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R H Foote

Publications and source records attributed to R H Foote.

At least 37 records · Page 2Linked to original sources
PubMed1998

Survival of bull sperm frozen at different rates in media varying in osmolarity.

The effects of freezing procedures, osmolarity, trehalose, and sucrose on survival of bull sperm in whole milk (WM) and egg yolk-Tris (EYT), semen extenders used worldwide, were studied. Sperm were added to extenders at 25 degreesC, cooled slowly to 5 degreesC, glycerolated, packaged in 0.5-ml straws, and frozen. Different freezing rates were accomplished in two steps. Straws were transferred from +5 degreesC to nitrogen vapor at temperatures ranging from -10 to -100 degreesC in the first step and to liquid nitrogen in the second step. Straws were thawed in water at 35 degreesC. A substantial decrease in sperm motility occurred between -10 and -20 degreesC, as abrupt nucleation occurred following supercooling to -13 degreesC. To study the interactions between osmolarity x cooling rate, WM and EYT extenders were prepared to yield media measuring 220 to 420 mOsm/L. The optimal first-step range of cooling in the two-step procedure was -30 to -70 degreesC, and the highest proportions of motile sperm after freezing and thawing were 61 to 62 in 260 to 300 mOsm/L WM and 63 to 64% in 300 to 340 mOsm/L EYT, equivalent to the results with the control procedure used commercially. As the cooling rate increased (first step to -100 degreesC) sperm motility was much higher in hypertonic than in hypotonic extenders (P < 0.05), indicating the importance of partial dehydration before rapid cooling. Replacing part of EYT and WM with equivalent solutions (same mOsm/L) of sucrose or trehalose had no appreciable effect. These results provide a basis for further investigating simple freezing systems that might be more effective in preserving bull sperm than those currently available.

Animals↗
PubMed1998

Quantification of bull sperm characteristics measured by computer-assisted sperm analysis (CASA) and the relationship to fertility.

Two experiments were conducted to evaluate semen quality of bulls housed under controlled conditions at a large AI facility and relate results to fertility. In Experiment 1 semen was collected from six 6-yr-old bulls twice daily at 3- to 4-d intervals for 3 d. In Experiment 2 eleven 6- to 11-yr-old bulls were used. Extensive breeding information was available and semen was collected as in Experiment 1 but replicated 4 times. Standard semen analysis and computer-assisted sperm analysis (CASA) with the Hamilton Thorne IVOS, model 10 unit, were performed on 36 first and second ejaculates in Experiment 1 and on 44 first ejaculates in Experiment 2. Sixteen fields (2 chambers with 8 fields per chamber) were examined per sample. In Experiment 1 the correlation between estimated sperm concentration by spectrophotometry and CASA was 0.91 (P < 0.01). Among bulls the range in the percentage of motile spermatozoa was 52 to 82 for CASA versus 62 to 69 for subjective measurements made by highly experienced technicians. Thus, CASA, with high repeatability, provided a more discriminating estimate of the percentage of motile sperm cells than did the subjective procedure. Bull effect was much greater than any other variable in the experiments. Chamber differences were small and so the results for the 2 chambers with 8 fields each were combined. One to five CASA values were correlated with bull fertility, defined as 59-day nonreturn rates corrected for cow and herd effects. The percentage of motile spermatozoa accounted for a small fraction of the total variation in fertility (r2 = 0.34). However higher r2 values (0.68 to 0.98) were obtained for 2 to 5 variables used in the multiple regression equations. The results are promising, and further testing will determine more precisely which of these CASA variables are most useful in estimating bull fertility potential.

Animals↗
PubMed1998

Bull sperm motility and membrane integrity in media varying in osmolality.

