{"id":{"repo_id":"missouri","oai_identifier":"oai:mospace.umsystem.edu:10355/88082"},"canonical_url":"https://search.dev.ndltd.org/etd/missouri/oai:mospace.umsystem.edu:10355/88082","repository":{"repo_id":"missouri","name":"University of Missouri","base_url":"https://mospace.umsystem.edu/oai/request"},"display":{"title":"Evaluation of the 7 and 7 synch protocol for control of the estrous cycle among beef cows prior to fixed-time artificial insemination with sex-sorted or conventional semen","abstract":"Experiment 1 was conducted to compare 7 and 7 Synch and the 7-day CO-Synch + controlled internal drug release (CIDR[copyright]) protocols prior to fixed-time artificial insemination (FTAI) of beef cows with conventional or sex-sorted semen. Cows (n = 1,538) were blocked based on age and days postpartum (DPP) and randomly assigned to protocol and semen type. Cows assigned to 7-day CO-Synch + CIDR (n = 769) received administration of gonadotropin-releasing hormone (GnRH) and insertion of an intravaginal progesterone-releasing insert (CIDR) on Day -10, and administration of prostaglandin F2[alpha] (PG) coincident with CIDR removal on Day -3. Cows assigned to 7 and 7 Synch (n = 769) received PG and insertion of CIDR on Day -17, GnRH on Day -10, and PG coincident with CIDR removal on Day -3. Estrus detection aids were applied to all cows. Cows received FTAI 66 h after CIDR removal with conventional (20 x 106 cells per unit) or sex-sorted (4 x 106 cells per unit) semen. Estrus expression was affected by protocol (P = 0.01) by protocol x DPP (P = 0.0004), with 7 and 7 Synch (82 percent; 629/769) resulting in a greater proportion of cows expressing estrus (82 percent [629/769] versus 64 percent [492/769]), especially among cows with greater DPP. Pregnancy rates to FTAI were reduced (P < 0.0001) when using sex-sorted semen but greater among cows treated with 7 and 7 Synch (conventional semen: 72 percent [280/389]; sex-sorted semen: 52 percent [199/380]) compared with 7-day CO-Synch + CIDR (conventional semen: 61 percent [233/383]; sex-sorted semen: 44 percent [171/386]). Experiment 2 was designed to evaluate later timing of fixed-time artificial insemination (FTAI) with sex-sorted semen among postpartum beef cows following the 7 and 7 Synch protocol, with the hypothesis that later timing would result in increased pregnancy rates (P/AI) among cows that expressed estrus prior to FTAI. Beef cows (n=414) were blocked based on age and days postpartum (DPP) and randomly assigned to receive FTAI at 66 or 72 h after administration of prostaglandin F2[alpha] (PG). Estrus was synchrized using the 7 and 7 Synch protocol, which consists of administration of PG (500 [mu]g cloprostenol) and insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38 g progesterone) on Day 0, gonadotropin-releasing hormone (GnRH; 100 [mu]g gonadorelin) on Day 7, and PG coincident with CIDR removal on Day 14. Estrus detection aids (EstrotectTM) were applied to all cows on Day 14, and activation status was recorded at fixed-time artificial insemination (FTAI) on Day 17. All cows that expressed estrus prior to FTAI received sex-sorted semen (4 x 106 cells per unit; SexedULTRA 4MTM). The proportion of cows expressing estrus prior to FTAI did not differ between treatments at this power of test (66 h: 71 percent [146/205]; 72 h: 76 percent [158/209]). Additionally, P/AI of estrous cows inseminated with sex-sorted semen did not differ between treatments (66 h: 45 percent [68/146]; 72 h: 40 percent [63/158]). In conclusion, later timing of FTAI following the 7 and 7 Synch protocol failed to improve P/AI of estrous cows inseminated h sex-sorted semen.","abstract_html":"Experiment 1 was conducted to compare 7 and 7 Synch and the 7-day CO-Synch + controlled internal drug release (CIDR[copyright]) protocols prior to fixed-time artificial insemination (FTAI) of beef cows with conventional or sex-sorted semen. Cows (n = 1,538) were