The effect of silage and concentrate type on intake behavior, rumen function, and milk production in dairy cows in early and late lactation.

The objective of this experiment was to evaluate the effect of feeding total mixed rations (TMR) that differ in structural and nonstructural carbohydrates to dairy cows in early and late lactation on short-term feed intake, dry matter intake (DMI), rumen fermentation variables, and milk yield. A 5 x 5 Latin square experiment with 15 dairy cows was repeated during early and late lactation. The 5 treatments were a TMR with (all on dry matter basis) 55% roughage (a 50:50 mixture of corn silage and grass silage) and 45% concentrate (a 50:50 mixture of concentrate rich in structural carbohydrates and concentrate rich in nonstructural carbohydrates; treatment CON), a TMR with the concentrate mixture and 55% grass silage (RGS) or 55% corn silage (RCS), and a TMR with the roughage mixture and 45% of the concentrate rich in structural carbohydrates (CSC) or the concentrate rich in nonstructural carbohydrates (CNS). Meal criteria, determined using the Gaussian-Gaussian-Weibull method per animal per treatment, showed an interaction between lactation stage and treatment. Feed intake behavior variables were therefore calculated with meal criteria per treatment-lactation stage combination. Differences in feed intake behavior were more pronounced between treatments differing in roughage composition than between treatments differing in concentrate composition, probably related to larger differences in chemical composition and particle size between corn silage and grass silage than between the 2 concentrates. The number of meals was similar between treatments, but eating time was greater in RGS (227 min/d) and lesser in RCS (177 min/d) than the other treatments. Intake rate increased when the amount of grass silage decreased, whereas meal duration decreased simultaneously. These effects were in line with a decreased DMI of the RGS diet vs. the other treatments, probably related to the high neutral detergent fiber (NDF) content. However, this effect was not found in CSC, although NDF content of the TMR, fractional clearance rate of NDF, and fractional degradation rate of NDF was similar between CSC and RGS. Rumen fluid pH was lesser, and molar proportions of acetic acid and of propionic acid were lesser and greater, respectively, in RCS compared with all other diets. Milk production did not differ between treatments. There was no effect of type of concentrate on milk composition, but diet RCS resulted in a lesser milk fat content and greater milk protein content than diet RGS. Lactation stage did affect short-term feed intake behavior and DMI, although different grass silages were fed during early and late lactation. The results indicate that short-term feed intake behavior is related to DMI and therefore may be a helpful tool in optimizing DMI and milk production in high-production dairy cows.

Frequent allocation of rotationally grazed dairy cows changes grazing behavior and improves productivity.

Twenty Holstein cows were blocked in 2 groups according to milk yield to evaluate the effect of frequency of allocation to new grazing plots on pasture intake, grazing behavior, rumen characteristics, and milk yield. The 2 treatments, daily allocation to 0.125-ha plots (1D) or allocation every 4 d to 0.5-ha plots (4D) of Lolium perenne L., were tested in a randomized block design (2 rotations with 3 or 4 measuring periods of 4 d each) with mixed model analysis accounting for repeated measures. There were no differences in the chemical composition of offered pasture and in pasture dry matter intake (DMI) between 1D and 4D. However, an interaction between treatment and rotation indicated a difference in pasture DMI between treatments during the first rotation (4D, 16.5 vs. 1D, 18.3 kg/d) but not during the second rotation (4D, 15.0 vs. 1D, 14.7 kg/d), possibly a result of a greater pasture mass in the first rotation. Grazing time (average 562 min/d) and ruminating time (average 468 min/d), observed using IGER graze recorders, were similar between treatments, but grazing time increased numerically (549 to 568 min/d), and ruminating time decreased linearly (471 to 450 min/d) within periods in the 4D treatment. Mean rumen pH (6.16 vs. 6.05) and rumen NH(3)-N concentration (113.7 vs. 90.1 mg/L) were higher in 4D than in 1D, and total volatile fatty acid (VFA) concentrations did not differ. Molar proportions of VFA, except butyrate, differed between treatments, causing the nonglucogenic to glucogenic VFA ratio to be greater in 4D than in 1D. Within days in the 4D treatment, the molar proportion of acetate increased and those of all other VFA decreased linearly. Rumen NH(3)-N concentration within the 4D treatment declined quadratically from 170.3 mg/L on d 1 to 80.7 mg/L on d 4. In contrast to rumen NH(3)-N concentration, milk urea content did not differ between treatments, but decreased quadratically from d 1 to 4 in the 4D treatment (from 26.7 to 20.7 mg/dL). Mean fat- and protein-corrected milk was greater in 1D than in 4D (23.5 vs. 22.8 kg/d), mainly due to a difference in milk yield (24.5 vs. 23.7 kg/d). Fat and protein content were slightly lower in the 1D than in the 4D treatment (3.66 vs. 3.76% and 3.28 vs. 3.34%, respectively). This study confirmed that increasing pasture allocation frequency from once every 4 d to every day improved milk production in grazing dairy cows, especially when offered pasture was high.

