Symptoms of oestrus in sows were detected twice a day in the presence of a boar
(visual and olfactory contact). Sows were inseminated with fresh semen (stored at
most 48 h at a temperature of 15°C) collected from the piggery’s own boars and
with spermatozoa concentration of 3.5 × 109 per 100 ml dose. Semen was diluted
in a seminal solvent BTS boar semen extender (Minitube). Before insemination, the
seminal dose was heated up to a temperature of 35°C. For intra-cervical insemination,
Safe Blue Clear Glide™ (Minitube) catheters were used. Reinsemination was
performed 24 h later.