blocked based on age and days postpartum (DPP) and randomly assigned to protocol and semen type. Cows assigned to 7-day CO-Synch + CIDR (n = 769) received administration of gonadotropin-releasing hormone (GnRH) and insertion of an intravaginal progesterone-releasing insert (CIDR) on Day -10, and administration of prostaglandin F2[alpha] (PG) coincident with CIDR removal on Day -3. Cows assigned to 7 and 7 Synch (n = 769) received PG and insertion of CIDR on Day -17, GnRH on Day -10, and PG coincident with CIDR removal on Day -3. Estrus detection aids were applied to all cows. Cows received FTAI 66 h after CIDR removal with conventional (20 x 106 cells per unit) or sex-sorted (4 x 106 cells per unit) semen. Estrus expression was affected by protocol (P = 0.01) by protocol x DPP (P = 0.0004), with 7 and 7 Synch (82 percent; 629/769) resulting in a greater proportion of cows expressing estrus (82 percent [629/769] versus 64 percent [492/769]), especially among cows with greater DPP. Pregnancy rates to FTAI were reduced (P < 0.0001) when using sex-sorted semen but greater among cows treated with 7 and 7 Synch (conventional semen: 72 percent [280/389]; sex-sorted semen: 52 percent [199/380]) compared with 7-day CO-Synch + CIDR (conventional semen: 61 percent [233/383]; sex-sorted semen: 44 percent [171/386]). Experiment 2 was designed to evaluate later timing of fixed-time artificial insemination (FTAI) with sex-sorted semen among postpartum beef cows following the 7 and 7 Synch protocol, with the hypothesis that later timing would result in increased pregnancy rates (P/AI) among cows that expressed estrus prior to FTAI. Beef cows (n=414) were blocked based on age and days postpartum (DPP) and randomly assigned to receive FTAI at 66 or 72 h after administration of prostaglandin F2[alpha] (PG). Estrus was synchrized using the 7 and 7 Synch protocol, which consists of administration of PG (500 [mu]g cloprostenol) and insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38 g progesterone) on Day 0, gonadotropin-releasing hormone (GnRH; 100 [mu]g gonadorelin) on Day 7, and PG coincident with CIDR removal on Day 14. Estrus detection aids (EstrotectTM) were applied to all cows on Day 14, and activation status was recorded at fixed-time artificial insemination (FTAI) on Day 17. All cows that expressed estrus prior to FTAI received sex-sorted semen (4 x 106 cells per unit; SexedULTRA 4MTM). The proportion of cows expressing estrus prior to FTAI did not differ between treatments at this power of test (66 h: 71 percent [146/205]; 72 h: 76 percent [158/209]). Additionally, P/AI of estrous cows inseminated with sex-sorted semen did not differ between treatments (66 h: 45 percent [68/146]; 72 h: 40 percent [63/158]). In conclusion, later timing of FTAI following the 7 and 7 Synch protocol failed to improve P/AI of estrous cows inseminated h sex-sorted semen.","abstract_has_math":false,"creators":["Andersen, Carson M."],"institution":"University of Missouri--Columbia","degree_name":"M.S.","degree_level":"Masters","degree_discipline":"Animal sciences (MU)","degree_department":null,"school":null,"contributors":[],"advisors":["Thomas, Jordan"],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021","date_published":"2021","updated_at":"2026-07-24T03:07:57Z","subjects":[],"languages":["eng","English"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.doi","label":"DOI","values":["https://doi.org/10.32469/10355/88082"],"render_values":[{"text":"https://doi.org/10.32469/10355/88082","href":"https://doi.org/10.32469/10355/88082","code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/10355/88082","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Thomas, Jordan"]},{"key":"dc:creator","label":"Author","values":["Andersen, Carson M."