RESUMO
The present study was developed to evaluate multiparous sow reproductive performance and backflow in post-cervical artificial insemination (post-CAI) using a reduced number of sperm than in cervical artificial insemination (CAI). The experimental groups were divided into sows inseminated by: 1) cervical artificial insemination (CAI): 3×10(9) spermatozoa/80 ml; 2) post-CAI: 1.5×10(9) spermatozoa/40 ml (post-CAI 1); 3) post-CAI using 1×10(9) spermatozoa/26 ml (post-CAI 2). Post-CAI 1 reproductive parameters were similar to those of post-CAI 2 (except for live born litter size which was greater in post-CAI 1) and better than for the CAI group (p<0.01). In a second experiment the backflow volume, number of sperm, and sperm quality in the backflow were studied in the 3 experimental groups. The % of volume and spermatozoa in the backflow was higher in the CAI group (p<0.05) than post-CAI groups (statistically similar between them). Moreover, the quality parameters (motility, progressive motility, viability, chromatin decondensation and morphology) in backflow semen were identical in all three experimental groups, but differed as regards the original insemination dose incubated inside a colostomy bag (sperm quality control group). The present study shows that the use of post-CAI (either post-CAI 1 or 2) in field conditions can be recommended because the efficiency is similar (in the case of post-CAI 2) or higher (post-CAI 1) than when using the traditional method (CAI), representing a reduction cost.
