Progress 10/01/04 to 09/30/10
Outputs
OUTPUTS: Pregnancy rates of bovine embryo transfer recipients are improved with inclusion of a prostaglandin F2alpha receptor antagonist in collection media. Furthermore, inclusion of a prostaglandin F2alpha receptor antagonist to collection media of embryos not only increased initial pregnancy rates but also subsequent pregnancy retention rates without influencing calf normality/viability. Two additional studies were conducted to evaluate efficacy of using a PGF2alpha receptor antagonist (FPr-A) in circumstances where bovine ova and early embryos (i.e., zygote and cleavage-stages) may be exposed to PGF2alpha. While previous efforts have documented negative effects of PGF2alpha on embryos at the 16 to 32-cell stage and beyond, the extent to which PGF2alpha may exert detrimental effects on earlier stages or maturing oocytes was unclear. Research had shown that cumulus-oocyte complexes produce PGF2alpha and both oocytes and cumulus cells have PGF2alpha receptors. It had also been shown that addition of PGF2alpha to oocytes decreased blastocyst development similar to application of heat stress to maturing oocytes. In the first experiment, development of heat-stressed ova matured in the absence or presence of an FPr-A was examined. In experimental replicates where the effect of heat stress was to decrease blastocyst development greater than 10%, a significant maturation temperature x FPr-A interaction was noted (P = 0.05). When data from the 400 and 1000 nM doses of AL-8810 were combined, decreased blastocyst development associated with heat stress was prevented (P = 0.06). Furthermore, when FPr-A was added to ova deemed developmentally-challenged (i.e., those in which < 20% developed to blastocyst), increased cleavage (60.4 versus 57.1%; P = 0.06) and blastocyst development (17.7 versus 13.1%; P = 0.07) were observed. In the second experiment, development of PZ cultured in the absence or presence of FPr-A was evaluated. Culture of developmentally-competent PZ with FPr-A (100 and 1000 nM) resulted in cleavage and blastocyst development comparable to controls, but increased the numerical stage score of resulting blastocyst-stage embryos (6.4 versus 6.3; P = 0.05). However, with PZ from ova that were otherwise developmentally-challenged, addition of FPr-A increased the proportion that cleaved to the 8 to 16-cell (51.3 versus 46.1; P = 0.06) and blastocyst stages (19.8 versus 14.1; P = 0.08). In summary, similar to later stage embryos, data illustrate that zygotes and maturing ova are also susceptible to negative effects of PGF2α. Since developmental competence of ova or early embryos at initiation of culture is unknown, addition of a PGF2alpha receptor antagonist could be beneficial to increase the efficiency of IVP. Data from this and other projects related to TN 311 have been presented orally to scientists, producers, veterinarians, and pharmaceutical representatives are a wide range of international and national professional meetings, continuing education seminars, field days and cow colleges, and tech training conferences. PARTICIPANTS: This project utilizes industry personnel at UT AgReseach RECs, Ultimate Genetics, Bioniche and other embryo transfer companies for collection of "on-farm" data. TARGET AUDIENCES: Our audience focus includes beef and dairy producers, scientists, extension personnel, veterinarians, industry representatives and embryologist in all mammalian species. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Efforts to improve fertility of farm animals is of agricultural significance as progress in this area would go towards reducing animal costs thereby providing cost benefits to the consumer, and could ultimately lead to increased productivity of fewer animals. Production of fewer animals but more of the most valuable sex would go towards conserving natural resources and enhancing the environment. Increased utilization of multiple ovulation embryo transfer (MOET) technology in the bovine industries as well as increased usage of assisted reproductive technology in humans has established the value-added quality of this research. Development and protection of intellectual property rights related to utilization of a prostaglandin F2alpha receptor antagonist during embryo recovery will significantly improve pregnancy rates of recipient animals and thus efficiency of production during usage of this technology. Current research targeted toward in vitro use of this technology will improve reproductive efficiency in multiple mammalian species. This research will lead to greater productivity of cattle farms, increased profits for farm families, and help ensure an adequate supply of a safe and nutritious food source for the US and world populations.
Publications
- Seals, RC, GM Schuenemann, JW Lemaster, AM Saxton, JC Waller and FN Schrick. 2005. Follicular dynamics in beef heifers consuming ergotamine tartrate as a model of endophyte-infected tall fescue consumption. Journal of Animal and Veterinary Advances 4 (1): 97-102.
- Schuenemann, GM, ME Hockett, JL Edwards, NR Rohrbach, KF Breuel, and FN Schrick. 2005. Embryo development and survival in beef cattle administered ergotamine tartrate to simulate fescue toxicosis. Reproductive Biology 5:137-150.
- Hockett, ME, RA Almeida, NR Rohrbach, SP Oliver, HH Dowlen, and FN Schrick. 2005. Effects of experimentally-induced clinical mastitis during the preovulatory period on endocrine function, follicular growth and ovulation. Journal of Dairy Science 88:2422-2431.
