Utilização de marcadores microssatélites na determinação da contribuição individual de machos suínos, para a paternidade de leitegadas produzidas por inseminação artificial intracervical e intra-uterina

Abstract

The possibility of using reduced sperm concentration with intra-uterine artificial insemination (IUAI) allows a more efficient use of boars across a large number of females. However, the frequent use of semen pools from two or more boars in heterospermic inseminations can hide de suboptimal performance of some boars. The objective of this study was to compare the use of IUAI against cervical AI (CAI) using heterospermic doses under routine farm conditions and also by using genetic based paternity tests to differentiate the individual contribution of each boar in both techniques. The study included 300 females from 2-5 parities submitted to CAI and IUAI with doses having concentrations of 3.0 x 109 spermatozoa/85 ml and 1.5 x 109 spermatozoa /60 ml, respectively. Paternity tests were conducted using 9 microsatellites (SW24, SW951, SW857, SO386, SO101, SO090, SW240, SO155, SO355). The SW24 microsatellite was monomorphic, whereas the SO090 did not amplify. Twenty-five litters, including 300 piglets were genotyped, but paternity was excluded for only 95 piglets. Farm level comparisons showed that IUAI presented inferior (P < 0.05) conception (90.7%) and farrowing rates (85.3%) than CAI (98.7% e 94.7%, respectively). However, total litter size did not differ (P > 0.05) for CAI (13.7) and for IUAI (13.0). The paternity test did not allow differentiation among individual boars in the distinct insemination techniques, possibly due to the genetic similarity present in the commercial herd evaluated in this study.