Exploiting multimedia in reproductive science education: research findings.

Education in reproductive science is operating from an outdated paradigm of teaching and learning. Traditionally, reproductive education follows the pattern where students read a textbook, listen to instructor presentations, re-read the textbook and class notes and then complete a test. This paradigm is inefficient, costly and has not incorporated the potential that technology can offer with respect to increases in student learning. Further, teachers of reproductive science (and all of science for that matter) have little training in the use of documented methods of instructional design and cognitive psychology. Thus, most of us have learned to teach by repeating the approaches our mentors used (both good and bad). The technology now exists to explain complex topics using multimedia presentations in which digital animation and three-dimensional anatomical reconstructions greatly reduce time required for delivery while at the same time improving student understanding. With funding from the Small Business Innovation Research program through the U.S. Department of Education, we have developed and tested a multimedia approach to teaching complex concepts in reproductive physiology. The results of five separate experiments involving 1058 university students and 122 patients in an OB/GYN clinic indicate that students and patients learned as much or more in less time when viewing the multimedia presentations when compared to traditional teaching methodologies.

Will there be another generation of reproductive scientists?

This paper outlines concerns pertaining to the future of professionals in the discipline of reproductive science. This discourse is based on the experiences, opinions and due considerations of the author. The major objective of this paper is to stimulate thinking, discussion and debate, as well as action aimed at correcting problems that may threaten the next generation of reproductive scientists. The most important points are that mentoring has been replaced with counting, and that academic positions with combined research and teaching components are less and less attractive due to the protracted PhD plus postdoctoral training periods, the extremely low funding rates for extramural grant proposals, and being rewarded on the basis of quantity rather than quality.

Evaluation of American Wagyu sires for scrotal circumference by age and body weight.

Thirty-six percent of American Wagyu bulls do not meet the current minimum standards set by the Society of Theriogenology for the breeding soundness exam. In contrast, only 15% of bulls of domestic breeds do not meet the minimum standards. Scrotal circumference measurements of Wagyu are smaller than those of other breeds. The objective of this research was to describe scrotal circumference of Wagyu bulls as it relates to age and BW. The data set consisted of 190 Wagyu bulls housed at two locations. One hundred forty-one bulls constituted the first set of data (location 1); scrotal circumference was measured one to six times per bull aged between 13 and 70 mo. Ninety-four of the bulls underwent semen evaluation for motility and morphology. Forty-nine bulls constituted the data set for which scrotal circumference and BW was measured one to nine times per bull between 5 and 21 mo of age (location 2). Mean scrotal circumference of bulls within each age group was as follows: 12 to 14 mo, 29.8 0.2 cm (mean +/- SE); 15 to 17 mo, 31.8 +/- 0.2 cm; 18 to 20 mo, 32.9 +/- 0.3 cm; 21 to 24 mo, 31.8 +/- 0.5 cm; and > 24 mo, 35.5 +/- 0.2 cm. Both age and BW were highly correlated to scrotal circumference (r = 0.81 and 0.82, respectively). Within each age group, there were a percentage of bulls that did not meet the minimum standard for scrotal circumference set by the Society of Theriogenology. The percentages were as follows: 12 to 14 mo, 46%; 15 to 17 mo, 25%; 18 to 20 mo, 33%; 21 to 24 mo, 42%; and > 24 mo, 32%. Morphology and motility were > 50% each in 91% of the bulls between ages 12 and 20 mo at location 1. Based on these data, it is recommended that Wagyu bulls be evaluated with the breed-specific minimum standards for scrotal circumference of 26 cm from 12 to 14 mo, 29 cm from 15 to 17 mo, and 30 cm from 18 to 20 mo of age.

Angiotensin II as a semen extender component increases retention of spermatozoa within the uterus of the heifer.

The effects of angiotensin II (Ang II) as a semen extender were studied. In the first experiment, individual ejaculates from 10 bulls were split and extended in egg yolk citrate in the absence or presence of varying concentrations of Ang II (10[-5]-10[-10] M) to a final concentration of 35 x 10(6) sperm per mL. The percentage of intact acrosomes and percentage motility were determined in all treatments for all bulls at 0 h (immediately post thaw) and after incubation for 4 h at 37 degrees C. Extension of the semen with Ang II did not affect spermatozoal viability at either time studied. In the second experiment, mixed breed virgin heifers were induced into oestrus with intramuscular injections of prostaglandin F2alpha on Days 0 and 3. Animals that stood to be mounted were paired for bilateral intracornual insemination using a 0.5-mL French straw on each side approximately 8 h later. One of the paired heifers received semen containing Ang II (10[-5] M) while the other received control semen. A 1-mL aspirate of vaginal mucus was collected at hourly intervals for 8 h after insemination. Concentration of spermatozoa was determined by haemocytometry. There was a significant reduction in cumulative semen loss into the vagina of heifers inseminated with Ang II extended semen (14.4%) compared with heifers inseminated with control semen (19.7%). This suggests that Ang II, when added to extended semen, may reduce retrograde sperm loss following insemination without affecting sperm viability.