- Schuenemann, GM, JL Edwards, FM Hopkins, FN Scenna, JC Waller, JW Oliver, AM Saxton, and FN Schrick. 2005. Developmental competence of oocytes fertilized in vitro with semen from yearling beef bulls grazing tall fescue pastures. Reproduction Fertility Development 17:479-486.
- Scenna, FN, ME Hockett, TM Towns, AM Saxton, NR Rohrbach, P Bridges, ME Wehrman, and FN Schrick. 2005. Pregnancy rates in cattle after administration of a prostaglandin inhibitor at embryo transfer. Prostaglandins 78: 38-45.
- Lawrence JL, FN Schrick, FM Hopkins, MG Welborn, MD McCracken, T Sonstegard, TJ Wilson and JL Edwards. 2005. Developmental losses associated with somatic cell nuclear transfer using serum-starved versus serum-fed bovine ovarian/granulosa cells. Reproductive Biology 5:171-184.
- Scenna, FN, JL Edwards, GM Pighetti and FN Schrick. 2006. Presence of Prostaglandin F2alpha Receptor In In Vitro-Derived Morula And Blastocyst Stage Bovine Embryos. Reproduction, Fertility and Development 18 (1): 180.
- Schuenemann, GM, SMLC Mendis-Handagama, SA Kania, NR Rohrbach, FM Hopkins, H Moorehead, P Lunn, HH Dowlen and FN Schrick. 2006. Testicular Development in Prepubertal Jersey Bull Calves Immunized Against Inhibin. Reproduction, Fertility and Development 18 (1): 261-262.
- Schrick, FN, AM Saxton and BK Stroud. 2006. Assessment of Semen Quality for Predicting Recovery of Viable Embryos in Superovulated Cattle. Reproduction, Fertility and Development 18 (1): 292.
- Schrick, FN, GM Schuenemann, JL Edwards, J Giordano, and AM Saxton. 2006. What is new in the area of semen sexing in the bovine and assessment of semen quality for predicting recovery of viable embryos in superovulated cattle. Proceedings of the XXIX Annual meeting of the Argentina Association of Animal Production (Mar del Plata, Argentina, Oct 18-20, 2006), Pp. 1-10.
- Schrick, FN, GM Schuenemann, JC Waller, FM Hopkins, and JL Edwards. 2006. Fertility of beef cattle grazing endophyte-infected tall fescue pastures. Proceedings of Applied Reproductive Strategies in Beef Cattle (St. Joseph, MO, Aug 30-31, 2006; Pp. 253-259.
- Schrick, FN, ME Hockett, JL Edwards, FN. Scenna, J Giordano, GM Schuenemann, FM Hopkins, AM Saxton and BK Stroud. 2006. Factors to consider in improving efficiency of multiple ovulation and embryo transfer (MOET) in cattle. Proceedings of the XX Annual South Carolina Large Animal Medicine Short Course (Columbia, SC, Nov 15-16, 2006), Pp. 150-165.
- Scenna, Fernando. 2006. Inhibition of direct prostaglandin F2alpha effects on pre-attachment embryos improves reproductive efficiency in cattle. PhD Dissertation.
- Schrick, FN, GM Schuenemann, JC Waller, FM Hopkins, and JL Edwards. 2007. Fertility of beef cattle grazing endophyte-infected tall fescue pastures. National Cattlemen's Association Cattle College. (Nashville, TN; January 2007).
- Schuenemann, GM, SMLC Mendis-Handagama, FM Hopkins, SA Kania, and FN Schrick. 2007. Changes in the testis seminiferous tubules and interstitium in prepubertal bull calves immunized against Inhibin at the time of gonadotropin administration. Reproduction, Fertility and Development 19:840-849.
- Giordano, Julio. 2007. Possible strategies to increase ovulatory follicle size and reduce ovulation time in lactating dairy cows. MS Thesis.
- Schuenemann, GM, C Mendis-Handagama, TM Prado, and FN Schrick. 2008. Alteration in testicular cell components following transiently induced ischaemia in prepubertal bulls. Reproduction, Fertility and Development 20:826-834.
- Scenna, FN, JL Edwards and FN Schrick. 2008. Detrimental effects of prostaglandin F2alpha on in vitro embryo development in bovine are inhibited by a receptor antagonist. Reproduction, Fertility and Development 20:153-154.
- Giordano, JO, JL Edwards, GM Schuenemann, N Rohrbach and FN Schrick. 2008. Strategies to increase ovulatory follicle size and reduce ovulation time in lactating dairy cows. Reproduction, Fertility and Development 20:87.
- Scenna, FN, JL Edwards, GM Schuenemann, DA Roper and FN Schrick. 2008. Pregnancy rates of recipient animals following application of a selective prostaglandin F2alpha receptor antagonist during embryo recovery. Reproduction, Fertility and Development 20: 154.
- Schuenemann, GM, SMLC Mendis-Handagama, TM Prado, HS Adair and FN Schrick. 2008. Recipient preparation for spermatogonial stem cell transplantation: Alteration in testicular cell components following transiently induced ischemia. Reproduction, Fertility and Development 20: 193-194.
