Estrus response to estrus synchronization using prostaglandin nanoparticle in beef cattle in Majalengka regency

Abstract The study was conducted to determine the estrus response to the applying of prostaglandin nanoparticles (PNp) in two different estrous synchronization protocols. The estrus synchronization occurred in the Majalengka Regency in different years at the same location. The first study (study 1), estrus synchronization was carried out using a single PNp injection protocol, which was preceded by corpus luteum (CL) selection (21 cows). The second study (study 2), double PNp injections were carried out at day-0 and day-11 without prior CL selection (23 cows). The observation of estrus: onset of estrus and estrus quality (score 0-3) were observed 1-5 days after the PNp injection. Results of the study showed that 100% of the cattle were in estrus 2-3 days after the injection of PNp (study 1). The study 2, the estrus response appeared 2-3 days after the PNp injection: 17.35% showed an estrus response after the first PNp injection, 78.26% showed an estrus response at the second PNp injection, and 4.35% showed no estrus response. The pregnancy rate after estrus synchronization is 66.7% and 68.2% for studies 1 and 2. It can be concluded that there is a good response to estrus and pregnancy rate in the application of PNp in both single injections preceding CL selection and double injections with two periods of insemination. Both methods can be applied for estrus synchronization for more savings in PNp hormone administration. The application of that method depends on hormone availability and technician expertise in CL detection.