Progress 09/01/99 to 08/31/03
Outputs
Our aims were to: 1) evaluate the stages of pregnancy when embryonic development and survival are most affected by exogenous bovine somatotropin (bST); 2) characterize bST-induced changes in oviductal and uterine synthesis of insulin-like growth factors (IGFs) and their binding proteins; 3) determine how bST stimulates embryonic development using an in vitro model; and 4) examine the effect of supplemental bST on uterine synthesis of PG, which causes luteal regression in cattle. Administration of bST at artificial insemination decreased the number of unfertilized ova, increased the percentage of transferable embryos, and stimulated embryonic development to the blastocyst stage. Pregnancy rates were higher in control recipient dairy cows receiving bST-treated embryos, than those receiving control embryos at 7 days post-estrus. There were no differences between control and bST embryos when transferred into bST-treated recipient cows at day 7 post-estrus. Supplemental bST
induced IGF-II mRNA as early as day 3 of a synchronized estrous cycle, suggesting that IGF-II may play a modulatory role in oviductal differentiation and early embryonic development. BST down-regulated IGF-II transcript in the endometrium at day 7 of the estrous cycle, when IGF-I transcripts tended to increase, implying that these mitogens may have either overlapping or distinct roles in the control of oocyte cleavage and the ensuing blastocyst development. Both bST and IGF-I stimulated embryo development in vitro and bST effects appeared to be independent from IGF-I. In cyclic Holstein cows, bST treatment during the first 14 days of the estrous cycle attenuated PG response to oxytocin. Results were further confirmed by in vitro experiments in which bST reduced phorbol ester-induced PG secretion in bovine endometrial cells. Recently, we have conducted a series of basic studies which indicated that the presence of an embryo in the uterus may be needed in order for exogenous bST to
exert positive effects on pregnancy outcome in lactating dairy cows.
Impacts
These findings provide convincing evidence that bST treatment during early pregnancy improves fertility responses in lactating dairy cows through mechanisms that involve both embryonic and maternal components. Results raise the interesting possibility that bST administration during early pregnancy may become a treatment to reduce embryonic mortality and increase pregnancy rates in dairy cows in which fertility is reduced due to high metabolic demands of high milk production.
Publications
- Badinga L, Guzeloglu A, Thatcher WW. 2000. Bovine somatotropin attenuates phorbol ester-induced PG release in bovine endometrial cells. Biol Reprod 2000; 62(Suppl 1):150.
- Moreira F, Badinga L, Burnley C, Thatcher WW. 2001. Effects of bovine somatotropin on embryo transfer in lactating dairy cows. Theriogenology 2001; 55: 367 (Abstract).
- Pershing RA, Thatcher WW, Badinga L. Effects of bovine somatotropin on oviductal and uterine genes encoding components of the IGF system in lactating dairy cows. Biol Reprod 2001; 62(Suppl 1):266.
- Moreira F, Paula-Lopes FF, Hansen PJ, Badinga L, Thatcher WW. Effects of growth hormone (GH) and IGF-I on development of in vitro derived bovine embryos. J Dairy Sci 2001; 84(Suppl.1): 466.
- Thatcher WW, Badinga L, Pancarci SM, Moreira F, Pershing RA, Guzeloglu A, Bilby TR, Kamimura S, Santos JE. Optimization of timed insemination programs and integration with bST to increase pregnancy rates in lactating diary cows. J Dairy Sci 2002; 85(Suppl.1):300.
- Guzeloglu A, Bilby TR, Kamimura S, Meikle A, Badinga L, Dinges AC, Hernandez O, Thatcher WW. Effects of pregnancy and bovine somatotrophin (bST) on endometrial estrogen receptor-alpha (ER), PGHS2, and PG secretion on day 17 after estrus in nonlactating dairy cows. Biol Reprod 2002; 66(Suppl 1):314.
- Balaguer SA, Pershing RA, Dinges AC, Thatcher WW, Badinga L. 2003. Interactions of bovine somatotropin and interferon-tau in the control of PG secretion in cattle. Biol Reprod 2003; 68 (Suppl 1):179.
- Moreira F, Badinga L, Burnley C, Thatcher WW. Bovine somatotropin increases embryonic development in superovulated cows and improves post-transfer pregnancy rates when given to lactating recipient cows. Theriogenology 2002; 57:1371-1387.
- Moreira F, Paula-Lopes F, Badinga L, Hansen PJ, Thatcher WW. Effects of growth hormone and insulin-like growth factor-I on development of in vitro-derived bovine embryos. Theriogenology 2002; 57:895-907.
