A 4‐year summary of the nonsurgical recovery of baboon embryos: A report on 498 eggs

A nonsurgical embryo recovery procedure, developed to allow the economical acquisition of cleavage stage baboon embryos, has been successfully used for 4 years. With this technique, 498 eggs have been recovered from 979 uterine flushes (50.9%) on 71 baboons. Of 467 eggs recovered from mated baboons, 290 (62.1%) were fertilized. Papio anubis females provided a higher percentage of fertilized eggs (75.3%) than did Papio hamadryas (47.8%) or Papio cynocephalus (44.3%) females following exposure to males during estrus, although sexual preference may be responsible for the reduced fertilization rate in the P. cynocephalus females. Recovery rates from individual baboons ranged from 0% (n = 11) to between 66% and 93% for ten baboons from each of which 12–33 eggs have been recovered. Fertilized eggs were at the two‐cell (n = 23) to blastocyst (n = 53) stage at recovery 1–6 days postdeturgescence (PD) of the sex skin, with morulae (n = 84) being the most frequent cell stage recovered (30%). The optimum time for performing the procedure was the third day PD, when 113 (40%) embryos were recovered. The abilities of baboons to become pregnant and to provide fertilized embryos were significantly related (P < 0.005), allowing the embryo recovery technique to be used as a screening procedure for evaluating baboon fertility.