The aim of the present study was to evaluate the effects of uterine double flushing on embryo recovery rates (total structures and viable embryos), after a resting period with the uterus filled with PBS. There were 210 embryo recovery procedures conducted using the uterine double flushing method, and the results were compaired with 432 conventional single flushing procedures. All procedures were conducted with Limousin (n=403) and Guzerá (n=239) cows, following the same superovulation protocol. Cyclic donors received a progestagen implant (CIDR) and 1mL of oestradiol benzoate (Estrogin®) at Day 0. Between Day 5 and Day 9 animals received doses ranging from 200 to 300UI (zebu cows) and 300 to 500UI (taurine cows) of FSH (Pluset® – Serono) in decreasing doses. Between Day 6 and Day 8 PGF2a (Ciosin®) was administered, followed by withdrawal of the progestagen after 24h. Artificial insemination was performed between 14 and 26h after the beginning of treatment. For the double flushing procedure, after the first uterine flushing of both horns with 1L DPBS (Nutricell), a Foley catheter was positioned in the uterine body in order to fill the uterus with the same solution (80 to 150mL). After this procedure the catheter was closed with a disposable 5-mL syringe gasket, and the animals were allowed to rest in the surroundings of the work place for 30min. After this period, a second flush was performed in order to recover the remaning liquid used during manipulation of the uterus. Animals from the control group (group A) were subjected to a single uterine flushing procedure. From 210 double flushing procedures (group B – test), 1409 viable embryos were produced, classified as grades I, II, III and IV (IETS), (average of 6.7 embryos per procedure), whereas, in the 432 single flushing procedure (group A – control), 1993 embryos were produced (average of 4.6). Statistical analysis showed the increase of viable embryo recovery rate. When consecutive double flushing was performed, the average of recovered embryos increased from 8.3 to 12.7 (P<0.05) in Limousin cows, and from 7.9 to 11.5 (P<0.05) in Guzerá cows. Comparing recovery after single flushing with that after double flushing, the mean number of viable embryos increased from 4.7 to 6.9 (P<0.05) in Limousin cows and from 4.5 to 6.4 (P<0.05) in Guzerá cows. In order to assure the nonexistence of negligence effects or operator influence on results, the mean values of total embryo recovery rate after single flushing (control group) was compared to the mean values of the same rate after the first uterine flushing on test group. Results indicated no difference between recovery rates. The present work showed the viability of using the uterine double flushing procedure for improvement of embryo recovery rates in cattle.
Laparoscopic Ovum Pick-Up Followed by In Vitro Embryo Production and Transfer in Assisted Breeding Programs for Ruminants