- Schrick, FN, FN Scenna, JL Edwards, DA Roper, AM Saxton, and ME Hockett. 2008. Pregnancy rates of transferred embryos following addition of a prostaglandin F2alpha receptor blocker to collection media. Proceedings of the American Embryo Transfer Association/ Canadian Embryo Transfer Association Meeting, Kansas City, MO. Pp. 1-9.
- Schuenemann, Gustavo. 2008. Spermatogonia Stem Cell Dynamics Following Hormonal Induction, Ischemic Disturbance in Vivo or Proliferation under in Vitro Culture in Pre- and Postpubertal Bulls. PhD Dissertation.
- Ward, Amanda. 2008. Impact of a PGF2alpha Receptor Antagonist During Oocyte Maturation and Early Embryo Development. MS Thesis.
- Young, C, FA Di Croce, D Roper, J Harris, N Rohrbach, JB Wilkerson, and FN Schrick. 2010. Effect of reproductive tract size on conception rates in lactating dairy cows utilizing a reproductive tract scoring system. Reproduction, Fertility and Development 23(1) 119.
- Schrick, FN, JL Edwards, JC Waller, and FM Hopkins. 2010. Nutritional Influences on Reproduction: Effects of Endophyte-Infected Tall Fescue. Applied Reproductive Strategies Conference Proceedings. Nashville, TN. Pp. 246-253.
- Di Croce, F, AM Saxton, D Casanova, and FN Schrick. 2010. Evaluation of fertility traits of Holstein cattle in Argentina. Reproduction, Fertility and Development 23(1) 111.
- Di Croce, F, AM Saxton, D Casanova, and FN Schrick. 2010. Genetic approach to improve fertility in cattle. Reproduction, Fertility and Development 22(1):168.
- Di Croce, Fernando. 2010. Development of Genetic and Genomic Predictors of Fertility in Argentinean Holstein Cattle. PhD Dissertation.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Pregnancy rates of bovine embryo transfer recipients have previously been improved with inclusion of a prostaglandin F2α receptor antagonist in collection media. Utilizing continued data collection, the current objectives were to determine pregnancy retention rates (PRR) of recipients and calf normality/viability when receiving fresh or frozen (ethylene glycol) embryos exposed during collection to commercial medium plus 1 mL DMSO (VEH), medium plus 100 nM of AL 8810 (AL100), or medium plus 1000 nM of AL 8810 (AL1000). From 1,734 transfers across 17 replicates, 910 confirmed pregnancies (VEH, n=294; AL100, n=267; AL1000, n=349) with calf data were utilized for analysis. Pregnancy retention rates were defined as the percentage of recipients calving that were diagnosed pregnant (30-90 days of gestation) after transfer. Pregnancy retention rates did not differ between AL100 and AL1000 (95% and 91%, respectively; P = 0.72); therefore, these groups were combined. Addition of AL 8810 to collection media of embryos increased PRR compared to VEH (92% vs. 83%, respectively; P = 0.01). Furthermore, a trend was noted for improved average daily gain between fresh and frozen embryos (1.13 kg vs. 1.02 kg, respectively, P = 0.07). Analysis of other production traits (gestation length, sex ratio, birth weight, weaning weight, death loss) revealed no differences due to media treatment, transfer type (fresh vs. frozen), or interactions. Therefore, inclusion of a prostaglandin F-2alpha receptor antagonist to collection media of embryos increased initial pregnancy rates and subsequent pregnancy retention rates without influencing calf normality/viability. Data from this and other projects related to TN 311 have been presented orally to scientists, producers, veterinarians, and pharmaceutical representatives are a wide range of international and national professional meetings, continuing education seminars, field days and cow colleges, and tech training conferences. Publications in respected peer-review journals have also been performed. PARTICIPANTS: This project utilizes industry personnel at Ultimate Genetics, Bioniche and other embryo transfer companies for collection of "on-farm" data. TARGET AUDIENCES: Our audience focus includes beef and dairy producers, scientists, extension personnel, veterinarians, industry representatives and embryologist in all mammalian species. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Efforts to improve fertility of farm animals is of agricultural significance as progress in this area would go towards reducing animal costs thereby providing cost benefits to the consumer, and could ultimately lead to increased productivity of fewer animals. Production of fewer animals but more of the most valuable sex would go towards conserving natural resources and enhancing the environment. Increased utilization of multiple ovulation embryo transfer (MOET) technology in the bovine industries as well as increased usage of assisted reproductive technology in humans has established the value-added quality of this research. Development and protection of intellectual property rights related to utilization of a prostaglandin F2alpha receptor antagonist during embryo recovery will significantly improve pregnancy rates of recipient animals and thus efficiency of production during usage of this technology. Current research targeted toward in vitro use of this technology will improve reproductive efficiency in multiple mammalian species. This research will lead to greater productivity of cattle farms, increased profits for farm families, and help ensure an adequate supply of a safe and nutritious food source for the US and world populations.