Fertility of bull semen packaged in .25- and .5-milliliter french straws.

The fertility of bull semen packaged in .25- and .5-mL french straws was compared. One ejaculate from each of five Holstein bulls was split, extended to 10 x 10(6) spermatozoa/inseminate dose in whole homogenized milk, packaged in .25- and .5-mL french straws, frozen in liquid nitrogen (LN) vapor, and stored in LN. Semen was thawed at 37 degrees C for 30 s. Synchronized heifers (n = 1,360) were inseminated (during a 12-mo period) with semen packaged in either a .25- or .5-mL french straw. Blood was collected on the day of insemination and the serum was assayed for progesterone. Heifers with blood progesterone levels of > 1 ng/mL were eliminated from the data. Blood was collected at 30 to 45 d after insemination and the serum was assayed for the presence of bovine pregnancy-specific protein B (bPSPB) by RIA to determine pregnancy. Conception was 63.6 and 62.0% (P = .55) for semen packaged in the .25- and .5-mL french straws, respectively. There was neither a bull x packaging unit interaction (P = .49) nor a day of insemination x packaging unit interaction (P = .87). Conception among bulls ranged from 57.1 to 68.0% (P = .19). No evidence was found that meteorological factors influenced conception. Under the conditions of this experiment, semen packaged in the .25- and .5-mL french straw had similar fertility.

Embryonic loss from 30 to 60 days post breeding and the effect of palpation per rectum on pregnancy.

This study was conducted over a 12-mo period to determine the rate of bovine embryo death between 30 and 60 d of gestation. In addition, palpation per rectum as a means of pregnancy detection was evaluated as a possible cause of embryo death. Estrus was synchronized in Holstein heifers (n = 1358), weighing > or = 385 kg, with a single intramuscular injection of 25 mg prostaglandin F(2alpha). Estrus was primarily detected by the absence of paint marks on the tailhead. The heifers were artificially inseminated with semen from 5 Holstein sires. Blood was collected between 30 and 45 d after breeding, and sera were evaluated for the presence of bovine pregnancy-specific protein B (bPSPB) by RIA to determine pregnancy. Palpation for fetal membrane slip was conducted by an experienced technician in approximately one-half of the inseminated heifers. To determine embryonic survival, a second blood sample was collected at approximately 60 d from 862 heifers that were determined to be pregnant at the first blood sampling. Embryonic loss averaged 5.3% during the interval between the initial detection of pregnancy at 30 to 45 d and the subsequent detection of pregnancy at 60 d of gestation. Embryo loss in heifers that were palpated was 6.5% compared with that of 4.3% in the control heifers (X(2): P = 0.145). These findings establish that there was substantial loss of embryos between 30 and 60 d post breeding but that embryo loss was not affected by palpation per rectum.

The estrus detection problem: new concepts, technologies, and possibilities.

The single most important problem limiting high reproductive efficiency in the national dairy herd is poor detection of estrus. Failure to detect estrus or erroneous diagnosis of estrus results in an estimated annual loss of over $300 million to the dairy industry in the US. New technologies for the solution of this problem must be more effective than visual observation and aids currently used to detect estrus. Ideally, technologies that provide the solution for detection problems should provide the following: continuous (24 h/d) surveillance of the cow, accurate and automatic identification of cows in estrus, operation for the productive lifetime of the cow, minimized labor requirements, and high accuracy in identifying the appropriate physiologic or behavioral events that correlate highly with ovulation. New approaches are aimed at providing automation of detection of estrus using electronic technology. Pedometry, implantable impedance sensors, and surface-applied and implantable pressure sensors are in various stages of development and use.

Specific antibody to Haemophilus somnus in the bovine uterus following intramuscular immunization.

