Key points are not available for this paper at this time.
The purpose of the study was to evaluate effective estrus synchronization protocols with hormones in anestrus cows guided by rectal palpation. About 200 dairy and beef cattle was selected at private and Govt. dairy farm of Rajshahi region from 1st July 2020 30th June, 2021. For this experiment animals were divided into 7 groups of different protocol and one control. Protocol-I, II and III was singly double and triple PGF2α injection Technique to inject PGF2α was @ 5ml Intramuscular at day 0, 11-14 and 9 & 11-14 days respectively 3 protocol and inseminated heated. Protocol -IV: GnRH–PGF2α–GnRH Technique to inject GnRH @ 5ml Intramuscular at day 0 and Check estrous and bred them. The second injection of PGF2α was administered 7 days after first injection similarly estrus and AI. The third injection of GnRH was administered 11-14 days after second injection similarly estrus and AI. Protocol -V: PGF2α–GnRH– PGF2α Technique to inject PGF2α @ 5ml Intramuscular at day 0 and the second injection of GnRH was administered 12 days after first injection. The third injection of PGF2α was administered 7 days after second injection similarly estrus and AI after 12-18 hours of fix times with GnRH injection. Protocol VI: GnRH– PGF2α Technique, to inject GnRH @ 5ml Intramuscular at day 0 and Check estrous and bred them. Second injection of PGF2α was administered 7 days after first injection similarly estrus and AI. Protocol -VII: hCG technique to inject hCG @ 1500 i.u. Intramuscularly at 0 day and observed up to 1 month. Protocol VIII: Control group (No treatment) (n=20), animal was observed for one month’s how many cows have shown estrus and check it after 120 day by rectal palpation. In results It showed that when hormonal treatment was given for induction of oestrus, higher (77.14%) proportion of cows showed oestrus compared to control counterpart (20.00%). The difference in the induction of oestrus in cows with different treatment protocol groups were 60%, 85%, 80%, 90% and 60% in PG, PG-PG, PG-PG-PG with fixed AI, PG-GnRH-PG with Fixed AI, GnRh-PG and hcG, respectively. It shows that the higher proportion of cows showed oestrus with hormonal treatment. Pregnancy rate of induction of estrous cycle by using different synchronization protocols were observed highest in 88.89% at PG-GnRH-PG fixed time AI technique and lowest 81.25% at GnRH-PG-GnRH fixed time AI protocol. Based on the experimental results. different treatment protocols compare in terms of their effectiveness in inducing estrus
Nishi et al. (Tue,) studied this question.