Efecto de la aplicación de eCG al día 14 pos IATF sobre características luteales y tasa de preñez en vacas doble propósito de la Amazonía Ecuatoriana

Abstract

This research was carried out in the province of Pastaza, which has a tropical climate where livestock production is particularly based on dual-purpose cattle, in this way the technical management of reproduction through biotechnologies such as AITF (Artificial Insemination at Time Fixed) allow the application of artificial insemination protocols such as those carried out in this investigation, J-Synch protocols plus the addition of eCG (Equine Chorionic Gonadotropin) on day 14 post AITF in order to evaluate the effect of eCG on luteal characteristics and rate of pregnancy, for which there was a population of 100 cows per treatment, of which units of 20 animals with 5 repetitions were determined. To start with the two protocols called T1 (J-Synch + eCG day 6) and T2 (J-Synch + eCG day 14 post-AITF), we proceeded with an evaluation of the ovarian status of each animal and during the execution of the protocols measurements of follicular development were taken, both at the removal of the DIB (Device Intravaginal Bovine) and at the IATF, after which the simple random sampling method was applied, selecting 10 cows per treatment, to measure serum values of progesterone (P4) and perform measurements of the size of the corpus luteum on days 14 and 30 post-AITF. Finally, pregnancy was confirmed on day 45 by means of transrectal ultrasound. The P4 values found in the investigation differed statistically between treatments both on day 14 and on day 30; however, no statistical difference was found in the size of the corpus luteum on day 14, but on day 30. Regarding the percentage of pregnancy, these they did not obtain a significant difference between the treatments, concluding in this way in the present investigation that there is no effect in the application of eCG on day 14 post-AITF.