- Pershing RA, Moore SD, Dinges AC, Thatcher WW, Badinga L. Short communication: Hepatic gene expression for gluconeogenic enzymes in lactating dairy cows treated with bovine somatotropin. J Dairy Sci 2002; 85:504-506.
- Badinga L, Gozeloglu A, Thatcher WW. Bovine somatotropin attenuates phobol ester-induced PG production in bovine endometrial cells. J Dairy Sci 2002; 85:537-543.
- Pershing RA, Lucy MC, Thatcher WW, Badinga L. Effects of BST on oviductal and uterine genes encoding components of the IGF system in lactating dairy cows. J Dairy Sci 2002; 85:3260-3267.
- Pershing RA, Dinges AC, Thatcher WW, Badinga L. Plasma and uterine insulin-like growth factor-I (IGF-I) and IGF-binding proteins in lactating dairy cows treated with bovine somatotropin. J Anim Vet Adv 2002; 2:67-73.
- Thatcher WW, Guzeloglu A, Meikle A, Kamimura S, Bilby T, Kowalski AA, Badinga L, Pershing R, Bartolome J, Santos JEP. Regulation of embryo survival in cattle. Reproduction 2002; Suppl. 61:253-266.
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Progress 09/01/99 to 08/31/02
Outputs
Our aims were to: 1) evaluate the stages of pregnancy when embryonic development and survival are most affected by exogenous bovine somatotropin (bST); 2) characterize bST-induced changes in oviductal and uterine synthesis of insulin-like growth factors (IGFs) and their binding proteins; 3) determine how bST stimulates embryonic development using an in vitro model; and 4) examine the effect of supplemental bST on uterine synthesis of PGF2a, which causes luteal regression in cattle. Administration of bST at artificial insemination decreased the number of unfertilized ova, increased the percentage of transferable embryos, and stimulated embryonic development to the blastocyst stage. Pregnancy rates were higher in control recipient dairy cows receiving bST-treated embryos, than those receiving control embryos at 7 days post-estrus. There were no differences between control and bST embryos when transferred into bST-treated recipient cows at day 7 post-estrus. Supplemental
bST induced IGF-II mRNA as early as day 3 of a synchronized estrous cycle, suggesting that IGF-II may play a modulatory role in oviductal differentiation and early embryonic development. BST down-regulated IGF-II transcript in the endometrium at day 7 of the estrous cycle, when IGF-I transcripts tended to increase, implying that these mitogens may have either overlapping or distinct roles in the control of oocyte cleavage and the ensuing blastocyst development. Both bST and IGF-I stimulated embryo development in vitro and bST effects appeared to be independent from IGF-I. In cyclic Holstein cows, bST treatment during the first 14 days of the estrous cycle attenuated PGF2a response to oxytocin. Results were further confirmed by in vitro experiments in which bST reduced phorbol ester-induced PGF2a secretion in bovine endometrial cells.
Impacts
These findings provide the first direct evidence that bST treatment during early pregnancy improves fertility responses in lactating dairy cows through mechanisms that involve both embryonic and maternal components. Results raise the interesting possibility that bST administration during early pregnancy may become a treatment to reduce embryonic mortality and increase pregnancy rates in dairy cows in which fertility is reduced due to high metabolic demands of high milk production.
Publications
- Pershing, R.A., Dinges, A.C., Thatcher, W.W. and Badinga, L. 2002. Plasma and uterine insulin-like growth factor-I (IGF-I) and IGF-binding proteins in lactating dairy cows treated with bovine somatotropin. J. Anim. Vet. Adv. 2:67-73.
- Pershing, R.A., Lucy, M.C., Thatcher, W.W. and Badinga L. 2002. Effects of BST on oviductal and uterine genes encoding components of the IGF system in lactating dairy cows. J. Dairy Sci. (in press).
- Thatcher, W.W., Guzeloglu, A., Meikle, A., Kamimura, S., Bilby, T., Kowalski, A.A., Badinga, L., Pershing, R., Bartolome, J. and Santos, J.E.P. 2002. Regulation of embryo survival in cattle. Reproduction (in press).
- Moreira, F., Badinga L., Burnley C. and Thatcher W.W. 2002. Bovine somatotropin increases embryonic development in superovulated cows and improves post-transfer pregnancy rates when given to lactating recipient cows. Theriogenology 57:1371-1387.
- Moreira, F., Paula-Lopes F., Badinga L., Hansen P.J. and Thatcher W.W. 2002. Effects of growth hormone and insulin-like growth factor-I on development of in vitro-derived bovine embryos. Theriogenology 57:895-907.