Publications
- Aiken, G.E., J.R. Strickland, M.L. Looper, L.P. Bush, and F. N. Schrick. 2009. Hemodynamics in the caudal artery of beef heifers fed different ergot alkaloid concentrations. Journal of Animal Science 2009 87: 2142-2150.
- DiCroce, F., A. M. Saxton, D.E. Casanova, J. L. Edwards, and F. N. Schrick. 2009. Genetic Parameter Estimation for Embryo Transfer Traits. Encyclopedia of Biotechnology in Agriculture and Food (In Press; Publication date June 2010).
- Schrick, F. N., F. M. Hopkins, T. M. Prado, J. L. Edwards, and J. C. Waller. 2009. Semen quality of bulls grazing tall fescue pastures. SERAIEG-8 Annual Report. Lake barkley State Resort Park, KY. 4-6 Oct. pp.135-136.
- Schrick, F. N., J. L. Edwards, J. C. Waller, and F. M. Hopkins. 2009. Forage effects on animal reproduction. Tennessee Forage and Grassland Council, 2009 Annual Meeting.
- Di Croce, F.A., A. M. Saxton, N. R. Rohrbach, and F. N. Schrick. 2009. Genetic parameter estimation for embryo transfer traits. Reproduction, Fertility and Development 21: 169.
- Roper D.A., F.N. Scenna, A. M. Saxton, J. L. Edwards, N. R. Rohrbach, and F. N. Schrick. 2009. Pregnancy retention of bovine recipients following transfer of embryos exposed to a prostaglandin F2a receptor antagonist during collection. Reprod. Fertil. Dev. 21(1):171.
- Schuenemann, G.M., J. L. Edwards, L. A. Rispoli, N. R. Rohrbach, A. M. Saxton, and F. N. Schrick. 2009. Impact of culture environment on colony formation of cells isolated from testes of prepubertal and adult bulls. Reprod. Fertil. Dev. 21(1):240.
- Ward A.M., F. N. Schrick, R.R. Payton, E. Peioxoto, and J. L. Edwards. 2009. Development of heat-stressed ova matured in the presence of a prostaglandin F2a receptor antagonist. Reprod. Fertil. Dev. 21(1):226.
- Roper, D. A. 2009. Pregnancy Retention and Calf Performance after Exposure to a Prostaglandin F2a Receptor Antagonist during Embryo Collection. Thesis.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Increasing efficiency & success of multiple ovulation embryo transfer (MOET) continues to be a goal of researchers & practitioners. While numerous studies report success in establishing pregnancies, fewer evaluate term development & report number of live calves born. In a previous study, Scenna et al. (2008; Reprod Fertil Dev 20:154) exposed embryos to different medium treatments while being collected from superovulated, beef donors on day 7. Medium treatments consisted of a commercially available medium plus 1 mL DMSO (CONTROL), commercial medium plus 100 nM of AL-8810 (AL100), or a commercial medium plus 1000 nM of AL-8810 (AL1000). Embryos were evaluated for grade & stage according to International Embryo Transfer Society guidelines. Embryos were transferred (fresh or frozen in ethylene glycol) by four experienced technicians. Pregnancy rates were determined by ultrasonography 28-35 days after transfer & were increased in recipients receiving embryos collected in media containing AL100 (65%) and AL1000 (60%) compared to CONTROL (50%; P < 0.05) as previously reported. As a continuum of this research interest, pregnancy retention rates (PRR) of recipient animals receiving embryos exposed to a prostaglandin F2alpha receptor antagonist (AL100 or AL1000) during collection or serving as non-treated controls were determined. Pregnancy retention rate was defined as the percent of animals calving which were diagnosed pregnant at 28 to 35 days after transfer. From this pool of recipient animals, calving information was available to date on 494 confirmed pregnancies (presence of an embryo with a heartbeat). Data were obtained on 192 CONTROL, 108 AL100 and 194 AL1000 recipients & analyzed using generalized mixed model analysis of variance (Glimmix) in SAS. Similar to initial pregnancy rates, PRR did not differ between AL100 and AL1000 (89% plus/minus 0.04 and 90% plus/minus 0.03, respectively; P > 0.10); therefore, these groups were combined (AL) for subsequent analysis of PRR. Regardless of treatment, overall pregnancy retention rates were 88% plus/minus 0.01 for fresh & 85% plus/minus 0.03 for frozen embryos. Additionally, gestation length (days) was similar between recipient animals receiving CONTROL (282 plus/minus 1.19), AL100 (281 plus/minus 1.30) or AL1000 (281 plus/minus 1.17, P > 0.10). However, addition of AL to collection medium of embryos increased PRR compared to CONTROL (90% plus/minus 