Studies were designed to evaluate bull sperm motility and membrane integrity following exposure to Tyrode's solution varying in osmolality from 100 to 1537 mOsm. Congo red and bisbenzimide (HOECHST 33258) stains were used to distinguish between sperm with intact versus disrupted plasma membranes. Sperm motility was subjectively evaluated. No significant differences were found between motile and unstained sperm (sperm with intact membranes) in solutions with nearly physiologic osmolalities between 200 and 300 mOsm. However, in 100- and 150-mOsm solutions, the percentage of motile sperm (5 and 19%), respectively) was lower than the percentage of sperm unstained with Congo red (18 and 35%). With HOECHST 33258 stain, the corresponding values were 7 and 14% versus 26 and 31%. The percentage of motile sperm declined greatly in the 500-mOsm medium, but the proportion of unstained sperm was affected little until the osmotic pressure exceeded 732 mOsm. Partial recovery of motility occurred when sperm were returned to the isotonic medium. This study indicated that the sperm plasma membrane was more resistant to osmotic damage than were the mechanisms responsible for sperm motility. Lack of motility in hypertonic media was not an absolute indicator of cell death, and unstained sperm overestimated sperm viability, which are factors to consider when sperm are being evaluated, especially relative to cryopreservation.

Animals↗
PubMed1997

Development of rabbit zygotes into blastocysts in defined protein-free medium and offspring born following culture and embryo transfer.

We report here on an improved, completely defined culture system for producing embryos in vitro which mimics development in vivo. This system avoids the confounding effects of the many unknowns introduced by the multivariate components of the serum or by unknowns attached to bovine serum albumin (BSA). Zygotes were obtained from superovulated rabbits and cultured in modified defined RPMI 1640:Dulbecco's MEM, 1:1 (RD) medium. The effect of a novel and potentially ideal antioxidant, tempol, was tested (20 to 0.001 mM) but found to be either toxic or ineffective. In the presence of 20% O(2), 600 units of Superoxide dismutase or 2.5 mM of taurine increased embryo hatching after 72 h of culture in RD medium to 75 and 76%, respectively, compared with 46% in the control (P < 0.05). The need for antioxidants was reduced with 5% O(2). The beneficial effects of RD medium were demonstrated when 60 zygotes cultured for 48 h to the early blastocyst stage in this medium were transferred and resulted in 30 young (50%) compared with 35/60 (58%) young from uncultured control transfers. Only 12% of the young were obtained from slower developing morulae. Thus, high viability was established for rapidly growing embryos in culture, but fewer slow growing embryos survived after transfer. A further comparison of embryos cultured in RD medium with a high potassium simple, optimized, defined medium (KSOM), revealed that both yielded results approaching those of direct transfer without culture. Simple defined media may also be useful for the culture of embryos of other species.

Journal Article↗
PubMed1997

Effects of amino acids and alpha-amanitin on bovine embryo development in a simple protein-free medium.

Five experiments, utilizing 3741 embryos produced in vitro, were designed to test the effects of Eagle's nonessential amino acids, and combinations of Eagle's essential amino acids and the RNA polymerase inhibitor alpha-amanitin on the development of preimplantation bovine embryos in a modified protein-free KSOM medium. Embryos were cultured in 5% O2:5% CO2:90% N2 at 39 degrees C for the first 40-44 hr in modified KSOM, and embryos with > or = 4 cells were cultured in modified KSOM-PVA with different amino acids in experiments 1-4, and with the addition of alpha-amanitin in experiment 5. In experiment 1, addition of 0.5x of the essential amino acids, with different concentrations of nonessential amino acids significantly increased hatching of blastocysts and decreased blastocyst degeneration, but increasing the nonessential amino acids from 1x to 5x, did not stimulate embryo development. In experiments 2-4, increasing only the glycine concentration, or adding each of the 12 essential amino acids singly or several in combination to the medium containing nonessential amino acids, did not significantly improve embryo development. Taurine (0.4 mM) in the modified KSOM medium reduced blastocyst degeneration. In experiment 5, alpha-amanitin (20 microM) completely inhibited further embryo development when it was added at several stages from 4-cell embryos to morulae. The study with protein-free KSOM plus amino acids provided a completely defined simple medium for culturing bovine embryos, with evidence that continuous mRNA activity and presumed protein synthesis was obligatory to meet the complex and continuous requirements for proteins by the developing blastocyst.

Amanitins↗
PubMed1997

Effects of gas atmosphere, platelet-derived growth factor and leukemia inhibitory factor on cell numbers of rabbit embryos cultured in a protein-free medium.

