Resumen

YANEZ-AVALOS, Darwin Omar; BARBONA, Ivana; LOPEZ-PARRA, Juan Carlos  y  ROBERTO MARINI, Pablo. PROTOCOLS J-SYNCH WITH AND WITHOUT ECG IN BROWN SWISS AND CROSSES WHITH BOS INDICUS COWS IN THE ECUADORIAN AMAZONS. La Granja [online]. 2021, vol.33, n.1, pp.8-20. ISSN 1390-8596.  https://doi.org/10.17163/lgr.n33.2021.01.

The incorporation of protocols with prolonged proestrus in extreme conditions has allowed to improve pregnancy. The objective was to evaluate the results of the protocol with prolonged proestrus called J-Synch with and without eCG, on follicular dynamics and pregnancy percentage in dual-purpose cows in the Ecuadorian Amazon. The project was developed of the Province of Pastaza - Ecuador, from October 2018 to October 2019. The study used 448 multiparous dual purpose Brown Swiss cows with calves and their crosses (Bos indicus). Four treatments were used, the cows were artificially inseminated at a fixed time on day nine T1: J - Synch + eCG + estrus FTAI 60 hours (n = 120); T2: J - Synch + eCG + without estrus + GnRH FTAI 72 hours (n = 118), T3: J - Synch + estrus FTAI 60 hours (n = 103); T4: J - Synch + without estrus + GnRH + FTAI 72 hours (n = 107). The pregnancy rate was 55% (T1), 49% (T2), 51% (T3) and 50% (T4) without showing significant differences. Follicular development and corpus luteum diameter showed significant differences (p≤0.05). It is concluded that the J-Synch treatments plus eCG at 60 hours and 72 hours had different behavior in follicular development and in the size of the corpus luteum. The pregnancy percentage did not differ between treatments. Although, there was a 44.5% more probability of getting a cow pregnant with T1 compared to T2. Furthermore, pregnancy would increase by 22.5% applying T1 compared to T3, and pregnancy with T3 would be 18% higher if compared to T2.

Palabras clave : follicular dynamics; pregnancy; progesterone; Fixed Time Artificial Insemination.

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