Sources of anti-Haemophilus somnus antibody in bovine uterine secretions following intramuscular immunization and subsequent intrauterine inoculation of killed H. somnus were investigated. Holstein cattle (n = 21) were immunized with a 270-kDa outer membrane protein from H. somnus (omp-270) by intramuscular injection. At estrus, the cattle were given an intrauterine inoculum of a heat-killed suspension of a homologous strain of H. somnus containing omp-270 (n = 7), a heterologous strain of H. somnus lacking omp-270 (n = 7), or phosphate-buffered saline (n = 7). Uterine secretions were sampled by saline lavage immediately prior to inoculation and at 6, 24, 48, 72, 96, and 120 h after inoculation. Immunoglobulin G subclass I (IgG1) and IgG2 antibody specific for omp-270 were detectable in estrous uterine secretions of all systemically immunized cattle from which an adequate sample was obtained. IgM antibody specific for omp-270 was detected in serum following immunization but was not consistently detected in the uterine secretions of any animal. IgA antibody specific for omp-270 was not detectable in either serum or uterine secretions following immunization or intrauterine inoculation. Ratios of antibody to immunoglobulin and ratios of immunoglobulin to albumin in serum and uterine secretions indicated that about half the IgG1 and essentially all the IgG2 in secretions originated in the serum. Relative titers of IgG1 and IgG2 omp-270-specific antibodies in the uterine lumen and serum gave no evidence for selective transport of either subclass from serum into local secretions. Neither heterologous nor homologous intrauterine inocula detectably altered the serum contribution to antibody in uterine secretions within the sampling period. On the basis of these results, development of a systemic IgG2 antibody response may provide the basis for local immunological protection in the bovine reproductive tract.

Neutrophil migration into the bovine uterine lumen following intrauterine inoculation with killed Haemophilus somnus.

Polymorphonuclear neutrophils (PMN) in bovine uterine flushings following intrauterine deposition of killed bacteria were measured and the effect of immune status on the influx of PMN into the uterine lumen during oestrus was determined. Holstein heifers were immunized with a 270-kDa outer-membrane protein (omp-270) from Haemophilus somnus. During oestrus, immunized heifers (n = 21) received an intrauterine inoculum of either a heat-killed suspension of a homologous strain of H. somnus containing omp-270 (n = 7), a heterologous strain of H. somnus lacking omp-270 (n = 7), or phosphate-buffered saline (n = 7). Five additional heifers were inseminated with extended bovine semen. Uterine contents were collected in saline lavage immediately before inoculation (t0) and at 6, 24, 48, 72, 96, and 120 h after inoculation. The semen-inoculated heifers were lavaged only at t120. All groups experienced PMN infiltration which peaked 6 h after inoculation and tended to decline thereafter. Differences were not observed between treatment groups, indicating that neither bacterial inoculation nor immune status was as important in eliciting PMN effusion as the flushing procedure itself.

Bulls show no preference for a heifer in estrus in preference tests.

The objective of this experiment was to determine whether sexually experienced bulls would demonstrate a preference (using primarily olfaction) between a heifer in estrus and a heifer in diestrus (luteal phase) when physical contact was denied. In Exp. 1, a heifer in estrus and a heifer in diestrus (n = 18 pairs) were individually enclosed in opposite ends of a pen. During each period (n = 18), three bulls were individually introduced into the pen and allowed 5 min to demonstrate preference between the heifer in estrus and the heifer in diestrus. The total time that a bull spent within 2.5 m of either heifer was used to evaluate his preference. The total time that bulls spent adjacent to the heifer in estrus was not greater (P greater than .05) than the total time that bulls spent adjacent to the heifer in diestrus. In Exp. 2, five bulls were used and were evaluated using the same method as in Exp. 1. In addition, the number of flehmen reactions were recorded for each bull. Six heifers were ovariectomized and each heifer was induced into estrus with one of three doses of estradiol 17 beta (5, 10, and 20 mg) over the 5-wk treatment period. Estradiol 17 beta-treated heifers were always paired with a non-estradiol-treated (control) heifer. The goal of Exp. 2 was to determine whether heifers treated with pharmacological doses of estradiol 17 beta would be preferentially selected from non-estradiol-treated (control) heifers by bulls.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of group thawing on post-thaw viability of bovine spermatozoa packaged in .5-milliliter French straws.

