In vitro and in vivo fertility of ram semen cryopreserved in different extenders

• DOI: 10.1016/j.anireprosci.2009.04.007
• Publication Date: 2009-05-05T09:18:34Z
• Authors: S.S. Valente; R.M. Pereira; M.C. Baptista; C.C. Marques; M.I. Vasques; M.V.C. Silva Pereira; A.E.M. Horta; J.P. Barbas
• Keywords: Cryopreservation; Male; Sheep; Trehalose; Fertilization in Vitro; Egg Yolk; Spermatozoa; 03 medical and health sciences; Fertility; 0302 clinical medicine; Semen; Sperm Motility; Animals; Female; Insemination, Artificial; Semen Preservation

Seminal traits of frozen-thawed (FT) ram semen and in vitro and field fertility in native Portuguese breeds were evaluated in 4 experiments. In exp. 1 and 2 the cryopreservation capacity of 2 extenders, E1 (15% egg yolk-EY) and E2 (4.5% EY and trehalose) was compared through morphological evaluation and in vitro fertilizability of FT ram semen. Exp. 3 aimed to determine the usefulness of in vitro homologous/heterologous fertilization tests as tools for predicting ram fertility. Exp. 4 was conducted to verify if the identified differences between the 2 extenders could be confirmed by field fertility. E1 showed a better cryoprotective action expressed by higher in vitro and field fertility results. In conclusion, EY is difficult to be replaced in ram semen extenders. Heterologous fertilization seems to be a useful tool for predicting fertility of FT ram semen.