While culture conditions for embryos have improved, development in vitro is not equivalent to in vivo growth. Platelet-derived growth factor (PDGF), mouse (mLIF) or human (hLIF) leukemia inhibitory factor and 10% fetal bovine serum (FBS) added to protein-free culture medium, as well as two gas atmospheres were evaluated for their effect on rabbit embryo development. Adding PDGF, mLIF or hLIF to the culture medium did not result in detectable differences in total cell number for blastocysts. The culture of rabbit embryos under a gas atmosphere of 10% CO2:5% O2:85% N2 resulted in improved total cell numbers (P < 0.01) for blastocysts compared to those developing under 5% CO2:95% air (230 vs 159, respectively). Supplementing RD (RPMI-1640 and Dulbecco's MEM, 1:1) medium with 10% FBS improved the number of total cells (264 vs 155) and inner cell mass cells (71 vs 47). These results indicate that when defined culture conditions promote a high proportion of two-cell embryos developing into blastocysts, the addition of certain growth factors did not have a detectable beneficial effect, while 10% FBS improved culture conditions.

Animals↗
PubMed1997

Computer-assisted sperm analysis for assessing initial semen quality and changes during storage at 5 degrees C.

Computer-assisted sperm analysis equipment was used to evaluate bull sperm initially in a modified Tyrode's solution, in Cornell University extender, and in egg yolk-glycerol-Tris extender (following cooling and storage in the latter two extenders). Two ejaculates of semen were collected from each of eight bulls. Semen was divided into aliquots using a factorial arrangement. The semen, diluted to approximately 20 x 10(6) sperm/ml, was loaded into two 20-micron chambers, and six microscope fields from each chamber were videotaped for each treatment of each ejaculate of semen. Eight sperm characteristics analyzed with the Hamilton Thorne integrated visual optical system (Hamilton Thorne, Beverly, MA) were reported, and some of these characteristics differed significantly among bulls. The initial values of motile sperm in modified Tyrode's solution, Cornell University extender, and egg yolk-glycerol-Tris extender were 87, 79, and 66%; little change followed cooling and storage at 5 degrees C in the latter two extenders. Also, there was a small but significant decline in sperm velocity during 3 d of storage. Hyperactive sperm increased slightly during storage. The procedures used can rapidly and accurately measure many sperm characteristics in fresh semen and in semen stored in egg yolk extenders, and differences among bulls can be detected.

Animals↗
PubMed1997

Evaluation of different protocols for prostaglandin synchronization to improve reproductive performance in dairy herds with low estrus detection efficiency.

The objective of this study was to evaluate different PGF2 alpha protocols against control protocols for herds with estrus detection efficiencies of 35, 55, and 75% using modeling and simulation: 1) PGF2 alpha treatments based on the presence of a corpus luteum diagnosed by rectal palpation, 2) PGF2 alpha treatments based on the presence of a corpus luteum diagnosed by an on-farm milk progesterone enzyme immunoassay, and 3) PGF2 alpha treatments based on a 14-d fixed treatment schedule without prior screening for ovarian status. After the start of each protocol, estrus detection efficiency was 75% for 7 d after treatment and 35 or 0% for the following week. For the third protocol, an additional modification at estrus detection efficiencies of 85 and 55%, respectively, in the 1st and 2nd wk after treatment was evaluated to establish a protocol for best case assumptions. All protocols improved reproductive performance relative to that of controls with estrus detection efficiencies of 35 and 55%. The mean number of days open was reduced from 124.3 d in the control herd to 95.9, 95.0, and 92.7 for the protocols based on rectal palpation, milk progesterone test, and the fixed treatment schedule, respectively. The protocols based on a fixed treatment schedule were superior to protocols based on rectal palpation and on-farm milk progesterone tests and resulted in better reproductive performance and a higher increase in net return per cow per year. Relative to a control herd with an estrus detection efficiency of 55%, it was cost effective to spend up to $10 per dose of PGF2 alpha, $9 per milk progesterone test, and $6 per rectal palpation.

Animals↗
PubMed1997

Sperm numbers inseminated in dairy cattle and nonreturn rates revisited.

