Reproductive Performance of Dairy Cows in Various Programmed Breeding Systems Including OvSynch and Combinations of Gonadotropin-Releasing Hormone and Prostaglandin F2

Abstract

In Experiment 1, 308 Holstein cows were assigned randomly to four treatments: 1) GnRH injection followed in 7 d by PGF2 alpha injection, then another GnRH injection 33 h later, and artificial insemination (AI) 16 to 18 h after the second GnRH injection; 2) GnRH injection followed in 7 d by PGF2 alpha injection and AI only after detected estrus; 3) injections of PGF2 alpha 14 d apart, GnRH injection 33 h after the second PGF2 alpha injection, and AI 16 to 18 h later; and 4) injections of PGF2 alpha 14 d apart, AI only after detected estrus following the second PGF2 alpha injection or, in the absence of detected estrus, at 80 h after the second PGF2 alpha injection. In Experiment 2, 227 Holstein cows were assigned randomly to two treatments: 1) GnRH injection followed in 7 d by PGF2 alpha injection, then another GnRH injection 48 h later, and AI 16 to 18 h after the second GnRH injection; and 2) GnRH injection followed in 7 d by PGF2 alpha injection and AI only after detected estrus. Although conception rates in both experiments resulting from AI made after detected estrus either tended to be greater or were consistently greater than those following GnRH injection and one fixed-time AI, pregnancy rates were of greater magnitude after fixed-time AI because of poor expression or detection of estrus.

Comparison of an oestrus synchronisation protocol with oestradiol benzoate and PGF2α and insemination at detected oestrus to a timed insemination protocol (Ovsynch) on reproductive performance of lactating dairy cows

“…Eight percent of the cows in OVS were detected in oestrus (by the ALPRO system) and inseminated before the second GnRH injection. Stevenson et al [9] reported that 8 to 16% of cows showed oestrus in the OVS protocol around the time of PGF 2α injection. According to Vasconcelos et al [10] these cows failed to ovulate after the first GnRH injection; they were primarily in the second half of the oestrous cycle when they received the first GnRH injection and exhibited oestrus before the second GnRH injection because the corpus luteum regressed and the cows naturally came into oestrus.…”

“…Therefore, development of treatment programs that can effectively induce oestrus and ovulation in cows can have a major effect on herd reproductive performance. The Ovsynch program was developed allowing cows to be inseminated without the need for oestrus detection and improving reproductive performance during the early postparum period (around 50 d) with no labour investment for detecting oestrous [6][7][8][9]. Such a protocol consists of an injection of GnRH agonist given at random stages of the oestrous cycle followed, 7 d later by an injection of PGF 2α .…”

Effect of cow parity and synchronization method with PGF2α on conception rates of Bos indicus cows in Cameroon

“…Such a scheme has the advantage to synchronize both the CL and follicular waves to inseminate cows at a fixed time. It increases the submission rate of cows for insemination and attenuates deficiencies associated with detection of oestrus (Xu et al, 1997;Stevenson et al 1999). Muruvi et al (2001) also found no difference in three groups of cows synchronized with PGF2α.…”

Use of Carazolol at Pre-Synchronized Timed Artificial Insemination in Cows

“…in this regard, Pr to cows inseminated were lower for the Ovsynch program compared to conception rates of cows inseminated following the detected oestrus (Burke et al 1996;Pursley et al 1997;Stevenson et al 1999). this lower Pr to inseminated cows of the Ovsynch protocol compared to services made at detected oestrus could be due to insemination of all cows regardless of their cyclicity status and reproductive problems; whereas in the current study, tightly synchronized ovulation between 24 and 32 h following the Ovsynch protocol, and administration of carazolol immediately prior to tai could probably result in numerically lower Pr.…”