The objective of this study was to determine the effects of thawing groups of 2, 5, 10, 15, or 20 .5-ml French straws on post-thaw spermatozoal viability. Thermostatically controlled and nonthermostatically controlled thawing baths were compared. Using a split-plot design, semen from 10 bulls was extended in egg yolk citrate, frozen, and then thawed (in the respective groups) at 36 degrees C in two types of thawing baths. Motility and percentage of intact acrosomes were determined immediately after thawing (0 h) and again after 4 h of incubation at the respective temperature of each thawing bath. Neither percentage of intact acrosomes nor motility was influenced by the number of straws thawed at 0 h (P greater than .05). Thawing bath had no effect (P greater than .05) on motility or percentage of intact acrosomes at 0 h. Bull variation was significant in both the 0- and 4-h evaluations. After 4 h of incubation, there was a significant (P less than .05) straw number x thawing bath interaction. When 15 or 20 straws were thawed in the thermostatically controlled bath there was a reduction (P less than .05) in motility and percentage of intact acrosomes. However, in the nonthermostatically controlled bath there was no reduction in motility and percentage of intact acrosomes as the size of straw group increased. Our results indicate that, when using a nonthermostatically controlled thawing bath, semen packaged in .5-ml straws can be thawed in groups of 20 without an effect on post-thaw sperm viability.

Seminal transferrin and spermatogenic capability in the bull.

The objective of this study was to determine the relationship between seminal transferrin and sperm output in ejaculates from mature dairy bulls. Caudal sperm reserves in mature Holstein bulls (n = 15) were depleted by 8 successive ejaculations during a 50-70-min period (depletion phase). Bulls were then ejaculated 6 times per week for a period of 4 weeks (6X phase). Weekly sperm output (WSO) and weekly transferrin output (WTfO) were the sums of sperm and transferrin levels in 6 ejaculates taken in 1 week of the study. Mean WSO ranged from 20.7 billion to 39.6 billion and mean WTfO ranged from 334 micrograms to 1872 micrograms among the bulls. Regression analysis of sperm and transferrin levels in ejaculates collected during the depletion phase indicated that approximately 40% of seminal transferrin was not related to sperm output and probably was from accessory fluids. A relationship between total seminal transferrin and total sperm in ejaculate was observed (p less than 0.01, r = 0.54). This relationship was stronger when the transferrin was corrected for accessory fluid contribution (p less than 0.01, r = 0.65). The relationship between WSO and WTfO corrected for accessory fluid transferrin contribution (cWTfO) was significant (p less than 0.01, r = 0.64). The relationship between WSO and cWTfO can be interpreted to reflect the relationship between actual testicular sperm production and transferrin from testicular or epididymal origin.

Effect of phenylephrine, ergonovine, oxytocin and norepinephrine as an extender ingredient on viability of bovine spermatozoa.

We evaluated effects of three concentrations of phenylephrine, ergonovine, oxytocin and norepinephrine (myometrial stimulants) on viability of spermatozoa when they were included in a seminal extender. Using a split ejaculate technique, ejaculates from each of 10 bulls were extended in egg-yolk citrate to a final concentration of 35 x 10(6) sperm/ml, including 20 mg/ml, 2 mg/ml and .2 mg/ml, of phenylephrine or ergonovine, 20 IU/ml, 2 IU/ml and .2 IU/ml oxytocin or 200 micrograms/ml, 20 micrograms/ml and 2 micrograms/ml norepinephrine prior to freezing. Extended semen without a myometrial stimulant served as the control. Percentage of intact acrosomes was determined prior to freezing for all treatments. Motility and percentage of intact acrosomes were determined immediately after thawing (0 h) and again after 4 h incubation at 37 degrees C. Percentage of intact acrosomes was reduced (P less than .05) prior to freezing by phenylephrine (20 mg/ml) and ergonovine (20 mg/ml) (phenylephrine = 56%; ergonovine = 63%; control = 74%). The same doses of phenylephrine and ergonovine reduced (P less than .05) post-thaw motility and percentage of intact acrosomes at both 0 and 4 h compared with controls. Sperm exposed even to the intermediate concentration (2 mg/ml) of ergonovine had lower (P less than .05) motility 4 h post-thaw. No other compound or concentration of compound or concentration of compound affected percentage of intact acrosome or motility. There were no two or three-way bull x compound and concentration interactions (P greater than .2).(ABSTRACT TRUNCATED AT 250 WORDS)

Concentrations of spermatozoa in the vagina of heifers after deposition of semen in the uterine horns, uterine body or cervix.

