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Journal of Biotechnology in Livestock Production

Effect of Synchronized ovulation Using Progesterone with PGF α and GnRH or hCG
2
After fixed time AI on pregnancy rate in crossbred Thai-native beef cattle.

Pakornkiert Mola Naronkoen Kasemsuk
1/
1/

Abstracts
The objectives of this study were to determine effect of synchronization of ovulation and artificial

insemination (TAI) at 48 hour using Progesterone with PGF 2α and GnRH or hCG in 30 crossbred Thai-native beef

heifers (15-24 months of age). The heifers were divided into 3 groups: Group 1 (Control): CIDR®+PGF 2α 10
heifers; Group 2 (GnRh): CIDR®+PGF 2α+GnRH 10 heifers; and Group 3 (hCG): CIDR®+PGF 2α+hCG 10 heifers.

The heifers treated with progesterone insert vaginal 14 days, subsequently given PGF 2α at progesterone removal

on and distill water or GnRH or hCG concurrent with fixed time artificial insemination (TAI) to synchronize ovulation
48 h later PGF 2α injectation. The detection of pregnant heifer was confirmed by rectal palpation 90 d after AI. The

results showed that pregnancy rate and conception rate in group 1, 2 and group 3 were as 20, 40 and 40%
respectively. The pregnancy rate of group 2 and group 3 were significantly greater than group 1 (40%, 40% vs

20%; P<0.05). However, the pregnancy rate were not significantly different between group 2 and group3 (P>0.05).
Thus, the results indicate that the synchronization of ovulation protocol using Progesterone with PGF 2α and GnRH

or hCG improved the pregnancy rate in crossbred Thai-native beef cattle.

Keywords: synchronization, progesterone, beef cattle, Thailand

Registered No. : 61(2)-0208-070
1/ Ubonratchathani Artificial lnsemination and Biotechnology Research Center, Maung District Ubon Province,

Thailand 34000

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