Effect of semen thaw method on conception rate in four large commercial dairy heifer herds.

Semen processed with procedures intended to permit a flexible thaw method is used to breed millions of cows yearly. One method of thawing straws, the "pocket thaw" is used extensively with semen prepared with these procedures. Published field data is lacking for thaw method comparisons with semen processed to permit flexible-thawing. The objective of the present study was to measure the effect of semen thaw method (warm-water or pocket thaw) over all seasons and its interaction with herds, inseminators, straw package size, and sperm number on conception rate in commercial dairy heifer herds using semen processed with procedures historically optimized for success with flexible-thawing. Professional inseminators performed 11,215 services over a 16-month period in four large herds, achieving a 67.6% conception rate. Thaw method was alternated weekly. Thaw effect on conception status, determined by 70 days non-return rate, was estimated by a generalized linear mixed model. Neither thaw method nor number of sperm per straw significantly affected probability of conception (P=0.658 and 0.769, respectively). No interactions of thaw method with herd, sperm number, season, straw size, and straw size by season were detected (P=0.297, 0.526, 0.365, 0.723, and 0.824, respectively). Bull, herd, inseminator within herd, year, season, and straw size affected conception rate (P=0.002, 0.000, 0.000, 0.000, 0.000, and 0.014, respectively). In conclusion, for semen processed with procedures that permit flexible-thawing, thaw method (pocket thaw versus warm-water thaw) did not affect conception rate under commercial conditions and with routine semen handling methods.

Correlation between clusterin-positive spermatozoa determined by flow cytometry in bull semen and fertility.

The objectives were to 1) develop a rapid and accurate method for detection of clusterin-positive spermatozoa (CPS) in bull semen and 2) determine the utility of incidence of CPS for prediction of fertility of bull semen in comparison to routine semen quality traits. Semen from 3 bulls was immunostained with anti-bovine clusterin antibody and with FITC-conjugated anti-rabbit IgG for method development. Clusterin-positive spermatozoa were determined by flow cytometry (FCM) and fluorescence microscopy, and results were compared by paired t test. There was no difference between FCM and microscopic techniques (P = .81). Flow cytometry was then used for determination of CPS in semen of 48 bulls with known fertility. Significant inverse relationships were found between the percentage of CPS and raw nonreturn rate (r = -.30), adjusted nonreturn rate (r = -.58), and estimated relative conception rate (ERCR; r = -.60). Estimated relative conception rate is potentially a very accurate method for determining fertility, and it resulted in highest correlation with CPS. An inverse relationship was observed between the percentage of CPS and prefreeze and postfreeze motility (r = -.51), whereas a direct relationship was found between CPS and primary, secondary, tertiary, and total sperm abnormalities (r = .52, .77, .32, and .58, respectively). The fractions of motile and abnormal spermatozoa, with the exception of tertiary abnormalities, were inversely correlated with 2 or more of the fertility estimates, but none of them showed the characteristic increase in correlation with improvement of accuracy of fertility estimate as demonstrated by CPS. We conclude that FCM is useful for objective and efficient detection of CPS in bull semen. The results suggest that the percentage of CPS in bull semen is potentially a better predictor of fertility than sperm motility or abnormal morphology.

Potential roles for quantitative ultrasound in the management of osteoporosis.

OBJECTIVE: To assess the validity of four models for the role of quantitative ultrasound (QUS) in the management of osteoporosis. DESIGN: Cross-sectional survey and review of literature. SETTINGS: Nuclear medicine departments of three teaching hospitals in Sydney. SUBJECTS: 1000 women aged 22 to 88 years (mean, 59 years) referred for assessment of osteoporotic fracture risk. MAIN OUTCOME MEASURES: BMD categories as defined by dual-energy x-ray absorptiometry (DEXA) of the lumbar spine and proximal femur, and QUS category as defined by calcaneal ultrasound stiffness; prevalence of DEXA-defined osteoporosis in the different QUS categories. RESULTS: In women with QUS Achilles stiffness < or = 70 the prevalence of axial osteoporosis was 51%, whereas in the group with stiffness > 70 the prevalence of axial osteoporosis was 8%. In women 65 years and over the corresponding values were 59% and 17%. CONCLUSIONS: Of the four possible models for QUS, the use of QUS for the estimation of BMD, or in a "standalone" model, can not be recommended at the current time. The model of QUS as a "prescreening" modality may be acceptable assuming adequate education of clinicians and patients of its limitations, particularly the risk of false negatives. The model of QUS as one factor in a composite risk factor assessment of patients is promising but more data are required.

Telemedicine: a new dimension in the practice of medicine.