Three experiments were conducted to test fertility when sperm numbers per insemination ranged from 10 x 10(6) to 40 x 10(6) total sperm. All semen was from Holstein bulls that were on a regular schedule of semen collection. The semen was extended with heated homogenized whole milk, cooled, glycerolated, and frozen according to standard procedures. Semen was distributed to a large group of inseminators to minimize differential field effects on treatment. All experiments were a randomized block design, including a split plot in Experiment 2. In Experiment 1, data for 31,399 first inseminations distributed among treatments of 20 x 10(6), 25 x 10(6), 30 x 10(6), and 40 x 10(6) total sperm resulted in 69.8, 70.0, 70.1, and 70.1% nonreturns at 59 d, respectively. In Experiment 2, data for 18,197 first inseminations divided over treatments of 12 x 10(6), 16 x 10(6), and 20 x 10(6) total sperm resulted in 70.2, 72.4, and 70.8% nonreturns at 59 d, respectively. In Experiment 3, 38,890 first inseminations distributed over treatments of 10 x 10(6), 13 x 10(6), 16 x 10(6), and 20 x 10(6) total sperm resulted in 70.5, 72.2, 73.1, and 71.5% nonreturns at 59 d, respectively. Bull nonreturns ranged from 64 to 76% in the three trials. These results indicate that, under good conditions, total sperm numbers per straw can be reduced to 10 x 10(6) total sperm with a reduction of nonreturn rates at 59 d, for most bulls, of about 1 percentage unit from the maximum when professional inseminators are use.

Animals↗
PubMed1996

Effect of amino acids and alpha-amanitin on the development of rabbit embryos in modified protein-free KSOM with HEPES.

Four experiments were conducted to test the effects of Eagle's non-essential amino acids (NEAA) and essential amino acids (EAA), glycine, and the RNA polymerase inhibitor, alpha-amanitin, on the development of preimplantation rabbit embryos in modified protein-free KSOM medium. Embryos were distributed randomly into different treatments and cultured in 5% O2:5% CO2:90% N2. In experiment 1, 100% of the embryos became blastocysts in the medium with Eagle's 1X NEAA and 0.5X EAA, but 100% stopped development at the morula stage in KSOM without amino acids. These morulae failed to develop further when transferred to amino acid supplemented medium after 72 hr of culture. Glycine alone in modified KSOM (experiment 2) was ineffective in supporting development of 8-16-cell stage embryos past the morula stage. In experiment 3, the addition of 1X NEAA and 0.5X EAA at 0, 12, 24, 36, and 48 hr of culture resulted, respectively, in 57, 65, 65, 44, and 14% blastocysts on Day 3 (P < 0.05) and 86, 77, 77, 78, and 69% on Day 5 (P > 0.05). Omission of Eagle's amino acids until 48 hr clearly delayed embryo development. In experiment 4, when alpha-amanitin (20 microM) was added to the medium containing Eagle's amino acids after 0, 12, 24, 36, and 48 hr of culture most embryos cleaved only once or twice after adding the alpha-amanitin. Without the inhibitor, 94% of the zygotes developed into blastocysts. These results indicate that modified KSOM or KSOM plus glycine could not support rabbit embryo development past the morula stage, but this block was overcome by adding Eagle's amino acids. An exogenous source of amino acids was not critical for embryo development during the first 24 hr of culture, but was required after that for development to equal controls. Addition of alpha-amanitin at multiple pre-blastocyst stages limited further embryo development to one or two cleavage divisions, with no blastocyst development.

Amanitins↗
PubMed1996

Sodium chloride, osmolyte, and osmolarity effects on blastocyst formation in bovine embryos produced by in vitro fertilization (IVF) and cultured in simple serum-free media.

PURPOSE: A simple serum-free medium (KSOM), relatively low in NaCl concentration, has been developed for culturing mouse zygotes produced in vivo. The present studies were designed to test modifications of this medium to establish optimal conditions for culture of bovine embryos produced in vitro. METHODS: Embryos were produced by standard in vitro fertilization procedures. They were cultured for 6 days in media varying in NaCl concentration and osmolarity with and without osmolytes, betaine or inositol. RESULTS: Increasing the NaCl concentration from 95 to 108.5 and 122 mM decreased blastocyst formation (P < 0.05). Partial substitution of NaCl by sorbitol indicated that both NaCl concentration and osmolarity were important. Neither betaine nor inositol protected the embryos against high concentrations of NaCl. CONCLUSIONS: The concentration of NaCl should not be higher than 95 mM and the total osmolarity of the medium should be between 250 and 270 mosmol.

