Efecto de dos metodos de crioconservaciÓn sobre la calidad seminal y tasa de preÑez en alpacas inducidas a ovulacion con plasma seminal

The objective was to evaluate the effect of two methods of freezing on seminal quality and effect of seminal plasma as an inducer of ovulation in pregnancy percentages in inseminated alpacas. The semen collection was made post copula. After the collection of the ejaculates, motility and volume were assessed. The ejaculates with volume (≥1 ml) and motility (≥ 60%) were mixed (pool), 80 % was used (3 samples/pool) and 20 % (2 samples/pool) during the experiment. Then and diluted in Tris-base with 20% egg yolk. The samples were cooled 1.5 hours at 5 °C. At that temperature it was combined with the basic dilutor plus glycerol, obtaining a final concentration of 5% glycerol, then they were packed in 0.5 mL (13 x 10⁶ spem/straw) straws to be frozen by horizontal and vertical methods. The seminal (semen + vaginal fluid) quality analysis was performed fresh and after cooling and thawing. Insemination was performed in two groups with thawed semen from two straws of the vertical method, the first group 20 females induced to ovulate with GnRH analog, the second group 20 females induced to ovulate with seminal plasma. When comparing, the results obtained of motility, viability, HOST and acrosomal integrity of fresh sperm, after the freezing process, decreased (p<0.05) compared to fresh and refrigerated samples. On the other hand, when comparing the freezing methods, the sperm values frozen by the vertical method were higher than those obtained by the horizontal method, with (p<0.05) in motility and HOST without (p>0.05) in acrosomal integrity and viability. The vertical semen freezing method can replace the horizontal method to obtain pregnancy.