Telemedicine has drawn increasing attention as one of the emerging service delivery vehicles running on the information highway. Until recently, the adoption of telemedicine has been discouraged by the cost of telecommunications and equipment and by the lack of infrastructure, standards, and evidence of cost-effectiveness and cultural acceptance. Although there have been attempts to reduce costs by making use of computer communication networks, they were technically limited by slow network speed and the lack of real-time audio/video compression technology. Ongoing technologic advances in telecommunications, imaging, multimedia computers, and information systems are making interactive telemedicine increasingly possible as high-speed video, voice, and data services are brought to large segments of the general population. The current synergy between health reform initiatives, which are redefining how health care services are accessed and delivered, and advances in technologies that support telemedicine has resulted in a proliferation of telemedicine projects. However, there is still no proof that telemedicine is necessarily cost-effective for a broad set of applications. Each prospective application requires its own business case analysis. Within the current environment, the development of a telemedicine strategy should be based on a sound knowledge of the current and future potential of telemedicine to improve health care access and quality while containing and possibly reducing health care costs.

Operation Joint Endeavor in Bosnia: telemedicine systems and case reports.

OBJECTIVE: For the last several years the U.S. Department of Defense (DoD) has operated a telemedicine test bed at the U.S. Army Medical Research and Material Command's Medical Advanced Technology Management Office. The goal of this test bed is to reengineer the military health service system from the most forward deployed forces to tertiary care teaching medical centers within the United States by exploiting emerging telemedicine technologies. METHODS: The test bed has conducted numerous proof-of-concept telemedicine demonstrations as part of military exercises and in support of real-world troop deployments. The most ambitious of those demonstrations is Primetime III, an ongoing effort to provide telemedicine and other advanced technology support to medical units supporting Operation Joint Endeavor in Bosnia. RESULTS: Several of the first instances of the clinical use of the Primetime III systems are presented as case reports in this paper. These reports demonstrate capabilities and limitations of telemedicine. CONCLUSION: The Primetime III system demonstrates the technical ability to provide current telecommunications capabilities to medical units stationed in the remote, austere, difficult-to-serve environment of Bosnia. Telemedicine capabilities cannot be used without adequate training, operations, and sustainment support. Video consultations have eliminated the need for some evacuations. The system has successfully augmented the clinical capability of physicians assigned to these medical units. Fullest clinical utilization of telemedicine technologies requires adjustment of conventional clinical practice patterns.

Validation and application of an assay for deoxyribonucleic acid to estimate concentrations of bull sperm.

Spectrophotometers are used for estimating sperm concentrations from raw ejaculates in semen processing laboratories. Unfortunately, these instruments have a limited detection spectrum and do not permit accurate quantification of sperm numbers in highly diluted or concentrated samples. The objectives of this study were to validate a DNA assay for quantification of sperm numbers in extended or undiluted semen samples and to determine precision of the assay. The principle of the assay is based upon a fluorescent dye that binds to adenine-thymine base pairs in double-stranded DNA. Semen samples and calf thymus DNA standards were sonicated in 2 M NaCl buffer with 1 mM EDTA. The DNA content of samples was compared to standards of calf thymus DNA using fluorometry. Sensitivity of the assay was determined to be 1.4 x 10(5) sperm cells. Concentrations of sperm estimated from DNA assay values did not differ from flow cytometric cell counts. Assays were performed in three different laboratories, using different equipment, to assess the assay's repeatability. Estimates of sperm concentrations determined by the DNA assay were similar, regardless of location and source of equipment used to perform the assays. This assay fulfills statistical criteria for being sensitive, accurate, and repeatable, and it can be employed in laboratories processing semen for artificial insemination as a tool for spectrophotometer calibration, a check for straw filling accuracy, or to quantify sperm numbers in extended, packaged semen.

Sperm in poor quality semen from bulls during heat stress have a lower affinity for binding hydrogen-3 heparin.

Binding assays with [3H] heparin were performed using spermatozoa collected prior to, during, and following summer heat stress to dairy bulls. Ejaculates collected in August 1983 after a period of ambient temperatures exceeding 29.4 degrees C exhibited a high frequency of abnormal sperm, and motility was reduced in some samples. Sperm in samples collected during heat stress possessed dissociation constants for binding [3H] heparin ranging from 134.5 to 163.2 nmol. In contrast, sperm in semen collected prior to and after heat stress had significantly lower dissociation constants (higher affinity) for [3H] heparin, 12.9 to 56.4 nmol. The number of binding sites for [3H] heparin on sperm did not change among collection periods. It was concluded that the binding affinity for [3H] heparin may reflect membrane integrity of bull sperm.

Differences in morning and evening sample milkings and adjustment to daily weights and percents.

Dairy Herd Improvement Association sample-day data were analyzed 1) to explain variation of month-to-month differences of single milking yields and fat percents and 2) to develop adjustment factors for estimating daily yield and fat tests from a single milking. Prior to analyses, single sample data were adjusted for month-to-month differences determined from standard two sample data. Guernsey and Holstein data involving 1,632 and 16,784 cows were available in the single sample files. Analyses were separate for Guernseys and Holsteins and for yield and test. Regression equations involving from 13 to 16 independent variables accounted for proportions of variance of the dependent variable ranging from .31 to .48 for the four combinations of breed and trait. Regression equations for adjustment of Dairy Herd Improvement Association single sample data were developed. Each equation included only two independent variables for adjustment purposes. Those equations developed from Holstein data have been implemented by the Pennsylvania Dairy Herd Improvement Association to adjust single sample data for all breeds.