PMID- 32062494
OWN - NLM
STAT- MEDLINE
DCOM- 20210128
LR  - 20210128
IS  - 1879-3231 (Electronic)
IS  - 0093-691X (Linking)
VI  - 146
DP  - 2020 Apr 1
TI  - Presynchronization with prostaglandin F(2alpha) and prolonged exposure to exogenous 
      progesterone impacts estrus expression and fertility in beef heifers.
PG  - 88-93
LID - S0093-691X(20)30112-6 [pii]
LID - 10.1016/j.theriogenology.2020.02.010 [doi]
AB  - To determine the effects of two presynchronization strategies in conjunction with 
      delayed fixed-time artificial insemination (TAI) on pregnancy rates to TAI 
      (PR/AI), 1700 Angus beef heifers at three locations in South Dakota were enrolled 
      in a completely randomized design with a 2 by 2 factorial arrangement of 
      treatments. Within location, all heifers were randomly assigned to one of four 
      treatments: 1) PG54 (n = 434), heifers were administered prostaglandin F(2alpha) 
      (PGF; 25 mg im) 7 d prior [Day -14] to the initiation of the 7-d 
      CO-Synch + controlled internal drug releasing (CIDR) protocol wherein they 
      received gonadotropin-releasing hormone (GnRH; 100 mug im) and a CIDR insert on 
      Day -7, PGF at CIDR removal on Day 0, and a second injection of GnRH concurrently 
      with TAI 54 +/- 2 h later; 2) PG72 (n = 426), heifers were exposed to the same 
      treatment as PG54, however, TAI was performed 72 +/- 2 h after CIDR removal; 3) 
      PG-CIDR54 (n = 422), same as PG54 but heifers received a CIDR insert on Day -14 
      rather than Day -7, in addition to PGF administration; 4) PG-CIDR72 (n = 418), 
      same as PG-CIDR54, however, TAI was performed 72 +/- 2 h after CIDR removal. Estrus 
      detection patches were applied to all heifers on Day 0 and were evaluated for 
      activation at TAI. Pregnancy was diagnosed via transrectal ultrasonography 
      between 30 and 47 d after TAI. The percentage of heifers exhibiting estrus 
      between Day 0 and TAI was greater (P < 0.01) in the PG72, PG-CIDR54, and 
      PG-CIDR72 treatments compared to the PG54 treatment (78.11, 86.59, and 91.09 vs. 
      31.05%, respectively). Furthermore, estrus response was greater (P < 0.01) in 
      PG-CIDR72 heifers when compared to PG72. Pregnancy rates to TAI differed among 
      treatments and were greater (P < 0.05) in the PG72 and PG-CIDR54 treatments when 
      compared to PG-CIDR72 (48.8 and 50.4 vs. 38.4%, respectively), and were greater 
      (P = 0.03) in PG-CIDR54 vs. PG54 (43.1%). Moreover, a tendency (P = 0.10) was 
      determined on PR/AI between PG54 and PG72. In conclusion, presynchronization 
      strategies and prolonged exposure to exogenous progesterone have the potential to 
      alter estrus expression and improve fertility in replacement beef heifers.
CI  - Copyright (c) 2020 Elsevier Inc. All rights reserved.
FAU - Oosthuizen, N
AU  - Oosthuizen N
AD  - Department of Animal Science, Texas A&M University, College Station, TX, 
      77843-2471, USA.
FAU - Fontes, P L P
AU  - Fontes PLP
AD  - Department of Animal and Dairy Science, University of Georgia, Athens, GA, 30602, 
      USA.
FAU - Porter, K
AU  - Porter K
AD  - Kleinsasser-Porter Veterinary Service, Huron, SD, 57350, USA.
FAU - Lamb, G C
AU  - Lamb GC
AD  - Department of Animal Science, Texas A&M University, College Station, TX, 
      77843-2471, USA. Electronic address: gclamb@tamu.edu.
LA  - eng
PT  - Journal Article
PT  - Randomized Controlled Trial, Veterinary
DEP - 20200207
PL  - United States
TA  - Theriogenology
JT  - Theriogenology
JID - 0421510
RN  - 33515-09-2 (Gonadotropin-Releasing Hormone)
RN  - 4G7DS2Q64Y (Progesterone)
RN  - B7IN85G1HY (Dinoprost)
SB  - IM
MH  - Animals
MH  - Cattle/*physiology
MH  - Dinoprost/administration & dosage/*pharmacology
MH  - Drug Administration Schedule
MH  - Estrus/*drug effects/physiology
MH  - Estrus Synchronization/methods
MH  - Female
MH  - Fertility
MH  - Gonadotropin-Releasing Hormone/administration & dosage/pharmacology
MH  - Pregnancy
MH  - Progesterone/administration & dosage/*pharmacology
OTO - NOTNLM
OT  - CIDR
OT  - Presynchronization
OT  - Prostaglandin F(2alpha)
OT  - Replacement beef heifer
EDAT- 2020/02/18 06:00
MHDA- 2021/01/29 06:00
CRDT- 2020/02/17 06:00
PHST- 2019/10/15 00:00 [received]
PHST- 2020/01/20 00:00 [revised]
PHST- 2020/02/06 00:00 [accepted]
PHST- 2020/02/18 06:00 [pubmed]
PHST- 2021/01/29 06:00 [medline]
PHST- 2020/02/17 06:00 [entrez]
AID - S0093-691X(20)30112-6 [pii]
AID - 10.1016/j.theriogenology.2020.02.010 [doi]
PST - ppublish
SO  - Theriogenology. 2020 Apr 1;146:88-93. doi: 10.1016/j.theriogenology.2020.02.010. 
      Epub 2020 Feb 7.