Ajuste del tiempo de inseminación con semen sexado en vacas superovuladas

Abstract

The results of the combination of sex-sorted sperm and superovulation (SOV) have not been very encouraging so far, due to the low quantity of sperms as well as their short life. In a previous study conducted in Brazil in Holstein cows, it was shown that using the protocol of SOV P36/Lh60 and inseminating with sex-sorted sperm at the 18 and 30 hours of application of the inductor of the ovulation (interval of 12 hs between the two inseminations) it is obtained an equal quantity of transferable structures than inseminating at the 12 and 24 hours with non-sorted sperm. The aim of this investigation was to adjust the hours of the artificial insemination (AI) in superovulated and inseminated cows with sex-sorted sperm to achieve better synchrony with ovulations, so in this way to increase the quantity of transferable embryos. This adjustment evaluated 2 moments of AI in which the interval diminished to 6 hs. For this, 30 superovulated lactating Holstein cows were used with the protocol P36/LH60 and were divided in three groups in an aleatory form; in the group IA18/30 (control group; n=10) the inseminations were carried out at the 18 and 30 hs of application of the inductor of the ovulation (GnRh); in the group IA18/24(n=10) was inseminated at the 18 and 24 hs of the GnRH and the group IA24/30(n=10) was inseminated at the 24 and 30 hs (it was used 2.1 x 106 sex-sorted sperm/insemination). It was not found statistical difference in the three groups; however, the group IA18/24 showed numeric advantage over the group IA24/30 and the Control (4,1±1,5 vs 1,3±0,4 and 1,9±0,6 respectively) in the quantity of transferable embryos, concluding that this adjustment in the hours of AI with sexed semen in superovulated lactating Holstein cows can be used with similar results to the previous works