Animals↗
PubMed1996

Differential sensitivity of one-cell and two-cell rabbit embryos to sodium chloride and total osmolarity during culture into blastocysts.

One-cell or two-cell rabbit embryos were cultured in protein-free media with various NaCl concentrations and osmolarity to determine relative sensitivity of embryos to changes in media composition. Embryos from replicates of donor rabbits were distributed randomly across treatments and cultured at 39 degrees C. Zygotes were cultured in Expts 1, 2A and B, and 3, and two-cell embryos were cultured in Expts 4A and 4B. In Expt 1, blastocyst formation and number of cells were highest (P < 0.05) in the control medium with 93 mmol NaCl l-1 (270 mosmols) compared with media containing 63, and 116 mmol NaCl l-1 (220 and 316 mosmols). In Expt 2, embryos were cultured in media with 70 or 93 mmol NaCl l-1, varying in osmolarity from 250 to 320 mosmols by adding sorbitol. In media with 70 mmol NaCl l-1 and osmolarities of 250, 280 and 300 mosmols, there were 41, 56 and 50% expanded blastocysts, respectively (P < 0.05). With 93 mmol NaCl l-1 and osmolarities of 270, 293 and 320 mosmols, embryos developed into 37.53 and 27% expanded blastocysts, respectively, (P < 0.05). In Expts 3A and 3B and 4A and 4B, the osmolarity of the medium was maintained at 270 mosmols by adding sorbito to media containing 40 or 60 mmol NaCl l-1, and other components were reduced in media containing 100 and 116 mmol NaCl l-1 to compensate for the higher NaCl. Zygote development into blastocysts was greatly suppressed (P < 0.05) in media with 40, 60, 100 and 116 mm NaCl l-1, compared with the control (93 mmol NaCl l-1), whereas development of two-cell embryos into blastocysts was much less affected. These results appear to reflect a direct sodium chloride as well as osmolarity effect on embryo development; and zygotes are much more sensitive to these effects than are two-cell embryos.

Animals↗
PubMed1996

Review: dairy cattle reproductive physiology research and management--past progress and future prospects.

Artificial insemination developed as the solution for two important problems in the dairy cattle industry during the past 50 yr: 1) the need for genetic improvement and 2) the elimination of costly venereal diseases. Cooperation among researchers, extension workers, veterinarians, dairy producers, and emerging AI organizations in pooling their expertise, was instrumental to the remarkably rapid development of AI. The cooperation of universities, government, and producers to fund teams of reproductive specialists to collaborate and transfer findings quickly to potential users was a major component of this successful venture. Money invested in these experiments was estimated to have returned about $100 for each $1 invested. Successful freezing of sperm led to the development of the field of cryobiology, and AI paved the way for embryo transfer. The development of ultrasound equipment; various types of rapid hormone assays; prostaglandins, progestogens, and GnRH; and computerization made possible various alternative management plans for controlling reproduction. Multidisciplinary, multigeographical teams that gather basic needed information have the potential for making excellent progress. As herd size increases, new programs for efficient reproductive management and for identifying needed research through computer modeling are a must. Sexed embryos from elite cows and bulls will be used selectively. When embryonic stem cell technology becomes practical, it will revolutionize cattle breeding.

Animals↗
PubMed1996

Motility and other characteristics of human sperm can be measured by computer-assisted sperm analysis of samples stained with Hoechst 33342.

