Timed Artificial Insemination with Estradiol Cypionate or Insemination at Estrus in High-Producing Dairy Cows

A total of 799 Holstein cows from 3 herds were randomly assigned at 37±3 d in milk (DIM) to timed artificial insemination (AI) or insemination at detected estrus. Cows were presynchronized with injections of PGF2α at 37 and 51 DIM. At 65 DIM, cows received an injection of GnRH, followed 7 d later by...

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Bibliographic Details
Published in:Journal of dairy science 2004-11, Vol.87 (11), p.3704-3715
Main Authors: Cerri, R.L.A., Santos, J.E.P., Juchem, S.O., Galvão, K.N., Chebel, R.C.
Format: Article
Language:English
Subjects:
Animal productions
Animals
Biological and medical sciences
Cattle - blood
Cattle - physiology
conception
dairy cow
dairy cows
Dinoprost - pharmacology
Estradiol - analogs & derivatives
Estradiol - pharmacology
estradiol cypionate
Estrus - drug effects
Estrus - physiology
estrus detection
estrus synchronization
Estrus Synchronization - blood
Estrus Synchronization - physiology
Female
Fertility Agents, Female - pharmacology
Food industries
Fundamental and applied biological sciences. Psychology
Insemination, Artificial - veterinary
Milk and cheese industries. Ice creams
Ovulation Induction - methods
Ovulation Induction - veterinary
Parity - physiology
Pregnancy
Pregnancy Rate
Pregnancy, Animal - drug effects
Pregnancy, Animal - physiology
progesterone
Progesterone - blood
Random Allocation
reproduction
Terrestrial animal productions
Time Factors
timed artificial insemination
Vertebrates
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Summary:A total of 799 Holstein cows from 3 herds were randomly assigned at 37±3 d in milk (DIM) to timed artificial insemination (AI) or insemination at detected estrus. Cows were presynchronized with injections of PGF2α at 37 and 51 DIM. At 65 DIM, cows received an injection of GnRH, followed 7 d later by PGF2α. Cows in the estrus-detected group were inseminated after being observed in estrus during the 7 d after the last PGF2α. Cows in the timed AI group received an injection of 1mg of estradiol cypionate (ECP) 24h after the last PGF2α. If detected in estrus≤24h after ECP, cows were inseminated then or at a fixed time 48h after ECP. Pregnancy was diagnosed by ultrasonography at 30 d and by palpation at 44 and 58 d after AI. Plasma progesterone was measured in 4 samples per cow collected on days of 1) second PGF2α, 2) GnRH, 3) third PGF2α, and 4) 48h after third PGF2α. Cows were classified as cyclic or anovulatory based on progesterone concentrations in samples 1 and 2. Similarly, cows were classified according to progesterone concentrations in samples 2, 3, and 4 (H = ≥1 ng/mL; L =
ISSN:0022-0302
1525-3198
DOI:10.3168/jds.S0022-0302(04)73509-2