0.03 vs. 83% plus/minus 0.03, respectively; P = 0.06). Currently, an interaction was not noted between freezing method and media treatment (P > 0.10). Although collection of data continues, addition of a prostaglandin F2alpha receptor antagonist to the collection medium of embryos improves pregnancy retention rates of recipient animals without altering gestation length. Data from this and other projects related to TN 311 have been presented orally to scientists, producers, veterinarians, & pharmaceutical representatives & a wide range of international & national professional meetings, continuing education seminars, field days & cow colleges, & technical training conferences. Publications in respected peer-review journals has also occurred. PARTICIPANTS: This project utilizes personnel at other universities (Florida, Oregon State) and USDA-ARS (Arkansas and Kentucky). We are also very involved with industry in the area of embryo transfer and pharmaceuticals. TARGET AUDIENCES: Our audience focus includes beef and dairy producers, scientists, extension personnel, veterinarians, and embryologist in all mammalian species. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Similar to initial pregnancy rates, Pregnancy Retention Rate did not differ between recipients receiving embryos collected with the prostaglandin F receptor antagonist at the AL100 and AL1000 dosage; therefore, these groups were combined for subsequent analysis. Regardless of treatment, overall pregnancy retention rates were 88% for fresh and 85% for frozen embryos. Additionally, gestation length was similar between recipient animals receiving CONTROL, AL100 or AL1000. However, addition of AL to collection medium of embryos increased pregnancy retention rate. Efforts to improve fertility of farm animals is of agricultural significance as progress in this area would go towards reducing animal costs thereby providing cost benefits to the consumer, and could ultimately lead to increased productivity of fewer animals. Production of fewer animals but more of the most valuable sex would go towards conserving natural resources and enhancing the environment. Increased utilization of multiple ovulation embryo transfer technology in the bovine industries as well as increased usage of assisted reproductive technology in humans has established the value-added quality of this research. Development and protection of intellectual property rights related to utilization of a prostaglandin F2alpha receptor antagonist during embryo recovery will significantly improve pregnancy rates of recipient animals and thus efficiency of production during usage of this technology. Current research targeted toward in vitro use of this technology will improve reproductive efficiency in multiple mammalian species. In all, this research will lead to greater productivity of cattle farms, increased profits for farm families, and help ensure an adequate supply of a safe and nutritious food source for the US and world populations.
Publications
- Aiken, GE, LK McClanahan, and FN Schrick. 2008. Steer Responses to Feeding Soybean Hulls on Toxic Tall Fescue Pasture. Professional Animal Scientist 24:399-403.
- Schuenemann, GM, SMLC. Mendis-Handagama, TM Prado, and FN Schrick. 2008. Alteration in testicular cell components following transiently induced ischaemia in prepubertal bulls. Reproduction, Fertility and Development 20:826-834.
- Scenna, FN, JL Edwards, GM Schuenemann, DA Roper and FN Schrick. 2008. Pregnancy rates of recipient animals following application of a selective prostaglandin F2alpha receptor antagonist during embryo recovery. Reproduction, Fertility and Development 20: 154.
- Schuenemann, GM, SMLC Mendis-Handagama, TM Prado, HS Adair and FN Schrick. 2008. Recipient preparation for spermatogonial stem cell transplantation: Alteration in testicular cell components following transiently induced ischemia. Reproduction, Fertility and Development 20: 193-194.
- Scenna, FN, JL Edwards and FN Schrick. 2008. Detrimental effects of prostaglandin F2alpha on in vitro embryo development in bovine are inhibited by a receptor antagonist. Reproduction, Fertility and Development 20:153-154.
- Giordano, JO, JL Edwards, GM Schuenemann, N Rohrbach and FN Schrick. 2008. Strategies to increase ovulatory follicle size and reduce ovulation time in lactating dairy cows. Reproduction, Fertility and Development 20:87.