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2021-11-18T22:18:12Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2021-11-18T22:18:12Z"]},{"key":"dc:date.issued","label":"Date","values":["2021"]},{"key":"dc:publisher","label":"Institution","values":["University of Missouri--Columbia"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Animal sciences (MU)"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Missouri--Columbia"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["https://doi.org/10.32469/10355/88082"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10355/88082"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Experiment 1 was conducted to compare 7 and 7 Synch and the 7-day CO-Synch + controlled internal drug release (CIDR[copyright]) protocols prior to fixed-time artificial insemination (FTAI) of beef cows with conventional or sex-sorted semen. Cows (n = 1,538) were blocked based on age and days postpartum (DPP) and randomly assigned to protocol and semen type. Cows assigned to 7-day CO-Synch + CIDR (n = 769) received administration of gonadotropin-releasing hormone (GnRH) and insertion of an intravaginal progesterone-releasing insert (CIDR) on Day -10, and administration of prostaglandin F2[alpha] (PG) coincident with CIDR removal on Day -3. Cows assigned to 7 and 7 Synch (n = 769) received PG and insertion of CIDR on Day -17, GnRH on Day -10, and PG coincident with CIDR removal on Day -3. Estrus detection aids were applied to all cows. Cows received FTAI 66 h after CIDR removal with conventional (20 x 106 cells per unit) or sex-sorted (4 x 106 cells per unit) semen. Estrus expression was affected by protocol (P = 0.01) by protocol x DPP (P = 0.0004), with 7 and 7 Synch (82 percent; 629/769) resulting in a greater proportion of cows expressing estrus (82 percent [629/769] versus 64 percent [492/769]), especially among cows with greater DPP. Pregnancy rates to FTAI were reduced (P < 0.0001) when using sex-sorted semen but greater among cows treated with 7 and 7 Synch (conventional semen: 72 percent [280/389]; sex-sorted semen: 52 percent [199/380]) compared with 7-day CO-Synch + CIDR (conventional semen: 61 percent [233/383]; sex-sorted semen: 44 percent [171/386]). Experiment 2 was designed to evaluate later timing of fixed-time artificial insemination (FTAI) with sex-sorted semen among postpartum beef cows following the 7 and 7 Synch protocol, with the hypothesis that later timing would result in increased pregnancy rates (P/AI) among cows that expressed estrus prior to FTAI. Beef cows (n=414) were blocked based on age and days postpartum (DPP) and randomly assigned to receive FTAI at 66 or 72 h after administration of prostaglandin F2[alpha] (PG). Estrus was synchrized using the 7 and 7 Synch protocol, which consists of administration of PG (500 [mu]g cloprostenol) and insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38 g progesterone) on Day 0, gonadotropin-releasing hormone (GnRH; 100 [mu]g gonadorelin) on Day 7, and PG coincident with CIDR removal on Day 14. Estrus detection aids (EstrotectTM) were applied to all cows on Day 14, and activation status was recorded at fixed-time artificial insemination (FTAI) on Day 17. All cows that expressed estrus prior to FTAI received sex-sorted semen (4 x 106 cells per unit; SexedULTRA 4MTM). The proportion of cows expressing estrus prior to FTAI did not differ between treatments at this power of test (66 h: 71 percent [146/205]; 72 h: 76 percent [158/209]). Additionally, P/AI of estrous cows inseminated with sex-sorted semen did not differ between treatments (66 h: 45 percent [68/146]; 72 h: 40 percent [63/158]). In conclusion, later timing of FTAI following the 7 and 7 Synch protocol failed to improve P/AI of estrous cows inseminated h sex-sorted semen."]