Intrafollicular oocyte transfer in cattle – a technical report

Abstract

The aim of the study was to develop and evaluate the functionality of a new equipment for intrafollicular oocyte transfer (IFOT) in dairy cattle. The new system for IFOT is composed of the applicator, the aspirator, and the injector. After aspiration of oocytes, the IFOT set is inserted into the working tube of the ultrasound transducer holder, the content of the applicator can be injected into the preovulatory follicle via transvaginal ultrasonography by one operator. The function of instruments used for IFOT was firstly verified in laboratory conditions. Slaughterhouse oocytes filled into the instruments were injected into Petri dishes. The highest recovery rates in vitro (97.5%) were achieved when the applicator was stored with the needle in a downward position. Synchronized Holstein heifers were used for in vivo test. Intrafollicular injection of saline (n = 9) was performed to find whether ovulation is affected by the injection. Then IFOTs of phosphate buffered saline with 20 oocytes (n = 21) were performed into the preovulatory follicles followed by 7-day-old embryo collection. Total ovulation rates were 86.7% (26/30). Total recovery rates (oocytes + embryos) were 23.1%, embryo recovery rates were 10.1%. The new instrument allows for the loading of oocytes and easy transportation to recipients, and also allows IFOT to be performed by one person in field conditions. The method does, however, need further investigation.

Transferência intrafolicular de oócitos imaturos (TIFOI) e taxa de recuperação embrionária em vacas zebuínas

“…Entretanto, a produção de embriões por meio da TIFOI tem sido baixa, variando entre as vacas ovuladoras, e com taxas de 10,1;15,3 e 17,3 % (SPRICIGO et al, 2016;HOELKER et al, 2017;ANDRLIKOVA et al, 2020). Em estudo feito com equinos, obteve-se 5,5 % de recuperação embrionária (DELEUZE, 2009), em humanos, por transferência intrafolicular direta na mesma paciente, 3 oócitos obtidos de aspiração intravaginal foram adicionados em uma preparação de esperma e injetados no folículo dominante, com isso fizeram o primeiro relato de gravidez a partir deste processo em uma mulher que não conseguia engravidar (WERNER- VON DER BURG et al, 1993).…”