- Badinga, L., Gozeloglu, A. and Thatcher, W.W. 2002. Bovine somatotropin attenuates phobol ester-induced prostaglandin F2a production in bovine endometrial cells. J. Dairy Sci. 85:537-543.
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Progress 10/01/00 to 10/01/01
Outputs
Objectives I and IV of this project were completed in year one and results were reported in last year's annual report. Specific aim #2. Twenty-one lactating, cyclic Holstein were synchronized to estrus using the Ovsynch program and then randomly assigned to receive bST (n=11) or serve as untreated control (n=10). Within each treatment group, cows were assigned to be sacrificed on D 3 or 7 post-ovulation. Samples of oviductal and endometrial tissues were collected from the oviduct and uterine horn ipsilateral to the corpus luteum and frozen at -80oC until subsequent analysis of IGF-I, IGF-II, IGFBP-2, IGFBP-3 and growth hormone receptor (GHR) mRNA contents. Concentrations of IGF-I transcripts did not differ between control and bST-treated cows. Levels of IGF-II mRNA were higher (+250%) in oviducts but lower (-60%) in uteri collected from bST-treated. Irrespective of the site or stage of the estrous cycle, IGFBP-3 mRNA levels were higher (+125%; P<0.05) in bST-treated
cows than the control cows. IGFBP-2 transcript levels did not differ between treatments or stages of the estrous cycle. The GHR mRNA was decreased (-30%) in bST-treated cows by D 7 of the estrous cycle. Results suggest that bST effects on fertility responses in lactating dairy cows may involve complex and tissue specific regulation of IGFs and IGFBPs within the uterus. Specific aim #3: Cumulus oocyte complexes (COCs) from slaughterhouse ovaries were matured in 50 ul drops of serum-free TCM-199 medium containing FSH (20 ug/ml) and estradiol (2 ug/ml) in groups of 10 oocytes per drop. During maturation, COCs were treated with 100 or 0 ng/ml of GH. COCs were inseminated, denuded, and transferred to 25 ul drops of serum-free KSOM medium containing essentially fatty acid-free bovine serum albumin (2 mg/ml) in groups of 10 presumptive embryos per drop for culture (d 0). Beginning at d 0, the following treatments were added to medium: 1) non-specific IgG (raised to heat shock protein 65 of
Mycobacterium bovis; 10 ug/ml), 2) GH (100 ng/ml) plus IgG (10 ug/ml; GH/IgG), 3) IGF-I (100 ng/ml) plus IgG (10 ug/ml; IGF/IgG), 4) antibody to IGF-I (10 ug/ml; anti-IGF), 5) GH (100 ng/ml) plus anti-IGF (10 ug/ml; GH/anti-IGF), 6) IGF-I (100 ng/ml) plus anti-IGF (10 ug/ml; IGF/anti-IGF), or 7) no further additions (control). Addition of GH to the maturation medium increased cleavage rates at d 3 compared to control (87.3% > 83.9 %) but had no effects on blastocyst development at d 7 and 8. Blastocyst development was greater for GH/IgG (16.2%) and IGF/IgG (16.5%) than for IgG (8.7%) at d 7. At d 8, blastocyst development was greater for GH/IgG (24.8%) and IGF/IgG (33.7%) than for IgG (16.1%) and greater for IGF/IgG than for GH/IgG. Blastocyst development at d 8 did not differ between anti-IGF (20.4%) compared to GH/anti-IGF (24.1%) and IGF/anti-IGF (17.7%), but it was greater for GH/anti-IGF than for IGF/anti-IGF. Both GH and IGF-I stimulated embryonic development and GH effects seem
to be independent of IGF-I signaling mechanism.
Impacts
Results suggest that bST effects on fertility responses in lactating dairy cows are likely to involve complex and tissue specific regulation of IGFs and IGFBPs within the uterus. Additionally, fertility responses to bST may involve IGF-dependent as well as IGF-independent signaling mechanisms. Results raise the interesting possibility that bST administration to lactating dairy cows during early pregnancy may become a treatment to reduce embryonic mortality and increase pregnancy rates in dairy cows in which fertility is reduced due to high metabolic demands of high milk production.
Publications
- Pershing RA, Thatcher WW, Badinga L. Effects of bovine somatotropin on oviductal and uterine genes encoding components of the IGF system in lactating dairy cows. Biol Reprod 2001; 64(Suppl 1):266.
