Efecto de la aplicación de GnRH al día 12, 14, 16, 18 y 20 post inseminación en vacas Holstein mestizas.

Abstract

The objective of this research was to determine the effect of a synthetic GnRH analog, post artificial insemination in crossbred Holstein cows; using 30 experimental units, distributed in 6 groups. The hormonal dose was 0.0105 mg of Buserelin acetate, applied intramuscularly on days12, 14, 16, 18 and 20, post insemination, except for the control group; samples were extracted byvenipuncture for subsequent determination of plasma progesterone levels. For the analysis of the results, the statistical program SPSS test version 22 for Windows was used: In the ANOVA of oneinter-subject factor the variable plasma progesterone levels presented a p-value =0.049, as there are significant differences between groups that received GnRH with a mean of 19.18 ng/ml compared to the control group (7.00 ng/ml). For the conception rate variable, the Chi-square test was applied, determining significant statistical differences, with a fertility rate of 88% for the experimental units that received GnRH post insemination, and 60% for the cows of the control group. For the embryo viability variable, ultrasound checks were performed at day 45, showing significant statistical differences p-value = 0.001 with 88% for the group that received treatment vs. 20% for the control group. The application of GnRH at day 14 post insemination in crossbredHolstein cows had a considerable influence in obtaining 100% embryo viability determined by ultrasound check at 45 days; assuming this information as a reference to suggest its application as an instrument to improve conception rates and embryo viability.