},{"key":"dc:title","label":"Title","values":["Evaluation of the 7 and 7 synch protocol for control of the estrous cycle among beef cows prior to fixed-time artificial insemination with sex-sorted or conventional semen"]}]}],"canonical_facts":{"dc:contributor.advisor":["Thomas, Jordan"],"dc:creator":["Andersen, Carson M."],"dc:date.accessioned":["2021-11-18T22:18:12Z"],"dc:date.available":["2021-11-18T22:18:12Z"],"dc:date.issued":["2021"],"dc:description.abstract":["Experiment 1 was conducted to compare 7 and 7 Synch and the 7-day CO-Synch + controlled internal drug release (CIDR[copyright]) protocols prior to fixed-time artificial insemination (FTAI) of beef cows with conventional or sex-sorted semen. Cows (n = 1,538) were blocked based on age and days postpartum (DPP) and randomly assigned to protocol and semen type. Cows assigned to 7-day CO-Synch + CIDR (n = 769) received administration of gonadotropin-releasing hormone (GnRH) and insertion of an intravaginal progesterone-releasing insert (CIDR) on Day -10, and administration of prostaglandin F2[alpha] (PG) coincident with CIDR removal on Day -3. Cows assigned to 7 and 7 Synch (n = 769) received PG and insertion of CIDR on Day -17, GnRH on Day -10, and PG coincident with CIDR removal on Day -3. Estrus detection aids were applied to all cows. Cows received FTAI 66 h after CIDR removal with conventional (20 x 106 cells per unit) or sex-sorted (4 x 106 cells per unit) semen. Estrus expression was affected by protocol (P = 0.01) by protocol x DPP (P = 0.0004), with 7 and 7 Synch (82 percent; 629/769) resulting in a greater proportion of cows expressing estrus (82 percent [629/769] versus 64 percent [492/769]), especially among cows with greater DPP. Pregnancy rates to FTAI were reduced (P < 0.0001) when using sex-sorted semen but greater among cows treated with 7 and 7 Synch (conventional semen: 72 percent [280/389]; sex-sorted semen: 52 percent [199/380]) compared with 7-day CO-Synch + CIDR (conventional semen: 61 percent [233/383]; sex-sorted semen: 44 percent [171/386]). Experiment 2 was designed to evaluate later timing of fixed-time artificial insemination (FTAI) with sex-sorted semen among postpartum beef cows following the 7 and 7 Synch protocol, with the hypothesis that later timing would result in increased pregnancy rates (P/AI) among cows that expressed estrus prior to FTAI. Beef cows (n=414) were blocked based on age and days postpartum (DPP) and randomly assigned to receive FTAI at 66 or 72 h after administration of prostaglandin F2[alpha] (PG). Estrus was synchrized using the 7 and 7 Synch protocol, which consists of administration of PG (500 [mu]g cloprostenol) and insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38 g progesterone) on Day 0, gonadotropin-releasing hormone (GnRH; 100 [mu]g gonadorelin) on Day 7, and PG coincident with CIDR removal on Day 14. Estrus detection aids (EstrotectTM) were applied to all cows on Day 14, and activation status was recorded at fixed-time artificial insemination (FTAI) on Day 17. All cows that expressed estrus prior to FTAI received sex-sorted semen (4 x 106 cells per unit; SexedULTRA 4MTM). The proportion of cows expressing estrus prior to FTAI did not differ between treatments at this power of test (66 h: 71 percent [146/205]; 72 h: 76 percent [158/209]). Additionally, P/AI of estrous cows inseminated with sex-sorted semen did not differ between treatments (66 h: 45 percent [68/146]; 72 h: 40 percent [63/158]). In conclusion, later timing of FTAI following the 7 and 7 Synch protocol failed to improve P/AI of estrous cows inseminated h sex-sorted semen."],"dc:identifier.doi":["https://doi.org/10.32469/10355/88082"],"dc:identifier.uri":["https://hdl.handle.net/10355/88082"],"dc:language":["English"],"dc:language.iso":["eng"],"dc:publisher":["University of Missouri--Columbia"],"dc:title":["Evaluation of the 7 and 7 synch protocol for control of the estrous cycle among beef cows prior to fixed-time artificial insemination with sex-sorted or conventional semen"],"dc:type":["Thesis"],"thesis:degree_discipline":["Animal sciences (MU)"],"thesis:degree_level":["Masters"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Missouri--Columbia"]},"updated_at":"2026-07-24T03:07:57Z"}