Efecto de la progesterona parental aplicada en el día 3 post inseminación artificial a tiempo fijo sobre la fertilidad de vacas de carne

Abstract

This study evaluated the effect of the application of low dose of progesterone (P4) with long acting, three days after to the artificial insemination (AI), on the percentage of early conception. This study was done in the “Hacienda La Clementina”, in Babahoyo-Ecuador, in 180 beef cows of Bos Indicus, between 30 and 40 months of age, body condition (CC) between 2 5 and 3, clinically healthy, fed by method of grazing, divided into three groups: a control G1 n1= 60), and two experimental groups: G2 (n2=60) 75mg of P4 and G3 (n3= 60) 100mg of P4, respectively. We performed a protocol of AITF based on BE, progesterone, prostaglandin and eCG to synchronize estrus, after of the programed AI, at 3 days post-AI was applied P4 (SC). The percentage of pregnancy in two instances was measured at 30 days and at 50 days. A completely randomized design (DBA) was used, data were analyzed using the chi-square test using the GENMOD procedure of the SAS statistical package (SAS University Edition, 2016), considering pregnancy as a binomial variable; Where no significant differences were detected in pregnancy diagnosis at 35 d (P = 0.77) or at 50 d (0.64) post AI. Average gestation rates were observed at 35 d of 53.35% and at 50 d of 46.5%. With respect to the control group; In addition, the treatments did not significantly influence (P = 0.83) the proportion of animals that remained pregnant at 50 days, compared to 35 days of gestation at the 35th day of pregnancy. 85.9% of pregnant cows at 35 d post IA , Maintained gestation at 50 d post IA. In conclusion, the exogenous administration of low doses of P4 via SC in Bos indicus beef cows in the tropical zone at 3 days post AI does not affect the percentage of conception.