- Aiken, GE, LK McClanahan, BH Kirch, and FN Schrick. 2008. Performance and Physiology of Steers Following Grazing of Toxic Tall Fescue as Influenced by Feeding Soybean Hulls on Pasture and Postgraze Steroid Implantation. Professional Animal Scientist 24:392-398.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Previous research from our laboratory has indicated that addition of a PGF2α receptor (FPr) antagonist to culture medium prevented the detrimental action of PGF2α on embryo development. Recently, we evaluated the addition of a FPr antagonist to collection medium on pregnancy rates after transferring of bovine embryos to recipient animals. An initial experiment was performed to determine in vitro development of in vivo-derived morula stage frozen-thawed embryos cultured in KSOM-PVA medium with 1000 nM AL-8810 (AL, n= 94; Cayman Chemical Inc., Ann Arbor, MI, USA), 1000 nM AL-8810 and 10 ng/mL PGF2α (AL+PGF, n= 94), 10 ng/mL PGF2α (PGF, n= 94; Cayman Chemical Inc., Ann Arbor, MI, USA), or serving as controls (CON, n= 91). Embryos remained in their treatment for a 30-h period until blastocyst development was recorded. In a subsequent experiment, embryos were recovered (n = 783) from superovulated donors on day 7 after artificial insemination with medium containing 1000 nM AL-8810 (AL), 100 nM AL-8810 (AL100) or with vehicle (VEH; 1 mL DMSO; Sigma-Aldrich, St. Louis, MO, USA) in a double blind study. Following collection, embryos were classified by stage and quality, and then transferred fresh to recipients or frozen (ethylene glycol, direct transfer). Frozen embryos were transferred following thawing during the subsequent breeding period. Pregnancy rates were determined by ultrasonography (28-35 days post transfer) and confirmed by calving date. Data were analyzed using GLIMMIX procedure of SAS (SAS Institute, Inc., Cary, NC, USA). Results from the initial experiment indicated that culture of in vivo-derived bovine embryos in medium containing AL-8810 improved blastocyst development compared to PGF (58.5% vs. 45.7%; P=0.05). In addition, a strong tendency to increase embryo development was observed in AL+PGF compared to PGF treatment group (57% vs. 45.7%; P=0.07). Overall pregnancy rates of fresh and frozen embryos were increased in the AL and AL100 groups (55% plus/minus 0.08 and 58% plus/minus 0.09, respectively) compared to VEH (43% plus/minus 0.08; P = 0.009). Since AL treatments did not differ in pregnancy rates, subsequent analysis combined AL and AL100 data. Transfer of frozen embryos collected with medium containing AL-8810 (n = 238) had increased pregnancy rates (AL, 45% plus/minus 0.05) compared to embryos recovered without (n = 221) AL-8810 (VEH, 34% plus/minus 0.04; P = 0.01). Transfer of fresh embryos collected with medium containing AL-8810 (n = 241) tended to have increased pregnancy rates (AL, 76% plus/minus 0.04) compared to control (n = 83; VEH, 66% plus/minus 0.06; P = 0.09). Although data collection continues, no abnormalities in calf health, birth weight or weaning weight have been observed between any treatments. In conclusion, recovery of embryos with flushing medium containing an FPr antagonist improved pregnancy rates after transfer. PARTICIPANTS: This project utilizes personnel at other universities (Florida, Oregon State) and USDA-ARS (Arkansas and Kentucky). We are also very involved with industry in the area of embryo transfer and pharmaceuticals. TARGET AUDIENCES: Our audience focus includes beef and dairy producers, scientists, extension personnel, veterinarians, and embryologist in all mammalian species.
Impacts
Increased utilization of multiple ovulation embryo transfer (MOET) technology in the bovine industries as well as increased usage of assisted reproductive technology in humans has established the value-added quality of this research. Development and protection of intellectual property rights related to utilization of a prostaglandin F2α receptor antagonist during embryo recovery will significantly improve pregnancy rates of recipient animals and thus efficiency of production during usage of this technology. Current research targeted toward in vitro use of this technology will improve reproductive efficiency in multiple mammalian species. This research will lead to greater productivity of cattle farms, increased profits for farm families, and help ensure an adequate supply of a safe and nutritious food source for the US and world populations.
Publications
- Schuenemann, GM, SMLC Mendis-Handagama, FM Hopkins, SA Kania, and FN Schrick. 2007. Changes in the testis seminiferous tubules and interstitium in prepubertal bull calves immunized against Inhibin at the time of gonadotropin administration. Reproduction, Fertility and Development 19:840-849.
- Looper, ML, TS Edrington, R Flores, JM Burke, TR Callaway, GE Aiken, FN Schrick, and CF Rosenkrans, Jr. 2007. Influence of dietary endophyte-infected (Neotyphodium coenophialum) tall fescue (Festuca arundinacea) seed on fecal shedding of antibiotic-resistance selected Escherichia coli O157:H7 in ewes. Journal of Animal Science. 85:1102-1108.
- Schrock GE, AM Saxton, FN Schrick, and JL Edwards. 2007. Benefits of early in vitro fertilization to improve development of heat-stressed ova matured in vitro. Journal of Dairy Science 90:doi:10.3168/jds.2007-0002.
- Aiken, GE, BH Kirch, JR Strickland, LP Bush, ML Looper, and FN Schrick. 2007. Hemodynamic responses of the caudal artery to toxic tall fescue in beef heifers. Journal of Animal Science 85:2337-2345.
- Merrill, ML, DW Bohnert, DL Harmon, AM Craig, and FN Schrick. 2007. The ability of a yeast-derived cell wall preparation to minimize toxic effects of high ergot-alkaloid tall fescue straw in beef cattle. Journal of Animal Science 85:2596-2605.
- Portillo, GE, GA Bridges, JW de Araujo, MV Shaw, FN Schrick, WW Thatcher, JV Yelich. 2008. Response to GnRH on day 6 of the estrous cycle is diminished as the percentage of Bos indicus breeding increases in Angus, Brangus, and BrahmanxAngus heifers. Animal Reproduction Science. 103:38-51.