- Moreira F, Paula-Lopes FF, Hansen PJ, Badinga L, Thatcher WW. Effects of growth hormone (GH) and IGF-I on development of in vitro derived bovine embryos. J Dairy Sci 2001; 84(Suppl 1):466.
- Badinga L, Guzeloglu A, Thatcher WW. Bovine somatotropin attenuates phorbol ester-induced prostaglandin F 2a production in bovine endometrial cells. J Dairy Sci 2001 (in press).
- Pershing RA, Moore SD, Dinges AC, Thatcher WW, Badinga L. Short communication: Hepatic gene expression for gluconeogenic enzymes in lactating dairy cows treated with bovine somatotropin. J Dairy Sci 2001 (in press).
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Progress 10/01/99 to 09/30/00
Outputs
Specific aims: The first objective of this project was to evaluate the stages of pregnancy when embryonic development and survival are most affected by exogenous bovine somatotropin (bST). The second objective was to characterize bST-induced changes in oviductal and uterine synthesis of IGFs and their binding. The third objective was to determine how bST stimulates embryonic development using an in vitro model. The fourth objective was to examine the effect of supplemental bST on uterine synthesis of prostaglandin F2a which causes luteal regression in cattle. Objectives I and IV have been completed to date and major findings and their potential significance to the US dairy industry are summarized in the following section. Results: Specific aim #1: Embryos were obtained after superovulation of donor Holstein cows that received a bST treatment at insemination (bST embryos; n=101) or did not receive a bST treatment at insemination (control embryos; n=80). All embryos
were flushed on Day 7 post-insemination, evaluated for morphological development and frozen in liquid nitrogen until embryo transfer. Administration of bST at artificial insemination decreased the number of unfertilized ova (bST, 1.0% < Control, 3.7%), increased the percentage of transferable embryos (bST, 77.2% > control, 56.4%), and stimulated embryonic development to the blastocyst stage (bST, 32.5% > Control, 9.3%). Lactating Holstein cows designated as recipients received either bST treatment 1 day after estrus (n=97) or were untreated controls (n=84). Either a bST or control frozen embryo was thawed and transferred directly into a recipient cow (control or bST) at day 7 after detected estrus. Pregnancy was determined by rectal palpation 40 to 45 days after embryo transfer. Pregnancy rates were higher in control recipient cows receiving bST embryos (56.1%) than those receiving control embryos (25.6%). There were no differences between control (43.2%) and bST embryos (43.3%) when
transferred into bST-treated recipient cows. Control embryos performed much better when transferred into bST-treated recipient cows (43.2%) than when transferred into control recipient cows (25.6%). There were no detectable differences between pregnancy rates of bST-treated recipient cows (43.2%) compared to control recipient cows (56.1%) receiving a bST embryo. Results indicate that bST treatment at insemination improves fertility responses in dairy cows through mechanisms that involve both embryonic and maternal components. Specific aim #4: Prostaglandin F2a responses were examined in control (n=6) or bST-treated (n=6) Holstein cows challenged with oxytocin on Day 16 of the estrous cycle. Bovine somatotropin treatment during the first 14 days of the estrous cycle significantly attenuated PGF2a responses to oxytocin. These results were further confirmed by in vitro experiments in which bST reduced phorbol ester-induced PGF2a secretion and cyclooxygenase-2 gene expression in bovine
endometrial (BEND) cells. From a reproductive management perspective, an inhibition or attenuation of PGF2a secretion will extend the corpus luteum lifespan and increase early embryonic survival.
Impacts
These findings provide convincing evidence that bST treatment at insemination improves fertility responses in lactating dairy cows through mechanisms that involve both embryonic and maternal components. Results raise the interesting possibility that bST administration to lactating dairy cows during early pregnancy may become a treatment to reduce embryonic mortality and increase pregnancy rates in dairy cows in which fertility is reduced due to high metabolic demands of high milk production. Additionally, these findings may have a major impact on the dairy industry in the southeastern United States where fertility in lactating dairy cows is severely depressed during the summer months of the year.
Publications
- Moreira F, Badinga L, Burnley C, Thatcher WW. Superovulatory responses in cows receiving bovine somatotropin. J Dairy Sci 2000; 83(Suppl 1):214.
- Moreira F, Badinga L, Burnley C, Thatcher WW. Effects of bovine somatotropin on embryo transfer in lactating dairy cows. Theriogenology 2001; (Abstract).
- Badinga L, Guzeloglu A, Thatcher WW. Bovine somatotropin attenuates phorbol ester-induced PGF2 alpha release in bovine endometrial cells. Biol Reprod 2000; 62(Suppl 1):151
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