Duroc not getting sows pregnant

the_catheter

Hi g'day, we had this junior duroc boar we are using for AI, lab tests got above 95% motility and morphology even FSI is good. after dilution and retention for 5 days semen samples are still viable. but we already got two batches with 0% pregnancy rate on the sows bred. what is the possible reason for this. we only breed them with pure duroc gilt and sow.

the_catheter

thanks  sanfer, interesting, that out of around 520sows bred that week, only the duroc sows and gilts got 0% they 20 gilt/sow. and others is 87-92% success rate ...