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Progress 01/01/06 to 12/31/06
Outputs
Numerous studies have demonstrated negative effects of prostaglandin F2α (PGF2α) on bovine reproduction. Moreover, previous data from our laboratory indicated that in vitro-derived pre-compacted embryos are more susceptible to the effects of PGF2α than compacted embryos. Presence of prostaglandin F2α receptors (FPr) in bovine embryos will allow for new therapeutic strategies aimed at improving reproduction in bovines. Therefore, two preliminary experiments were performed to investigate any toxic effect of AL-8810, an FPr antagonist, on in vitro development of bovine embryos. In preliminary experiment 1, pre-compacted embryos were culture in: 1) 100 AL (100 nM AL-8810 in KSOM-PVA; n= 94); 2) 50 AL (50 nM AL-8810 in KSOM-PVA; n= 94); 3) 25 AL (25 nM AL-8810 in KSOM-PVA; n= 94); 4) CON (KSOM-PVA; n= 95). In preliminary experiment 2, pre-compacted embryos were culture in: 1) 1000 AL (1000 nM AL-8810 in KSOM-PVA; n= 282); 2) 500 AL (500 nM AL-8810 in
KSOM-PVA; n=274); 3) 250 AL (250 nM AL-8810 in KSOM-PVA; n=274); 4) CON (KSOM-PVA; n= 278). Embryos remained in treatments until blastocyst assessment. Next, two experiments were performed to determine efficiency of AL-8810 on preventing detrimental effects of PGF2α on pre-compacted embryos. In Experiment 1, pre-compacted embryos were cultured in: 1) 100 AL (100 nM AL-8810 in KSOM-PVA; n= 121); 2) 10 PGF (10 ng/mL of PGF2α in KSOM-PVA; n=91); 3) AL100+PGF (100 nM AL-8810 and 10 ng/mL of PGF2α in KSOM-PVA; n=116); 4) CON (KSOM-PVA; n= 96). In Experiment 2, embryos were cultured in: 1) 1000 AL (1000 nM AL-8810 in KSOM-PVA; n= 87); 2) 10 PGF (10 ng/mL of PGF2α in KSOM-PVA; n=87); 3) AL1000+PGF (1000 nM AL-8810 and 10 ng/mL of PGF2α in KSOM-PVA; n=84); 4) CON (KSOM-PVA; n= 84). In both experiments, embryos remained in treatments for 48 h when development to morula was assessed. Results showed that addition of 100, 50 and 25 nM did not compromise embryonic
development to blastocyst compared to controls (60.2%, 55.8 %, 55.4%, and 49.9% respectively). In addition, orthogonal contrasts indicated that 100 nM AL-8810 improved development to blastocyst (100 AL= 61% vs. CON= 50.6%, P=0.01). Similarly, 1000, 500, 250, nM AL-8810 did not affect in vitro development to blastocyst compared to controls (40%, 39%, 34.8% and 37.7%, respectively, P>0.05). Finally, addition of 1000 nM AL-8810, but not 100 nM, to culture medium of pre-compacted embryos exposed to PGF2α increased the ability of embryos to undergo compaction 48 h later (1000 AL+PGF=51% vs. PGF=40%; P=0.05%). In conclusion, AL-8810 at a concentration of 1000 nM inhibits detrimental effects of PGF2α on development of pre-compacted bovine embryos and may prove beneficial for other assisted reproductive techniques in cattle.
Impacts
The recent surge in utilization of embryo transfer technology in the beef and dairy industries due to economic gains (improved genetics) as well as increased usage of assisted reproductive technology in humans has established the importance and value-added quality of this research. Development and protection of intellectual property rights related to utilization of a prostaglandin F2" receptor antagonist during embryo collection (recovery) will significantly improve pregnancy rates of recipient animals and thus efficiency of production during usage of this technology. This research will lead to greater reproduction and productivity of cattle farms, increased profits for farm families, and help ensure an adequate supply of a safe and nutritious food source for the US and world populations.
Publications
- Larson, JE, GC Lamb, JS Stevenson, SK Johnson, ML Day, TW Geary, DJ Kesler, JM DeJarnette, FN Schrick, and JD Arseneau. 2006. Synchronization of estrus in suckled beef cows using GnRH, prostaglandin F2α(PG), and progesterone (CIDR): a multi location study. Journal of Animal Science 84:332-342.
- Aiken, GE, SF Tabler, ML Looper, DK Brauer, JR Strickland, and FN Schrick. 2006. Influence of stocking rate and implantation on growth performance and rate of recovery from heat stress for steers grazing endophyte-infected Kentucky-31 tall fescue. Journal of Animal Science 84:1626-1632.
- Scenna, FN, JL Edwards, GM Pighetti and FN Schrick. 2006. Presence of Prostaglandin F2α Receptor In In Vitro-Derived Morula And Blastocyst Stage Bovine Embryos. Reproduction, Fertility and Development 18 (1): 180.
- Schuenemann, GM, SMLC Mendis-Handagama, SA Kania, NR Rohrbach, FM Hopkins, H Moorehead, P Lunn, HH Dowlen and FN Schrick. 2006. Testicular Development In Prepubertal Jersey Bull Calves Immunized Against Inhibin. Reproduction, Fertility and Development 18 (1): 261-262.
