Success of several programed AI-breeding protocols including ovsynch
Success of several programed AI-breeding protocols including ovsynch
Jeffrey S. Stevenson
K . E. Thomp son
Y. Kobayashi
Follow this and additional works at: https://newprairiepress.org/kaesrr Part of the Dairy Science Commons Recommended Citation Stevenson, Jeffrey S.; Thomps on, K. E.; and Kobayashi, Y. (1996) "Success of several programed AI-breeding protocols including ovsynch," Kansas Agricultural Experiment Station Research Reports: Vol. 0: Iss. 2. https://doi.org/10.4148/2378-5977.3252
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Article 327
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Success of several programed AI-breeding protocols including ovsynch
Abstract
In Experiment 1, four programmed AIbreeding treatments were tested. The s o-called OvSynch program,
which requires no heat detection before a fixed-time insemination, decreased conception rates compared with
a similar treatment in which inseminations occurred after detected estrus (30 vs 51%). The tr aditional
twoinjection prostaglandin program produced greater conception rate for cattle inseminated after a detected
estrus (53%) than after one fixed-time insemination was given in the absence of estrus (31%). A similar
protocol of two prostaglandin injections plus an injection of gonadotropin-releasing hormone (GnRH or
Cystorelin®) before one fixed-time insemination produced lower conception rates (33%) than when cattle
were inseminated after detected estrus (53%). In Experiment 2, the OvSynch program was retested with the
interval between the PGF and the second GnRH 2a injection being 48 hr (36 hr in Experiment 1).
Conception in 27 cows on the OvSynch48 program with timed insemination (37%) was comparable with
43% in 21 cows on a similar program without the second GnRH injection but inseminated at estrus.; Dairy
Day, 1996, Kansas State University, Manhattan, KS, 1996;
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Thi s Research Report article is available in Kansas Agricultural Experiment Station Research Reports: https://newprairiepress.org/
kaesrr/vol0/iss2/327
Dairy Day 1996
SUCCESS OF SEVERAL PROGRAMMED
AI-BREEDING PROTOCOLS INCLUDING OVSYNCH
Summary
In Experiment 1, four programmed AI
breeding treatments were tested. The so-called
OvSynch program, which requires no heat
detection before a fixed-time insemination,
decreased conception rates compared with a
similar treatment in which inseminations
occurred after detected estrus (30 vs 51%). The
traditional two-injection prostaglandin program
produced greater conception rate for cattle
inseminated after a detected estrus (53%) than
after one fixed-time insemination was given in
the absence of estrus (31%). A similar protocol
of two prostaglandin injections plus an
injection of gonadotropin-releasing hormone
(GnRH or Cystorelin®) before one fixed-time
insemination produced lower conception rates
(33%) than when cattle were inseminated after
detected estrus (53%). In Experiment 2, the
OvSynch program was retested with the
interval between the PGF2α and the second GnRH
injection being 48 hr (36 hr in Experiment 1).
Conception in 27 cows on the OvSynch48
program with timed insemination (37%) was
comparable with 43% in 21 cows on a similar
program without the second GnRH injection
but inseminated at estrus.
(Key Words: OvSynch, Synchronized Estrus,
Conception Rates.)
Introduction
Since prostaglandin F2α (PGF2α) was
demonstrated to be effective in controlling the
estrous cycle for programmed breeding,
attempts to develop estrus-synchronization
systems for lactating dairy cows and dairy
heifers to accommodate fixed-time
inseminations have met with limited success.
Conception rates following PGF2α usually produced
the best results when inseminations were
performed after observed signs of heat. Our early
attempts to use fixed-time inseminations at first
services in lactating dairy cows demonstrated
that conception rates were less than desirable.
Follicular development must be controlled
and synchronized with the regression of the
corpus luteum after PGF2α in order to reduce
variation in the intervals to estrus. Precise
control of follicular development with the
regression of the corpus luteum should allow
improved conception rates associated with one
fixed-time insemination. Such a synchronized
ovulation protocol (OvSynch) has been tested. (...truncated)