Cost-effectiveness of saline-assisted hysterosonography and office hysteroscopy in the evaluation of postmenopausal bleeding: a decision analysis.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate whether hysterosonography (HSG) is a more cost-effective initial diagnostic examination than office hysteroscopy in the evaluation of postmenopausal bleeding (PMB). MATERIALS AND METHODS: A computer model simulated the diagnosis and treatment of PMB in otherwise healthy women. The hypothetical patient who had one episode of PMB precipitating a clinic visit would undergo either HSG or office hysteroscopy as the initial examination. Algorithms were designed such that a finite number of false-negative and false-positive findings would be expected, and clinical decision making would rely on the reported results. Performance characteristics for diagnostic tests and other clinical probabilities were taken from the literature. Costs were based on actual 1997 Medicare reimbursements. The primary clinical outcome considered was the correct diagnosis of any anatomic abnormality that was amenable to definitive treatment. The primary cost outcome considered was the cost per abnormality detected. Sensitivity analysis was performed to examine the effect of varying performance characteristics for diagnostic techniques. RESULTS: HSG and office hysteroscopy correctly depicted 68.1 and 67.6 anatomic abnormalities per 100 patients, respectively. The average cost per abnormality detected was $7,978 with HSG and $8,400 with office hysteroscopy. CONCLUSION: HSG depicted more abnormalities at a lower cost per abnormality, which suggests that it should be the preferred initial diagnostic examination in the setting of PMB.

Acute exacerbation of chronic bronchitis: disease-specific issues that influence the cost-effectiveness of antimicrobial therapy.

BACKGROUND: Acute exacerbation of chronic bronchitis (AECB) is a common condition, with substantial associated costs and morbidity. Research efforts have focused on innovations that will reduce the morbidity associated with AECB. Health care payers increasingly expect that the results of evidence-based economic evaluations will guide practitioners in their choice of cost-effective interventions. OBJECTIVES: To provide a framework on which to base effective and efficient antimicrobial therapy for AECB, we present a concise clinical review of AECB, followed by an assessment of the available data on the economic impact of this disease. We then address several AECB-specific issues that must be considered in cost-effectiveness analyses of AECB antimicrobial interventions. METHODS: Published literature on the clinical and economic impact of AECB was identified using MEDLINE, pre-MEDLINE, HealthSTAR, CINAHL, Current Contents/All Editions, EMBASE, and International Pharmaceutical Abstracts databases. Other potential sources were identified by searching for references in retrieved articles, review articles, consensus statements, and articles written by selected authorities. RESULTS: In evaluating cost-effectiveness analyses of AECB antimicrobial therapy it is critical to (1) use the disease-free interval as an outcome measure, (2) evaluate the sequence of multiple therapies, (3) address the impact of both current and future antibiotic resistance, and (4) measure all appropriate AECB-associated costs, both direct and indirect. CONCLUSIONS: Incorporating these approaches in economic analyses of AECB antimicrobial therapy can help health care organizations make evidence-based decisions regarding the cost-effective management of AECB.

Incorporation of patient preferences in the treatment of upper urinary tract calculi: a decision analytical view.

PURPOSE: Patient preferences, or utilities, may be crucial to select an appropriate treatment plan for stone disease. We used decision modeling to understand better patient choices and decision making in the overall management of recurrent nephrolithiasis. MATERIALS AND METHODS: We interviewed 180 consecutive patients with active stone disease. Demographic data and historical experiences with calculi were recorded. Patients were presented with 6 hypothetical clinical scenarios and various treatment options. The standard gamble method was used to obtain utility values for each option. RESULTS: Nephrectomy had the lowest mean utility value of 0.883. Percutaneous nephrolithotomy for severe, moderate and mild pain had utilities of 0.924, 0.932 and 0.947, respectively. Shock wave lithotripsy for the management of mild pain was the most attractive option (mean utility 0.968). The utility for long-term medical therapy was 0.949, which was between that of percutaneous nephrolithotomy and shock wave lithotripsy for mild pain. Patients with a surgical history of stone removal assigned lower utilities to invasive procedures (nephrectomy, percutaneous nephrolithotomy, p <0.05). As the incidence of spontaneous stone passage increased, a higher utility was given to long-term medical therapy (p <0.05). Patients on medical therapy less than 1 year did not appreciate a significant benefit of medical prophylaxis. However, longer compliance with medical management led patients to perceive increasing benefits of continuing such medical treatment (p <0.05). Patients who had undergone stone removal via endoscopic or open surgery also had a higher preference for medical therapy (p <0.05). CONCLUSIONS: Patients who had undergone stone removal wanted to avoid future invasive procedures. They ranked long-term medical therapy below shock wave lithotripsy but above invasive procedures, such as percutaneous nephrolithotomy. Most importantly, patients appreciated the benefits of medical therapy the longer that they complied with specific recommendations. These results support the concept that patients perceive long-term medical therapy to prevent recurrent nephrolithiasis as a desirable treatment option.

Performing cost-effectiveness analysis by integrating randomized trial data with a comprehensive decision model: application to treatment of acute ischemic stroke.

A recent national panel on cost-effectiveness in health and medicine has recommended that cost-effectiveness analysis (CEA) of randomized controlled trials (RCTs) should reflect the effect of treatments on long-term outcomes. Because the follow-up period of RCTs tends to be relatively short, long-term implications of treatments must be assessed using other sources. We used a comprehensive simulation model of the natural history of stroke to estimate long-term outcomes after a hypothetical RCT of an acute stroke treatment. The RCT generates estimates of short-term quality-adjusted survival and cost and also the pattern of disability at the conclusion of follow-up. The simulation model incorporates the effect of disability on long-term outcomes, thus supporting a comprehensive CEA. Treatments that produce relatively modest improvements in the pattern of outcomes after ischemic stroke are likely to be cost-effective. This conclusion was robust to modifying the assumptions underlying the analysis. More effective treatments in the acute phase immediately following stroke would generate significant public health benefits, even if these treatments have a high price and result in relatively small reductions in disability. Simulation-based modeling can provide the critical link between a treatment's short-term effects and its long-term implications and can thus support comprehensive CEA.