In Exp. I, virgin Holstein heifers (N = 18) were induced into oestrus with PGF-2 alpha. Animals which stood to be mounted were paired for insemination approximately 8 h later with 56.1 x 10(6) spermatozoa from a single bull. Semen was deposited in the uterine body of one female. Each matched female was inseminated by deposition of one-half of the inseminate into the right uterine horn and one-half into the left uterine horn approximately 7.0 cm anterior to the internal cervical os. In Exp. II, additional heifers (N = 18) were induced into oestrus and inseminated by deposition into the uterine horns or cervix (2.0 cm anterior to the external cervical os). A 1.0 ml aspirate of vaginal mucus was collected at hourly intervals for 8 h after insemination. Concentration of spermatozoa was determined by haemocytometry. In Exp. I, cumulative percentage spermatozoa recovered in an 8 h collection period were similar (P greater than 0.10) for insemination into the uterine horns (17.9 +/- 2.9%) and uterine body (18.5 +/- 4.5%). In Exp. II, cumulative % sperm recovery from the vagina was greater (P less than 0.10) for cervical deposition (59.1 +/- 14.1%) than for that into the uterine horns (30.9 +/- 7.8%). In Exp. II, the insemination treatment x hour of sample interaction was significant (P less than 0.08). Recovery of spermatozoa from the vagina was greatest (P less than 0.05) within 3 h after cervical insemination (31.4 +/- 9.9% compared to 9.4 +/- 2.5% for uterine horn deposition). Percentage recovery of spermatozoa from the remaining hourly collections were similar (P greater than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of cornual insemination on conception in dairy cattle.

The objective of this study was to compare conception to artificial insemination (AI) services in dairy cattle when semen was deposited into the uterine body or into both uterine horns (cornual insemination). Nine herdsman inseminators (HI) in four commercial dairy herds in Washington constituted the experimental units. Herds ranged in size from 393 cows to 964 cows. The duration of the experiment was 12 mo in three herds and 18 mo in the fourth herd. At the beginning of the experiment all inseminators were trained to deposit semen in the body of the uterus. Inseminators were instructed to use this method for 6 mo. Following employment of body deposition, the same inseminators were retrained to deposit one-half of the semen into the right uterine horn and one-half into the left uterine horn. Cornual inseminations were performed for 6 mo. A total of 4,178 services constituted the data set. Milk samples were collected from cows on the day of insemination and later were assayed for progesterone (P4). There was variation (P less than .01) in conception associated with month of insemination and insemination method (P less than .001). The monthly variation was not associated with season of the year. Least squares means for conception when semen was deposited in the uterine body was 44.7%, compared with 64.6% when cornual insemination was employed. The insemination treatment X inseminator interaction was not significant. Results suggest that cornual insemination provides an alternative to deposition of semen in the uterine body.

Relationship of scrotal surface temperature measured by infrared thermography to subcutaneous and deep testicular temperature in the ram.

The right testis of 9 anaesthetized rams was removed from the parietal tunica vaginalis and replaced by a surrogate testis (water-filled balloon) through which water of known temperature was circulated. Thermistors were inserted in the surrogate testis, between the scrotal skin and parietal tunica vaginalis on the right side, and deep within the intact left testis. Scrotal surface temperatures over the surrogate and intact testes were measured by infrared thermography. Scrotal surface temperature was correlated (P less than 0.01) with both subcutaneous (r = 0.95) and surrogate (r = 0.91) testicular temperature. The temperature differential between scrotal surface (30.1 +/- 0.1 degrees C) and deep testicular temperature over the intact side (34.9 +/- 0.09 degrees C) was 4.8 degrees C at an ambient temperature between 24.0 and 26.6 degrees C. Contact with the scrotal skin is not required to measure scrotal surface temperature by infrared thermography. This, coupled with the close association between scrotal surface temperature and that of underlying structures, will enhance our ability to understand better testicular temperature regulation and scrotal/testicular function.

Relationships between days post partum, observed estrus and uterine microflora in commercial dairy cows.

This study was conducted to determine relationships between the uterine microflora and reproductive characteristics of dairy cows. Uterine lumina were swabbed during estrus immediately prior to artificial insemination (A I). Swabbings were cultured for bacteria and accessed for cytologic evidence of inflammation. The time of sampling averaged 104 d post partum. Bacteria in the uterus were cultured from 65% of the cows (n = 85). The number of cows with any given microbial genus ranged from 1 to 35 and the number of different genera per cow ranged from 0 to 8. There were on significant correlations between amount and type of uterine microflora, days post partum, numbers of observed estrus, conception rate and uterine inflammation. The number of observed estrus periods was not correlated with the presence of aerobic bacteria. No significant relationships were found between microbes and uterine inflammation or conception to the A.I. service at the time of sampling. A negative correlation between uterine inflammation and conception approached significance (r=-0.24, P > 0.10). Acquisition of uterine lumen samples by the technique utilized had no effect on conception to A I service.