Effect of the Addition of eCG on day 14 Post-Ftai on the Pregnancy Rate in Cows from The Ecuadorian Amazon

Abstract

The effect of the addition of eCG on day 14 after FTAI was evaluated in 200 cows from the Ecuadorian Amazon, with a calf at the foot, of Brown Swiss breeds and their crosses (Bos indicus). Two treatments (T): T1 (J-Synch + eCG day 6) and T2 (J-Synch + eCG day 14 post-FTAI). The pregnancy rate for T1 (57%) and T2 (48%) without showing a significant difference (p≥0.05). The pregnancy percentage was higher (62.5%) in cows in estrus (125/200). Plasma progesterone levels differ between T1 and T2, evaluated on day 14: (7.1 ng/mL); (13.5 ng/mL), respectively, as well as on day 30: T1 (9.6 ng/mL) and T2 (13.7 ng/mL), (p≤0.05). The diameter of CL measured on day 14 (20.8 ± 3.3 mm) and day 30 (28.2 ± 6.2 mm) differed significantly (p≤0.05). Estrous expression is positively associated with an increased pregnancy rate, but improving eCG on day 14 post-FTAI does not improve the pregnancy rate in Ecuadorian Amazon cows.