those culled for non-reproductive reasons were
excluded. The effects of treatment, number of oestrous cycles (2 and 3), age of semen (≤24 and >24 h) and boars were included as class variables in these models. Total born piglets was analysed using the MIXED procedure,with inclusion of the fixed effects of treatment, number of oestrous cycles, boars and age of semen, whereas the trio of gilts was included as a random effect.