USE OF EQUINE SEMEN COOLING SYSTEMS TO STABILIZE SEMINAL SAMPLES BEFORE FREEZING

Abstract

cooling device to stabilize equine straws before freezing. The samples were diluted in Botu-Sêmen® extender and centrifuged at 600xg for 10 minutes. Then, the pellets were ressuspended with Botucrio® cryopreservation extender, loaded into 0.5 mL straws and divided into three groups. On Group M, straws were placed horizontally in a Minitub® refrigerator at 5 °C for 20 minutes. For groups B and E, the straws were placed in Botutainer® and Equitainer® devices, respectively. Both systems were previously stabilized at 5 °C and straws were maintained for 20 minutes, and then frozen. The straws were thawed at 46 °C for 20 seconds. Sperm samples were evaluated by CASA for Total Motility (TM) and Progressive Motility (PM) and by fluorescent microscopy for Plasma Membrane Integrity (MPI). Statistical differences were not observed (p>0.05) for Total Motility (GM=67.1%; GB=65.2% and GE= 63.4%) and Progressive Motility (GM=32.1%; GB=31.9% and GE=30.4%). Although MPI percentages were not different between groups M and B, group E showed a decrease in comparison to the other groups (GM=49.4%, GB= 48.7%, GE= 44.9%). These results demonstrate that passive cooling devices can be used to stabilize equine straws before freezing, being an alternative for replacing refrigerators, making easier the cryopreservation in the field.

KEYWORDS: Equine, semen, stabilization, cryopreservation.