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Pregnancy rate after fixed‐time transfer of cryopreserved embryos collected by non‐surgical route in Lacaune sheep
Author(s) -
Figueira Lucas Machado,
Alves Nadja Gomes,
Batista Ribrio Ivan Tavares Pereira,
Brair Viviane Lopes,
Lima Renato Ribeiro,
Oliveira Maria Emilia Franco,
Fonseca Jeferson Ferreira,
SouzaFabjan Joanna Maria Gonçalves
Publication year - 2019
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.13550
Subject(s) - cryopreservation , vitrification , estrous cycle , andrology , domestic sheep reproduction , embryo , pregnancy , embryo transfer , pregnancy rate , biology , zoology , gynecology , medicine , genetics , microbiology and biotechnology
This study investigated the feasibility of applying fixed‐time (cryopreserved) embryo transfer in ewes. Embryos ( n = 106) were non‐surgically recovered from superovulated donors ( n = 39) on day 6–7 after oestrus. Straws containing one or two embryos (morulae and/or blastocysts) subjected to either slow freezing (SF, n = 62) or vitrification (VT, n = 44) were randomly used within fixed‐time embryo transfer on Day 8.5. Recipient ewes were nulliparous ( n = 58) bearing corpora lutea after synchronous oestrous induction protocol. The pregnancy rate was higher ( p = .03) in SF (39.4%) than VT (16.9%) and survival rate tended ( p = .08) to be higher in SF than in VT (25.8% vs. 15.9%). Lambing rates were similar ( p = .13) between SF (20.9%) and VT (15.9%). Embryos recovered by non‐surgical route after cervical dilation treatment and later cryopreserved by either slow freezing or vitrification produced reasonable pregnancy rates after FTET.