- Schrick, FN, AM Saxton and BK Stroud. 2006. Assessment Of Semen Quality For Predicting Recovery Of Viable Embryos In Superovulated Cattle. Reproduction, Fertility and Development 18 (1): 292.
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Progress 01/01/05 to 12/31/05
Outputs
Culture of in vitro and in vivo-derived embryos in medium containing prostaglandin F2alpha (PGF) decreased embryonic development to blastocyst stage and reduced hatching rates. Moreover, administration of an inhibitor of PGF synthesis at the time of embryo transfer in bovine recipients improved pregnancy rates. These findings indicate a direct negative effect of PGF on embryonic development. However, to our knowledge, no evidence of PGF receptor expression in the morula or blastocyst stage of bovine embryos is available in the literature. Therefore, the objective of the current study was to determine the presence of PGF receptor mRNA using real time RT-PCR and protein expression by Western blotting in the morula or blastocyst stage of bovine embryos in vitro. Briefly, isolated total RNA from compact morula or blastocyst stage embryos and from bovine tongue epithelium (positive control for PGF receptor mRNA) were reverse-transcribed into cDNA. Volume from the RT
reaction equivalent to ten embryos per tube was utilized to determine transcripts for PGF receptor and Histone H2A (standard PCR control). Polymerase chain reaction was performed and identity of PCR fragments was confirmed by ethidium-bromide-stained 2% agarose gel electrophoresis and by DNA sequencing. To determine protein expression, morula and blastocyst stage embryos were lysed in lysis buffer (10%SDS, 1M Tris pH 7.5, 1 M NaF, 1MDTT, 0.1M EGTA with protease inhibitors) and stored at -20 C. Crude proteins isolated from bovine corpora lutea (positive control for PGF receptor protein), embryo samples, and pre-stained standards were separated by 12% SDS-PAGE under reducing conditions. Proteins were electro-transferred onto a PVDF membrane. Non-specific binding sites in the PVDF membrane were blocked with 10% non-fat dry milk and the blot washed and incubated for 1 h at room temperature with a 1:1000 dilution of the primary antibody (rabbit polyclonal antibody against PGF receptor
protein). Subsequently, the blot was washed and incubated for 1 h at room temperature with 1:1000 dilution of mouse anti-rabbit IgG conjugated with horseradish peroxidase. Finally, the blot was washed and revealed by chemiluminescence in a CCD camera. Results indicated that transcripts as well as the protein for PGF receptor were present in early stage bovine embryos. Identification of PGF receptor in morula and blastocyst stage bovine embryos may in part explain the increase in pregnancy rates after administration of a PGF synthesis inhibitor at the time of embryo transfer and opens up the possibility to develop new strategies to prevent detrimental effects of PGF during early embryonic development.
Impacts
Continued refinement and development of novel anti-prostaglandin F2alpha substances added directly to media (flushing, transfer, and/or freezing) will significantly improve pregnancy rates and economic impact of embryo transfer technology in the beef and dairy industries, as well as assisted reproductive technology currently used for the human population. Such research should thus help ensure a continued abundance of economically-affordable food supply, as well as provide technologies to help combat fertility problems in humans.
Publications
- Hockett, ME, RA Almeida, NR Rohrbach, SP Oliver, HH Dowlen, and FN Schrick. 2005. Effects of experimentally-induced clinical mastitis during the preovulatory period on endocrine function, follicular growth and ovulation. Journal of Dairy Science 88:2422-2431.
- Schuenemann, GM, JL Edwards, MD Davis, HE Blackmon, FN Scenna, NR Rohrbach, AM Saxton, HS Adair, FM Hopkins, JC Waller and FN Schrick. 2005. Effects of administration of ergotamine tartrate on fertility of yearling beef bulls. Theriogenology 63:1407-1418.
- Seals, RC, GM Schuenemann, JW Lemaster, AM Saxton, JC Waller and FN Schrick. 2005. Follicular dynamics in beef heifers consuming ergotamine tartrate as a model of endophyte-infected tall fescue consumption. Journal of Animal and Veterinary Advances 4 (1): 97-102.
- Schuenemann, GM, JL Edwards, FM Hopkins, FN Scenna, JC Waller, JW Oliver, AM Saxton, and FN Schrick. 2005. Fertility aspects in yearling beef bulls grazing endophyte-infected tall fescue pastures. Reproduction Fertility Development 17:479-486.
- Scenna, FN, ME Hockett, TM Towns, AM Saxton, NR Rohrbach, P Bridges, ME Wehrman, and FN Schrick. 2005. Influence of a prostaglandin synthesis inhibitor administered at embryo transfer on pregnancy rates of recipient cows. Prostaglandins 78: 38-45.
- Schuenemann, GM, ME Hockett, JL Edwards, NR Rohrbach, KF Breuel, and FN Schrick. 2005. Embryo development and survival in beef cattle administered ergotamine tartrate to simulate fescue toxicosis. Reproductive Biology 5:137-150.
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