OBJECTIVE: To develop methods for using a DNA-specific dye to discriminate between motile and nonmotile sperm and static particulate matter in fresh and diluted semen, using computer-assisted sperm analysis (CASA) with the Hamilton Thorne IVOS, TOX version (Hamilton-Thorne Research, Beverly, MA). DESIGN: Donor semen was divided for treatment as fixed stained sperm (Hoechst 33342 stain; Sigma Chemical Company, St. Louis, MO), fresh motile and nonmotile stained sperm, and unstained control sperm. SETTING: Normal human volunteers in an academic research and medical environment. PATIENTS: Selected healthy student volunteers. INTERVENTIONS: Delivered semen to the laboratory within 1 hour of collection. MAIN OUTCOME MEASURE: Semen quality measured by CASA. RESULTS: Fixed or fresh human sperm stained with Hoechst 33342 dye should be diluted to < or = 50 x 10(6) sperm/mL to count sperm accurately. Motile and nonmotile sperm were stained suitably with 5 to 10 micrograms/mL of dye when diluted with a simple diluent, but the dye concentration should be increased to 40 micrograms/mL when egg yolk is in the diluent. CONCLUSIONS: The DNA-specific dye, Hoechst 33342, can be used to discriminate between motile and nonmotile sperm and other particulate matter when evaluated by CASA with instrumentation equipped with suitable optics.

Benzimidazoles↗
PubMed1995

Bovine oviductal epithelial cells (BOEC) and oviducts: I. For embryo culture. II. Using SEM for studying interactions with spermatozoa.

The oviduct (uterine tube) plays a major role in reproduction. It is a dynamic organ which selectively permits a few sperm to undergo capacitation and reach the oocyte which has continued to undergo maturation following ovulation. Then following fertilization the embryo undergoes cleavage before arriving in the uterus. Extensive information has become available from in vitro studies on oocytes as well as spermatozoal interactions with oviductal cells. Bovine oviduct epithelial cell (BOEC) monolayers with simple media provide an environment in which zygotes can be cultured to blastocysts in 6 days with cell numbers essentially equivalent to blastocysts grown totally in the donor animal. These yield normal pregnancy rates upon transfer. The simple protein-free media currently under test hold promise for elucidating specific requirements of the preimplantation embryo and these defined conditions facilitate many related studies on in vitro fertilization and genetic engineering of embryos. The second part of this paper is an extensive study on the interaction of fresh and frozen-thawed bull spermatozoa with BOEC and segments of intact oviducts as viewed by SEM. Both types of oviductal cells were incubated at 39 degrees C for 0, 3, 6, and 9 hours, using material obtained from periovulatory cows. Sperm attached immediately to both types of epithelium and reached a peak at 3 hours. They were found primarily in the furrows of the intact oviducts. Secretory droplets appeared rapidly on the anterior portion of the sperm head and acrosomal changes were evident in 3 hours, similar to those reported in vivo. Changes were more rapid with frozen-thawed sperm.

Animals↗
PubMed1995

Rabbit blastocyst: allocation of cells to the inner cell mass and trophectoderm.

The proportion of total cells in the blastocyst allocated to the inner cell mass (ICM) and trophectoderm (TE) is important for future development and may be sensitive indicator to evaluate culture conditions. The number of cells and their distribution within the two primary cell lineages were determined for the rabbit embryo developing in vivo after superovulation or nonsuperovulation or embryo transfer and compared with embryos developing in vitro. Comparisons were made with cultured embryos or embryos grown in vivo until 3.5, 4.0, and 4.5 days of age. Embryos from superovulated rabbits developed in vivo for 3.5, 4.0, and 4.5 days, respectively, had 361, 758, and 902 total cells (P < 0.05), and in nonsuperovulated rabbits 130, 414, and 905 total cells (P < 0.05), with increasing proportions of ICM cells over time (P < 0.05). One-cell embryos recovered from superovulated females and transferred to nonsuperovulated recipients developed more slowly with 70, 299, and 550 total cells after 3.5, 4.0, and 4.5 days of culture (P < 0.05), respectively. The proportion of ICM cells increased with age of the embryo. Corresponding values for one-cell embryos cultured in vitro resulted in 70, 299, and 550 total cells (P < 0.05). However, in vitro culture of morula-stage embryos in the presence of fetal bovine serum for 24 hr did not delay growth. In addition, the proportions of ICM/total cells were 0.17, 0.25, and 0.29 for embryos developing in vitro at 3.5, 4.0, and 4.5 days respectively, similar to those for embryos developing in vivo at each of the three recovery times.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