title: Using estrus detection patches to optimally time insemination improved pregnancy risk in suckled beef cows enrolled in a fixed-time artificial insemination program.
abstract: A multilocation study examined pregnancy risk (PR) after delaying AI in suckled beef cows from 60 to 75 h when estrus had not been detected by 60 h in response to a 7-d CO-Synch + progesterone insert (CIDR) timed AI (TAI) program (d -7: CIDR insert concurrent with an injection of GnRH; d 0: PGF injection and removal of CIDR insert; and GnRH injection at TAI [60 or 75 h after CIDR removal]). A total of 1,611 suckled beef cows at 15 locations in 9 states (CO, IL, KS, MN, MS, MT, ND, SD, and VA) were enrolled. Before applying the fixed-time AI program, BCS was assessed, and blood samples were collected. Estrus was defined to have occurred when an estrus detection patch was >50% colored (activated). Pregnancy was determined 35 d after AI via transrectal ultrasound. Cows ( = 746) detected in estrus by 60 h (46.3%) after CIDR removal were inseminated and treated with GnRH at AI (Control). Remaining nonestrous cows were allocated within location to 3 treatments on the basis of parity and days postpartum: 1) GnRH injection and AI at 60 h (early-early = EE; = 292), 2) GnRH injection at 60 h and AI at 75 h (early-delayed = ED; = 282), or 3) GnRH injection and AI at 75 h (delayed-delayed = DD; = 291). Control cows had a greater ( < 0.01) PR (64.2%) than other treatments (EE = 41.7%, ED = 52.8%, DD = 50.0%). Use of estrus detection patches to delay AI in cows not in estrus by 60 h after CIDR insert removal (ED and DD treatments) increased ( < 0.05) PR to TAI when compared with cows in the EE treatment. More ( < 0.001) cows that showed estrus by 60 h conceived to AI at 60 h than those not showing estrus (64.2% vs. 48.1%). Approximately half (49.2%) of the cows not in estrus by 60 h had activated patches by 75 h, resulting in a greater ( < 0.05) PR than their nonestrous herd mates in the EE (46.1% vs. 34.5%), ED (64.2% vs. 39.2%), and DD (64.8% vs. 31.5%) treatments, respectively. Overall, cows showing estrus by 75 h (72.7%) had greater ( < 0.001) PR to AI (61.3% vs. 37.9%) than cows not showing estrus. Use of estrus detection patches to allow for a delayed AI in cows not in estrus by 60 h after removal of the CIDR insert improved PR to TAI by optimizing the timing of the AI in those cows.
authors.forename: S L
authors.initials: SL
authors.lastname: Hill
authors.forename: D M
authors.initials: DM
authors.lastname: Grieger
authors.forename: K C
authors.initials: KC
authors.lastname: Olson
authors.forename: J R
authors.initials: JR
authors.lastname: Jaeger
authors.forename: C R
authors.initials: CR
authors.lastname: Dahlen
authors.forename: G A
authors.initials: GA
authors.lastname: Bridges
authors.forename: F
authors.initials: F
authors.lastname: Dantas
authors.forename: J E
authors.initials: JE
authors.lastname: Larson
authors.forename: A M
authors.initials: AM
authors.lastname: Muth-Spurlock
authors.forename: J K
authors.initials: JK
authors.lastname: Ahola
authors.forename: M C
authors.initials: MC
authors.lastname: Fischer
authors.forename: G A
authors.initials: GA
authors.lastname: Perry
authors.forename: E L
authors.initials: EL
authors.lastname: Larimore
authors.forename: T L
authors.initials: TL
authors.lastname: Steckler
authors.forename: W D
authors.initials: WD
authors.lastname: Whittier
authors.forename: J F
authors.initials: JF
authors.lastname: Currin
authors.forename: J S
authors.initials: JS
authors.lastname: Stevenson
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D015237:Dinoprost / Q000008:administration & dosage; D004971:Estrus / Q000502:physiology*; D004972:Estrus Detection / Q000295:instrumentation*; D004973:Estrus Synchronization / Q000379:methods; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage; D007315:Insemination, Artificial / Q000662:veterinary*; D007774:Lactation; D011247:Pregnancy; D018873:Pregnancy Rate; D011374:Progesterone / Q000097:blood; D014481:United States
chemical_list: D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D015237:Dinoprost