EVALUATION OF EFFECTIVENESS OF AN INNOVATIVE SEMEN EXTENDER (FORMULA®) COMPARING WITH A TRADITIONAL EXTENDER (LEPUS®) FOR ARTIFICIAL INSEMINATION IN RABBITS DOES

This study aimed to investigate the preservability and viability of the rabbit spermatozoa diluted in a new semen extender Formula® in comparison with Lepus® at 17°C of storage. The mainly characteristic of the new extender formulation is the use of an enzymatic agent associated to a polysaccharide as energy source precursor, added with gentamycin. During 8 trials ejaculates from 70 bucks were collected and diluted at 1:10 ratio with both the extenders, after 24 hours of storage the semen doses were used for the artificial insemination (AI). Aliquots of the semen doses for each trial were stored at 17°C, the total and progressive motility were checked at 0, 4, 12, 18, 24, 36, 48, 60, 72, 84, 96, 108 hours of storage. A total of 1267 and 1525 does were inseminated, respectively with Formula® and Lepus®. During storage the mean total and progressive motility (77.23% and 72.854% respectively) was significantly higher for Formula® (P<0.01) and the progressive motility at almost 70% was maintained for at least 60 hours vs the 24 hours of storage for Lepus® with significantly differences after 12 hours of storage (P<0.05). The new extender reported a higher pregnancy rate (P<0.05) and an average of 9.25 rabbits born per litter versus 8.83 for the traditional extender (P<0.05), while the mean of the newborn alive was 9.08 using Formula® vs 8.51 with Lepus® (P<0.05). In conclusion the use of Formula® is recommended for rabbit semen AI programs.