These tools, based on sequential PGF2a and GnRH administrations,
or its analogues, before TAI, are focusing on both
corpus luteum and follicle control [6], resulting in
economical and practical protocols to synchronize ovulation
[7]. Recent strategies include P4 intravaginal supplementation
as part of classic synchronization protocols for
TAI, such as Ovsynch, and several studies have demonstrated
increased pregnancy rate (PR), up to 40% at first AI
in dairy cows [8–10]. This controlled internal drug release
(CIDR) device can also synchronize the return-to-estrus of
nonpregnant cows