prolonged (P<.05) stability of all products. Stability of products stored at room temperature was greater than those stored in the nursery (P<.05). Medication had a slight adverse affect on the product stability. There were no differences between samples stored in sealed or open containers. These results demonstrate that the stability of viable lactobacillus products can be influenced by storage environment, length of storage, and type of medication in the feed

Predicting voluntary forage intake in cattle

A large database was compiled of forage intake observations published during the past 20 years. Inputs included a wide range of factors believed to be related to voluntary intake. An analysis was designed to pinpoint which feed and animal characteristics were most valuable in predicting voluntary intake across a range of feeding situations and to compare the ability of different models to predict intake. Results emphasized the complexity of intake prediction. A wide range was evident in the variables included in the optimal models for predicting intake within different data subsets. In many cases, we observed that ratios between feed values (e.g., forage acid detergent fiber:forage crude protein) were more useful in predicting intake than the measures themselves

Influence of fall protein supplementation with a self-fed liquid supplement on performance of beef cows grazing tallgrassprairie range

We evaluated the effect of providing a liquid, high-protein supplement during the fall grazing period on beef cow and calf performance. Mature, pregnant, spring-calving cows (n=122) grazing native range were assigned to supplementation treatments. All calves were weaned on October 15. Control cows received no fall supplementation and then were handfed a dry supplement (40% crude protein; as fed basis) from December 17 until calving. Supplemented cows were either allowed access to a liquid protein supplement (40% crude protein; as-fed basis) approximately 2 months before weaning until calving (fall supplementation from August 14 to December 17) or from weaning until calving (fall supplementation from October 15 to December 17). Supplement intake of the control cows from December 17 until calving was adjusted to match the estimated supplement intake of the liquid-fed groups and was prorated and fed 3 days/week. Supplementation was terminated upon calving, at which time all cows were treated similarly. Provision of liquid supplement during the fall increased cow body weight and body condition in the post-weaning period. However, cows not supplemented during the fall phase were able to overcome their lesser previous nutrition when they were suitably supplemented during the winter phase. The pre-weaning rate of gain of calves was not affected by fall supplementation. Calves produced by cows receiving no fall supplementation gained more weight from birth to the start of the summer grazing season. Subsequent pregnancy rate was not affected by fall supplementation

Effect of ruminal versus postruminal administration of degradable protein on utilization of low-quality forage by beef steers

Twelve ruminally fistulated steers were used to evaluate the effects of supplying a highly degradable protein source (casein) both ruminally and postruminally on intake and digestibility of low-quality native hay. Both protein supplementations substantially increased voluntary intake, organic matter digestion, rate of passage, ruminal ammonia, and blood urea concentrations, but intakes were considerably greater when protein was given ruminally as opposed to postruminally

Consumo e digestibilidade de feno de baixa qualidade suplementado com nitrogênio não protéico em bovinos Intake and digestibility of low-quality hay with nonprotein nitrogen supplementation in cattle

O objetivo deste trabalho foi avaliar o efeito de níveis de inclusão de nitrogênio não protéico, em suplementos fornecidos a tourinhos Hereford, com 17 meses e peso médio de 220 kg, alimentados com feno de tifton (Cynodon dactylon) ad libitum. Os tratamentos avaliados foram: feno + suplemento sem uréia; feno + suplemento com 0,28 g de uréia kg-1 PV0,75; feno + suplemento com 0,55 g de uréia kg-1 PV0,75; feno + suplemento com 0,83 g de uréia kg-1 PV0,75 e feno + suplemento com 1,11 g de uréia kg-1 PV0,75. O feno apresentou, na média, 3,86% de proteína bruta e 84,66% de fibra em detergente neutro. Não se constatou efeito da suplementação sobre a digestibilidade da matéria orgânica, matéria orgânica do feno, fibra em detergente neutro, celulose e hemicelulose; o consumo total desses itens respondeu quadraticamente à suplementação com níveis crescentes de nitrogênio não protéico. A suplementação não afetou a excreção fecal metabólica de matéria orgânica, o que sugere aumento na taxa de passagem (variação no consumo) e na taxa de digestão (digestibilidade constante). O consumo de matéria orgânica digestível apresentou comportamento quadrático com aumento dos níveis de uréia na dieta. Quando o nível de proteína degradável no rúmen foi equivalente a 8,1% da matéria orgânica digestível, a relação de consumo entre esses componentes foi otimizada.<br>The objective of this work was to evaluate the effect of nonprotein nitrogen supplementation levels on the digestibility of low-quality hay (Cynodon dactylon), which was offered ad libitum to Hereford bulls aging 17 months and weighing 220 kg. The evaluated treatments were: hay + no urea supplement; hay + supplement with 0.28 g urea kg- 1 BW0.75; hay + supplement with 0.55 g urea kg-1 BW0.75; hay + supplement with 0.83 g urea kg- 1 BW0.75 and hay + supplement with 1.11 g urea kg- 1 BW0.75. Hay composition presented 3.86% of crude protein and 84.66% of neutral detergent fiber. Digestibility of organic matter, organic matter of forage, neutral detergent fiber, cellulose and hemicellulose were not affected by nonprotein nitrogen level; total intake of these components showed a quadratic response to nonprotein nitrogen supplementation. Organic matter metabolic fecal excretion was not affected by supplementation, suggesting a simultaneous increase in both passage (intake increase) and digestion rates (stable digestibility). The digestible organic matter intake showed a quadratic response with the increase of urea supplementation levels. The relationship between rumen degradable protein intake and digestible organic matter intake showed a maximization point, when rumen degradable protein intake was equivalent to 8.1% of digestible organic matter intake